The pyrotechnicss and firecracker production industry in our country faces issues such as low mechanization and lack of safety guarantees. It heavily relies on manual labor. This study focuses on the 36-shot pyrotechnic molding process and aims to address the existing problems in pyrotechnicss production by designing and developing an autonomous platen grinding appliance to replace manual labor in the 36-shot pyrotechnic sheet grinding operation.
This paper first proposes two different design approaches for the platen molding appliance, analyzes and discusses the selected mold forming solution. Subsequently, the structural design of the 36-shot pyrotechnic sheet molding tool is divided into six parts, including mold design, overall frame design, transmission mechanism design, positioning mechanism design, traction mechanism design, and shearing mechanism design. The motion simulation part of the 3D design software CATIA is briefly introduced, and the 3D design hole and assembly of the parts are completed using CATIA software. Finally, motion simulation is conducted on the main components, and an animated video is created.
Furthermore, the control system of the 36-shot pyrotechnic platen molding appliance is designed, including pneumatic system design, program logic, and safety system design. A typical electromechanical integrated autonomous production equipment composed of PLC, sensors, and pneumatic components is designed. Both PLC technology and pneumatic technology excel in sequential action logic systems. This autonomous production equipment fully utilizes the advantages of PLC control and pneumatic technology, ensuring production safety while developing a software and hardware control system that meets the production requirements based on the actual needs of the factory.
Finally, the on-site assembly and trial operation results of the 36-shot pyrotechnic sheetn molding appliance are presented, along with the operating specifications and relevant parameters of the platen molding appliance. The results of the trial production run indicate that this equipment is easy to operate, quick to learn, easy to maintain, and possesses strong safety and stability. When used in conjunction with a gluing apparatus, this equipment can reduce labor intensity while ensuring product yield, significantly improving production efficiency by twice the output of manual operation, fully meeting the design requirements specified by the manufacturer.
Currently, this equipment has been implemented in the pyrotechnicss production facility and has demonstrated stable performance since its deployment. It fundamentally reduces the labor intensity of workers, greatly enhances labor productivity, and reduces operational costs for the company. It is a meaningful attempt to reform traditional production modes through technological innovation, and it has excellent prospects for practical application and development.
Chapter 1 Introduction
1.1 Research Background
China is the world’s leading creator of pyrotechnicss, accounting for approximately 75% of the global production. According to reliable statistical data, there are over 7,000 enterprises engaged in pyrotechnicss production in our country. There are nearly 300,000 units dedicated to the sale of pyrotechnicss. The annual total production of pyrotechnicss exceeds 100 million boxes, with a revenue of up to 20 billion yuan. The number of people employed in the pyrotechnics industry has exceeded 12 million. The prosperity of the pyrotechnics industry not only leads to the consumption of suitable raw materials but also stimulates the growth of the global consumer base for pyrotechnicss.
Due to the unique nature of pyrotechnicss, there are significant safety hazards involved in their production, transportation, storage, and ignition. Once problems occur, they are likely to cause large-scale casualties. Based on the death rate of production safety accidents calculated according to the criterion of creating one hundred million yuan of GDP, the pyrotechnics industry is already a highly dangerous industry. Improper operation or failure to comply with production regulations not only seriously endangers property safety but also poses a threat to people’s lives. Therefore, how to address the aforementioned issues and achieve sustainable and safe production in the pyrotechnics industry is a major strategic focal point we currently face [1-6].
Currently, the enterprises engaged in pyrotechnicss production in our country are mostly rural and individual businesses. The workers are primarily local farmers. The peak season for pyrotechnicss production and sales coincides with the agricultural off-season when farmers have relatively less work. During busy farming seasons, farmers focus on agricultural tasks, while during idle periods, they work in the pyrotechnics industry. The pyrotechnicss and firecracker industry has not only transformed the rural economic structure but also provided employment opportunities for the surplus labor force in rural areas.
On the one hand, pyrotechnicss form the foundation of rural financial revenue. On the other hand, the overall low quality of the workforce severely hampers the development of this industry. Since the liberation of the entire nation, various enterprises have developed a wide range of automated appliancery and equipment for pyrotechnicss production, which has greatly improved labor productivity. However, from an industry-wide perspective, most pyrotechnicss production enterprises still rely on manual labor, primarily carried out by farmers.
Although this effectively solves the issue of employment for surplus labor in rural areas, the numerous variables associated with manual operations make it difficult to ensure the safety of the production process. According to statistical analysis, approximately 90% of accidents occur due to the failure of practitioners to strictly follow operational procedures or adhere to safety regulations, as well as the absence of necessary tools required by regulations. Furthermore, manual operations make it challenging to produce high-quality pyrotechnicss products.
Therefore, gradually achieving mechanization in pyrotechnicss production and subsequently transitioning to automation and intelligent control of the entire pyrotechnicss production process are essential prerequisites for the sustainable and stable development of the industry.
Presently, the trend of implementing automated production in the pyrotechnics industry has become inevitable. The research, development, and promotion of mechanical automation are also flourishing. The primary purpose of this trend is to achieve safe and stable production while improving the production efficiency of pyrotechnicss and firecrackers.
The future prospects of mechanical automation are promising, and the concept is ideal. However, in practical operation, there still exists a considerable gap between the design level and the safety requirements for pyrotechnicss and firecracker production. Therefore, considering mechanical automation as a guarantee of safety in pyrotechnicss and firecracker production is the foundation of safe production. However, the current role played by mechanized equipment is far from thorough.
In summary, pyrotechnicss technology is advancing towards mechanization in terms of pyrotechnicss formulation research, process production, product updates, technological innovation, and pyrotechnicss safety and environmental protection [10-11]. The research on the formulation used in pyrotechnicss has gradually become more scientific, and the development of environmentally friendly pyrotechnicss has also been gradually initiated. Smokeless pyrotechnicss have already appeared before the public.
The management of pyrotechnicss production safety and quality is being strengthened, and pyrotechnicss processing techniques are progressing rapidly. pyrotechnics product updates and technological innovations are steadily developing. Although in the past few decades, the pyrotechnicss production industry has developed many automated appliances for pyrotechnicss and firecracker production, only a small portion of these appliances have universal performance, while most of the other tools have relatively poor efficiency and performance. Due to its particularity, it is not possible for pyrotechnicss production to be fully mechanized. However, continuous improvement and refinement of equipment have resulted in the replacement of most labor-intensive manual operations with mechanized operations, initially achieving semi-mechanization and transitioning to full mechanization, which is the direction for the future development of all pyrotechnicss production enterprises.
For example, dangerous processes such as fuse installation, charging, mixing, and drying can be replaced by robots or mechanical hands, and the use of developed pulp, waste paper, bamboo, and wood shavings for casting cylindrical shells can eliminate many intermediate production steps, greatly improving labor productivity, enhancing production stability, reducing product costs, ensuring production process safety, and reducing environmental pollution.
The pyrotechnics industry is plagued by low mechanization and safety concerns due to heavy reliance on manual labor. Discover how our groundbreaking study focuses on revolutionizing the 36-shot pyrotechnic molding process through the design and development of an autonomous sheet molding appliance. Uncover two innovative design approaches, advanced motion simulation, and a sophisticated control system. Witness impressive trial results, including reduced labor intensity, enhanced productivity, and significant cost savings. Join us in reshaping traditional production methods through cutting-edge technology for a safer and more efficient pyrotechnics industry.
1.2 Significance of the Study
As the largest producer and exporter of pyrotechnicss in the world, ensuring the safety of pyrotechnicss production is of utmost importance for the development of the pyrotechnics industry in our country. The unsafe aspects of pyrotechnicss production in China can be summarized as follows: firstly, the unreasonable composition and unscientific formulation of raw materials; secondly, the outdated production methods and processes employed by most companies; thirdly, the failure to strictly follow prescribed operational procedures during production; and finally, the occurrence of safety hazards during storage, transportation, and ignition [12-13]. Due to the highly hazardous nature of pyrotechnicss, strict control measures are necessary during the export process. If several safety hazards associated with pyrotechnicss can be resolved, it would not only enhance the sales capacity of China’s pyrotechnics industry globally but also position our country as a dominant player in the pyrotechnicss trading market.
Compared to traditional manual production, mechanized production in pyrotechnicss manufacturing companies offers numerous advantages. Firstly, it can increase labor productivity and improve product quality, especially during times when the availability of labor is scarce. Secondly, it can enhance the competitiveness of companies in the market, leading to cost savings, higher efficiency, and increased profits. Most importantly, it can reduce safety issues in the production process. Therefore, it is evident that the mechanization of the pyrotechnics industry has become an inevitable trend for its development.
(1) With the standardized development of the market economy, major production companies and markets have higher quality requirements for pyrotechnicss. However, due to significant differences in the engineering skills and overall qualifications of employees in production companies, varying levels of understanding of safety production and operational processes, and the inability to strictly adhere to quantitative standards in manufacturing processes, manual production remains the main cause of the inconsistent quality of pyrotechnicss products. Mechanization can completely address this crucial quantitative issue and significantly improve product quality.
(2) Compared to traditional manual operations, mechanized production can increase production efficiency by at least five times. Additionally, as production companies continue to expand and global market demand increases, issues such as rising costs and scarcity of labor force the pyrotechnicss manufacturing industry to adopt mechanized production. This not only reduces labor costs and improves product quality to meet market demand, but also resolves labor conflicts, ensures the sustainable development of companies, increases production output, and give warranty sparkler production safety.
(3) With the advancement of pyrotechnicss and firecracker production techniques, improvements in production formulas, and the increase in scientific and technological content of gunpowder, the use of multiple combinations of gunpowder is growing. The dosage of gunpowder is also gradually increasing. Mechanized production of pyrotechnicss and firecrackers can effectively reduce the number of interactions and contact time between production workers and gunpowder, ensuring the safety of employees and also considering the production safety of the company.
(4) Along with the increase in global pyrotechnicss trade, market competition is becoming increasingly fierce. High sales volume, high profits, and cost minimization are the key factors for pyrotechnicss and firecracker companies to maintain a strong position in the market. Mechanized production not only reduces the number of workers and the company’s footprint but also saves the company funds in terms of land and personnel wages. At the same time, mechanized production not only improves product quality but also enhances labor productivity and ensures safety during the production process.
Through the engineering breakthroughs of this project, the automated ignition of 36-shot pyrotechnic sheets can be systematically addressed, effectively resolving the safety hazards associated with ignition and improving the high-risk nature of the pyrotechnicss and firecracker industry. This effort aims to achieve the industry’s transformation into a safe and sustainable development sector. Therefore, this project not only has promising prospects for development but also entails significant economic benefits.
1.2.1 Current Situation of Domestic pyrotechnicss Production
Due to the hazardous nature of raw materials, the pyrotechnicss and firecracker industry in China is a very special processing industry. Various relevant departments in China have always paid high attention and importance to it, as well as the research and development of related manufacturing processes. However, due to its uniqueness and other factors, there has always been a significant gap between the achievements of research and innovation and the actual requirements for safe production.
Currently, only a few universities and research institutions are involved in research and development, leading to a lack of breakthrough developments. Meanwhile, the demand for pyrotechnicss and firecrackers in the market has been continuously increasing. Therefore, the development of new manufacturing processes, production methods, and new appliancery has become a top priority for the pyrotechnicss and firecracker industry in China.
China’s pyrotechnicss and firecracker manufacturing industry has a history of thousands of years, but manual production has always been dominant. Although it is a high-risk labor-intensive industry, there are still thousands of enterprises engaged in pyrotechnicss and firecracker manufacturing. Most of these enterprises operate in small-scale production workshops with rudimentary appliancery.
The manual operations of production workers involve significant uncertainties. With the rapid development of society, the increasing demand for pyrotechnicss and firecrackers, the continuous increase in the number and scale of production enterprises, and the growing variety of demands, the importance of mechanized production is becoming more apparent.
In order to ensure the healthy and stable development of the pyrotechnicss and firecracker industry, reduce the occurrence of safety accidents, improve the safety performance during the production process, and guarantee the safety of the lives and properties of practitioners, it is also necessary to achieve the design concepts and implementation standards of pyrotechnicss and firecracker apparatusry.
It is essential to ensure that every appliance put into production meets the norms and requirements of safe production. Therefore, China has successively issued a series of relevant industry standards and safety production guidelines, with a focus on promoting the transformation of the pyrotechnicss and firecracker industry from manual to mechanized production. The main ones include: Safety and Quality of Fireworks and Firecrackers (GB10631-2004), Design Regulations for Electrical Equipment in Explosive and Fire Hazardous Environments (GB50058-1992), Safety Production Operation Regulations for pyrotechnicss and Firecrackers (GB11652-89), Safety Design Specifications for Fireworks and Firecracker Enterprises’ Plants (GB50161-1992), pyrotechnicss and Firecracker Ignition Fuse, Display Shells, Combination Fireworks (planting machine).
In addition, there are various regulations and requirements for the production, equipment, storage, transportation, and management of pyrotechnicss and firecrackers. The main industry standards include: Safety Evaluation Standards for Enterprises (AQ4113-2008), pyrotechnicss and Firecracker Mechanical Ignition Wire Machine (AQ4108-2008), Fireworks and Firecracker Mechanical Firecracker Insertion equipment (AQ4109-2008), pyrotechnicss and Firecracker Mechanical Fuse Tying Machine (AQ4110-2008), etc.
Since the establishment of the first research institute in the 1960s to the present, China has also applied for various patents in the field of autonomous production lines for pyrotechnicss and firecrackers. During this period, the following mechanical equipment has been developed: rolling appliances, medicine pulverizers, granulating appliances for medicine clusters, pyrotechnic product molding tools, and glue dispensers.
New materials developed include: new formulas for sound-producing agents in pyrotechnicss, chlorine-free black grind for firecrackers, smokeless pyrotechnic agents, delay agents for scratchers, new types of pyrotechnicss paper, and improvements in packaging materials. More than 3,000 types of pyrotechnicss have been developed and improved. These achievements demonstrate the increasing innovative strength in China’s pyrotechnicss production field.
The Chinese finding patent , applied by our research group, describes an autonomous glue dispensing device for molding the outer tube of pyrotechnicss. It utilizes a servo motor to drive the pneumatic glue dispensing head along the dispensing path. The main components of the device include: a walking mechanism, a control mechanism, a conveying mechanism, a positioning mechanism, a glue dispensing valve, and a glue supply mechanism.
The distinguishing features are as follows: the walking control mechanism mainly consists of two cross-mounted sliding tables, a servo motor, and an electrical control cabinet; the glue supply mechanism is connected to the glue dispensing valve and installed correspondingly with the equipment frame and conveying mechanism; the positioning mechanism is installed on the equipment frame and coordinates with the walking mechanism. Figure 1.1 illustrates the structural diagram of this finding patent.
Figure 1.1: Structural Diagram of Invention Patent
1 – Starting end molded pyrotechnic 2 – Chain crossbar 3 – Glue tube 4 – Barrier sheet5 – Gluing valve 6 – Electric control cabinet 7 – Cross slide 8 – Fixture 9 – Circular solid 1 10 – Circular solid 2 11 – Motor 12 – Base 13 – Chain 14 – Sensor
The specific working process of the invention is as follows: The molded pyrotechnic is placed at the starting workstation. Under the push of the chain crossbar, it approaches the gluing workstation. The control mechanism senses the position of the molded pyrotechnic and sends a signal to stop the motor. The fixture clamps the molded pyrotechnic in place under the push of Circular solid 1, and Circular solid2 lifts the launching tube molding die to the set height.
At the same time, the moisture-proof glue in the glue tube enters the gluing valve under the extrusion of external compressed air. The gluing process starts when the gluing valve is controlled by the solenoid valve. Meanwhile, driven by the cross slide, the gluing process is completed following the set path in the PLC of the electric control cabinet. The gluing valve returns to the starting point, and Circular solid1 and Circular solid 2 reset. The motor starts running, and the glued pyrotechnic is pushed away from the gluing workstation by the crossbar, completing the entire gluing process.
The pyrotechnic equipment mentioned is part of the subsequent working process of this device, which is also a part of the autonomous production line for 36 forced pyrotechnic molds. It is a developed product with higher automation and safety performance compared to the previous generation of pyrotechnic production equipment.
1.2.2 Current Situation of Fireworks Production Abroad
Apart from China, countries that have a pyrotechnicss production industry include the United States, Canada, Japan, India, Spain, and others . Due to the long history of China’s pyrotechnics industry, it has been the benchmark for manufacturing processes, production methods, and product variety, which have been imitated but never surpassed by foreign countries.
However, with the development of time and advancements in the pyrotechnics industry, foreign countries have also established large-scale pyrotechnicss industries, with their advanced manufacturing processes and production technology now catching up to China , and some even surpassing China’s manufacturing level.
In fact, most pyrotechnicss manufacturing enterprises abroad are military factories, and their levels of manufacturing processes and mechanical automation are quite high [18-19]. They have conducted in-depth research on formulation and production processes, particularly in automating various hazardous procedures in pyrotechnicss production.
The high level of mechanization not only improves labor productivity and reduces labor intensity but also ensures production safety and stability. Even in the event of safety hazards or accidents, they do not cause harm to workers. They have also improved the mixing process in the operating procedures through complete mechanization, significantly enhancing the speed of drug mixing. In the drying stage, far-infrared or vacuum drying techniques are employed [20-22]. Furthermore, they have also made improvements and optimizations in the formulation.
As early as the beginning of the 17th century, Japan gradually started the production and manufacturing of pyrotechnicss and firecrackers. In the early stages, all pyrotechnicss were imported domestically, and research was gradually conducted on their main components. It is not difficult to imagine that their production technology was initially learned from domestic sources. Initially, the raw material for pyrotechnicss and firecrackers in Japan was only black grind.
It wasn’t until the late 18th century that Japan imported potassium chlorate from Europe, and soon after, they developed and mastered the manufacturing process of colored pyrotechnicss. The rapid development of Japan’s appliancery manufacturing industry also played a crucial role in the rapid rise of pyrotechnicss and firecracker production and manufacturing. In particular, the online monitoring system, which enables real-time monitoring of the entire pyrotechnicss production process, not only improves labor productivity but also plays a vital role in eliminating safety hazards.
In the 19th century, science and technology in Europe were also rapidly developing, so they made significant breakthroughs in the innovation, manufacturing, and production of pyrotechnicss. Due to their continuous breakthroughs in the field of chemistry, they developed pyrotechnic propellants that were widely used.
At the same time, improvements and advancements in the loading of pyrotechnicss and pyrotechnic components greatly enhanced the brightness of pyrotechnicss, expanded the range of colors, increased the width and height of pyrotechnic displays, and improved their explosive power and duration to varying degrees.
With the increasing prosperity of global pyrotechnicss production and the intensifying competition in various industries, pyrotechnicss manufacturing companies are facing challenges such as rising transportation costs, increased prices of raw materials, and various management expenses. In many countries around the world, pyrotechnicss manufacturers are in such predicaments.
As a result, some large-scale production companies have gradually realized that mechanized production is the foundation for the sustainable development of pyrotechnicss. They have reorganized or even merged small and medium-sized pyrotechnicss production companies to form large-scale, mechanized pyrotechnicss production enterprises. At the same time, there is a need to develop the technology and processes with a focus on theory, foundation, safety, environmental protection, and innovation.
pyrotechnicss and firecrackers’ environmental and safety issues are key challenges for pyrotechnicss and firecracker manufacturers. European countries, the United States, Japan, and other nations have a high level of concern regarding the production safety of pyrotechnicss and firecrackers. As a result, they import the majority of their pyrotechnicss and have very little domestic production. Additionally, many developed Western countries have strict regulations for the storage, transportation, and display of pyrotechnicss and firecrackers.
Furthermore, specialized management associations have emerged, such as the International Fireworks Standard Testing Service Limited, American Pyrotechnics Association , and Japan pyrotechnicss Association. Meanwhile, international pyrotechnicss-related organizations have also issued a variety of regulations for pyrotechnicss and firecracker safety, such as the German Fireworks and Firecracker Regulations, British pyrotechnicss and Firecracker Regulations, and Spanish Fireworks and Firecracker Regulations. In comparison to Western countries, China lacks comparability in pyrotechnicss and firecracker production, storage, transportation, and management. Therefore, it is necessary to increase innovation and research efforts in order to improve domestic technological and management levels, while also enhancing the competitive ability of the domestic pyrotechnicss and firecracker industry in the international market.
1.3 Main Research Content of the Thesis
This thesis focuses specifically on the research of the molding and fuse assembly steps in the pyrotechnicss production industry, which have the highest production volume and require the most labor. The study, referred to as “Pan Yin” for short, mainly investigates the specific structure of the pyrotechnic molds, production processes, and safety practices in combination, and carries out engineering demonstration applications.
Taking the 36-shot molded pyrotechnics created by Hunan Liuyang Yihelong pyrotechnicss Group Co., Ltd. as the research object, this study draws on the dispensing appliance for 36-shot molded pyrotechnicss. Through in-depth research, it proposes specific mechanical structures and engineering solutions. The entire production process is comprehensively monitored, a fire alarm system is installed, and a 36-shot molded pyrotechnic “Pan Yin” appliance is developed. Continuous improvements are made to ensure that the 36-shot molded pyrotechnic “Pan Yin” apparatus becomes an exemplary project for safe production.
The design concept used in the 36-shot molded pyrotechnic “Pan Yin” appliance is modular and implements pneumatic operations. In the electrical part, the control system and modules are unified as a whole, while each module remains independent. The main research content of this thesis includes:
(1) Overall research on the scheme of the 36-shot molded pyrotechnic “Pan Yin” appliance
Through functional analysis of the 36-shot molded pyrotechnic “Pan Yin” appliance, the necessary basic components and specifications for the “Pan Yin” step are determined. The modular design concept is adopted, including the main machine frame, control mechanism, conveying mechanism, positioning mechanism, “Pan Yin” mechanism, cutting and fuse assembly mechanism, smoke alarm system, and tension control system. Additionally, a three-dimensional structural model of the “Pan Yin” appliance is constructed using CATIA software. The modeling process enables a more comprehensive inspection of the overall structure of the “Pan Yin” appliance, identifying any potential issues and checking for interference in the motion trajectory and coordination of actions.
(2) Design of Control System and Pneumatic System for the 36-Module
pyrotechnic Ignition sheetn molding Within the entire system, the control system can be considered the most crucial part, playing a vital role in ensuring the overall stability of the 36-module pyrotechnic ignition sheet molding. The performance of the control system not only affects the equipment but also directly influences production efficiency and safety. Since pyrotechnicss are highly flammable and explosive materials, the production process exclusively employs pneumatic components with circuitry arrangements. Compatible PLC modules [23-24] are carefully selected, and specific work processes are programmed to create a cohesive framework for the system.
(3) Modeling and Performance Simulation Research on the 36-Module pyrotechnic Ignition
Sheet molding Based on the established 3D model, the Catia motion simulation module is utilized to conduct comprehensive real-time simulations of the movement processes among various modules of the ignition sheetn molding. This ensures enhanced safety and reliability aspects of the prototype.
(4) Development, Debugging, and Optimization of the 36-Module pyrotechnic Ignition
sheet molding Using the three-dimensional virtual model, two-dimensional engineering drawings are created, and the manufacturing of components commences. Strict testing is conducted, encompassing every module within the equipment. Additionally, on-site testing is carried out to guarantee the safety and reliability of every action performed by the 36-module pyrotechnic ignition sheet molding. This ensures that the automatic ignition sheet molding can operate safely and reliably once put into production, effectively securing the smooth operation of the 36-module pyrotechnic ignition system.
Chapter 2: Overall Design of autonomous Winding and Ignition Machine for Fireworks
2.1 Overall Design Requirements
According to the requirements stated by Liuyang Yihelong pyrotechnicss Group Co., Ltd., the overall design requirements for this automation equipment are as follows:
(1) Stability and improvement of product quality: The quality of the product directly affects its intrinsic value and the value of automated processing equipment. This project aims to achieve a production success rate of over 95%.
(2) Increase labor productivity: The profitability of a company largely depends on the level of labor productivity. At the same time, labor productivity is a basic criterion for evaluating the superiority of automated production lines over conventional production. This project aims to increase labor productivity by 40%-50%.
(3) Due to the high intensity required in the winding process and the continuous concentrated labor, it places a heavy burden on workers. This project will optimize working conditions, promote civilized production, and use appliancery to complete the winding process, thereby reducing the labor intensity of workers and achieving civilized, safe, and sustainable production.
(4) Reduce product costs to improve product economic benefits: The reduction of product costs not only reduces the burden on enterprises but also enhances the market competitiveness of the products. This project plans to standardize each production cycle, improve product yield, and mechanize the entire process, thus reducing labor costs and improving economic efficiency.
(5) Ensure production safety: As pyrotechnicss and firecrackers are flammable and explosive materials, safety accidents often occur during the production process. Safety considerations are of paramount importance in the research and development of automated production apparatusry for pyrotechnicss and firecrackers. Due to the combustible nature of the fuse used in the winding process, the primary consideration of this project is the safety of the production process. Specifically, real-time monitoring of the production process will be combined with fire prevention equipment to greatly enhance safety performance. Even in the event of a safety accident, it can be detected and automatically responded to in a timely manner, thus avoiding harm to workers during production.
2.2 Technical Indicators
The specific indicators to be achieved for the 36-shot pyrotechnic disc fuse assembly are as follows: (1) Production Cycle: Achieve a cycle every 6×X seconds. (2) Product Accuracy: Meet the requirements of the design drawings. (3) Product Yield: Greater than or equal to 95%. (4) Product Requirements: After the fuse assembly is completed, the length of the main fuse of the pyrotechnicss should be 8cm-10cm, without a secondary fuse. (5) Safety: Ensure the personal safety of the staff and enable real-time monitoring throughout the production process. (6) Productivity: Increase productivity by at least 40%. (7) Reliability: Ensure continuous production for at least 12 hours.
2.3 Current Status of the 36-Shot pyrotechnic Disc Fuse Assembly by Yihelong Company
2.3.1 Product Design
As shown in Figure 2.1, the production object is the 36-shot pyrotechnic with a molded disc fuse, which uses a traditional black grind fuse. The molded pyrotechnic fuse has two openings, namely the main fuse and the secondary fuse. According to the requirements of pyrotechnic production, the main fuse should have a length of 8cm-10cm without a secondary fuse.
This type of molded pyrotechnic has a huge production volume, with an annual output value of nearly tens of millions of yuan for a single product. The labor required for workers is enormous, and the efficiency is low, making it easy to have inaccurately forced fuses, resulting in product quality issues.
Figure 2.1: 36-shot pyrotechnic compressed by a mold
Figure 2.2: Finished product image
2.3.2 Actual Production Situation
The actual production status of molded pyrotechnicss disc fuses is shown in Figure 2.3.
Figure 2.3: Current Situation of Molded pyrotechnic Production
Issues in the production process: (1) All operations in the production process are manually performed, with long working hours and high intensity for the workers, resulting in low production efficiency. (2) Due to manual operations, there is a high degree of human error in the production process, resulting in inadequate assurance of production quality and a risk to production safety. Any accidents that occur will lead to unimaginable losses. (3) Despite low efficiency in manual production, the demand is high, often resulting in shortages and causing operational losses for the company.
As per the company’s requirements, it is necessary to achieve automated production in the sheet traction production process, improve production efficiency, enhance production quality, and reduce labor intensity and labor costs for workers.
2.4 Overall Design and Selection of Molded pyrotechnic Plate Traction Machine
The main steps of the sheet traction appliance for molded pyrotechnicss can be roughly divided into traction, sheet traction, pressure traction, and cutting traction. Since the fuse is wound on a reel, manual disassembly and replacement of the reel are necessary. In addition to this, the placement of unfinished pyrotechnicss and the extraction of finished pyrotechnicss are also manually operated, while the rest is completed by appliancery. Considering that pyrotechnicss are highly flammable and explosive, all designed mechanical movements use pneumatics to ensure the safety of the production process, improve production speed, and thus shorten the production cycle.
2.4.1 Overall Scheme
Design In this section, based on the principles of modern design methods  and engineering application research , two reference schemes are presented. Finally, a most reliable scheme is obtained through analysis and discussion considering the reliability and feasibility of the schemes.
- Scheme Overview The process principle is as follows: Lead initialization → Placing the forced pyrotechnic at the starting end → Motor drives the sprocket to start moving → Photoelectric sensor detects the pyrotechnic → Sprocket stops moving → Circular solid drives the fixture to lock and push the pyrotechnic to a fixed position → Small motor is powered on → The lead is fed into the disc mold → After the lead is in place, the film is molded to embed the lead into the groove of the molded pyrotechnic → Circular solid drives the fixture reverse to its original position → Repeat for the next procedure.
- Main Structural Description The traction mechanism is controlled by a motor and consists of four rubber rolling pulleys. The four rubber rolling pulleys are arranged horizontally in pairs on the traction module board, with a distance of 2.0mm between each pair, as shown in Figure 2.4. The lead is clamped between the two sets of rubber rolling pulleys. During operation, the motor drives the rubber rolling pulleys to rotate, achieving the traction function through the friction between the pulleys and the lead.
Figure 2.4: Traction Pulley System
The traction mechanism consists of traction molds shown in Figure 2.5. Rubber rollers are installed in each circular groove. When the thread passes through the traction mechanism into the traction module, the motor drives the rubber rollers to rotate actively. The traction function is achieved through the friction between the pulleys and the thread. Finally, the thread is molded into the molded pyrotechnic groove by the molding process.
Figure 2.5: Disk Induction Mold
The overall structure of the appliance is shown in Figure 2.6:
Figure 2.6: Schematic Diagram of the Overall Structure
(1) Overview of the Alternative The process principle is as follows: Lead initialization → Chain motor starts, chain crossbar drives the mold to grinder the pyrotechnic → Photocell sensor installed on the baffle detects the position of the molded pyrotechnic → Chain motor stops → Positioning cylinder starts to clamp the forced pyrotechnic → Lateral traction Circular solidstarts to pull the lead wire → Convex U-shaped mold circular solid starts to push the lead wire and release the traction fixture during the process of pushing the lead wire → Top circular solid starts to push the forced pyrotechnic upward → Lateral traction circular solid resets → Clamp the wire → Cut the wire → Mold circular solid starts to grinder the wire and immediately resets → All circular solids reset in sequence → Chain motor starts, chain crossbar pushes the molded tube away from the conveyor belt.
(2) Main Structural Description As shown in Figure 2.7, the main components of the structure are: U-shaped die, support sheet A, support sheet B, compression die, positioning sheet, rotary latch A, rotary latch B, guide pole, cylindrical flange roller bearing, torsion spring, and guide bearing. The support sheet A is fixed, and the lower surface of the U-shaped die is flush with the lower surface of support sheet A. The bottom centers of rotary latch A and rotary latch B are equipped with torsion springs and fixed to the front end of support sheet A. Support sheet B is fixed above support sheet A by guide rods.
The compression die is fixed on the positioning sheet, and the positioning plate is fitted on the guide pole with a cylindrical flange roller bearing, allowing it to slide between support sheet A and support sheet B. The guide bearing is installed at the front end of the U-shaped die and support sheet A to reduce friction when the two dies are forced against each other during the disc formation process. The working principle is as follows: when the wire is between support sheet A and the U-shaped die, the U-shaped die moves forward and collides with the rotary latch.
As a result, rotary latch A rotates counterclockwise and rotary latch B rotates clockwise, ultimately forming the desired shape by compressing against support sheet A. The formed wire is then forced into the groove of the molded pyrotechnic fuse using the compression die. After completing a process, the U-shaped die retracts, and rotary latch A and rotary latch B return to their original positions with the help of torsion springs.
Figure 2.7: Diagram of the disc feeding mechanism
1- U-shaped mold, 2- support sheet A, 3- support sheet B, 4- compression mold, 5- positioning plate, 6- rotary latch A, 7- rotary latch B, 8- guide pole, 9- circular flange rolling bearing, 10- torsion spring, 11- guide bearing
The overall structure is shown in Figure 2.8.
Figure 2.8:Schematic Diagram of the Overall Structure
2.4.2 Determination of the Overall Scheme
(1) Analysis of the Overall Scheme
Firstly, from the perspective of safety, Scheme 1 mainly uses a small motor to control the rotation of the rubber rolling pulley. In Scheme 2, all the moving driving components are pneumatic, and the main component of the detonator is black grind. The motor is circuit-controlled, and safety cannot be guaranteed. Production accidents may occur if sparks or heat are generated during the production process, causing the detonator to ignite.
Secondly, in terms of functionality, Scheme 1 achieves winding by frictional force between the rubber rolling pulley and the detonator. It is a gradually formed process and theoretically feasible. However, in actual production, the difficulty coefficient of motor installation for each rubber rolling pulley is high, and it is difficult to ensure the trajectory of the detonator’s movement. It is prone to jamming, bending, folding, and production interruptions. There is also a high level of loss, and the rubber rolling pulleys need to be replaced frequently. However, its advantages are fast winding speed, minimal interference between modules, and simple control.
Scheme 2 achieves winding through the combined motion of various modules, completely relying on mechanical motion. It is a one-time forming process. Although the mold processing is difficult and requires high precision, the connection between the modules is tight, and the yield of finished products is greatly improved.
Finally, from the perspective of the execution system, the execution system should have characteristics such as precise positioning, quick response, and safety and reliability. In Scheme 1, a rolling pulley is added, which is controlled by a motor for rotation. Due to the high precision requirement of the disc guide mold for the wire path, controlling the rotational motion is much more difficult than linear mechanical motion, and it is also challenging to ensure the required precision. However, on the other hand, Scheme 1 has a lower overall complexity than Scheme 2, and there are relatively fewer assembly components.
(2) Determination of the overall scheme
Based on the above analysis, we can conclude that safety and reliability [27-28] are the key focus of the structural design. Compared to Scheme 1, Scheme 2 has higher reliability, is relatively convenient in operation, and has advantages such as accurate positioning. Therefore, the overall scheme can adopt Scheme 2. In order to meet practical production requirements, progressive optimization and improvement can be carried out for Scheme 2 in subsequent designs.
2.5 Summary of this chapter
This section has determined the specifications of the 36-disc pyrotechnic fuse mold, based on which two different design ideas have been proposed and preliminarily modeled, analyzing their feasibility. Finally, the design approach for mold forming has been selected, which has high reliability, convenient control, and accurate positioning. Preliminary structural design of the pyrotechnic fuse mold has been carried out, laying a solid foundation for subsequent work.
Chapter 3: Design of the Ignition Mechanism for the Molded pyrotechnic Disc
3.1 Design of the Overall Frame
The designed ignition mechanism for the molded pyrotechnic disc can be summarized into the following main components: control mechanism, transmission mechanism, positioning mechanism, winding mechanism, traction mechanism, cutting mechanism, smoke alarm system, and tension control system.
To facilitate subsequent design work, it is necessary to determine the dimensions and structure of the overall frame. For ease of manual operation and maintenance, the overall frame is designed to have a length of 2500mm, width of 400mm, and height of 1300mm.
The overall frame can be divided into two parts: the main frame and the auxiliary frame. The main frame consists of the frame body and the supporting convex sheet. The main frame is mainly used to install the transmission mechanism, winding mechanism, positioning mechanism, and some parts of the winding mechanism. The auxiliary frame is mainly used to install the traction mechanism, cutting mechanism, and another part of the winding mechanism. The auxiliary frame and the supporting convex sheet are respectively welded and fixed to the front end of the main frame, as shown in Figure 3.1.
Figure 3.1: Host Frame Structure Diagram
3.2 Design and Installation of Molds
3.2.1 Verification of Relevant Parameters for Plate Guiding
Due to the high precision requirements for composite mold processing, the dimensions of the pyrotechnicss model directly affect the dimensions of the composite mold. Therefore, the pyrotechnicss model is first scanned in three dimensions to obtain its external dimensions and groove contour dimensions, laying a solid foundation for subsequent design and production. The specific dimensions are shown in the following table:
Table 1: Fireworks External Dimensions
Figure 3.2: Fireworks Shape
The dimensions of the pyrotechnicss groove contour are shown in the following figure:
Figure 3.3:pyrotechnic groove contour dimensions
3.2.2 Structure design and installation of sheet drawing mold
First, based on the special contour of the molded pyrotechnic groove, the basic structure of the sheet drawing mold is designed. This design scheme adopts mold extrusion molding. The groove contour, as shown in Figure 3.3, is in a sealed W shape.
Therefore, it can be formed by combining a W-shaped male mold and a U-shaped female mold. As for the inward angle after the mold forming, this scheme uses a rotating buckle corresponding to the contour, which is fixed on the W-shaped male mold by a torsion spring. During the process of mold closure, the rotating buckle is driven to rotate by the top block at the rear end of the U-shaped male mold, thus completing the formation of the inward angle of the fuse front end. The specific design of the mold structure is shown in Figure 3.4.
Considering the raised part of the upper edge of the molded pyrotechnic, the structure of the W-shaped female mold is optimized to better complete the subsequent fuse molding step. The lower end contour height is increased, so that the added part outside is tangent to the inner surface of the raised part of the molded pyrotechnic edge, making it difficult for the fuse to come off the mold during the subsequent membrane forcing step, as shown in Figure 3.5.
Figure 3.4:Mold Design for Plate Drawing
1- U-shaped punch, 2- W-shaped die, 3- Rotating latch A, 4- Rotating latch B, 5- Torsion spring
Figure 3.5: Structure of W-shaped die
The designed sheet drawing mechanism mainly consists of W-shaped die, U-shaped punch, circular flange rolling bearing, guide pole, rotating latch, punch support sheet, and circular solid. As shown in Figure 3.6, the W-shaped die is directly fixed to the main frame supporting sheet by screws, while the U-shaped punch is fixed to the punch support plate through guide poles and circular flange rolling bearings. The circular solid is fixed on the other side of the punch support sheet, and the circular solid piston pole is connected to the U-shaped punch. The sheet drawing process is completed by controlling the forward and backward movement of the circular solid.
Figure 3.6: Structure Diagram of Disc Traction Mechanism
3.2.3: Structural Design and Installation of Pressure Traction Mold
Due to the need to the lead wire, which has already been molded, into the groove of the pyrotechnicss mold with a width of 2.2mm, the mold design is made as a protruding pin with a width of 2.0mm corresponding to the contour of the pyrotechnicss groove. Due to the toughness of the steel material, it is difficult to maintain the specified shape with a pin that is too thin. Therefore, the pin is welded onto a steel sheet with dimensions of 80mm50mm3.0mm. This not only solves the deformation problem but also facilitates the installation and fixation of the mold. The mold structure is shown in Figure 3.7.
Figure 3.7: Schematic diagram of the pressing structure
The designed molding mechanism mainly consists of support sheet A, support sheet B, circular flange rolling bearing, guide pole, and circular solid. As shown in Figure 3.8, support sheet A is fixed to the W-shaped mold through a circular flange rolling bearing and guide pole, while the molding die is fixed to the lower end of support sheet A with screws. The circular solid is fixed to the upper end of support plate B, and the piston pole of the circular solid is connected to support sheet A. By controlling the forward and backward movement of the circular solid, support sheet A is driven to reciprocate on the guide pole to complete the pressing machine process.
Figure 3.8: Installation Diagram of Molding Press
3.3 Design of Traction Mechanism
The traction mechanism is the first step in controlling the motion throughout the production process, and it is an important mechanism for fixing and controlling the movement of the wire. Specifically, it is necessary to first pull the wire to the designated position at the beginning of production to facilitate the top wire of the U-shaped convex mold. Secondly, it is necessary to find and clamp the wire before the cutting traction is completed, in order to prepare for the next production.
Finally, the wire needs to be coiled and fixed on the frame, and coordinated with the passive unwinding process during traction. Inaccurate traction positioning and inability to find the wire again will result in production interruptions, requiring manual readjustment before production can resume. If the wire is coiled too tightly, it will cause traction or top wire failure, and even break the wire, posing a production hazard. If the wire is fixed too loosely, it will not provide the necessary tension force for top wire, resulting in the wire being loose and floppy during insertion into the groove of the molded pyrotechnic.
The designed traction mechanism can be divided into the main traction mechanism and the auxiliary traction mechanism. To ensure the safety of the production process, the main traction mechanism is installed on the auxiliary frame, while the auxiliary traction mechanism is installed at the rear end of the main frame, ensuring a certain distance between the drawn wire and the wire selection coil.
The main traction mechanism consists of a slide table, slider, guide pole, circular flange rolling bearing, retractable guide pole, pneumatic fixture, and circular solid. circular solid A is responsible for the lateral movement of the slide table, while circular solid B is responsible for the vertical movement of the retractable guide pole. This allows the main traction mechanism to have a wider and more flexible range of motion, avoiding interference with other working components and preventing mutual interference of workpieces.
As shown in Figure 3.9, the slider is installed inside the slide table through the guide pole. circular solid A is fixed to one side of the slide table through a flange, and the piston pole of circular solid A is connected to the slide table through a thread. circular solid B is installed at the upper end of the slider, and the piston pole of circular solid B is connected to the retractable guide pole.
The retractable guide pole is divided into two sections, with the front section connected to the circular solid as the movable part and equipped with a pneumatic fixture, and the rear section serving as the positioning part fixed to the lower end of the slide table. During operation, the traction fixture is kept in a normally open or normally closed state as required by the mechanism. The lateral traction is achieved by controlling the forward and backward movement of circular solid A, while the vertical traction is achieved by controlling the forward and backward movement of circular solid B.
Figure 3.9: Schematic Diagram of the Main Traction Mechanism
The auxiliary traction mechanism consists of a wire guide shaft, a fixed nut, bearing seat, and several guide wheels, as shown in Figure 3.10. The wire guide shaft is fixed to the mainframe through the bearing seat. The wire coil passes through the wire guide shaft and is locked by a fixed nut, and its tightness can be adjusted according to production requirements. When the main traction mechanism is in operation, the fixture drives the movement of the wire, and the wire guide shaft rotates the passive wire coil, working in coordination with the main traction mechanism. The guide wheels installed on the main frame guide the wire to the pneumatic fixture.
Figure 3.10: Structure Diagram of Auxiliary Traction Mechanism
3.4 Design of Shearing Mechanism
The shearing mechanism is used to cut off the wire connected to the wire coil at a specified position each time. Due to the wire being flammable and having a large size, high hardness, and a required length of 760mm for each finished wire, the shearing scheme can only involve cutting and not sawing or slicing. Sawing and slicing, which rely on friction to perform cutting, generate heat easily and can cause wire combustion and production accidents. Therefore, in the design process, the shearing mechanism is both a focus and a difficulty.
During the design process, we considered that the installation space for the shearing mechanism is small and there is a lot of interference. At the same time, we found that it must cooperate with the traction mechanism to complete the shearing steps. Therefore, we installed the shearing mechanism as a whole on the traction mechanism, and they move together, meeting the design requirements while reducing the design cost.
As shown in Figure 3.11, the specific components of the shearing mechanism include shearing blades, circular solids, circular solid fixing sheets, and circular solid connectors. The dimensions of the shearing blades are shown in Figure 3.12. The blades are installed parallel to the traction fixture, with the opening angle matching that of the traction fixture. One end of the blade is fixed, while the other end is movable and connected to the circular solid piston pole through the circular solid connector.
The circular solid is installed on the slide table through the circular solid fixing plate and moves together with the slide table. During operation, the wire is clamped by the traction fixture and positioned at the opening of the shearing blades. The circular solid pushes the movable blade through the circular solid connector to complete the shearing and then immediately retracts. It should be noted that the traction fixture must be in the working state during shearing. Otherwise, the next coil winding step cannot proceed, and manual retraction is required.
Figure 3.11:shows the schematic diagram of a cutting mechanism
Figure 3.12: Dimensions of the cutting blade
3.5 Design of the transmission mechanism
The function of the transmission mechanism is simple and clear, mainly used for the transportation of unfinished pyrotechnicss and finished pyrotechnicss, working in coordination with the positioning mechanism. To meet the production speed and improve efficiency, the designed speed of pyrotechnicss movement is 0.5 m/s.
As shown in Figure 3.13, the transmission mechanism consists of a motor, sprockets, levers, chain wheels, bearing seats, and so on. During operation, the motor drives the chain to rotate, and the guide pole installed on the chain pushes the pyrotechnicss forward.
Figure 3.13: Schematic Diagram of the Transmission Mechanism
3.6 Design of the Positioning Mechanism
The positioning mechanism’s main function is to achieve the positioning of pyrotechnicss through control of the motor. Considering the high requirement for positioning accuracy and the need to complete the clamping and toppling steps in sequence, it is crucial to properly design the dimensions of the fixture and control the force of the circular solid. If the dimensions are designed improperly, it may result in production accidents such as pyrotechnicss being pierced or toppled. If the force of the fixture circular solid is too strong, the lower toppling circular solid will not move, and if it is too weak, the fixture may not clamp properly. The structure of the fixture is shown in Figure 3.14.
Figure 3.14: Fixture Structure Diagram
The positioning mechanism consists of several main components: support convex sheet, guide footsheet, fixture, photoelectric sensor, and circular solid. As shown in Figure 3.15, the support convex sheet is installed on both sides of the frame, and the guide footsheet and fixture are installed inside the two support convex plates. The designed fixture is fixed on the support convex sheet through fixture guide rods and a circular flange rolling bearing.
circular solid A is fixed on the outer side of the support convex plate on one side of the fixture, and the circular solid piston pole is connected to the fixture. The photoelectric sensor is fixed at the front end of the guide footplate to detect if the pyrotechnicss have reached the designated position. If they have, it controls the motor to stop and initiates the production of the next step.
Figure 3.15:Schematic Diagram of Positioning Mechanism Structure
3.7 3D Modeling and Simulation of Molded pyrotechnic Plate Initiator
3.7.1 3D Modeling of Molded pyrotechnic Plate Initiator [29-31]
Software is used to establish the model and simulate the designed mold, and the simulated feedback results can be used to handle and upgrade potential design flaws and key factors that may cause production failures during its actual operation. This ensures the early detection of potential design defects and the optimization process, preventing interference between the movements of various mechanisms during motion and reducing the expensive cost of reworking workpiece dimensions due to design errors during later prototype debugging. It also reduces the design cycle.
CATIA software is used for the 3D modeling of the components of the 36-shot molded pyrotechnic plate initiator in this set of automation equipment modeling. The mold design is implemented using CATIA software. In the design process, the 3D models of all components are completed, and then the components are constrained to each other and assembled to observe the assembly relationship between the components.
The overall assembly drawings are shown in Figures 3.16-3.18.
Figure 3.16: Overall Assembly Diagram
1 – Initial end pressed pyrotechnicss, 2 – Chain crossbar, 3 – Support plate, 4 – Motor, 5 – Lead wire winding axis nut, 6 – circular solid 4, 7 – Tension sensor, 8 – Fireproof gas cutter, 9 – Guide pole, 10 – Convex U-shaped die, 11 – Concave U-shaped fixed plate, 12 – Guide wheel, 13 – Molding, 14 – Electric cabinet, 15 – Positioning fixture, 16 – Guide fixture.
Figure 3.17:Assembly Diagram Front View
17 – circular solid 1, 18 – circular solid 5, 19 – Shearing blade, 20 – circular solid 6, 21 – Traction fixture, 22 – Extendable guide pole, 23 – Double guide pole slide table.
Figure 3.18:Assembly Diagram Top View
24 – circular solid 3, 25 – circular solid 2, 26 – Fixture guide pole, 27 – Chain, 28 – Bracket, 29 – Chain guard, 30 – Lead wire coil.
3.7.2 Motion Simulation of the Ignition Device for Pressed Fireworks Disk
Figure 3.19: Catia Motion Mechanism Simulation Analysis Process Flowchart
Using CATIA DMU to achieve simulation and simulation design, the animation production process is as follows: first, establish a single mechanism motion; then set the motion speed and distance for each mechanism; finally, arrange the motion sequences in ascending order according to the motion order, as shown in Figure 3.20.
Figure 3.20:Motion Playback and Sequence Diagram
Section 3.8: Summary of this Chapter
This chapter mainly describes the mechanical design of the 36-shot pyrotechnic disc igniter, which is divided into six parts, including mold design, overall frame design, transmission mechanism design, positioning mechanism design, traction mechanism design, and cutting mechanism design. By introducing the simulation function of the CATIA simulation software, the design and installation of each component were completed, and then the motion simulation of each component was accomplished using CATIA, creating a simulation animation.
Chapter 4: Design of Pneumatic System and Control System for the Compression pyrotechnic Plate Ignition Mechanism
The automation [32-35] and intelligent control [36-42] of the entire pyrotechnic production process are essential requirements for the development of the industry. This design adopts a typical pneumatic integrated autonomous production equipment composed of PLC-sensors-pneumatic components. The application of PLC is based on a microprocessor as the core to establish a flexible program control system [43-44].
In both PLC and pneumatic fields, their superiority is demonstrated through sequential actions. This is a common feature shared by both and a prerequisite for ensuring their superiority. The switch control of PLC and the output and positional control or compound control of pneumatic technology are the pillars of modern industrial control [45-46]. This autonomous production equipment fully utilizes the advantages of PLC control and pneumatic technology.
4.1 Design of the Pneumatic System
4.1.1 Installation and Selection of circular solids
The selection of circular solids must be based on the working conditions and requirements of the system, and the circular solids should be chosen correctly. All selected circular solids in this design are single-piston pole double-acting circular solids. The specific selection steps are as follows:
(1) circular solid stroke: The output force of the circular solid is reflected by its size. The selection of output force is determined based on load and pressure requirements, thus determining the circular solid selection.
(2) circular solid Size: The circular solid stroke is usually determined based on the movement distance of the mechanism. In general, avoid selecting circular solids with a full stroke whenever possible.
(3)Calculation of circular solid stability performance.
(4) circular solid installation method: In most cases, the installation method of the circular solid is determined based on assembly space and requirements.
(5) Magnetic switch: When the circular solid motion is controlled by a circuit, magnetic switches can be installed to sense and provide feedback on the circular solid’s position.
(6) Buffering Tool: Determine whether to install a buffering method based on the setting and operational requirements.
(7) circular solid shape: For compact installation positions, choose a round circular solid, and for general situations, choose a square circular solid.
(8) Other requirements: When used in environments with a lot of dust, a protective cover should be installed. For pollution-free production, choose a lubricant-free circular solid.
Based on the assembly form of the circular solid and the actual working load requirements of the circular solid, calculate the lateral load under the circular solid’s working mode using equation (4.1), and determine the load rate β of the circular solid. β is related to the average operating speed of the circular solid.
β = The actual load of circular solid F / The theoretical output force of circular solid FB 100% — (4.2)
The motion status and load rate of the circular solid are shown in Table 4.1.
Table 4.1:circular solid motion status and load table
Calculate the theoretical output force Ft = F/Fβ (4.3), then select the working pressure of the circular solid. Based on the production environment, we choose a circular solid pressure of 0.6 Mpa. The theoretical thrust of a double-acting circular solid is:
The formula for calculating the circular solid bore dia D can be obtained by integrating equations 4.1-4.4, where D represents the circular solid bore diameter, p represents the working pressure, and η represents the circular solid efficiency.
According to the previous information, the working efficiency of a circular solid is directly related to the load pressure and diameter of the circular solid. Increasing the working pressure or increasing the circular solid bore diameter will improve the circular solid efficiency (η). In most cases, the operating efficiency of a circular solid fluctuates within the range of 0.7-0.95. Figure 4.1 illustrates the trend of circular solid operating efficiency .
Figure 4.1: circular solid Efficiency Curve
Based on the above steps and considering the working load stroke, the appropriate circular solid model is determined. The parameters of the selected circular solid are shown in
Table 4.2: Table 4.2 circular solid Selection
For convenience of installation and standardization, all circular solid installations  use the flange connection method. The flange installation components are shown in Figure 4.2.
Figure 4.2: Flange Installation Components
4.1.2 Design of Pneumatic Circuit
In this design, the circular solid serves as the main operating component of the equipment. A vacuum transport channel with a pressure load of 0.8 Mpa is installed in the production workshop, directly connected to the equipment, effectively improving its operational efficiency. The selected circular solid is a double-acting circular solid, meaning gas delivery pipelines are installed at both ends of the circular solid. The key requirement is to control the direction of the pneumatic circuit. Considering safety issues, a two-way five-port electromagnetic valve is used for the execution of limit mechanism, while a two-way three-port is used for the one-way execution mechanism. The pneumatic connections are shown in Figure 4.3.
Figure 4.3: Pneumatic Connection Diagram
To avoid the occurrence of impurity leakage from processed gas to the solenoid valves and circular solids, a filter pressure regulator is installed in the air source. It can stabilize the pressure and filter out moisture from the compressed air, making the air source more stable and cleaner.
This equipment involves 8 pneumatic control mechanisms, with 7 of them using three-way five-port solenoid valves. They are installed in pairs on the solenoid valve manifold. The remaining one uses a two-way three-port solenoid valve and is installed separately. The pneumatic component controlled by the two-way three-port solenoid valve is the traction fixture. For ease of operation, a separate momentary switch is installed to control the opening and closing of the traction fixture. Its control program is independent of the entire system and works separately.
4.2 Design and Implementation of the Control System
4.2.1 Working Steps and Drawing Process of the Reeling Machine
As mentioned earlier, according to the 36-shot pyrotechnics reeling process, the detailed working steps of the reeling machine are as follows:
Step 1:Secure the fixed shaft nut of the wire reel and guide the wire from the wire reel through the guide wheel and tension controller into the clamped traction fixture along the specified trajectory.
Step 2: The worker places the molded pyrotechnic at the starting end of the conveyor chain. The crossbar of the chain pushes the molded pyrotechnic forward towards the positioning mechanism under the drive of the motor.
Step 3:The photoelectric sensor installed on the guiding fixture senses the stoppage of the motor after the pyrotechnicss are molded. circular solids 2 and 3 receive the signal, and circular solid 3, through a double-guide pole slide table, pushes the traction fixture to the other end of the slide table. At the same time, circular solid 2 drives the positioning fixture to clamp the molded pyrotechnicss.
Step 4:When circular solids 2 and 3 reach the lower limit, circular solid 4 receives the signal and pushes the protruding U-shaped die to push the completed lead wire, allowing it to be pressed against the concave U-shaped fixed plate to form the desired shape. The traction fixture is released before the protruding U-shaped die reaches the end point.
Step 5:When circular solid 4 reaches the lower limit, circular solids 1 and 3 receive the signal. circular solid 1 drives the push plate to push the molded pyrotechnicss until the upper surface of the molded pyrotechnicss matches the lower surface of the concave U-shaped fixed plate. At the same time, circular solid 3 drives the extendable guide pole, traction fixture, cutting blade, and circular solid 6 back to their initial positions, and the traction fixture clamps the lead wire again.
Step 6:When circular solid 3 reaches the upper limit and circular solid 1 reaches the lower limit, circular solid 6 receives the signal and pushes the cutting blade to cut the lead wire connected to the coiled lead, and then immediately resets.
Step 7: After circular solid 6 resets, circular solid 5 receives the signal and drives the die to grinde the lead wire with the desired shape into the groove of the molded pyrotechnic’s lead wire, and then immediately resets.
Step 8: After circular solid 5 resets, circular solids 1, 2, and 4 receive the signal. The positioning fixture and push plate descend one after another, the U-shaped die resets, and the motor-driven chain starts.
Step 9: The coiled lead pyrotechnicss, which have been guided and wound, leave the conveying mechanism under the push of the chain crossbar, completing the entire winding process.
4.2.2 Hardware Selection
The designed automatic disc firing tool for 36 pyrotechnic models, based on the control requirements and the spare capacity of input/output points, incorporates the CPU224XP model PLC due to its characteristics. The control system is implemented to control the autonomous assembly appliance .
The parameters of the CPU224XP AC/DC/relay programmable controller are shown in Table 4.3, and its structural diagram is shown in Figure 4.4.
Table 4.3:Technical Parameters of CPU224XP AC/DC/Relay
Figure 4.4:Schematic Diagram of Structure
According to the control requirements of the design, the I/O allocation of the PLC is as follows: (1) Input terminals: One point each for emergency stop, inverter alarm, and photoelectric sensors. One point each for controlling the up, down, and alarm limit of 7 circular solids, totaling 21 points. However, circular solids 6 and 7 do not have a lower limit, so subtract one point each.
Therefore, there are a total of 22 output terminals. (2) Output terminals: Two points for raising and lowering circular solid 1, two points for clamping and releasing circular solid 2, two points for advancing and retracting circular solid 3, two points for advancing and retracting circular solid 4, two points for pressing and releasing circular solid 5, two points for advancing and retracting circular solid 6, one point for cutting circular solid 7, one point for gripping fixture, and one point for inverter forward rotation. In total, there are 15 output points.
Table 4.4: provides a brief introduction to the I/O terminals of the PLC control system for the 36-shot pyrotechnic launching appliance.
4.2.3 System Sequence Diagram
Based on the working principle of the 36-launch model pyrotechnic disc igniter, this appliance completes the loading work in a sequential order, ensuring that each action begins only after the previous one has ended. The PLC control program sequence for modifying the action requirements of the 36-launch model pyrotechnic disc igniter is shown in Figure 4.5. The overall debugging diagram of the electronic control system is shown in Figure 4.6.
Figure 4.5: PLC Control Program Sequence Diagram
Figure 4.6:Overall Power-On Debugging Diagram of the Electrical Control System
4.3 Design of Security Protection System
4.3.1 Design of Smoke Alarm System
Due to the use of flammable materials and the presence of black powder in the production process, there are safety hazards. Especially during the wire-cutting process, the constant friction between the blade and the wire, as well as the scattering of powdered grind when the wire is cut, can easily lead to fires and more serious production accidents if they come into contact with an open flame or sparks. Therefore, to ensure the safety and reliability of the wire-cutting process, we have added a smoke alarm system to the design. The smoke alarm system consists of smoke detectors and fire-resistant gas cutters [50-51].
Ionization smoke detectors are extremely sensitive to fine smoke particles and react quickly. Therefore, while ensuring production safety, they can also monitor the production environment in real-time to prevent unsafe behaviors such as smoking by workers during the production process. The detachable sensing probe also facilitates regular replacement by workers to prevent a buildup of particles at the probe due to prolonged use, which could result in reduced sensitivity and failure to meet specified requirements.
As shown in Figure 4.7, the ionization smoke detector is installed below the traction slide and directly above the wire-cutting position, while the fire-resistant gas cutter is installed in the middle of the main frame’s guide wheel, providing safety protection for high-risk production processes. When the smoke alarm detects smoke particles, it immediately sends a signal to the PLC host. The PLC host stops the operation and transmits the signal to the fire-resistant gas cutter.
The gas cutter separates the front end of the wire from the wire coil to prevent the wire coil from igniting, thereby preventing more significant production accidents and further ensuring the safety of the production process. After the safety hazard is eliminated, the gas cutter needs to be manually operated to return to its original position to ensure that the fire-resistant gas cutter is properly initialized before restarting the operation.
Figure 4.7:Schematic diagram of smoke alarm installation.
Figure 4.8 shows the working principle diagram of the smoke alarm system.
Figure 4.8: Working Principle of Smoke Alarm System
4.3.2 Design of Tension Control System [52-53]
Due to the need to maintain a certain tension during the winding process and the constant presence of wire friction, monitoring the wire tension becomes crucial. It is an important guarantee for the normal operation of the equipment. When the tension exceeds the normal working range at any step, it indicates a equipment failure, and it is necessary to stop the appliance promptly for repairs.
Therefore, we have installed three wheel-positioned tension sensors at the front end of the wire reel, as shown in Figure 4.9, to monitor the tension changes in real-time during the production process. The set tension is 4000. When the wire is used up or a fault occurs in a certain step causing the wire to jam, the tension sensor will send a feedback signal to the PLC, automatically triggering an emergency stop to prevent further damage to the production equipment.
Figure 4.9: Tension Sensor Installation Diagram
Chapter 4 Summary
This chapter provides a detailed explanation of the management system for the 36-shot pyrotechnic disc initiator, including introductions to aerodynamic design, program modes, and safety system design. A typical pneumatic integrated autonomous production equipment composed of PLC-sensor pneumatic components has been designed. In both the PLC and pneumatic fields, their superiority is demonstrated through sequential actions, which is a common feature and prerequisite for ensuring their superiority. PLC utilizes switch functions to ensure the accuracy of pneumatic thrust and achieve position management and simultaneous management of two functions. The 36-shot pyrotechnic disc initiator described in this paper fully leverages the advantages of PLC control and pneumatic technology. It develops a software and hardware control system that meets production requirements based on actual production needs while ensuring production safety.
Chapter 5 – 36-shot pyrotechnic autonomous Tray Ignition Machine On-site Debugging and Operation
5.1 Assembly and Debugging of the 36-shot pyrotechnic Tray Ignition Machine
● Assembly Sequence and Precautions
First, install the main equipment and transmission appliances. After assembly, manually adjust the frequency converter to control the motor-driven sprocket rotation and observe the idle running condition. Next, assemble the tray ignition mold and pressure ignition mold. Install the convex U-shaped mold and concave W-shaped mold separately, and observe the mold closing condition before installing the pressure mold. The positioning mechanism should be determined based on the installation position of the concave W-shaped mold to ensure that the protruding part of the concave W-shaped mold is in the same axial line as the positioned pyrotechnic, meeting the assembly requirements. After the tray ignition mold is installed, assemble the traction mechanism and shearing mechanism. To ensure proper installation at their respective positions, manually operate the main traction mechanism to move horizontally and vertically, visually checking the movement path and distance. Verify the rationality of the auxiliary traction mechanism’s travel route. To facilitate and ensure smooth manual debugging, install the circular solid solenoid valve and proximity switch components after completing the machining part installation.
● Debugging Method
After all the components are assembled and manual test runs are completed, the positions of the photoelectric sensors and proximity switches need to be determined. The specific steps are as follows: (1) Adjust the pressure regulator valve to 0.5MPa, connect the air source, and set the air source pressure to 0.8MPa. (2) Turn on the appliance power, set the motor frequency converter response time to 0.1s, and manually run the motor in single-step mode to check if it rotates properly.
(3) Adjust the position of the photoelectric sensor so that it can sense the pyrotechnicss within its sensing range and be clamped by the positioning fixture. (4) Independently adjust the lower limit position of circular solids 1-6 under actual working conditions, ensuring that the corresponding proximity switch indicator lights up when the circular solids are in the correct position. The physical appearance of the tray ignition appliance prototype is shown in Figures 5.1 and 5.2.
Figure 5.1: Prototype of a disc winding appliance
Figure 5.2: Prototype of a Disk Ignition Machine
5.2 Operation Steps for the 36-Shot pyrotechnic Disk Ignition Machine
● Startup Steps
(1) Thread the fuse through the fuse spindle and secure it with a locking nut. (2) Close the switch on the side of the electrical cabinet, reset the emergency stop button, check if the indicator light is green, ensure the electrical cabinet fan is functioning properly, and confirm that the system alarm on the display interface is in gray state. The control mode should be set to automatic.
(3) Check if the clamp is in the initial position and if the slide table circular solid’s lower limit switch and the expansion and contraction circular solid’s lower limit switch on the slide table are lit. (4) After confirming the above operations are correct, connect the air source and thread the fuse into the clamp according to the specified path, then the quick release key to clamp the fuse. (5) After confirming the above operations are correct, click the autonomous start button.
Once the chain is running normally, place the molded pyrotechnics, paying attention to their placement direction and ensuring they are placed in the middle of the grid. (6) During the production process, frequently check if the fuse for the 36-shot pyrotechnic disk ignition apparatus is running out and if the pressure gauge is displaying normally. (7) During the production process, frequently check for any abnormal sounds coming from the 36-shot pyrotechnic disk ignition appliance.
● Shutdown Steps
(1) Click the “Auto Stop” button. (2) Press the emergency stop button. (3) Disconnect the power supply. (4) Unplug the motor plug and disconnect the air source.
The actual operation is shown in Figure 5.3, and the production process is illustrated in Figure 5.4.
Figure 5.3: Actual Operation Diagram
Figure 5.4: Production Process Diagram
5.3 Trial Operation Status
Due to the complexity of the disc drawing process, the quality of the disc drawing directly determines the quality of the product, and external factors can also affect the disc drawing. Therefore, to ensure product quality, it should be executed from multiple aspects such as mold design, product design, and production parameters.
These aspects are interdependent during the product design process, which increases the design difficulty. In summary, the precision of processing is the basic condition for ensuring product quality, while reasonable product design and correct mold design are important factors in ensuring product quality, and a complete system program is the guarantee of success.
In the first operation of this equipment, the stability of the disc drawing machine should be maintained as much as possible to ensure product quality. Through multiple tests, the operating parameters for the injection appliance are set as follows: Air supply pressure: 0.6MPa circular solid running speed: 1m/s Working interval time: 0.1s Secondary drawing control proximity switch distance from the lower limit: 3cm
The production pressure can be increased to 0.8MPa according to production needs, and the length of the secondary drawing can be adjusted by changing the proximity switch of the secondary drawing control according to the regulations for pyrotechnicss export in domestic and foreign markets. Other parameters can also be adjusted according to production needs. Through multiple tests, the results are shown in Table 5.1. The staff, as the workers using this equipment for the first time, experienced stable operation without any faults.
The occurrence of defective products and the reasons for their occurrence were analyzed, as shown in Table 5.2. The manufacturer summarized this situation. The manual operation of the disc drawing by skilled workers is 12 seconds per piece, while the conservative time required by this design is 8 seconds, which is 1.5 times longer than manual operation, fully meeting the design requirements.
Table 1: Summary of Trial Operation
Table 2: Analysis of unfinished products and suggested measures
5.4 Summary of This Chapter
This chapter mainly elaborated on the on-site assembly and trial operation results of the 36-shot pyrotechnic firing appliancewith a compressed mold. It also provided the operating specifications and relevant indicators for the 36-shot pyrotechnic firing tool.
The final production test showed that the equipment is fully functional, easy to operate, convenient to maintain, and has relatively high stability and safety performance. The appliance works in synergy with the dispensing machine, aiming to improve the product qualification rate and reduce the labor intensity of workers. This has significantly increased the production efficiency of the products, meeting the production requirements set by the manufacturer.
Chapter 6: Summary and Outlook
6.1 Full Text Summary
This paper focuses on the development and analysis of a 36-shot pressed pyrotechnic disc initiator. The main accomplishments are as follows:
Based on the high cost and low efficiency of the current state of pressed pyrotechnic disc initiators with hydraulic press, this paper designs a 36-shot pressed pyrotechnic disc initiator. Two automated production and operation schemes for disc initiation are proposed and compared. The comparative results are analyzed, and it is proven that using a combined disc initiation mechanism is scientifically feasible for device installation.
It is also simpler in structure, easy to manage, and provides higher safety performance. The automation of 36-shot pressed pyrotechnic disc initiation is achieved while ensuring stable operational performance and improved production efficiency. The modular design allows each module to work independently while collaborating continuously.
The designed 36-shot pressed pyrotechnic disc initiator consists of five modular mechanisms: disc initiation mechanism, traction mechanism, cutting mechanism, transmission mechanism, and positioning mechanism. It also includes two systems: a smoke alarm system and a tension control system. The electrical cabinet and electromagnetic valve module are installed above the appliance, facilitating worker operation and equipment maintenance. This significantly enhances safety performance compared to manual production methods.
The pyrotechnics industry’s flammable and explosive nature requires production equipment to have high safety and stability. Therefore, all movements of the 36-shot pressed pyrotechnic disc initiator are pneumatically operated. The control system adopts PLC control combined with a human-machine interface. The motor and circular solid are the running parts, and precision control of the electromagnetic valve is achieved through PLC and switches. The advantages of this system are primarily demonstrated in the following aspects:
(1) The use of circular solids to directly manage the components enables each module to work independently, thereby enhancing the stability of equipment operation. Multiple tests have proven that this control mode meets the production action requirements of the 36-shot pressed pyrotechnic disc initiator.
(2) It has powerful functions, convenient operation, easy learning, and improves the operators’ manipulation ability and work efficiency.
(3) The entire system programming is concise, the sequence is reasonable, the functions are clear, and it is easy to maintain and troubleshoot.
Implemented functions such as running direction testing, instant obstacle alarm prompts, and fault prompts. The implementation of these intelligent functions provides guidance for equipment maintenance and upkeep. A three-dimensional model of the 36-shot pyrotechnic disc igniter was established using CATIA software. Through animation simulation of the equipment, it was determined that the prototype’s operational simulation process meets the design and production requirements.
A prototype of the 36-shot pyrotechnic disc igniter was developed, and on-site assembly and debugging were carried out. Based on the debugging results, the stability of the 36-shot pyrotechnic disc igniter’s operation was proven. Although the overall movement is complex, there is no interference between components, and the circular solid forces in various parts are reasonable. It meets the production requirements well.
Currently, as shown in Figure 6.1, this equipment has been installed and used in the pyrotechnicss production workshop. The results of its usage have demonstrated that the equipment has strong stability during operation, improving the working intensity of the laborers and creating a better working environment. Additionally, it has increased product qualification rates and reduced the manufacturer’s financial costs. It is a meaningful attempt to technologically reform traditional production methods and has strong practicality with good development prospects.
Figure 6.1: Production Diagram of Enterprise Workshop
6.2 Prospects for Future Work
This thesis addresses the issues of low operational efficiency, lack of operational safety assurance, and high labor intensity in the production of 36-shot pyrotechnic disc igniters. To solve these problems, a 36-shot pyrotechnic disc igniter appliance was designed. After completing the full design of the equipment, operational testing was carried out, and its performance met the production requirements of the manufacturer.
However, due to limitations in my mechanical design capabilities, I encountered many detours in the process of equipment design and installation. Although the development of the 36-shot pyrotechnic disc igniter machine was eventually completed, there are still some shortcomings in this automated equipment that cannot be avoided. It requires further optimization and upgrades. Through continuous analysis and research, I believe that the following points can be considered for upgrading the equipment in future operations:
(1) The reset mechanism of the rotating buckle in the disc igniter model adopts a reset spring installed below the rotating buckle. However, in long-term production, the elasticity of the reset spring will continuously weaken, eventually causing the rotating buckle to fail to reset.
Moreover, the special structure at the installation site of the rotating buckle makes its disassembly extremely inconvenient. It is necessary to remove the concave W-shaped mold and the pressure mold completely in order to replace the reset spring of the rotating buckle, which is extremely troublesome. During processing, the concave W-shaped mold can be structurally optimized by reducing its edge thickness, allowing the rotating buckle to be directly disassembled and installed.
(2) When designing the auxiliary traction mechanism, installing too many guide wheels to ensure the stability of the wire’s travel path can result in excessive resistance during the traction of the main traction mechanism and the top pull of the convex U-shaped mold, which has a certain impact on production speed. By appropriately reducing the number of guide wheels, the wire’s travel path remains unaffected, and it can also reduce resistance, thereby improving production speed.
(3) Although the smoke alarm system considers fire prevention measures to separate the wire head from the coiled wire when the wire head catches fire, the combustion of the wire used in production generates a significant reactionary force, especially when short wires burn irregularly and unpredictably. This can easily cause burns, scalds, and even fires to workers. After optimization, a protective cover should be installed below the worker’s workstation to prevent ignited wires from flying out.
(4) After each cutting and traction step in the cutting mechanism, black powder from the cut wires falls down under the scissors. Prolonged production will lead to an accumulation of black grind, posing a safety hazard. A small fan should be installed below the sliding table to prevent the accumulation of black powder.
(5) For the development of the prototype, all system hardware and circular solids are imported, which slightly increases the cost. Based on the development of the prototype, domestic components can be used as replacements, such as PLC, circular solids, and proximity switches, to reduce costs.
(6) By using multiple 36-pyro disk igniters to connect the system’s main port, simultaneous operation and management of the appliances can be achieved, enabling large-scale production and remote control. This further reduces costs and ensures safety.
However, overall, the 36-pyro disk igniter has advantages such as simplicity, strong stability during operation, and convenient operation. It effectively improves the production cost and product yield of pyrotechnicss manufacturers, providing broad development opportunities and competitive advantages. At the same time, it also provides ideas for the future development of automated pyrotechnicss equipment.
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