A discussion on the process interaction analysis method of steel drum quality

A discussion on the process interaction analysis method of steel drum quality

Yang Wenliang

At the "New National Standard for Steel Barrels and Technical Lectures and Quality Certification Promotion Seminar" held in Beijing in July this year, I participated in this meeting as a technical expert and gave technical lectures to the participants. At the meeting, I proposed a new method of quality analysis for the first time, which is the Process Interaction Impact Analysis Method. This method is used to analyze the materials, processes and operation methods that affect the quality of steel drums. The peers said: "I am very inspired!".
After the meeting, many people in the industry sent letters to ask for a speech. However, I know very well that there is no detailed explanation of the "process interaction impact analysis method" in the lecture. It is difficult to grasp this analysis method through the lecture, and this method is the part that everyone is interested in. This issue was reflected by the peers during the meeting. A technician from Guangdong said to me: "The quality of our steel drum manufacturers has many problems. Although there are commonalities, the problems that arise in each family are different. It is special. We hope that you will teach us how to analyze the problem. We can gradually analyze and solve the problem when we encounter the problem." In order to solve this problem, I gave a detailed introduction on how to use the second day of the meeting. Process Interaction Analysis Method to analyze practical problems in production.
In fact, this "Process Interaction Analysis Method" is my fabrication. In the long-term technology and production practice, I gradually formed my own method of analyzing problems, but I have never noticed that it may become a "study" or "theory." "So, in theory, it is not mature. For this reason, I did not specifically talk about it, but through specific examples to illustrate its usage. Today, everyone "forces me" to speak the theory, and I try to form a theory. As long as everyone can understand it, it means that I have made it clear.
Once I went to the field to participate in the seminar to give lectures to the technical training class. A university student working in the local area came to see me and said to me inexplicably: "Just your steel drum, that bucket! That technology?" The meaning of steel drum is very simple, there is no technology. Of course, I am very angry. I said, "If you only do one or a few steel drums, you may not need any technology. As long as you have a good craftsman, you may be able to do it beautifully. But it should be produced in large quantities. Steel drums, and to ensure the quality of the products, it is impossible to rely on the craftsmen, which requires technology!" The old classmate smiled and said: "Don't be so hot, I am joking with you..." In fact, in our barrel industry Internally, there are not many people who think that steel drums do not need technology. This has caused our steel drums to have poor quality, high cost and low grade. When I first came into contact with steel drums after graduating from college, I also felt this way, but through years of work and practice, my original idea was wrong. Steel drums not only have technology, but also involve a wide range of technologies!
Steel drum production technology is actually a specific application of a comprehensive technology. The production process seems simple, but it involves many technical fields. For example, the unwinding and leveling process of steel sheets belongs to the steel rolling and shaping technology; the grinding or milling of the barrel steel plate (commonly referred to as edging or milling) is a metal cutting technology; the barrel is rounded, flanged and The process of expanding the ribs and the like belongs to the plastic deformation cold processing technology of the metal material; the spot welding and the seam welding process belong to the welding technology of the metal material; the steel barrel crimping sealing process penetrates the essence of the sealing technology and the plastic deformation cold processing technology of the metal material Application; the production process of the bottom of the barrel and the barrel mouth are cold stamping technology; the process of degreasing and derusting of the barrel body belongs to the chemical surface treatment technology; the painting of various methods on the surface of the steel drum belongs to the metal surface coating technology; The drying process of the coating film belongs to the far-infrared heating technology and other heating technologies; the patterning on the finished steel drum belongs to the category of printing technology, etc., etc., such as rolling technology, forging technology, hydraulic transmission technology , pneumatic transmission technology, expansion technology, automatic control technology. Therefore, barreling technology is not a separate discipline. To be proficient in it, it is necessary to relax and study carefully.
There are a lot of technical problems affecting the quality of steel drums. If you look up and analyze them separately, you will see that the trees are not visible in the forest, which is not conducive to solving the problems. Through long-term practice and research in the steel drum industry from technology to production, we find that these technologies and processes have an intrinsic relationship, which affect each other, are mutually unified, and are interconnected. Therefore, it is necessary to carry out all-round interactive analysis. Only in this way can we find the essence of quality problems and achieve the three unifications of technology, technology and quality.
Using the Process Interaction Analysis Method to analyze the problem, we can see how the impact of each process in the steel barrel production process affects, how it can be affected or less affected. Because most of the process problems do not seem to affect the final product quality at first glance, but after using the "Interaction Analysis Method" analysis, it will find that it may have certain impact on other processes, thus affecting the final product quality. .
So, what exactly is the process interaction impact analysis method?
We know that there are dozens of processes in the production process of steel drums, and there is only one final product, and these processes all work on the same product, and there must be an interaction between the processes. But sometimes this factor is hard to find, and the final product has quality problems, but what is the problem in that process? Different people or different analytical methods may produce different results. But there is always one correct answer!
Process interaction impact analysis, to put it bluntly, is "successful." You can perform the analysis in the following steps.
I. Inclusion
Start with the phenomenon of finished product quality and avoid premature conclusions. First look at the reasons why the quality problem may occur. If you are not sure, you may want to include more than one process; if the problem is more complicated, you can include it all. Of course, the process to be included should be the top-level process, because "successful" can not be touched by melons, or it may miss some major factors that cause problems. For example, if there is leakage in the seam welding and sealing triangle of the steel drum, then the process directly involved in the analysis is definitely the crimping process, and it is not the painting process, because the coating is unlikely to cause the part to seep. Leakage; it is not possible to directly incorporate the seam welding process, because the seam welding process is far from the winding process, not the upper layer. But it is also one of the factors that may affect the quality of the seal, not the only one. If it is directly incorporated into the seam welding process, it is possible to ignore or dilute other factors, and it is possible to miss the real cause. For the convenience of the description, we refer to the process that is included in the "A" process.
Second, expand
Incorporating the process to be analyzed, we will carry out this process, and the expansion is actually further integration. The direct process that affects the quality of this process must be fully incorporated and fully listed. Paying attention to the direct meaning is to directly produce the process of this process, and the indirect production process is not to be expanded here. For example, the expansion process of the steel drum sealing process, the direct process has a barrel body flange, the bottom of the barrel, the top pre-rolling, glue coating and the like. The seam welding, the bottom cover of the bucket and the molding of the top of the bucket are all indirect processes and cannot be expanded here. This unfolding process is called the "B" process and the "C" process.
Third, analysis
For the directly unfolded process, the analysis begins. The main work of the analysis is measurement, that is, whether the products of these processes are qualified according to the requirements of the process documentation. This is actually a process of arranging the touch. For the process that passes the test, we calibrate it and the next step is no longer unfolded. For the process that is found to be unqualified after the test, we have to carry out further analysis.
There are two further steps to further analysis:
The first step is to analyze the five links of "people, machine, material, law, and ring" to see if there are any problems in these places. If something goes wrong, solve this problem first. After the problem is solved, the process test is carried out. If the problem is solved, it indicates that it is the cause of the process. In this way, all problematic links are analyzed, and the problems are solved and verified through process tests until they are resolved. For example, when the problem of the "B" process is solved, the analysis of this process ends here and no longer develops. If the problems "B" and "C" of all the unfolded processes are solved, we will return to the "A" process to carry out the process test. In general, the problem of the "A" process is solved at this time. In this way, our quality analysis is over. However, if there is one, for example, the "C" process still has problems in the analysis process, and it cannot be solved during the process, then it is necessary to proceed to the next step.
The second step is to further include, for example, there is still a problem in the "C" process, and we will further incorporate the processes that affect its quality according to the above methods. For example, the "C" process is a flanging process, and we will incorporate the seam welding process of the previous layer for further development and analysis. We call this process a "D" process.
Fourth, reintegration, expansion and analysis
This process is actually the same as the above steps, and the method is similar, but the content is different. For all relevant processes to be checked and denied from the back to the front, the real problem will be found. Sometimes, there may be more than one process problem affecting the final quality. It is a concentrated expression of many problems. Only by using this "mine-clearing" method can all problems be solved. Otherwise, the problems may not be solved completely, and some problems will be solved. appearing again. When the problem of a certain process is solved, it is necessary to return to the previous process for verification to see if the source of the problem is really found. When the verification is affirmed, the analysis process can be ended. Otherwise, it must be pursued until it is resolved. The problem is so far.
The effect of process interaction means that the factors affecting the quality of the process do not necessarily appear in this process, and may occur in another process, but in the analysis of another process, it may be found that it may be another process. For example, if there is a crack in the flange, it will definitely affect the quality of the seam, but the cause of the flange crack may be the quality of the seam welding process, or the quality of the edge grinding process, or it may be cutting. The quality of the process, and further development may be the quality of raw materials and so on. To accurately identify the real problem of the problem, it is impossible to rely on subjective judgment, nor can it rely solely on experience. Scientific analysis and investigation must be carried out. If this is not the case, there may be no real problem. In practice, sometimes the cause of the problem is unexpected, so it is often wrong to make a decision.
Fortunately, the process of making our barrels is not very complicated, and it is not too complicated to analyze. In practice, many of the complex analysis processes described above are actually easy to implement, because everyone knows the process and equipment, and sometimes the analysis process will be completed with a little consideration and observation.
The five factors of "human, machine, material, law, and ring" surrounding the analysis are commonly used methods for analyzing quality problems. Here is a brief description of the following.
"People" refers to the quality of the operators, proficiency, strong sense of responsibility, good mood and so on. For example, if a person works overtime for more than ten hours, he may have insufficient energy or bad mood, which may affect the quality of his operation and affect the quality of the product;
"Machine" refers to the operating state of the equipment, whether it is faulty, whether it is worn, whether it is easy to operate, whether it can meet the process requirements, and so on. For example, the forming roller of the crimping sealing machine is worn out, and the forming curve is changed, so that the crimping process can not meet the process requirements, thereby causing quality problems;
"Material" refers to whether the quality of the raw materials used in this process is qualified, whether it can meet the process requirements, whether quality inspection has been carried out, and so on. For example, the carbon content of steel drum raw materials is too high, the steel plate itself becomes brittle and cracks are easy to occur, so it will affect the quality problems of the subsequent processes;
"Law" refers to whether the operation method is correct; whether the process route is reasonable or not. For example, some manufacturers spray glue on the curling edge during the winding process. There is a timing problem. The correct operation method is to spray the glue before starting the curling, so that the glue will be wound into the curling edge to form a glue. Sealing the seal to achieve a seal, but if the crimping has started or is about to end, the seal will not be achieved.
"Ring" refers to whether the production environment can meet the process requirements, including ambient temperature, humidity, dust, noise, and so on. For example, when a factory is producing in the summer, the workers spray a lot of water on the ground for cooling, causing a large amount of rust in the barrel. This is the impact of the environment. There are many examples of this.
When systematically analyzing the various factors of "human, machine, material, law, and ring", we should not neglect any small link. This is actually the so-called "carpet-style" investigation and analysis. Generally speaking, it will not leak. This analysis process is the basic skill of quality analysis. It must be fully mastered and skillfully applied in order to lay a solid foundation for the use of process interaction analysis. It can also be said that it is the basis of the process interaction analysis method.
Now, we should have some understanding of the "process interaction analysis method". I think the essence here should be the word "interaction". The analysis process mentioned above does not reflect the essence of these two words. In fact, it is reflected in Throughout the process. Because each process has its own interaction and connection, it is impossible for all problems to independently affect other processes. Therefore, using this analysis method, it is easier to distinguish their relationship and influence. For example, the problem that the raw material is brittle and the hardness is increased due to high carbon content, so that the processing property is poor, will affect the quality of the process in many subsequent processes, which greatly reduces the strength of the weld, thereby causing the barrel to be Cracks occur during the flanging process, cracks or cracks may occur during the expansion process, and then the quality of the leak occurs due to internal cracks in the crimping seal; in addition, the bottom of the barrel is also created. Cracking occurs during top drawing, and cracks occur in the barrel flanging and pressing process. These will cause serious quality problems in the final product.
Therefore, the interaction effect is a process of inheritance of a problem. Just like an infectious disease, it will be "infected" along with a process and a process. The interaction analysis method must not only find the source of the "infectious disease" but also eliminate the infection. The effect of the disease until it is completely eliminated.
In practice, we intentionally or unintentionally use this method to analyze the problem, but we have not raised it to the theoretical level, to summarize and apply. Therefore, most of them are not systematic and comprehensive, and often have poor results. Today, we summarize it as a theoretical method of analyzing problems. In the future work, we will use this method to analyze and solve problems. It must be applied systematically and scientifically to play its role.
I think what I should say is, of course, Simplified and Traditional may not be the case, but it can only be done, because it can not be called "theory", so you need more practice, you may be easier to master from practice. it.