Discussion on Process Interactive Influence Analysis Method of Steel Drum Quality

In July this year, I held a seminar on new national standards and technics for steel drums and seminars on promotion of quality certification. I participated as a technical expert in this conference and gave technical seminars for delegates. At the meeting, I first proposed a new method for quality analysis. This is the “Process Interaction Analysis Method” and used this method to analyze the material, process, and operation methods that affect the quality of steel drums. The colleagues said: "I was inspired!".
After the meeting, many people in the industry wrote a letter asking for a speech. However, I was very clear in my mind that the "artificial interaction influence analysis method" in the lecture did not give a detailed explanation. It was also difficult to grasp this analysis method through lecture notes. However, this method is exactly what everyone is interested in. This problem was reflected during the meeting. A technician from Guangdong said to me: "There are many problems with the quality of our steel drum manufacturers. Although there are many common problems, the problems are not the same. Its particularity. We hope that you teach us ways to analyze problems. We can gradually analyze and solve problems when we meet them." To solve this problem, when I lectured on the second day of the conference, I explained in detail how to use Process interaction analysis method to analyze the actual problems in production.
Actually, this "process interactive influence analysis method" is my fabrication. In the long-term technology and production practice, I gradually formed my own method of analyzing problems, but I never noticed that it could become a "doctrine" or "theory." "So, theoretically, it is not yet mature. For this reason, I didn't specifically talk about it. I used specific examples to illustrate its usage. Today, everybody "forces" me to give a theory, and I try to form a theory. As long as everyone understands it, it means that I have made it clear.
One time I went to a seminar in a foreign country to give lectures to a technical training class. A university student working in the local area came to visit me and said to me in disbelief: "That's your bucket, that bucket! Which technology?" The meaning of steel drums is a very simple thing, there is no technology. Of course, I was very angry. I said, "If you only do one or a few steel drums, you may not want any technology. If you have a good craftsman, you can do it. Maybe he may also be beautiful and beautiful. But it must be produced in large quantities. Steel drums, but also to ensure product quality, only * craftsmen do not work, which requires technology!" The old classmates smiled and said: "Don't be so hot, I was joke with you ...." In fact, in our barrel industry Internally, there are not many people who think that steel drums do not require technology. This has caused our drums to have poor quality, high cost, and low quality. When I first came into contact with steel drums after graduating from college, I also had this feeling, but after many years of work and practice, I proved that my original idea was wrong. The steel drums not only had technology, but also involved a wide range of technologies!
The 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 decoiling and leveling process of steel plates belongs to rolling steel shaping technology; the process of grinding or milling steel plate (usually called edging or milling) belongs to the metal cutting technology; the barrel body is rolled round and flanging and The ribs and other processes belong to the plastic deformation cold processing technology of metal materials; spot welding and seam welding processes belong to the welding technology of metal materials; the steel drum crimp sealing process penetrates the essence of sealing technology and the plastic deformation of the metal material cold processing technology Application; barrel bottom and barrel mouth and other production processes are cold stamping technology; barrel body degreasing and rust removal process, belong to the chemical surface treatment technology; steel barrel surface various methods of painting is a metal surface coating technology; The drying process of the coating film belongs to far-infrared heating technology and other heating technologies; the pattern production on the finished steel drum belongs to the category of printing technology, etc.. Among them, rolling technology, forging technology, and hydraulic transmission technology are also used. , pneumatic transmission technology, expansion technology, automation control technology. Therefore, the barrel making technique is not a separate subject. To master it, we must relax our eyes and study it carefully.
The technical problems affecting the quality of steel drums are numerous. If they are searched and analyzed separately, they will only see the trees not seeing the forest, which is not conducive to the solution of the problem. Through long-term practice and research in the steel barrel industry from technology to production, we have found that these technologies and processes are intrinsically related to each other. They influence each other, are unified, and are interconnected. Therefore, we must conduct a full range of interactive analysis. Only in this way can we find the essence of the quality problem and achieve the unification of technology, process, and quality.
Using the "process interaction analysis method" to analyze the problem, we can see the impact of each process on the quality of the steel drum production process, how it affects, and how it can not affect or reduce the impact. Because most of the process problems may not affect the quality of the final product at first glance, the analysis using the “cross-impact analysis method” will find that it may have a certain impact on other processes, thus affecting the final product quality. .
So, what exactly is the process interaction analysis?
We know that there are dozens of processes in the steel drum production process, and there is only one final product, and these processes all work on the same product, and there must be mutual influence between the processes. However, sometimes it is difficult to find this factor. The quality of the final product has become a problem. But what exactly is the problem? Different people or different methods of analysis may produce different results. But the correct answer is always only one!
The analysis of the interaction effects of the process means that it is "successful". The following steps can be used for analysis.
First, start with the phenomenon of the quality of finished products, and avoid underground conclusions prematurely. Let's look at the several processes that may be responsible for the cause of the quality problem. If you are not sure, you may want to include a few more processes. When the problem is more complex, you can include all of them. Of course, the included procedures should be the top-level ones, because "sweeping melons" cannot be touched by melons, or else some of the major problems may be missed. For example, it was found that seam welding of steel drums and leakage in the triangle area of ​​the envelops were the first steps that were directly included in the analysis. This was definitely a curling process, not a painting process, because the painting could not make the area seep. Leakage; can not be directly into the seam welding process, because the seam welding process and the sealing process farther apart, not its upper layer. But it is also one of the factors that may affect the quality of the seal, not the only one. If the seam welding process is directly incorporated, it may be possible to ignore or dilute other factors and possibly miss the true cause. For the convenience of narrative, we refer to this included process as the "A" process.
Second, we must include the process to be analyzed. We must carry out this process, and the actual implementation is a further step. The direct process that affects the quality of this process must be fully incorporated and fully listed. Paying attention to this direct meaning is to directly produce the process of this process, and the indirect production process should not be expanded here. For example, the unfolding process of steel drums, the direct process of the barrel body flanging, bottom of the barrel, the top pre-crimping, coating and so on. The seam welding, bottom lids, and top lids are all indirect processes that cannot be developed here. This unfolding process we call "B" process and "C" process.
Third, the analysis of the process for the direct start, start the analysis, the main work of the analysis is to measure, that is, in accordance with the requirements of the process documentation, testing the products of these processes are qualified. This is actually a process of row-touching. For the inspection of qualified processes, we have calibrated them and the next step is no longer unfolding. For the unqualified processes after detection, we must further analyze them.
There are two steps to further analysis:
The first step is to analyze the five links “people, machine, material, law, and ring” to see if there are any problems in these areas. If something goes wrong, we will first solve this problem. After the problem is solved, the process test is performed. If the problem is indeed solved, it means that it is the cause of the process. According to this method, all problematic links are analyzed, and problems are solved and verified through process tests until these problems are resolved. For example, when the problem of the "B" process has been solved, the analysis of this process will stop here and will not be expanded. If the problems "B" and "C" of all the open processes have been resolved, we will return to the "A" process to conduct the process test. Under normal circumstances, the problem of the "A" process is resolved at this time. In this way, our quality analysis will end here. But if there is one, such as "C" process still has problems in the analysis process, and can not be resolved during the process, then we must go to the next step.
The second step is to further include, for example, the “C” process still has problems. We will further incorporate the processes that affect its quality according to the above methods. For example, the "C" process is a flanging process. We will incorporate the seam welding process of the previous layer for further development and analysis. We call this process a "D" process.
4. The process of incorporation, development and analysis of the process is the same as the above steps. The practices are similar, but the content is different. For all the relevant processes, from the back to the front of the investigation and negation, will eventually find the real problem. Sometimes, there may be more than one process problem affecting the final quality. This is a concentrated reflection of many problems. Only by using this “demining” approach can we solve all problems. Otherwise, the problem may not be completely resolved, and some problems will be solved. appearing again. When solving a process problem, you must return to the previous process to verify that the root cause of the problem is actually found. When the verification is affirmed, the analysis process can be completed. Otherwise, it must be chased until it is resolved. So far.
Process interaction influence means that the factors that affect the quality of the process do not necessarily appear in this process, but may appear in another process, but in the analysis of another process, it may be found that the process that affects it may be another process. For example, there is a problem of cracking in the flanging. It will definitely affect the quality of the curling. However, the cause of the cracking may be the quality of the seam welding process, or the quality of the milling process, and it may be the cutting of the material. The quality of the process, and then proceeding further, may also be the quality of raw materials and so on. To accurately find out the real problem, only subjective judgment is not enough, nor can we only experience, we must carry out scientific analysis and investigation. If not, we may not find the real problem. In practice, sometimes the cause of the problem is unexpected, so it is often mistaken.
Fortunately, the process of making our barrels is not very complicated, and analysis does not take much trouble. In practice, many of the complex analysis processes discussed above are actually very easy to implement, because everyone is familiar with these processes and equipment, and sometimes it takes a little consideration and observation to complete the analysis process.
The five factors “people, machines, materials, methods, and rings” that are included in the analysis are common methods for analyzing quality problems. Here is a brief explanation as follows.
“Person” refers to the quality of the operatives, their proficiency, their sense of responsibility, their mood and so on. For example, if a person works overtime for more than ten hours, he or she may lack energy or have a bad mood. This may affect the quality of his work and affect the quality of the product.
"Machine" refers to the operating status of the equipment, whether there is a fault, 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 seaming machine wears, and the forming curve changes. This will make the crimping process unable to meet the process requirements, resulting in quality problems;
"Material" means whether the quality of the raw materials used in this process is acceptable, whether it can meet the process requirements, whether quality inspections have been carried out, etc. For example, the carbon content of steel drum raw materials is too high, the steel plate itself becomes brittle and cracks are easily generated, so it will affect the quality problems of the downstream processes;
The "law" refers to whether the method of operation is correct, and whether the process route is reasonable. For example, some manufacturers apply glue to the curling edge during the roll-sealing process. There is a timing problem here. The correct method of operation is to apply glue before the curling is started, so that the glue liquid will be rolled into the curling edge to form a The sealing ring, so that the seal is achieved, but if the curling has begun or will be sprayed at the end of the seal, the sealing effect will obviously not be achieved.
The "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, a lot of water is sprayed on the floor by workers in order to cool them, causing a lot of rust on the barrels. This is the environmental impact. There are many examples.
When systematically analyzing various factors such as "human, machine, material, law, and ring", we must not ignore any small links. This is actually the so-called "carpet-style" investigation and analysis. Generally speaking, it will be able to achieve perfect results. This analysis process is the basic function of quality analysis. It must be fully mastered and skillfully applied in order to lay a solid foundation for good process interaction analysis. It can also be said that it is the basis of process interaction analysis.
Now, we should have some understanding of the “process interaction analysis method”. I think the essence here is the word “interaction”. The above analysis does not reflect the essence of the two words. In fact, it is reflected in Throughout the process. Because each process has its own role and connection with each other, it is impossible that all problems can independently affect other processes. Therefore, by using this analysis method, their relations and influences can be easily cleared. For example, due to the high carbon content of raw materials, brittleness and hardness increase, which will result in poor processing performance, it will affect the quality of the process of many processes in the later, it will greatly reduce the strength of the weld, which will make the barrel Cracks occur during the flanging process, and cracks or cracks also occur during the process of bulging, and then the quality of the leakage due to internal cracks in the crimping seal; in addition, the bottom of the barrel is also caused. During the top-stretch molding, cracking occurs, and cracks may also occur in the barrel flange and crimping processes. These will cause serious quality problems in the final product.
Therefore, the interaction effect is the process of inheritance of a problem. Like an infectious disease, it will go through a process and then a process to “contagion.” The cross-impact analysis method not only needs to find the source of the “communicable disease” but also eliminates the “infection.” The impact of the disease until it is completely eliminated.
In practice, we have intentionally or unintentionally used this method to analyze the problem, but we have not raised it to the height of the theory, and have summarized and applied it. Therefore, when used, most of them are not systematic and comprehensive, and often do not work well. Today, we have summarized it as a method of theoretical analysis. In the future work, we will use this method to analyze problems and solve problems. It must be applied systematically and scientifically in order to play its role.
I think all I have to say is, of course, may be inappropriate, but it can only be this, because it can not be called "theory", so you also need more practice, from practice you may be more easily mastered it.