Analysis of material and process problems affecting the quality of steel drums (5)

Eight, bottom cover molding and pre-rolling process issues

The quality problems that often occur in the production process of the bottom cover include: stretch cracking, punching and flanging cracks, cover depth or edge width error, barrel mouth pieces pressing and loosening, pre-rolling edge poor, uneven glue injection and the like.

1, the tensile crack

Tensile cracking generally occurs at the bottom edge of the bottom of the bottom of the barrel, and there are three reasons: First, the material has poor tensile properties, low plasticity, high hardness, and high brittleness; Second, the error or gap occurs after the wear of the tensile dies. Unequal; Third, the material is too thick, so that the mold gap is relatively small.

Stretched and cracked parts can not be repaired, can only be treated as waste, but in actual production, such parts often do not appear in batches, mass production is sometimes difficult to find, once entered the subsequent sealing process after the formation of the finished product With the waste, the loss will increase. Therefore, it is generally required to conduct a serious fixed-point inspection in this process.

2, punching edge cracking

In the case of punching and burring for the locking of the mouthpieces, there is also a phenomenon of flanging. This is mostly due to mold problems, and partly due to the brittleness of raw materials. The punching and flanging cracks buried the hidden dangers in the locking process of the next barrel mouth piece, and the quality problem of leakage at the barrel mouth may occur.

3, bottom depth and edge width difference

In the process of bottom cover type of the bucket, sometimes the bottom depth and side width are out of tolerance. In most cases, these two conditions occur simultaneously because the blanking size has been determined before molding, if the cover depth after molding is insufficient, the process requirements The edge width must be very wide; if the lid depth exceeds the process requirements, the lid edge size will become narrow.

When the width is too wide, the pre-roll may be curled too much or the width of the pre-roll may be too wide. When the seal is assembled, the bottom cover is easily reeled and the barrel is poor in tolerance, resulting in false seven. Layer curling.

If the side width is too narrow, there may be a defect that the pre-rolling is not in place or the side width is insufficient after the pre-rolling. When the sealing assembly is performed, the edge of the bottom cover may not contain the barrel flange, thereby causing a false roll phenomenon.

4, the wire is too loose

When the tubing mouth ring is pressed together, looseness may sometimes occur. This is due to insufficient pressure in the mold or wear of the mold. Under normal circumstances, the press can be adjusted or the mold can be repaired. Pressing too loosely will cause leakage at the barrel mouth, and it cannot be repaired after the seal assembly. Therefore, regular and detailed inspection is required.

5, bottom cover pre-rolling margin

The pre-rolling of the bottom cover of the drum sometimes produces an out-of-tolerance phenomenon. No matter what kind of error occurs in the crimped part, it will produce a bad crimping effect in the sealing assembly. A variety of hemming defects are generated, so it cannot be ignored.

6, pre-roll injection problems

Generally, during the pre-crimping process, the plastic injection is performed at the same time. The plastic injection is used to add a flexible plastic filler in the crimping seal to facilitate the curling and sealing. The general process requires that the plastic injection be uniform and sufficient. If it is not reached, it will definitely affect the sealing performance of the crimp.

In addition, in actual production, some companies often carry out the process of undercutting and crimping under the condition that the pre-rolling glue has not been solidified. This means that a serious leakage risk is buried, because when the wet glue is involved in the sealing, The internal glue is in a sealed container that is relatively isolated from the air, and it is difficult to be cured. When the steel drum is bumped during use, the sealant will lose its sealing effect and leak. We once carried out drop tests on finished steel drums separated by one year. It is found here that there is still white liquid glue flowing out in the leakage.

The above analysis of the main technical issues affecting the quality of steel drums has been systematically analyzed. From this we can see that each process quality issue is related to each other, mutual constraints, and mutual influence. Therefore, to make the final steel drum product fully qualified and stable in quality, it is necessary to conduct detailed research and control of the interrelationship between the processes. This is not easy to achieve in the traditional quality management, but fortunately, ISO9000 The quality assurance system has provided us with a scientific working platform, which has guaranteed the quality of the steel drum in a real sense. With the help of ISO9000 quality assurance system, we have scientifically controlled all aspects of steel drums from procurement, design, production, sales, etc., in order to straighten out the relationship between various links and processes, and to drive the management of the entire enterprise to become standardized, scientific, and modern. This will enable the company to achieve an efficient, conscious, and rigorous management system, and achieving low cost and high efficiency is not a dream.