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Analysis of common problems in stamping
Analysis of common problems in stamping forming Stamping forming is a new molding method used in the production of daily-use ceramics in the United States in the 1970s. With the recent market competition, many manufacturers have begun to use stamping technology, but in use. In the process, I often encounter some problems, the main performances are as follows:
First, the split mode
1。 There is a problem with the quality of the gypsum, even without using professional stamping gypsum or using some unstable gypsum。
2. The molding process is not correct. The pumping rate and stirring speed of the vacuum gypsum machine will affect the mechanical strength of the gypsum mold.
3. The moisture content of the mud cake is too low, and the mud cake is too hard to cause the plaster mold to rupture.
4, the shape of the mold frame causes cracking, many companies in order to save the amount of gypsum, the rectangular disk products are also made into a rectangular frame, according to the principle of leverage, often the direction of the long side will split. Therefore, the general stamping frames are rounded.
5, the manufacturing precision of the mold frame is too poor and the steel plate too will lead to cracking, the accuracy mainly refers to the parallelism of the same roundness and plane of the mold frame, the thickness of the steel plate is generally 20~18m/m。
6. In the process of making the stone mold, there is no plaster mold on the side of the stamping die steel plate, and the plaster mold is broken.
7。 Some squares and deep-formed products are more likely to crack the bottom part of the mold。 Most of the solutions are to increase the thickness of the plaster mold or increase the moisture content of the mud cake。
Second, product cracking
1. The whole product is cracked irregularly, and it is the proportion of severe cracking when the product is dry. It is generally caused by too much molding pressure and too fast forming speed.
2. The poor ductility of the mud cake is the main cause of product cracking. To strengthen the ductility, it is often controlled from the soil formula or the fineness of the grain. Appropriate increase of water content will improve the ductility of the mud, and the moisture content of the mud will increase. It is around 24-26%.
3. Strengthen the management of the purchase of mud and the manufacturing process. If there are foreign particles in the mud or in the process of cutting the cake, the cut surface has obvious scratches, and the product tends to crack outside the particles and scratches.
4. The vacuum of the mud strip is not enough or the mud machine does not have sufficient agitation of the mud. If the mixture is evenly mixed and squeezed tightly, the product may crack. Generally, the degree of vacuum should reach 73-76HG/cm, and the mud should be 2-3 times and aged for about 3 days. When it is used, it can be used once again.
5, the product edge crack. Most of the reason is that the mud cake has poor ductility, and there is a problem with the edge shape of the mold or insufficient pressure.
6, the product in the production process, the mold contains too much water, did not dry immediately, and the product's mud edge did not tear clean, resulting in product cracking.
7。 The molding blowing time is too early。 This product will not only crack, but also have bubbles on the surface of the product。
Third, the difficulty of demoulding
1。 New molds or molds that have been on hold for a long time are difficult to demould, mostly because the mold is too dry or the air pressure is too small。
2. In the process of making the mold, the arrangement of the air pipe is uneven or unreasonable, which makes the product difficult to demould. This phenomenon can be achieved by blowing air and seeing whether the air vapor is consistent, and whether the water on the surface of the blow mold is turned off immediately. Suck back to judge.
3。 The gypsum performance is unstable, and the poor gas permeability is also the main factor causing the difficulty of demoulding。
4. The pressure regulation of the pressure regulating valve is too low, or the supply of the factory is insufficient and unstable.
5, the product shape is very deep or the shape is very complicated, it will make the product difficult to demould, generally improve the corner transition arc, or increase the ratio of the mouth and bottom size of the product.
6, the pressure holding time is too long, usually around 2-3S clock.
Fourth, product deformation
1。 The moisture content of the mud cake is too high, which is the main reason for the deformation of the product。 The general moisture content of the pressed mud cake is controlled between 22-24%。
2, the shape of the product, generally too book or square products are relatively easy to deform。
3. The deformation of the product is also related to the quality of the mud cake in the practice of mud. When practicing the mud, it is necessary to control the degree of vacuum and the number of times the mud is practiced.
4。 The stamped product has a relationship with the firing temperature and the firing curve and method。 The higher the firing temperature, the greater the deformation。
5, the soil formula can also improve the degree of product deformation, usually by changing the variety and content of plastic raw materials and alkaline materials。
6. Product deformation has a great relationship with the operation of the workers. The amount of mud and the torn edges must be strictly controlled.
In summary, in order to improve the quality of stamping products, it is necessary to carefully analyze all aspects, grasp the main contradiction of things, from the original material formula to the manufacturing process and on-site management, etc., in order to effectively improve the quality of products. And production effectiveness