Key Word: Taili Plastic Machinery; Taili Plastic Machinery-Capacity Improving Expert; Efficient; Stable; Internal Stress
Mr. Liao’s plastic factory has been providing substitute processing service for a large brand of plastic parts for more than ten years. His products are generally used in the famous brand’s electronic and mechanical products, and have been trusted by the brand side for its high quality and timely delivery. Recently, however, Mr. Liao was troubled by the fact that a batch of injection molded parts made of ABS materials were returned in large quantities by the brand side. Because the physical strength of the parts used for the key parts did not meet the expectation as they easily got broken.
Mr. Liao is also puzzled. He is a person who attaches great importance to quality and never easily changes materials, processes and injection molding machines. Thus, it’s really confusing that this batch of products can’t pass the mechanical test. So he contacted us on Wechat, hoping that we could help him find the problem.
After a close look at the products provided by Mr. Liao, we find that His products are common metal inserts in mechanical products. Due to the large difference of thermal expansion factors between metal surface and plastic raw materials, the phenomenon of "internal stress" concentration is relatively easy to occur. Therefore, under the premise of no significant change in raw materials, the "internal stress" not properly eliminated should be considered as the reason that the mechanical properties of products are greatly reduced.
In view of Mr. Liao's problems, we have proposed following three aspects that should be considered.
1. Preheat the metal insert
The preheating of metal insert can improve the surface temperature of metal, reduce the temperature difference between the melted plastic raw material and the metal surface as much as possible, so as to reduce the internal stress.
2. Heat treatment
Put the produced products in the air oven for heat treatment to reduce the internal stress of the products. The temperature of ABS materials is generally 65-75 ℃.
3. Parameter adjustment of injection molding machine
Reduced the injection pressure and holding pressure as much as possible. Use the mold temperature machine to reduce the internal stress of the product. Adopt the multi-stage injection for the product, so as to ensure that the ABS raw material can maintain a relatively uniform speed into the mold with different wall thickness.
Taili Plastic Machinery always keeps in mind that what a good injection molding machine factory should do is to help improving the capacity and boosting the profits, rather than offer the similar products the customers need. This is also what Taili Plastic Machinery keeps doing.
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