Dalian injection molding is produced on suitable equipment, and the scrap rate can be controlled below 0.5%. Production efficiency is directly related to the economic benefits of the factory. On the premise of ensuring low scrap rate, the purpose of improving economic benefits is achieved through the preparation of forming process. Generally, according to the type of products, the process personnel in the injection molding plant formulate a unified process file format, and compile the process procedures of products through the correct molding process programming to guide the production.
Trial production and commissioning, set the drying process, barrel temperature, mold temperature and heat the equipment according to the material performance parameters; Set forming time, pressure and other parameters according to similar products; Set the mold opening and closing limit and ejection mode according to the mold thickness and structure. The opening and closing stroke shall be reasonable, the speed shall be scientific and appropriate, and the ejection speed, pressure and stroke shall meet the product requirements. Core pulling in place, stable and reliable.
The time, pressure and speed meet the forming requirements. Further revision of parameters. If two pieces of waste products occur continuously in the production process, the process shall be revised in time, and the influencing factors shall be recorded and included in the production operation essentials. The operation shall include: possible or existing defects in product production and relative policies taken; Essential operation requirements for normal production of products, such as treatment methods for product defects, no shutdown during shift handover, etc.
During production, shift change and shutdown will cause great waste. When the parts are placed at an appropriate angle under the light and observed with the naked eye, it can be found that there are obvious bonding lines, which is the formation mechanism of fusion marks. Weld marks not only affect the appearance of plastic parts, but also cause stress concentration due to the loose microstructure, which reduces the strength of this part and breaks.
In the later stage of pressure maintaining, the material density continues to increase and the plastic parts are gradually formed. The pressure maintaining stage should continue until the gate is cured and sealed. At this time, the mold cavity pressure in the pressure maintaining stage reaches a high value. In the pressure maintaining stage, the plastic presents partial compressibility due to the high pressure., After demoulding, the deformation of plastic products due to external force can be avoided. Because the cooling time accounts for about 70% ~ 80% of the whole molding cycle, a well-designed cooling system can greatly shorten the molding time, improve the injection molding productivity and reduce the cost. The cooling time accounts for a significant proportion, about 70% ~ 80%. Therefore, the cooling time will directly affect the molding cycle and output of plastic products.
