Key Word: Taili Plastic Machinery; Taili Plastic Machinery-Capacity Improving Expert; Efficient; Stable; Injection Guide; Shrinkage Rate
Mr. Li of Chongqing is a manufactures of PC products, who mainly produces the outer shell of various precision instruments, such as meters, measurers, spectrometers, etc.
Recently, a famous integrated cooker manufacturer in China connected Mr. Li in Chongqing, asking him to produce injection molded light guide plates for lighting. But they had high requirements for the products. In addition to the most basic optical requirements, such as no yellowing, no weld marks and no shooting lines, the products are required to be measured in a constant temperature chamber with temperature of 23 ℃ and humidity of 50% after 48 hours of cooling. The shrinkage scale shall not exceed 0.1mm and the radial length shrinkage rate shall not exceed 0.5mm. Mr. Li is a bit tangled: “the profit of this order is really high, but I don't know if I can do it?”

Mr. Li took the product to Taili Plastic Machinery and asked for our suggestions. In fact, for this kind of products with shrinkage requirements, and the mold is provided by customer, the following aspects can be considered if he wants to finish the order well.
1. Raw Materials
If you want to reduce the shrinkage of reinforced PC products, you can consider increasing the proportion of reinforced front position to reduce the internal stress. At the same time, you can add a small amount of nucleating agent in raw materials to reduce the impact of internal stress on the dimensional accuracy of products.
2．Injection Process
In order to reduce the shrinkage of the product, we must keep on to several requirements in the process of injection: reduce the barrel temperature, reduce the injection pressure and carry out multi-stage injection. We should also ensure the injection speed as high as possible in the process of filling the mold cavity and control the holding pressure. The pressure should not be too high, the time should not be too long.
The shrinkage of the product is mostly caused by the cooling stress of the product, so in the process of debugging, try to reduce the cooling stress of the product. As the orientation stress of the product is mostly related to the strength of the product. In the case of low strength requirement, the effect of process on orientation stress can be ignored.
3．Mold
Generally, mold temperature machine can be used to manufacture the products with requirements for surface accuracy and shrinkage rate. Generally, the lower the mold temperature is, the faster the temperature decreases, the heavier the product weight is, the worse the product accuracy is, and the more difficult the production will be.
With our suggestions, Mr. Li got it successfully and the product he produced passed the test smoothly.
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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