SMD bearing belt manufacturer

What are the main factors affecting carrier tape injection molding failures?

When designing plastic products, the first step is to select engineering plastic materials. Engineering plastics suitable for precision injection molding must be those with high mechanical properties, dimensional stability, good creep resistance, and resistance to environmental stress cracking. Secondly, a suitable injection molding machine should be selected based on the chosen plastic material, the dimensional accuracy of the finished product, the weight of the part, quality requirements, and the intended mold structure. During processing, the main factors affecting precision injection molded products are the mold's accuracy, injection shrinkage, and variations in ambient temperature and humidity.

In carrier tape injection molding, the mold is one of the key components for obtaining carrier tape plastic products that meet quality requirements. The mold used for carrier tape injection molding should precisely meet the requirements for product dimensions, accuracy, and shape. However, even if the mold's accuracy and dimensions are consistent, the actual dimensions of the molded plastic products will vary due to differences in shrinkage. Therefore, effectively controlling the shrinkage rate of plastic products is crucial in precision injection molding technology.

The design of the mold for the support belt directly affects the shrinkage rate of plastic products. The mold cavity dimensions are derived by adding the estimated shrinkage rate to the dimensions of the plastic product. The shrinkage rate, in turn, is a value within a range recommended by the plastic manufacturer or engineering plastics handbook. It is related not only to the gate type, gate location, and distribution, but also to the crystal orientation (anisotropy) of the engineering plastic, the shape and size of the plastic product, and its distance and location from the gate.

The main factors affecting the shrinkage rate of plastics include thermal shrinkage, phase change shrinkage, orientation shrinkage, compression shrinkage, and elastic recovery. These influencing factors are related to the molding conditions or operating conditions of precision injection molded products.