Generally, two materials, PC and ABS, can be used in the processing of mechanical plastic shell. PC and ABS have certain compatibility. However, the compatibility of PC and ABS is greatly influenced by the model, ratio and processing technology of the two components. In order to improve the interfacial compatibility, compatibilizer is added into the blending system.

The PC/ABS alloy used in the processing of small mechanical plastic shell can combine the excellent properties of both. On the one hand, it improves the heat resistance and tensile strength of ABS; on the other hand, it reduces the melt viscosity of PC, improves the processing performance, and reduces the sensitivity of internal stress and impact strength to product thickness.

In addition, modified PBT material is also possible, suitable for connectors, switch parts, household appliances, spare parts, small electric caps, auto parts and mechanical equipment. However, although ABS is widely used, it does not have advantages in toughness and strength. Of course, there are still price advantages. Small machinery plastic shell processing generally want to compare prices.

During the thermoforming process of mechanical plastic shell, some polymer sheets undergo orientation and crystallization processes, which often affect the quality of the molded parts. For example, when forming amorphous polymer plexiglass, the molecular chain will be oriented along the direction of forming action. At this time, if the forming temperature is too low, high internal stress will remain in the oriented structure, which is prone to biochemical stress cracking.

For crystalline polymer or semi-crystalline polymer materials, the crystallinity, crystal size, density, transparency, tensile strength, impact toughness and other properties required by the products can be adjusted by changing the forming conditions. In general, it is easy to generate incomplete and less crystal structure during rapid cooling. Plastic products have better transparency but lower strength and stiffness. The crystal growth is more complete, the strength and stiffness are higher, but the transparency and impact resistance are lower.