精密注塑成型是指注塑制品的外型精度应满足严格的尺寸公差、形位公差和表面粗糙度。要进行精密注塑必须有许多相关的条件，而最本质的是塑料材料、注塑模具、注塑工艺和注塑设备这四项基本因素。设计塑料制品时，应首先选定工程塑料材料，而能进行精密注塑的工程塑料又必须选用那些力学性能高、尺寸稳定、抗蠕变性能好、耐环境应力开裂的材料。其次应根据所选择的塑料材料、成品尺寸精度、件重、质量要求以及预想的模具结构选用适用的注塑机。
Precision injection molding means that the external precision of injection products should meet strict dimensional tolerance, geometric tolerance and surface roughness. In order to carry out precision injection molding, there must be many related conditions, and the most essential are four basic factors: plastic material, injection mold, injection process and injection equipment. In the design of plastic products, engineering plastic materials should be selected first, and those materials with high mechanical properties, stable size, good creep resistance and environmental stress cracking resistance must be selected for engineering plastics that can be used for precision injection molding. Secondly, the suitable injection molding machine should be selected according to the selected plastic material, finished product size accuracy, part weight, quality requirements and expected mold structure.