The key fundamental reasons for the poor precision of the injection molded parts are: the problems in the precision of stamping dies and manufacturing. The forming process standards have caused a great change in the collection of handicrafts. The handicrafts caused by forming raw materials are not stable and balanced. Changes over time caused by natural environmental standards.
- 1. The manufacturing precision of each part of the injection mold will immediately adversely affect the specification precision of the crafts. The fitting of the fixed mold and the movable mold, the specific location of the clinical diagnosis surface, the structure of the side male mold, etc. will all cause the error value of the craft specifications. Long-term application of injection molds will cause deformation or slack of the injection mold due to factors such as the working pressure of the die and the amount of material locked. When designing the injection mold for the solution, the compressive strength and tempering treatment of the metal material must be considered.
- 2. The shrinkage of injection parts is caused by the relative density change of the solution when the plastic is cooled from the forming temperature to the working temperature. It is not only related to the conversion of the forming temperature, but also related to the restraint of the production (the specific location of the core and insert, etc.) ). When designing injection molds for plastic mold design staff, they must fully consider the adverse effects of processing technology standards and the personal behavior of raw materials, and fully consider the design scheme of the refrigeration system, the geometry of the flow channel and the inlet, etc. The pouring system software should be upgraded to ensure stable and balanced swimming to prevent uneven gathering caused by over-voltage and under-voltage; for multi-cavity injection molds, the die layout should also be increased to ensure the thermal balance of the injection mold system software temperature and enhance the convexity The design of the cooling water circuit of the mold and the concave mold to ensure the uniform temperature of the mold.
- 3. The change over time caused by natural environmental standards is the change in the specifications of the handicrafts after the shaped handicrafts are placed in the atmosphere for several days. The key is caused by the following root causes: working temperature, crystallization after forming, relaxation of residual stress, etc. The above-mentioned working temperature transition, crystallization transition and the specification transition caused by residual stress are all related to time, and generally stabilize after about 10 days. These transformations must be fully considered when designing solutions for high-precision specification crafts.
