Heat Treatment Problem with Plastic Injection Mould

Update:06-05-2019
Summary:

It is usually carried out after the plastic mold is rou […]

It is usually carried out after the plastic mold is roughed, after heat treated do the precision work. However, there are risks in the process of treatment. Improper handling will cause cracks in The steel, resulting in scrapping.

What causes the mold steel to be abnormal:

1) There is severe network carbide segregation in the mold material.

2) There are machining or cold plastic stresses in the plastic mould.

3) Improper heat treatment of the plastic mould (heating or cooling too fast, improper selection of quenching cooling medium, cooling temperature is too low, cooling time is too long, etc.).

4) The shape of the mold is complicated, the thickness is uneven, the sharp corners and the thin threaded holes are used, so that the thermal stress and the structural stress remain excessive.

5) When the plastic mould is quenched, the heating temperature is too high to cause overheating.

6) The tempering of the mold after quenching is not timely or the tempering holding time is insufficient.

7) When the plastic mold is repaired and quenched, it is heated and quenched without intermediate annealing.

8) Improper grinding process for mold heat treatment.

9) During the electrical discharge machining of the mold after heat treatment, there are high tensile stresses and microcracks in the hardened layer.