The surface of the plastic moulding exhibits different levels of gloss even though the mould surface finish is uniform.
1. Experiment with increasing the mould temperature.
2. Increase the melt temperature.
3. Increase the hold pressure.
4. Check and optimise hold time.
5. Optimise the point at which the changeover to hold pressure is made.
6. Optimise the injection rate.
7. Improve consistency of the melt by increasing the back-pressure and / or screw speed.