Beer bottle caps are prone to paint film peeling and burr in the process of punching and injection molding production, mainly caused by poor paint film adhesion and stamping resistance. Here are some reasons to find:
1. The raw material characteristics of the tinplate material and paint itself are poor or do not meet the actual use requirements.
2. Tinplate tin layer oil layer.
After passivation, the surface of the tinned steel plate is coated with a layer of DOS oil or dioctyl grease to prevent rust during storage and friction between iron sheets during transportation. Large oil layer or uneven application will cause poor film adhesion, beer bottle cap production can be based on the situation to empty the iron sheet to bake again (150~170 °C is appropriate) and then film production.
3. The oven itself has poor performance.
Unstable furnace temperature or poor temperature uniformity are also important factors leading to poor film adhesion, which should generally be inspected every six months or one year depending on the actual production situation. When testing the furnace temperature performance, it is not difficult to see from the temperature control change curve: the furnace temperature pre-temperature zone (heating zone) with good performance should be 2~3min, the uniform temperature zone should be 12~13min and the change curve is relatively stable, and the high and low temperature difference is 3~5 °C.
