What causes parts not to fit after painting? Film thickness and masking.
After painting, the pin does not fit into the hole and does not fit into the corresponding part. The cause is the thickness of the paint film. This explains the masking and film thickness that should be specified in the drawings.
Before painting, there were no issues, but after painting, the parts do not fit. Did you notice this for the first time on the assembly line and are you in a hurry? 【First, please check here】 □ Pins or bolts do not fit into the holes → The inner sides of the holes have paint film, reducing the diameter □ Only the fitting surfaces are tight → The fitting areas were not masked □ Depending on the lot, some fit and some do not → There is a large variation in film thickness 【Why does this happen?】 The diameter of the holes becomes smaller by twice the thickness of the paint film. Even a slight thickness can affect parts where fitting precision is critical. 【Countermeasures you can implement starting today】 1. Indicate the masking surfaces and holes on the drawings 2. Specify the upper limit of film thickness with numbers 3. Confirm the fit with actual parts in the first lot 【Free materials】 We have compiled the management standards for film thickness and masking in the related catalog "Eiwa Kogei_Paint Quality Control Guidelines_Process Management Standards." You can download it for free from this page.
- Company：永和工芸
- Price：Other
