What causes the paint to chip only at the corners of the parts? Film thickness and overbaking.
While the flat surfaces are fine, only the paint film on the corners and edges is chipped, revealing the substrate. This explains the causes of chipping concentrated at the corners and how to identify it.
After assembly and transportation, the paint is chipped only at the corners of the parts. Although the flat surfaces are clean, why is it only the corners? 【First, please look here】 □ The paint film at the chipped area is thick and raised. → The paint accumulates at the corners, making the film too thick. □ The chipped fragments are hard and break off sharply. → The paint film has become brittle due to overbaking. □ The base material is cleanly visible from the chipped area. → The pretreatment is weak, and there is insufficient adhesion to the base material. 【Why does it concentrate on the corners?】 Corners are places where objects are likely to hit, and force is concentrated at a single point. If there is a film that is too thick or brittle there, even a small impact can cause chipping. 【Countermeasures that can be implemented from today】 1. Specify corner chamfering in the drawings. 2. Measure the film thickness at the corners and set an upper limit. 3. Check the records of baking temperature and time. 【Free Materials】 We have compiled a guide on how to identify painting troubles, including chipping, in the related catalog "Eiwa Kogei_Painting Trouble Introduction_Identification and Countermeasure Guide." It can be downloaded for free from this page.
basic information
Defect type: Chipping (corner chipping). How to identify: Bumpiness, hardness of fragments, appearance of the base material. Management items: Beveling, film thickness at corners, baking temperature and time, pretreatment.
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Applications/Examples of results
Metal parts, frames, and brackets that are prone to chipping during assembly and transportation. Quality assurance personnel's defect analysis, establishment of appearance inspection standards, and training materials for new employees.
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We are not just a "subcontracted painting factory." Established in 1958, our company has a foundation of painting technology and also specializes in chemical treatment, stripping, and cleaning, functioning as the "external surface treatment department" in your organizational chart. Based on our philosophy of "preparation is eight-tenths of the work," we emphasize participation from the "upstream process" before the drawings are finalized. We conduct test painting on a wide range of metals and difficult materials, and we produce the entire process from assembly, packaging, to delivery, thereby reducing your management workload. Additionally, by being able to perform zinc phosphate treatment in-house, we achieve stable painting quality. Furthermore, our micro-heating stripping technology, which does not use chemicals, maintains the electrical state of the "jigs (hangers)" that influence painting quality. Our approach of "pre-treatment determines painting quality" ensures the stability of the paint film during mass production. Rather than simply "applying specified standards," we work backwards to achieve optimal painting specifications and prevent scratches during transportation, sparing no effort in thorough discussions from the outset. This diligent preparation is the shortest path to preventing rework and minimizing total costs. From the development stage, please utilize the expertise of our specialists as part of your production line.