What causes the paint film to blister a few days later? Management of wash water.
There was no problem at the time of shipment, but a few days later, the paint film swells like blisters. The cause is the salt remaining in the washing water from the pretreatment.
The shipping inspection passed, but a few days later, the paint film started to swell. If found in the customer's warehouse, it will become an issue for the entire lot. ────────────── ■Cause of Occurrence If the pre-treatment rinsing is insufficient, the salt from the chemicals remains on the surface of the material. When painted over, moisture that passes through the paint film is attracted to the salt. ■Truth Water gathers around the salt, pushing the paint film up from the inside. This results in blister-like swelling. Since it is not noticeable immediately after painting, it cannot be detected during the shipping inspection. ■Improvement Measures Since the final rinsing water is prone to contamination, we will measure and manage its conductivity daily. We will set numerical standards for water replacement and keep records. After rinsing, we will immediately drain and dry to ensure no moisture remains on the surface of the material. Eiwa Kogei handles everything from zinc phosphate chemical coating to baked painting. Please download and utilize the materials summarizing the confirmation points of the process.
basic information
Defect: Blistering. Management items: Conductivity of final rinse water, water replacement criteria, draining and drying, humidity.
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Applications/Examples of results
Powder coating of steel plate parts, automotive parts, and metal products used outdoors. Market defect analysis by the quality assurance department, process audits of painting subcontractors, 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.