Paint, plating, bonding, printing, and other surface finishes should be specified together with the molded substrate. The result depends on the resin grade, additives and color, molded surface condition, finish supplier, preparation method, and intended use. A finish name alone does not define adhesion, appearance, durability, or fit.
1. Define the finish and the use conditions
Describe the required color, gloss or texture, coverage, visible zones, handling, cleaning, temperature, chemical exposure, and expected service conditions. Identify areas that must remain uncoated, such as mating surfaces, threads, electrical contacts, or assembly features. State whether the finish is decorative, functional, or both.
2. Confirm resin and finish compatibility
Provide the exact resin supplier and grade, color, additives, and any permitted alternatives to the finishing supplier. Ask what evidence supports compatibility with the proposed preparation and coating system. Do not select a solvent, acid, primer, or activation treatment from a generic article; chemical compatibility and safe use depend on the actual material and controlled process.
Material-maker references such as Covestro’s painting, plating, and decorating guidance discuss thermoplastic finishing considerations. Confirm that any external recommendation applies to the selected grade and current finishing process.
3. Put acceptance criteria in the drawing or specification
Define the acceptable appearance, coverage boundaries, finish thickness if it affects fit, critical interfaces, and sample approval method. Agree on the adhesion or durability test, test conditions, sample count, and pass criteria with the customer and finishing supplier. Avoid relying on descriptions such as “strong adhesion” or “high quality” without a defined evaluation.
4. Validate representative samples
Use parts molded from the intended grade and color, with the representative surface texture and geometry. Review cosmetic appearance and the specified adhesion or durability evidence on production-representative samples. If the resin, color, texture, mold surface, preparation process, or coating changes, assess whether the previous approval remains applicable.
5. Control the supplier handoff
- Record the resin grade, color, molded-part revision, and finishing specification.
- Mark cosmetic zones, protected surfaces, and dimensions that the finish could affect.
- Identify the approved finishing supplier and the agreed test method and acceptance criteria.
- Keep sample approvals, process changes, and nonconformance records linked to the part revision.
For the upstream design review, see DAYIN’s hướng dẫn thiết kế sản phẩm đúc phun. For manufacturing scope and project discussion, visit the đúc phun tùy chỉnh hoặc send the material and finish requirements to DAYIN.