Coating-line engineers, quality teams, production managers and industrial powder buyers
Film thickness is a product and project requirement
There is no universal powder coating thickness for every formulation, color, texture, substrate or end use. Start with the exact product TDS and the governing project specification. Define the required cured-film range, permitted tolerance, measurement state, method and acceptance rule before production; do not transfer a value from another powder simply because its chemistry name is similar.
Both low and excessive film build can create problems
A film below the approved range may show poor hiding, incomplete coverage, exposed high points or insufficient barrier continuity. Excessive build can change flow, gloss, texture, flexibility, edge behavior, outgassing response or orange-peel appearance. These effects depend on the formulation and part, so more powder is not automatically better and a cosmetic surface alone does not prove conformance.
Match the measurement method to substrate and coating
The base metal and coating state determine the suitable instrument and procedure. ISO 2178 describes the magnetic method for non-magnetic coatings on magnetizable metal, while ISO 2360 describes the amplitude-sensitive eddy-current method for non-conductive coatings on non-magnetic conductive metal. ISO 2808 covers multiple wet, dry and uncured-layer approaches. Confirm the method named by the customer, product document or quality plan instead of assuming one probe fits every substrate.
Verify the gauge on a representative base
Follow the instrument instructions and the governing procedure for calibration, verification and adjustment. Substrate composition, thickness, curvature, roughness, edge distance and probe position can affect readings. Use appropriate traceable references and, when the method requires it, an uncoated base representative of the production part. Record the instrument, probe, reference, date and operator rather than relying on an undocumented zero check.
Use a sampling plan, not one convenient reading
Film build varies across flat faces, edges, corners, recesses, welds, rack positions and parts within a load. Define measurement areas, reading count, locations, averaging rule and treatment of high or low readings before inspection. Include locations most likely to be thin or heavy and retain the individual results. A single reading from an easy flat area cannot represent a complex component or an entire production batch.
Information for film-build and line review
Send the exact powder name and TDS revision, substrate and pretreatment, part geometry, target range and tolerance, measurement standard or method, gauge and probe, verification references, sampling locations, recorded results, cure profile and observed defects. DAMEI can then discuss the relevant formulation, sample or line trial without presenting a generic thickness as an order-specific specification.
FAQ
What is the correct powder coating film thickness?
Use the range in the exact product TDS and project specification. Formulation, color, texture, substrate, geometry and performance requirements differ, so DAMEI does not publish one universal thickness.
Should thickness be measured before or after cure?
The inspection plan must define the measurement state and method. ISO 2808 includes methods for wet film, dry film and uncured powder layers; final acceptance should follow the state named in the governing specification.
Which gauge should be used for steel or aluminum?
Magnetic methods are commonly selected for non-magnetic coatings on magnetizable steel, while eddy-current methods are used for non-conductive coatings on non-magnetic conductive metals such as aluminum. Confirm the instrument, probe and procedure for the actual substrate.
Is one thickness reading enough?
No. Coating thickness varies with geometry, electrostatic field, gun path and rack position. Use the specified sampling plan with defined locations, reading count, averaging and acceptance rules, and keep the individual results.