A coated assembly may look satisfactory while temporary masks remain in place. Their removal exposes the final edge of the coating and the surfaces that must remain usable. Define an inspection after removal rather than assuming an earlier coating check covers the finished condition.
Qualify the mask with the process
Techspray’s 2108 coating data sheet identifies masking as part of protecting selected components during coating. Compatibility must be established for the selected mask, coating, application method, and cure sequence. A product intended for one operation should not be assumed suitable after a different thermal or chemical exposure.
Identify every masking location on the coating keepout map, including contacts hidden inside a connector. Record whether the mask is tape, a cap, a fixture, or a dispensed material. State the approved point in the coating/cure sequence at which it is removed and who performs the operation.
Inspect the newly exposed boundary
| Feature | Inspection purpose |
|---|---|
| Contact or mating surface | Find coating ingress or residual masking material. |
| Coating edge | Check for unintended lifting, tearing, or uncovered required regions. |
| Connector cavity | Confirm no fragments remain in inaccessible recesses. |
| Nearby components | Check for disturbance during mask removal. |
Use lighting and access suited to the feature. Fluorescence can help locate some coatings, but it is not a complete test of contact usability or adhesion. Keep this review separate from the thickness and cure assessment.
Resolve difficult removal before production
For example, a connector cap may lift cleanly on a flat sample but pull on a coating bridge formed beside a tall component. A trial with the populated board reveals the actual removal direction and access. Redesigning the mask geometry or application path may be more repeatable than asking operators to cut around every cap.
Retain photographs of acceptable and unacceptable boundaries where they improve consistency. Define how residual mask material and coating damage are handled, using qualified rework instructions rather than improvised solvents. Reinspect any repaired area after its complete processing sequence.
Finally, reconcile the masks applied with those removed before the assembly moves to test or packaging. This simple operation count complements detailed inspection and prevents a well-coated board from shipping with a hidden temporary plug still installed.
Move from reading to a build-ready project
Use the fabrication and assembly checklists to prepare drawings, production files and test requirements.
Open the DFM checklist