Applying an even finish to thin-walled components is inherently difficult due to their fragile design and large area-to-volume proportion. These components are easily affected by deformation, irregular coating thickness, and surface flaws including runs and pinholes. To ensure reproducible, high-quality finishes, several key practices must be followed.
First, proper surface preparation is essential. Clean the part thoroughly using appropriate solvents or degreasing agents to clear away lubricants, debris, and native oxides. For metals, consider light abrasion or plasma treatment to enhance adhesion without compromising wall integrity. Avoid aggressive cleaning methods that could distort the part.
Maintain precise environmental conditions throughout the coating process. Keep the coating chamber within a narrow range of heat and moisture. Unstable conditions risk uneven evaporation, causing patchy or blistered finishes. Install HEPA or particulate filters to block dust and debris until the coating sets.
Tailor the application process to suit delicate geometries. Choose low-pressure, high-volume spray heads to create a gentle, consistent film. Maintain fixed standoff and constant travel rate, with slight pass overlap to ensure full coverage. Precisely time the submersion and extraction to avoid voids or over-thickening.
Evaluate the flow behavior and thickness of the coating formulation. Reduced thickness enhances flow uniformity and minimizes sagging or Tehran Poshesh puddling on delicate surfaces. Modify viscosity using approved diluents or rheology modifiers—validate with small-scale trials.
Fifth, employ fixtures or jigs to hold parts securely during coating. This prevents movement and ensures consistent orientation. Gently turn or angle the component during spraying to reach hidden or recessed zones. Never overlap or group components—this blocks coating flow and creates uneven coverage.
Sixth, monitor curing conditions closely. Thin-walled parts heat up and cool down faster than thicker ones, so use controlled, gradual temperature cycles to prevent thermal shock or uneven curing. Forced-air ovens deliver more uniform heat than infrared or radiant heaters.
Finally, perform in-process inspections using non-destructive methods such as visual checks under magnification or thickness gauges. Catching inconsistencies early allows for immediate correction before the coating fully cures.
When surface prep, application discipline, and environmental control are unified, consistent results become standard across all units.
