- A color code locates the target; an approved metal panel controls production appearance.
- Define gloss and color difference with GU, geometry and ΔE00.
- Texture can reduce visible waviness but cannot excuse substrate defects.
- Specify film, PMT cure, masking and visual-inspection conditions.
Values in this guide are practical starting points for RFQ, DFM and prototype validation. They do not replace load calculations, regulations, material certificates, qualified procedures or approved production drawings.
Use a Code to Locate and a Sample to Approve
Use RAL Classic, Pantone or a customer system, but similar codes across systems are not equivalent. Record powder manufacturer, product code, resin and batch control. For brand colors or matched assemblies, approve a metal panel using the same substrate, pretreatment, film and texture. Paper cards and screens are for preliminary selection only.
Specify Gloss Units and Geometry
Measure gloss under ISO 2813 or ASTM D523. 60° is common; 85° improves resolution on low-gloss surfaces and 20° on high gloss. Replace subjective “matte” with a project range such as 10–20 GU at 60°. Texture affects readings, so fix instrument, angle, locations and orientation.
Use Delta E with Controlled Visual Review
CIELAB and ΔE00 can compare production with a master. Cosmetic projects often discuss limits in the ΔE00≤1.0–2.0 range, but color, texture, batch and customer sensitivity determine the actual limit. Metallic, coarse-texture and low-gloss powders should not rely on one reading. Define D65 illuminant, observer, aperture and at least 3–5 locations, retaining an approved panel for visual arbitration.
Texture Changes Both Appearance and Inspection
Fine texture can reduce the visibility of minor substrate waviness, fingerprints and fine scratches. Coarse texture hides more but traps dirt, is harder to clean and may affect labels or mating surfaces. Smooth high gloss reveals weld blending and panel waviness. Texture cannot excuse burrs, spatter, craters or pretreatment defects.
Control Film, Cure and Masking
A common single-layer film starts around 60–120 μm, subject to powder TDS and corrosion requirement. Low film reduces coverage; excessive film can create orange peel, pinholes, edge buildup and fit interference. Cure is controlled by part metal temperature (PMT) and time at temperature, not oven-air reading alone. Mark masking boundaries and allowable overspray at threads, grounds, inserts, bearing holes and sliding faces.
Define Cosmetic Inspection Conditions
Define illumination (for example 800–1,000 lx as an indoor starting point), source, distance (such as 600–1,000 mm), viewing time (such as 5–10 s), angle and A/B/C surface limits. Adjust values to the product. Without a common viewing method, inspectors will judge the same particle or shade differently.