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Surface Finishing for Sheet Metal
Don’t let the “last process step” decide the yield of an entire production run. For overseas programs, SR MFG provides a one-stop surface finishing solution—from pretreatment through coating (powder coating, e-coat, anodizing, or plating), inspection, and documentation—so you get consistent appearance, no assembly interference, verifiable corrosion performance, and more predictable delivery.
Controlled film build：Powder coating typically runs 60–80 μm (2–3 mils). We set project-specific targets and can mask or limit build on critical mating surfaces to reduce the risk of fit-up issues.
Verifiable corrosion performance：We can run salt spray testing per ISO 9227 / ASTM B117 to benchmark coating quality (e.g., porosity or damage) and corrosion resistance, with acceptance criteria defined to your specification.
Complete documentation：We support FAI, in-process, and final inspection records, along with relevant reports to simplify overseas receiving and lot traceability.
Our Surface Finishing Capabilities
SR MFG operates an automated powder coating line with a multi-gun setup (Gema spray guns). We also use a refrigerated + desiccant air-drying system to maintain stable compressed-air quality and support continuous production. During coating, we record and control key environmental and process parameters—such as temperature/humidity, air supply conditions, and curing settings—to improve coating consistency and batch-to-batch stability.
For quality verification, we can perform coating thickness and adhesion testing to your project requirements and provide the corresponding inspection records. If performance validation such as salt spray testing is required, we can arrange third-party testing and provide official reports.
We also have sampling, screen printing, and packaging equipment in-house, enabling one-stop delivery from sample approval through final packing and shipment. For expedited orders, we can evaluate the fastest possible lead time based on production scheduling and material availability.
For compliance, we can provide material declarations such as RoHS/REACH and support third-party testing (e.g., SGS) when needed. Lot-level traceability is available to reduce export compliance risk.
Surface Finishing Processes
Finish
Description
Our Service
Compatible Materials
Information Needed from Customer
Durable, consistent appearance; available in matte / gloss / textured finishes
Coat & cure to your spec; color approval via swatch / approved sample; coating thickness + visual inspection records available
Carbon steel, stainless steel, aluminum
Color (RAL / Pantone / physical sample), gloss level, texture requirement, target thickness range, service environment (indoor / outdoor / coastal), masking areas & hanging-point requirements, cosmetic acceptance criteria, test standard (if applicable)
Wide color range with finer surface finish; suited for cosmetic or functional paint systems
Primer/topcoat system per your spec; color swatch approval; cosmetic standard alignment; inspection records available
Carbon steel, stainless steel, aluminum
Paint system (PU / acrylic / epoxy, etc.), color / gloss, target thickness, cosmetic grade (allowable defects), chemical / scratch resistance requirements, test standards (if applicable)
Improves corrosion resistance and appearance for aluminum; natural / black and other colors available
Anodizing + sealing per your spec; color sample approval; appearance + thickness records available (as required)
Aluminum alloys (e.g., 5052 / 6061)
Color/sample, coating type/class (if specified), thickness class, sealing requirement, appearance requirements (color variation, mottling, allowable scratches), whether conductive/EMI contact areas are required, performance requirements and standards (salt spray / wear, etc.)
Corrosion protection, conductivity, and wear resistance; common for fasteners and functional parts
Plating + post-treatment per your spec; coating thickness inspection; compliance documents available (as required)
Mainly steel parts (for zinc plating); copper alloys / others per spec
Plating type (zinc / nickel, etc.), spec/standard (if applicable), “significant surfaces” definition, thickness class, passivation/sealing requirement, finish color (clear/yellow/black, etc. where applicable), corrosion target (hours + standard), hydrogen embrittlement baking requirement (if applicable)
Very uniform coverage (including recesses/cavities) with strong corrosion protection
E-coat to your spec; can be paired with follow-on powder/wet paint (if required); thickness + visual inspection records available
Steel is most common; aluminum/galvanized may be possible depending on spec and line capability
Color (typically black/gray unless specified), thickness range, corrosion target and test standard, whether powder coat / wet paint follows, appearance requirements, masking/contact-area requirements
Uniform satin/matte cosmetic texture; commonly used for panels and appearance parts
Processed to approved sample or target texture/roughness; masking supported; visual inspection records available; protective film & packaging options
Stainless steel, aluminum (also other metals per spec)
Media type (glass bead / aluminum oxide, etc.), media size/mesh, target roughness (Ra) or approved texture sample, cosmetic grade (allowable scratches/dents), masking areas, whether follow-on coating/anodizing is required, protective film & packaging requirements
Improves corrosion resistance of stainless steel while keeping the natural metal appearance
Passivation to your spec; process + inspection records available (as required)
Stainless steel (e.g., 304/316, etc.)
Standard (ASTM/ISO, etc.), surface condition requirements (pickling/polishing needed or not), appearance requirements, corrosion/salt spray requirements (if any), parts cleanliness requirements before passivation
Base layer to improve adhesion and corrosion resistance before organic coatings (powder/paint/e-coat)
Pretreatment parameters and inspection per your spec; matched to downstream coating process; optional chrome-free sealing/finishing (if required)
Ferrous materials; zinc/cadmium alloys; aluminum/zinc alloys may be possible per spec
Downstream coating type (powder/paint/e-coat), corrosion target + test standard, adhesion requirement + test method (if applicable), restricted-substance requirements (RoHS/REACH/ELV, etc.), appearance/cosmetic requirements, masking/contact-area requirements
Surface Finish Tolerances (Coating Build-Up Guide)
We typically control powder coating thickness at 60–100 μm (typical 60±10 μm). To balance assembly fit, corrosion protection, and cosmetic consistency, we recommend setting the target thickness by application:
- Precision assemblies: target 40–60 μm (or 40±5 μm case-by-case, depending on edge coverage, geometry, and powder system). Critical mating surfaces / grounding points can be masked.
- Outdoor / heavy corrosion environments: target 80–120 μm (project-defined). Adhesion testing per GB/T 9286 / ISO 2409 or ASTM D3359 (target rating per spec).
- Cosmetic parts: color and gloss are controlled to the approved sample; ΔE and gloss tolerance are defined per project based on agreed measurement conditions.
To ensure “first-pass” assembly success, please include in your RFQ:
- Are drawing dimensions base metal or finished (after coating) dimensions?
- CTQ features and mating/grounding areas (masking required or controlled build-up).
- Use environment and target validation standard (indoor/outdoor/coastal/chemical exposure; salt spray requirement if applicable).
Sheet Metal Finishing FAQs
Surface Finishing Technical Resources
