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Practical, standards-based guidance to help R&D, engineering, and procurement teams select and implement the right surface finishing solutions.
Surface finishing is the set of post-machining treatments applied to CNC parts to modify the outermost layer for performance or appearance. After CNC cutting leaves tool marks and raw metal surfaces, finishing improves corrosion and wear resistance, controls friction, enhances cosmetics, and prepares parts for assembly or sterilization.
Selecting the right finish aligns the part’s performance, look, and lifecycle cost with its real-world use.
Anodizing grows a controlled, porous Al₂O₃ ceramic on aluminum alloys in an electrolyte under DC power (workpiece = anode). The film can be sealed and/or dyed for corrosion protection, wear resistance, cosmetics, and electrical insulation.
Degrease → Rinse → Alkaline etch (opt.) → De-smut (nitric/fluoride) → Rinse → Acid activate
→ Anodize (Type II/III in H2SO4, DC) → Rinse → (Dye, opt.)
→ Seal (boiling DI / nickel acetate / nickel-free organic) → Dry → Inspect (thickness/appearance)
Consumer electronics housings/bezels (Type II + dye + seal).
Aerospace structures & fasteners (CAA/TSA/PAA as paint/bonding pre-treat).
Powertrain/industrial: valves, cylinders, tooling (Type III for wear/corrosion).
Auto/motorcycle: pedals, levers, heat-sink shells (Type II/III).
Optics/instruments: low-reflectance black (Type II/III dyed black).
7～20 μｍ
A1050,A2014,A2017,A2024,
A5052,A5056,A6061,A6063,A7075
Corrosion: Type II + good seal → ≈336–1000 h NSS (ISO 9227/ASTM B117), alloy & dye dependent.
Wear: Type III superior; dry μ ≈ 0.3–0.6; PTFE/graphite post-impregnation can reach μ ≈ 0.1–0.2.
Hardness: Type II ≈ 250–400 HV; Type III ≈ 350–550 HV (locally higher with cold, high CD).
Appearance: Type II supports bright/satin colors; Type III natural gray-brown to black (often dyed).
Electrical: Insulating; dielectric strength typically ≈15–40 V/µm; sealing increases resistivity.
Thermal: Inorganic film stable to ~200 °C; organic dyes may fade >100 °C; thermal cycling can open pores if under-sealed.
Chemical: Resists solvents, mild acids/bases; attacked by strong alkali and fluorides.
Relative cost:
Type II: $–$$ (color uniformity drives effort).
Type III: $$–$$$ (low-temp/high-current, tighter window).
CAA/TSA/PAA: $$–$$$ (compliance/special fixtures).
Cost drivers: pre-finish (polish/brush), target thickness, dye/black, seal type, size & nesting density, masking, rework/strip.
Typical lead time: prototypes 3–5 days; production 5–10 days (Type III or multi-color may be longer).
Cr(VI): Type I (CAA) contains hexavalent chromium → generally not RoHS/REACH compliant without exemption; requires reduction/precipitation and licensed disposal.
Type II/III: Cr(VI)-free; typically RoHS/REACH compatible. Nickel-seal introduces Ni in effluent; consider nickel-free seals.
Aerospace replacements: TSA often replaces CAA; PAA for bonding.
Wastewater: acid, Al³⁺, surfactants/dyes → pH neutralization + coagulation + carbon; sludge as hazardous waste per local law.
Q1. Can I get the same black on 6061 and 7075 without visible color shift?
A1. Hard to guarantee. Standardize alloy & temper, surface Ra (e.g., 0.4–0.8 µm), and dye lot/time/temp; issue a limit sample and specify a ΔE tolerance (e.g., ≤1.0–1.5).
Q2. My threads/bores are tight after hardcoat—what’s the fix?
A2. Prefer masking or pre-oversize per ID shrink ≈ t and OD growth ≈ 0.5 t. If already coated, strip & re-run or post-machine (tap/ream) carefully to avoid film lifting.
Q3. Do I always need sealing?
A3. For corrosion resistance and dye fastness: yes. For maximum hardness/low friction on Type III, consider no-seal or low-temp organic seal, accepting lower corrosion.
Hard anodizing is an electrochemical process that forms a thick, dense aluminum oxide (Al₂O₃) layer on aluminum and its alloys.
Typically referred to as Type III Anodize (per MIL-A-8625F).
Produces coatings 25–125 µm thick, significantly harder and more wear/corrosion resistant than decorative anodizing (Type II).
Used where abrasion, insulation, and corrosion resistance are critical.
Degreasing / Alkaline Cleaning
↓
Rinse (DI water)
↓
Etching / Desmutting (acidic, removes intermetallics)
↓
Hard Anodizing (Sulfuric acid bath, ~0–5 °C, 12–24 A/dm²)
↓
Rinse
↓
Sealing (hot DI water / nickel acetate / PTFE seal – optional for wear vs corrosion trade-off)
↓
Drying & Inspection
25～125 μｍ
A1050,A2014,A2017,A2024,
A5052,A5056,A6061,A6063,A7075
Corrosion resistance: >1000 h NSS (with proper sealing, per ASTM B117).
Wear resistance: 10× improvement over bare Al; friction coefficient 0.1–0.4 depending on lubrication.
Hardness: 350–500 HV, comparable to hardened steel.
Electrical: Highly insulating (resistivity >10¹² Ω·cm).
Temperature: Stable up to ~400 °C before degradation.
Color: Natural gray to dark bronze/black; varies by alloy/thickness.
Cost factors: Alloy type, masking complexity, required thickness, sealing choice, batch size.
Relative cost: $$ (higher than decorative anodizing, lower than EN plating).
Lead time: 5–7 working days typical; 2–3 days possible for expedited small batches.
Cr(VI)-free process (sulfuric-based), compliant with RoHS & REACH.
Wastewater treatment required: acidic waste, dissolved Al salts.
Optional nickel sealing may trigger Ni compliance checks under REACH.
Alternative sealing: hot DI water, mid-temp proprietary seals.
Q1. Can hard anodizing be dyed?
→ Generally no; dense oxide limits dye penetration. Dark gray/black is natural for thick coatings.
Q2. Will it change critical dimensions (threads, bores)?
→ Yes, anodize grows inward & outward; masking or post-machining required for tight tolerances.
Q3. Is sealing always required?
→ Not necessarily. For wear-focused parts, unsealed is harder; for corrosion protection, sealing is essential.
Black oxide is a conversion coating that chemically reacts with the surface of ferrous metals (and sometimes copper, brass, stainless steel) to form a thin, black magnetite (Fe₃O₄) or oxide layer.
Typical coating thickness: <1 µm (0.2–0.8 µm).
Primarily for appearance, mild corrosion protection (with oil/wax), and reduced light reflection.
Minimal dimensional change, making it suitable for precision parts.
Degreasing / Cleaning
↓
Rinse
↓
Pickling / Acid Etch (rust/scale removal)
↓
Black Oxide Bath (alkaline salt solution, 135–150 °C)
↓
Rinse
↓
Post-treatment (oil / wax / polymer seal for corrosion resistance)
↓
Drying & Inspection
Automotive: gears, fasteners, clamps, fuel system parts.
Tooling: cutting tools, drill bits, gauges.
Firearms & defense: gun barrels, sights.
Machine parts: shafts, couplings, housings.
Consumer hardware: decorative fittings, optical instruments.
0.2–0.8 µm
Carbon Steel,Alloy Steel,Stainless Steel,Copper / Brass
Corrosion resistance: Poor without oil/wax (<2 h NSS); with oil seal: 24–96 h NSS typical.
Wear resistance: Minimal; oxide is thin and easily worn off.
Hardness: No significant change (substrate-dependent).
Appearance: Matte black to glossy depending on oil/wax used.
Friction: Slightly reduced, anti-galling effect.
Electrical: Conductive surface.
Temperature stability: Stable up to ~300 °C (before oxidation discoloration).
Cost factors: oil/wax sealing type, part size, batch volume, surface prep.
Relative cost: $ (very low, among the cheapest coatings).
Lead time: 2–3 days typical; bulk hardware can be coated in same day.
Uses caustic soda + nitrates; requires wastewater neutralization.
Traditional process is Cr(VI)-free, RoHS & REACH compliant.
Post-treatment oils/waxes may require VOC compliance check.
Alternatives: cold blackening (room-temp) available, but less durable.
Q1. Is black oxide as corrosion resistant as plating (zinc, nickel)?
→ No. Without oil, black oxide offers almost no corrosion resistance; with oil, short-term protection only. For long-term outdoor exposure, use zinc/nickel plating.
Q2. Will it change dimensions on precision parts?
→ No. Coating is <1 µm and does not affect tolerances.
Q3. Can stainless steel be black oxided?
→ Yes, but requires special acid activation. Color may range from gray-black to dark black.
Electroless Nickel (EN) is an auto-catalytic chemical reduction process that deposits a uniform nickel-phosphorus (Ni-P) or nickel-boron (Ni-B) alloy coating on conductive substrates, without external electrical current.
Ni-P EN is the most common (P content ~2–14 wt%).
Provides uniform thickness, even on complex geometries and inner surfaces.
Known for wear resistance, corrosion protection, and dimensional uniformity
Degreasing / Cleaning → Water Rinse → Acid Activation → Electroless Nickel Bath (NiSO4 + NaH2PO2, pH 4.5–5.0, 85–92 °C) → Water Rinse → Post-treatment (Heat treatment / Passivation / Grinding) → Drying → Inspection
Aerospace: hydraulic components, landing gear bushings.
Automotive: fuel system parts, piston rings, transmission valves.
Electronics: connectors, printed circuit boards (PCB), EMI shielding.
Oil & gas: pump rotors, valves, downhole tools.
Precision machining: molds, gears, shafts requiring wear + corrosion resistance.
10–25 µm/h (depends on bath chemistry).
Carbon Steel,Alloy Steel,Stainless Steel,Al alloys,Cu alloys
Corrosion resistance:
Ni-P (high P >10%): >1000 h NSS (ASTM B117).
Ni-P (mid P ~6–9%): ~500–1000 h NSS.
Wear resistance: Good; hardness up to 900–1100 HV after heat treatment.
Friction coefficient: 0.1–0.2 (with PTFE/SiC co-deposition).
Temperature stability: Up to ~400 °C (after heat treatment).
Appearance: Bright silver-gray to semi-matte finish.
Cost level: $$ (higher than Zn, lower than hard chrome).
Lead time:
Small parts: 3–5 days typical.
Complex/large parts: 5–10 days.
Cost drivers:
Thickness requirement.
Substrate pre-treatment (Al, SS more complex).
Heat treatment requirement.
Batch size (EN bath capacity).
RoHS / REACH compliant (no Cr(VI)).
Bath contains Ni salts + hypophosphite → wastewater treatment needed (heavy metals).
Proper fume extraction needed due to phosphine (trace byproduct).
Alternative: Ni-B EN (boron-based, harder but less corrosion resistance).
Q1: How is EN different from electroplated nickel?
→ EN provides uniform thickness even inside holes and recesses, while electroplated nickel tends to build up at edges.
Q2: Which EN type should I choose?
→ High P EN (>10%) for corrosion resistance; low-mid P EN (2–9%) for hardness/wear resistance.
Q3: Can EN replace hard chrome plating?
→ Yes, in many wear applications (after heat treatment), but EN is softer at high temperatures and less cost-efficient for thick layers (>100 µm).
Nickel electroplating is an electrolytic process that deposits a layer of nickel metal onto a conductive substrate for improved corrosion resistance, wear resistance, appearance, or functional properties (e.g., conductivity).
Provides decorative bright finish (mirror-like) or semi-bright matte.
Can serve as undercoat (barrier layer) before chrome, gold, or tin.
Functional nickel plating for wear resistance, hardness, and corrosion protection.
Degreasing / Cleaning → Water Rinse → Acid Pickling / Activation → Nickel Electroplating (Watts / Sulfamate / Other Bath) → Water Rinse → Post-treatment (Passivation / Hydrogen Relief Bake) → Drying → Inspection
Automotive: trim parts, connectors, piston rings.
Consumer goods: bathroom fittings, kitchen hardware, electronics housings.
Electronics: connectors, contact points, shielding.
Aerospace & defense: landing gear components, fasteners (functional nickel).
Tooling & machinery: molds, shafts, gears.
5–30 µm
Carbon Steel,Alloy Steel,Stainless Steel,Al alloys,Cu alloys
Corrosion resistance: Moderate; NSS 24–96 h without topcoat, can exceed 240–480 h when combined with Cr or passivation.
Wear resistance: Good (better than Cu, poorer than hard chrome).
Hardness: 400–600 HV (as-plated, depends on bath & additives).
Conductivity: Good electrical conductivity (bulk Ni ~7 µΩ·cm).
Temperature range: Continuous use up to 200 °C; >300 °C risk of embrittlement/oxidation.
Appearance: Bright, semi-bright, matte depending on bath additives.
Cost level: $–$$ (lower than hard chrome, higher than zinc).
Drivers: part size, surface finish requirements (bright vs matte), masking, geometry complexity.
Lead time:
Prototypes: 3–5 days.
Production lots: 5–10 days typical.
Expedited: <3 days possible with surcharge.
Nickel salts: carcinogenic; strict handling, PPE, and wastewater treatment required.
RoHS/REACH: Nickel electroplating is generally RoHS compliant; restriction applies to Ni release in skin-contact parts (e.g., EU Nickel Directive <0.5 µg/cm²/week).
Wastewater: requires metal recovery (ion exchange, precipitation).
Cr(VI): not used directly in Ni plating (but may be in subsequent chrome topcoats).
Alternatives: Electroless Ni (EN), trivalent chrome topcoats, PVD coatings.
Q1: Can nickel plating alone provide long-term outdoor corrosion protection?
A: Not recommended. Nickel should be combined with topcoats (e.g., Cr, clearcoat, passivation) for >500 h NSS.
Q2: How to avoid hydrogen embrittlement on high-strength steels?
A: Bake at 190–220 °C for 2–4 h within 1 h after plating; follow ASTM B850.
Q3: What’s the difference between Watts vs sulfamate nickel?
A: Watts bath is common for decorative finishes; sulfamate nickel gives low-stress, ductile, thick deposits (functional).
Hard chrome plating (also called industrial chrome plating) is an electrolytic process that deposits a thick layer of chromium metal onto a substrate, primarily for wear resistance, low friction, corrosion resistance, and dimensional restoration. Unlike decorative chrome, it is not intended for aesthetic purposes but for functional performance.
Degreasing / Cleaning → Water Rinse → Acid Pickling / Activation → Hard Chrome Electroplating → Water Rinse → Hydrogen Relief Bake (if steel) → Polishing / Grinding → Final Inspection
Automotive: piston rods, crankshafts, valves, molds.
Aerospace: landing gear, hydraulic actuators, turbine shafts.
Machinery: rolls, dies, press tools, cylinders, gears.
Oil & gas: pump shafts, drilling equipment, sealing surfaces.
Injection molding: cavity and core surfaces for wear/corrosion resistance.
5–300 µm
| Material / Alloy | Typical Thickness (µm) | Hardness (HV) | Roughness Impact (Ra, µm) | Notes |
|---|---|---|---|---|
| Carbon Steel | 10–500 | 800–1100 | +0.2–0.6 (can be ground <0.1) | Needs hydrogen relief bake |
| Stainless Steel | 10–300 | 800–1100 | +0.1–0.5 | Requires activation strike |
| Tool Steel | 20–200 | 800–1100 | +0.2–0.6 | Used for molds, dies |
| Copper/Brass | 10–50 | 800–1100 | +0.1–0.3 | Limited use (adhesion risk) |
| Al alloys | 15–50 | 800–1100 | +0.2–0.4 | Requires Ni strike first |
Corrosion resistance: Good but porous at >20 µm; enhanced by duplex Ni/Cr system.
Wear resistance: Excellent (hardness 800–1100 HV).
Friction coefficient: 0.12–0.20 (dry, against steel).
Temperature range: Stable up to ~400 °C; risk of microcracking at higher T.
Appearance: Dull gray to shiny, depending on polishing.
Cost level: $$–$$$ (higher than Ni or Zn plating; comparable to HVOF thermal spray).
Drivers: part size, required thickness, post-polishing/grinding, masking complexity.
Lead time:
Prototypes: 5–7 days.
Production lots: 1–2 weeks.
Expedited: 3–5 days possible with surcharge.
Hexavalent chromium (Cr(VI)): carcinogenic and highly regulated (OSHA, REACH, RoHS).
Waste treatment: Cr(VI) reduction to Cr(III) + precipitation required.
Alternatives:
Trivalent chrome plating (Cr(III), lower hardness).
Electroless Ni–PTFE or Ni–P coatings.
HVOF (High Velocity Oxygen Fuel) thermal spray coatings (WC–Co, Cr₃C₂).
Compliance: aerospace & automotive industries actively phasing out Cr(VI).
Q1: Why choose hard chrome over electroless nickel?
A: Hard chrome offers higher hardness, wear resistance, and dimensional restoration capability, but EN provides better uniformity and corrosion resistance.
Q2: Is hard chrome plating being phased out?
A: Yes, due to Cr(VI) regulations. Alternatives include HVOF thermal spray and trivalent chrome.
Q3: Can hard chrome be applied thickly?
A: Yes, up to 0.5 mm or more, but high stress and cracking increase with thickness; grinding is typically required.
Powder coating is a dry finishing process where finely ground thermoplastic or thermoset powders are electrostatically sprayed onto a conductive substrate and cured under heat to form a continuous, durable coating.
Provides decorative and protective finishes.
Available in a wide range of colors, gloss levels, and textures.
Alternative to liquid paints, with superior durability and environmental compliance.
Degreasing / Cleaning → Rinse → Surface Pretreatment (Phosphate / Chromate / Conversion Coating) → Rinse → Drying → Electrostatic Powder Spraying → Curing (Oven 160–220 °C, 10–30 min) → Cooling → Final Inspection
Automotive: wheels, chassis parts, brackets, engine covers.
Appliances: refrigerators, washing machines, ovens.
Architecture: aluminum extrusions, curtain walls, railings.
Consumer goods: furniture, lighting fixtures, bicycles.
Industrial equipment: enclosures, machinery housings, racks.
60–120 µm
| Material / Substrate | Typical Thickness (µm) | Hardness (HB) | Roughness Impact (Ra, µm) | Notes |
|---|---|---|---|---|
| Mild Steel | 60–120 | +10–20 | +2–10 | Requires phosphate pretreatment |
| Aluminum | 50–100 | +10–20 | +2–8 | Chromate / zirconium conversion recommended |
| Galvanized Steel | 60–120 | +10–20 | +2–10 | Special pretreatment to prevent outgassing |
| Stainless Steel | 40–80 | +10–20 | +1–4 | Requires mechanical roughening or primer |
Corrosion resistance: Excellent when used with pretreatment; up to 1000 h salt spray (ASTM B117).
Wear resistance: Good (better than liquid paints, lower than hard coatings).
Hardness: HB 2–4 (resin dependent).
Chemical resistance: Good for epoxies; limited UV resistance (polyesters preferred outdoors).
Temperature range: –40 to 120 °C continuous (some powders withstand up to 200 °C).
Appearance: Wide variety (matte → high gloss, smooth → textured).
Cost level: $–$$ (cheaper than liquid paint for volume production).
Drivers: part size (oven load), masking complexity, color changeover time.
Lead time:
Small batches: 3–5 days.
Production runs: 5–10 days typical.
Expedited: 2–3 days possible.
No VOCs or solvents (compared to wet paint).
RoHS/REACH compliant powders available (TGIC-free polyesters recommended).
Waste reduction: overspray can be reclaimed (up to 95% utilization).
Pretreatments: chromates restricted in EU; alternatives: zirconium, titanium, silane conversion coatings.
Q1: Can powder coating be applied to non-metal substrates?
A: Yes, with conductive primers or special formulations (MDF, plastics), but performance is lower.
Q2: How does powder coating compare to anodizing?
A: Powder coating gives thicker, more color-varied layers; anodizing provides thinner, harder, more wear-resistant surfaces.
Q3: Can powder coating be repaired locally?
A: Small scratches can be touched up with liquid paint, but major damage requires stripping and recoating.
MFZn2-C is a standard zinc electroplating coating system with supplementary chromate conversion coating (C = colorless/clear/passivation) as defined in ISO 4042 / DIN 50979 and similar automotive/fastener standards.
“MF” = Mechanical Fasteners (standardized system).
“Zn2” = Coating thickness class (≥ 5 µm, typically 5–8 µm).
“C” = Clear passivation (Cr(III) based, RoHS compliant).
It is primarily used for fasteners and small precision components where basic corrosion resistance and assembly compatibility are required.
Degreasing / Cleaning → Water Rinse → Pickling / Activation → Zn Electroplating (acidic/alkaline electrolyte) → Water Rinse → Passivation (Clear / Cr(III)) → Water Rinse → Drying / Baking → Inspection
Automotive fasteners (bolts, nuts, screws, washers).
General machinery fasteners with low-to-moderate corrosion requirements.
Electrical & electronic housings/fasteners requiring RoHS compliance.
White goods (appliances) screws & fittings.
Industrial assemblies requiring basic sacrificial corrosion protection.
typically 5–8 µm
Carbon steel | Alloy steel | SS400 |
Corrosion resistance:
White rust (Zn corrosion products): ~72–96 h NSS (ASTM B117 typical).
Red rust (base metal): ~120–240 h NSS.
Wear resistance: Low, zinc is soft (HV ~70–120).
Electrical properties: Conductive surface, suitable for grounding fasteners.
Temperature resistance: Effective up to ~120 °C; discoloration above 150 °C.
Appearance: Bright to semi-bright metallic, clear/passivated finish.
Cost level: $ (low) compared with Zn-Ni ($$) and Zn-flake ($$$).
Lead time:
Mass fasteners: 3–5 days typical.
Prototypes / rack plating: 5–7 days.
Cost drivers:
Geometry (rack vs barrel plating).
Thickness & corrosion class.
Hydrogen embrittlement relief baking.
Sorting/inspection requirements.
Chromate used: Trivalent Cr(III) → RoHS & REACH compliant.
No hexavalent Cr(VI) allowed (banned in EU automotive/EEE).
Wastewater treatment: Zn and Cr(III) must be neutralized and precipitated.
Alternative options:
Zn-Ni (higher corrosion performance, NSS >720 h).
Zn-flake (non-electrolytic, no hydrogen embrittlement risk).
Q1: Why is NSS only ~120–240 h for MFZn2-C, while my customer asks for >500 h?
→ MFZn2-C is a basic zinc coating; consider Zn-Ni or Zn-flake for higher salt spray hours.
Q2: Do I need hydrogen embrittlement relief baking?
→ Yes, if fastener material strength ≥1000 MPa (ISO 4042 requirement).
Q3: Can MFZn2-C be used in exterior automotive parts?
→ Limited; recommended for interior or secondary components. Exterior visible/critical fasteners need Zn-Ni or organic topcoat.
Electropolishing (also known as electrochemical polishing) is an anodic dissolution process where a metal part is immersed in an electrolytic bath and connected as the anode. Material is selectively removed from the surface at a microscopic level, leveling micro-peaks and reducing roughness.
Produces a bright, smooth, reflective finish.
Removes embedded contaminants, burrs, and surface stresses.
Improves corrosion resistance by enriching Cr/Ni ratio on stainless steels.
Degreasing / Cleaning → Water Rinse → Acid Pickling (activation) → Electropolishing (acid bath, DC power) → Water Rinse → Neutralization → Final Rinse (DI water) → Drying → Inspection
Medical: surgical instruments, implants, stents, orthodontic devices.
Food & Beverage: dairy tanks, piping, valves, mixers.
Semiconductor & Pharma: ultra-clean piping, fittings.
Automotive & Aerospace: fuel systems, exhaust components, springs.
General engineering: stainless fasteners, wire baskets, mesh.
5-50μｍ
SUS304/316/Ti alloys (medical)/Carbon steel
Corrosion resistance: Enhanced, especially for SS (ASTM A967).
Surface finish: Shiny, smooth, uniform; free from burrs.
Cleanliness: Removes inclusions and embedded contaminants.
Biocompatibility: Improved for medical implants (removes nickel surface enrichment).
Dimensional tolerance: Controlled removal (5–50 µm typical).
Temperature use: No degradation (not a coating, but removal process).
Cost level: $$ (higher than passivation, lower than plating + polishing).
Drivers: part size, alloy, desired Ra reduction, geometry complexity.
Lead time:
Prototypes: 3–5 days.
Production: 5–7 days typical.
Expedited: 2–3 days possible.
Uses strong acids (H₂SO₄, H₃PO₄) → requires acid-resistant tanks, PPE.
Wastewater: heavy metal + acid neutralization required.
No Cr(VI) involved (unlike some plating processes).
RoHS/REACH: Generally compliant (provided waste treated).
Alternatives: mechanical polishing, passivation only (lower performance).
Q1: How is electropolishing different from passivation?
A: Passivation removes free iron to improve corrosion resistance but does not change surface finish. Electropolishing smooths and brightens while also improving corrosion resistance.
Q2: Will electropolishing change part dimensions significantly?
A: Material removal is controlled (5–50 µm). Critical tolerance areas should be considered in design.
Q3: Can welds be electropolished?
A: Yes, weld discoloration and heat tint are removed, but surface roughness of weld bead may still remain visible.
Mirror barrel polishing is a mechanical surface finishing process using a vibratory or centrifugal barrel (tumbler) with abrasive and polishing media to progressively smooth and polish parts.
Achieves high-gloss, mirror-like finish on metals and alloys.
Removes burrs, scratches, and tool marks.
Commonly used for decorative parts, precision components, and jewelry.
Deburring (coarse media) → Water Rinse → Fine Grinding (ceramic/plastic media) → Water Rinse → Polishing (resin media with abrasives) → Bright Polishing (porcelain/stainless balls with compound) → Drying (corn cob / walnut shell media or hot air) → Final Inspection
Consumer goods: watches, jewelry, eyeglass frames, phone housings.
Automotive: trim, stainless steel exhaust tips, aluminum wheels.
Medical: surgical tools, dental implants.
Aerospace: turbine blades, fasteners (for surface smoothing).
General hardware: stainless steel fasteners, cutlery, handles.
5～50μｍ
| Material / Alloy | Material Removal (µm) | Hardness Impact | Surface Finish Achievable (Ra, µm) | Notes |
|---|---|---|---|---|
| Stainless Steel | 5–50 | None | Ra 0.05–0.2 (mirror) | Very common |
| Brass / Copper | 5–30 | None | Ra 0.05–0.2 (mirror) | Risk of tarnish without coating |
| Aluminum alloys | 5–20 | None | Ra 0.05–0.2 | Needs sealing/anodizing to protect |
| Titanium alloys | 2–10 | None | Ra 0.1–0.3 | Longer cycles required |
| Carbon Steel | 5–50 | None | Ra 0.1–0.3 | Must be oiled/coated post-process |
Appearance: High-gloss, reflective, mirror-like.
Corrosion resistance: Improved if oxide layer is enhanced (e.g., SS). No intrinsic corrosion protection → may require passivation or coating.
Wear resistance: No significant improvement (not a coating).
Cleanliness: Removes burrs, tool marks, embedded abrasives.
Applications: Mainly decorative + surface quality improvement.
Cost level: $–$$ (cheaper than electropolishing or plating for high-volume small parts).
Drivers: part size, cycle time, media wear, finish grade (functional vs mirror).
Lead time:
Prototypes: 2–4 days.
Production: 5–7 days typical.
Expedited: 1–2 days possible.
Slurry contains abrasives and metal fines → requires wastewater treatment.
Media disposal (ceramic, resin, porcelain) per local regulations.
No Cr(VI) or toxic chemistry involved (unlike plating).
Generally RoHS/REACH compliant if no restricted compounds used in polishing compounds.
Q1: Can mirror barrel polishing replace electropolishing?
A: No, electropolishing improves corrosion resistance significantly. Barrel polishing is mainly for surface finish and aesthetics.
Q2: Will the polished finish last on stainless steel?
A: Yes, stainless retains mirror polish. Brass, copper, and aluminum require clear coating or anodizing to prevent tarnish.
Q3: Can complex parts achieve uniform mirror polish?
A: External surfaces polish well; blind holes or deep internal passages remain matte unless combined with other finishing processes.
Texture etching is a surface modification process where controlled chemical, electrochemical, or laser etching is applied to create micro- or macro-textures on metal or plastic surfaces.
Provides decorative patterns, functional textures (anti-glare, grip), or mold surface finishes.
Often used on injection molds to transfer patterns to plastic parts.
Enables branding, matte finish, or functional roughness control.
Surface Cleaning / Degreasing → Masking (photoresist / stencil / laser resist) → Etching (chemical or laser) → Rinse / Neutralization → Mask Removal → Post-treatment (passivation / polishing if needed) → Inspection
Automotive: dashboard mold textures, trim patterns, anti-slip pedals.
Consumer electronics: laptop casings, phone housings (anti-fingerprint textures).
Medical: surgical tool handles (grip enhancement).
Mold-making: SPI/SPE standards for mold surface finishes.
Luxury goods: watch dials, jewelry patterns.
2–200 µm
| Material / Substrate | Typical Etch Depth (µm) | Hardness Impact | Surface Roughness (Ra, µm) | Notes |
|---|---|---|---|---|
| Tool Steel (molds) | 5–200 | None | Ra 1–20 | Common in injection molds |
| Stainless Steel | 2–50 | None | Ra 0.5–5 | Decorative & functional |
| Aluminum alloys | 5–100 | None | Ra 1–10 | Risk of over-etching |
| Plastics (ABS, PC) | Laser etching only | None | Ra 1–5 | For logos / textures |
| Brass / Copper | 2–30 | None | Ra 0.5–3 | Watch dials, ornaments |
Appearance: Matte, patterned, or textured surfaces (from fine satin to deep grain).
Grip / anti-slip: Enhanced with deeper textures.
Anti-reflection: Matte textures reduce glare.
Adhesion: Improved paint or coating adhesion.
Wear / corrosion resistance: No intrinsic improvement; must be combined with coating/passivation.
Cost level: $$ (higher than polishing, lower than PVD coatings).
Drivers: pattern complexity, depth, area size, masking method (photolithography vs. laser).
Lead time:
Simple matte textures: 3–5 days.
Custom patterns (logos, designs): 7–10 days.
Mold texture services: 1–2 weeks typical.
Chemical etching generates acid/metal waste → requires neutralization and heavy metal recovery.
Ferric chloride, nitric acid: hazardous handling required.
Laser etching: cleaner, no chemicals, but higher cost.
RoHS/REACH: compliant if waste streams treated properly.
Q1: How durable are etched textures in molds?
A: With proper etching depth (30–80 µm) and mold steel hardness, textures can withstand millions of cycles.
Q2: Can etched parts be post-polished?
A: Yes, but polishing reduces depth and may blur the texture.
Q3: Is laser etching better than chemical etching?
A: Laser etching provides precision, eco-friendliness, and easy customization, but is slower and costlier for large areas.
TiN (Titanium Nitride), TiCN (Titanium Carbonitride), and CrN (Chromium Nitride) are physical vapor deposition (PVD) coatings applied in vacuum chambers.
TiN: golden-yellow, high hardness, good wear resistance.
TiCN: dark gray/blue, higher hardness and lower friction than TiN.
CrN: silver-gray, excellent corrosion resistance, good ductility.
They are widely used for cutting tools, dies, molds, and decorative purposes.
Surface Cleaning / Ultrasonic Degreasing → Ion Etching / Plasma Cleaning → PVD Coating (Cathodic Arc / Magnetron Sputtering) → Cooling → Inspection
Cutting tools: drills, end mills, inserts (TiN, TiCN).
Forming tools: stamping dies, extrusion dies (TiCN, CrN).
Plastic injection molds: abrasion and corrosion resistance (CrN).
Medical devices: surgical instruments, implants (TiN, CrN).
Consumer goods: watch cases, luxury hardware, decorative golden finish (TiN).
1–5 µm
| Substrate Material | Typical Thickness (µm) | Hardness (HV) | Coating Color | Notes |
|---|---|---|---|---|
| Tool Steel | 2–5 | TiN: 1800–2200 | Gold yellow | Needs polish & clean before PVD |
| Carbide | 1–4 | TiCN: 2500–3200 | Gray-blue | Excellent for cutting inserts |
| Stainless Steel | 1–4 | CrN: 1500–2000 | Silver gray | Excellent corrosion resistance |
| Titanium alloys | 1–3 | TiN/TiCN/CrN | — | Medical implants |
| Al alloys | 1–3 | — | — | Requires Ni/Cr interlayer for adhesion |
TiN:
Hardness: 1800–2200 HV.
Friction coefficient: 0.4–0.6.
Wear resistance: Very good.
Temperature limit: up to 500 °C.
TiCN:
Hardness: 2500–3200 HV (higher than TiN).
Friction coefficient: 0.2–0.4 (lower).
Color: gray-blue.
Best for abrasive wear and cutting tools.
CrN:
Hardness: 1500–2000 HV.
Excellent corrosion resistance (better than TiN/TiCN).
Good ductility, resists cracking.
Preferred for molds and medical use.
Cost level: $$–$$$ (higher than electroplating, lower than CVD for small parts).
Drivers: coating type, part size, chamber utilization, surface prep.
Lead time:
Prototypes: 3–5 days.
Production: 5–10 days typical.
Expedited: 2–3 days possible with surcharge.
PVD process: clean, no Cr(VI) or toxic chemicals.
RoHS/REACH compliant.
Energy-intensive vacuum process, but environmentally friendly compared to electroplating.
Waste: spent targets (Ti, Cr) recyclable.
Q1: How to choose between TiN, TiCN, and CrN?
A:
TiN → general-purpose, decorative + cutting tools.
TiCN → higher hardness, low friction, best for wear-intensive cutting.
CrN → best for corrosion + ductility, used for molds and medical.
Q2: Can PVD coatings replace hard chrome?
A: Partially. PVD is thinner and harder, better for tools; chrome better for dimensional build-up.
Q3: Do PVD coatings need post-polishing?
A: No, but substrate must be polished before deposition for mirror-like finish.
DLC (Diamond-Like Carbon) is an amorphous carbon coating deposited via PVD or PECVD methods.
Combines properties of diamond (hardness, wear resistance, low friction) and graphite (lubricity).
Typically applied as a thin film (1–3 µm).
Used where low friction, high hardness, and wear/corrosion resistance are required.
Surface Cleaning / Degreasing → Ion Etching / Plasma Cleaning → DLC Deposition (PVD / PECVD, often with interlayers like Cr or Ti) → Cooling → Inspection
Automotive: piston pins, camshafts, tappets, fuel injector parts.
Cutting tools: drills, milling cutters (for non-ferrous machining).
Medical: surgical blades, orthopedic implants, dental tools.
Consumer goods: watch bezels, luxury hardware, smartphone parts.
Aerospace: bearings, hydraulic parts, valves.
1–3 µm
| Substrate Material | Typical Thickness (µm) | Hardness (HV) | Friction Coefficient | Notes |
|---|---|---|---|---|
| Tool Steels | 1–3 | 2000–5000 | 0.05–0.15 | Needs polished substrate |
| Stainless Steel | 1–3 | 2000–4000 | 0.05–0.15 | Used for medical tools |
| Carbides | 1–2 | 2500–5000 | 0.05–0.15 | Excellent adhesion |
| Al alloys | 1–2 | 2000–3000 | 0.05–0.15 | Requires interlayer (Cr/Ti) |
| Ti alloys | 1–2 | 2000–4000 | 0.05–0.15 | Biomedical implants |
Hardness: 2000–5000 HV (depends on hydrogen content).
Friction coefficient: 0.05–0.15 (extremely low, self-lubricating).
Wear resistance: Excellent, prolongs life of moving parts.
Corrosion resistance: Very good barrier against oxidation.
Temperature resistance: up to 300–400 °C continuous (above this, risk of graphitization).
Appearance: Black to dark gray, decorative applications possible.
Cost level: $$–$$$ (higher than TiN/CrN PVD, due to process complexity).
Drivers: coating thickness, batch size, chamber utilization.
Lead time:
Prototypes: 5–7 days.
Production: 7–10 days typical.
Expedited: 3–5 days possible.
RoHS/REACH compliant (no Cr(VI), no toxic metals).
Eco-friendly compared to electroplating.
PECVD uses hydrocarbon gases (CH₄, C₂H₂), handled with ventilation.
Waste is mainly spent targets (recyclable).
Q1: Can DLC replace lubrication (oil/grease)?
A: For some applications (low-load bearings, sliding surfaces), yes. For high-load systems, DLC reduces but does not fully replace lubrication.
Q2: How does DLC compare to TiN?
A: DLC has lower friction and higher wear resistance but is less temperature-resistant (TiN can go up to 500 °C).
Q3: Is DLC suitable for decorative purposes?
A: Yes, DLC’s black finish is used in watches, jewelry, and phone parts, combining aesthetics and durability.
Bead blasting and shot blasting are abrasive surface treatment processes where media (glass beads, ceramic beads, steel shot, or grit) are propelled at high velocity onto a part’s surface.
Bead blasting: Uses glass/ceramic beads → produces smooth, satin, matte finish.
Shot blasting: Uses steel shot/grit → stronger impact, for cleaning, descaling, or peening.
Both are used for surface cleaning, texturing, or stress-relief peening.
Degreasing / Cleaning → Masking (if selective blasting) → Bead / Shot Blasting (air pressure or wheel turbine) → Air blow / Rinse → Drying → Inspection
Automotive: engine blocks, gear housings, suspension parts.
Aerospace: turbine blades (shot peening), landing gear.
Medical: orthopedic implants (bead blasting for matte finish).
Consumer products: stainless steel housings, kitchen appliances (decorative satin).
General engineering: weld cleaning, rust removal, pre-coating surface prep.
50–200 µm
| Material / Substrate | Typical Effect | Roughness Range (Ra, µm) | Notes |
|---|---|---|---|
| Stainless Steel | Satin matte finish | 0.5–3.0 | Common for decorative or medical implants |
| Aluminum alloys | Matte finish, oxide removal | 1.0–4.0 | Risk of deformation if thin |
| Carbon Steel | Scale/rust removal | 2.0–6.0 | Often followed by painting/coating |
| Tool Steel | Shot peening (compressive stress) | 1.5–5.0 | Improves fatigue life |
| Titanium alloys | Bead blasting (implant texture) | 1.0–3.0 | Enhances osseointegration in medical |
Surface finish: satin matte (beads) or roughened (shot).
Corrosion resistance: improved if oxide removed + passivation applied; bare blasted steel will corrode faster.
Fatigue strength: shot peening increases fatigue life by inducing compressive stresses.
Adhesion: excellent substrate for paints, coatings, anodizing.
Appearance: uniform matte or satin finish.
Cost level: $ (low, relative to coatings).
Drivers: part size, required surface profile, masking needs, media cost.
Lead time:
Small batches: 1–2 days.
Production runs: continuous flow possible.
Dust generation: requires dust collectors and operator PPE.
Media recycling: steel shot reusable; glass beads recyclable but degrade faster.
No hazardous chemicals → eco-friendly compared to acid pickling.
Noise: shot blasting >100 dB, requires hearing protection.
RoHS/REACH compliant if no hazardous media additives.
Q1: What’s the difference between bead blasting and sandblasting?
A: Bead blasting uses round beads (gentler, satin finish). Sandblasting uses angular grit (aggressive, rough finish).
Q2: Can bead blasting be used as a final finish?
A: Yes, especially for stainless steel and titanium in decorative or medical parts, but passivation or coating may be needed for corrosion protection.
Q3: How does shot peening differ from shot blasting?
A: Shot peening is controlled blasting specifically to induce compressive stresses (fatigue life improvement), not just cleaning.
Passivation is a chemical treatment process (typically nitric or citric acid solutions) applied to stainless steel and other corrosion-resistant alloys.
Removes free iron and contaminants from the surface.
Promotes the formation of a uniform, stable oxide layer (Cr₂O₃ for stainless steel).
Enhances corrosion resistance without changing dimensions or appearance.
Degreasing / Cleaning → Water Rinse → Acid Passivation (Nitric / Citric, controlled time & temperature) → Water Rinse → Neutralization (if nitric used) → Drying → Inspection
Medical: surgical instruments, implants, orthopedic devices.
Food & beverage: stainless tanks, piping, mixers.
Aerospace: fasteners, fuel systems, landing gear components.
Electronics: connectors, housings (stainless).
General engineering: fasteners, machined SS parts, valves, pumps.
—
| Material / Alloy | Effect of Passivation | Thickness Change | Notes |
|---|---|---|---|
| SS 304 / 316 | Removes free iron, enhances Cr oxide | None (chemical only) | Standard application |
| SS 17-4PH, 15-5PH | Improves resistance in aerospace/medical | None | Requires specific spec compliance |
| Martensitic SS (410/420) | Limited improvement | None | May require tempering + passivation |
| Al, Cu, Carbon Steel | Not applicable | — | Different surface treatments needed |
Corrosion resistance: Significant improvement, NSS (ASTM B117) >200 h typical (depends on alloy).
Surface appearance: No major change (may slightly brighten).
Cleanliness: Removes oils, machining residues, embedded iron.
Wear resistance: Not improved (passivation is chemical, not mechanical).
Conductivity: No impact.
Cost level: $ (low, compared to coatings).
Drivers: part size, alloy type, nitric vs citric, masking needs.
Lead time:
Small parts: 1–3 days.
Large fabrications: 3–5 days typical.
Nitric acid passivation: generates NOx fumes, hazardous waste.
Citric acid passivation: safer, environmentally preferred.
RoHS/REACH compliant when citric used.
Wastewater treatment: neutralization + metal ion removal required.
Industry moving toward citric-based passivation.
Q1: Does passivation add a coating layer?
A: No, it chemically enhances the natural oxide film. Thickness change is negligible.
Q2: When to choose citric vs nitric passivation?
A: Citric is safer and environmentally friendly; nitric may still be specified in aerospace/military standards.
Q3: How long does passivation last?
A: Permanent as long as the surface is not mechanically damaged; corrosion resistance depends on stainless grade and service environment.
Gold chem film is a chromate conversion coating applied to aluminum alloys.
Produces a thin, gold-to-brown colored film.
Provides corrosion resistance and good electrical conductivity.
Often used as a base layer before painting or as a standalone conductive finish.
Degreasing / Alkaline Cleaning → Rinse → Deoxidizing / Desmut → Rinse → Immersion in Chromate Conversion Solution → Rinse → Drying → Inspection
Aerospace: aircraft structures, electrical housings.
Defense: missile and radar housings, connectors.
Electronics: chassis, ground planes, EMI shielding.
General industrial: aluminum panels, enclosures, fasteners.
0.3–1.5µm
| Material / Alloy | Typical Thickness (µm) | Electrical Resistance (mΩ/sq·in) | Notes |
|---|---|---|---|
| Al 2024, 6061, 7075 | 0.3–1.5 | <5 (Class 3, conductive) | Widely used alloys |
| Cast Al alloys | 0.5–2.0 | <10 | Porosity affects uniformity |
| Pure Al | 0.3–1.0 | <5 | Excellent adhesion |
Corrosion resistance:
Class 1A: >168 h in ASTM B117 salt spray (best protection).
Class 3: 24–72 h (optimized for conductivity).
Conductivity: Maintained (better than anodizing).
Paint adhesion: Excellent as pretreatment.
Wear resistance: Poor (very thin film).
Appearance: Gold to iridescent brown.
Cost level: $ (low, relative to anodizing or plating).
Drivers: alloy type, masking requirements, Class 1A vs 3.
Lead time:
Small parts: 2–3 days.
Large structures: 5–7 days typical.
Traditional gold chem film uses hexavalent chromium (Cr⁶⁺) → carcinogenic, restricted under RoHS/REACH.
Modern alternatives: trivalent Cr (Cr³⁺) chem films, appearance more transparent/iridescent than gold.
Waste treatment: requires Cr⁶⁺ reduction before disposal.
Aerospace/defense still specify MIL-DTL-5541 Type I (Cr⁶⁺); commercial sector moving to Type II (Cr³⁺).
Q1: What’s the difference between Class 1A and Class 3 chem film?
A: Class 1A gives maximum corrosion protection (thicker film), Class 3 is thinner, more conductive (used for electrical bonding).
Q2: Can chem film replace anodizing?
A: For conductivity and paint base, yes; for wear or decorative applications, anodizing is better.
Q3: Is gold chem film still allowed under RoHS?
A: No, hexavalent Cr (gold color) is restricted; only trivalent Cr alternatives (clear/iridescent) are RoHS-compliant.
| Must Mask | Why | Typical Examples |
|---|---|---|
| Tight fits ≤ ±0.02 mm | Finish adds/removes microns; assemblies jam/loosen | H7/H8 bores, locating pads |
| Threads (anodize/powder) | Coating fills flanks; gauges fail | M4/M6 internal/external |
| Grounding pads | Keep conductivity for bonding/EMI | ☐8×8 pad, screw land |
| Datum/locating faces | Preserve alignment accuracy | Datum A/B flats |
| Material | Type II | Type III | Alodine | EN | Passivation | Powder |
|---|---|---|---|---|---|---|
| Al 6061/7075 | ✅ | ✅ | ✅ | ✅ | — | ✅ |
| SS 304/316 | — | — | — | ✅ | ✅ | ✅ |
| Carbon Steel | — | — | — | ✅ | — | ✅ |
| Brass | — | — | — | ✅ | — | ✅ |
| Notes: High-Si cast Al shows color variation; 7xxx tends to darken under black anodize. |
| Finish | Typical Thickness (μm) | Plan for Dimensional Change* | Surface/Other Effects | Speed/Cost (relative) |
|---|---|---|---|---|
| Type II Anodize | 5–25 (use 10–15) | ≈ T (ID −T / OD +T) | Slight Ra↑; dyeable | $ · 3–5 d |
| Hard Anodize III | 25–75 (use 35–45) | ≈ T (mask/post-size fits) | 350–550 HV; dark tone | $$ · 5–7 d |
| Alodine (Chromate) | 0.25–1 | ~0 | Conductive; paint base | $ · 2–3 d |
| Electroless Nickel (EN) | 5–25 (use 8–12) | ≈ T (uniform) | Conductive; HT up to ~1000 HV | $$ · 5–7 d |
| Passivation (SS) | 0 | 0 | Corrosion ↑; no color change | $ · 2–3 d |
| Powder Coating | 60–120 (use 70–90) | ≈ T (strong edge build) | Durable color; RAL palette | $$ · 5–7 d |
| *Rule of thumb for diameter/width features. Threads for anodize/powder must be masked. |
| Primary Need | Recommended Finish | Typical Thickness (μm) | Dimensional Change (ID/OD) | Conductive | Key Notes |
|---|---|---|---|---|---|
| Grounding / electrical continuity (Al) | Chromate Conversion (Alodine) | 0.25–1 | ~0 | Yes | Paint base; specify contact resistance if critical |
| Conductivity on Al/SS/Steel/Brass | Electroless Nickel (EN), medium-P | 8–12 | ≈ T | Yes | Uniform on complex geometry; heat-treat optional |
| Wear + corrosion on aluminum | Hard Anodize (Type III) | 35–45 | ≈ T | No | 350–550 HV; mask or post-size fits |
| High-grade cosmetics on aluminum | Anodize Type II (dyed or clear) | 10–15 | ≈ T | No | Unify blast; control ΔE ≤ 2.0 on A-surfaces |
| Durable color on assemblies | Powder Coating (phosphate pretreat) | 70–90 | ≈ T (edge build) | No | Strict masking on interfaces; chamfer edges |
| Zero build on stainless | Passivation (ASTM A967) | 0 | 0 | N/A | Removes free iron; boosts corrosion without size change |
Wear- and corrosion-resistant finishes for shafts, pistons, brackets, and exterior trim; PPAP-ready documentation.
Hard anodizing and passivation for lightweight alloys; process control records aligned with AS9100 traceability.
Uniform cosmetic finishes (anodize, bead-blast, brushing) and conductive coatings for enclosures and heat sinks.
Mirror polishing and passivation for stainless steels and Ti; biocompatible surface prep and validated cleaning.
Hard chrome and electroless nickel for slides, rollers, and tooling—low friction, long service life, easy rebuild.
Cr(VI)-free alternatives and documented chemistry controls for global compliance and sustainable manufacturing.
We solve: undersize H7 bores after hardcoat, oversize shafts after EN, costly rework. How we do it: Engineering Fit Budget Sheet (pre- vs post-finish) to plan growth/shrink on every fit. Targeted masking on H7/H8 bores, threads, grounding pads; post-ops (hone/lap/skim grind) only where required. Conductivity assured on pads (contact-resistance check) while keeping paint-ready surfaces. What you receive: marked drawings, allowance table per feature, traveler linking each feature to its post-op, photo proof. Acceptance: 100% gauging on critical features with before/after data; conductivity PASS on specified pads.
We solve: assembly color mismatch, returns, brand-risk on exposed panels. How we do it: Color Control Pack: master tile, ΔE method (DE2000, D65/10°), same alloy lotting, unified glass-bead #180–220 surface prep. Tight bath/seal windows with SPC; rack orientation to avoid witness marks. What you receive: spectro report with five fixed zones/part, master tile ID, process guardrails on the traveler, photo proof. Acceptance: ΔE ≤ 2.0 on all A-zones; automatic containment if any zone exceeds the limit.
We solve: post-assembly flaking or poor adhesion on aluminum; thin areas on complex geometry. How we do it: Pretreatment audit (alkali clean → etch → desmut → double zincate for plated stacks when applicable) to lock adhesion. Thickness mapping (XRF, 5+ points/part) and cross-hatch adhesion on pilot lots; rack design to avoid shadowing. Optional EN stack for conductive zones with masking map to keep aesthetics. What you receive: pretreat checklist, XRF heat-map, adhesion test photos & results, lot photos tied to zone
We solve: O-ring grooves / datum faces getting coated so assemblies won’t fit; clamp-mark “witness” on A-surfaces. How we do it: Operator-ready Masking Map (M1/M2… zones, method, band width, “no-witness” rules) + plug/tape kit list, plus rack strategy to hide marks. Unified blast grade, controlled dye & sealing windows; ΔE tracking lot-by-lot. What you receive: masking drawings, plug/tape BOM, photo proof per lot, and zone-ID labeling that matches your drawing. Acceptance: visual conformance to the map; any critical zone out-of-bounds (fit, color, witness) triggers rework before ship.
Examples of SPI’s work with customers across various industries and manufacturing processes.
ASM Handbook: Surface Engineering | https://www.asminternational.org/
Metal Finishing Guidebook | https://www.finishing.com/
CNC Machining Design Guide
Discover How SPI ™Super-ingenuity Delivers Precision CNC Machining for High-Performance Prototypes and Production Parts
