Coordinate surface finish with material, manufacturing process, tolerance, cosmetic zones, masking, color, texture, and end-use requirements. ApexProto manages preparation, treatment, inspection, and documentation for machined, fabricated, molded, and 3D-printed parts.
| Finish / Process | Surface Result | Dimensional Consideration | Compatible Materials / Processes | Functional Use |
|---|---|---|---|---|
| As-Machined | Visible CNC tool paths with the specified machined roughness | No added thickness | CNC-machined metals and plastics | Internal, functional, or non-cosmetic surfaces where machining marks are acceptable |
| Deburring & Edge Break | Burrs removed and specified sharp edges softened | Local material removal at edges; define maximum edge break | Machined, cut, and fabricated metals and plastics | Safer handling, assembly clearance, and removal of loose or sharp material |
| Bead Blasting | Uniform low-gloss or satin texture | Negligible material removal; protect critical surfaces | Aluminum, stainless steel, titanium, and rigid plastics | Reduce tool-mark contrast, glare, and directional surface variation |
| Media Tumbling | Smoothed surfaces with rounded exposed edges | Geometry-dependent material removal, concentrated at edges | Small metal parts and selected rigid plastics | Batch deburring, edge smoothing, and preparation for subsequent finishing |
| Directional Brushing | Controlled linear grain in a specified direction | Slight surface removal; grain direction must be defined | Stainless steel, aluminum, and brass | Consistent cosmetic surfaces for panels, housings, and customer-facing parts |
| Mechanical Polishing | Satin, bright, or mirror-reflective surface | Controlled material removal; geometry and edge definition may change | Stainless steel, aluminum, brass, and polishable plastics | Improve reflectivity, cleanability, and the appearance of cosmetic surfaces |
| Electropolishing | Brightened and microscopically smoothed surface | Controlled electrochemical material removal; specify allowance on critical features | Stainless steel and selected conductive alloys | Improve cleanability, corrosion resistance, and surface smoothness |
| Finish / Process | Surface Result | Dimensional Consideration | Compatible Materials / Processes | Functional Use |
|---|---|---|---|---|
| Type II Sulfuric Anodizing | Clear, black, or dyed metallic oxide finish | Typical film thickness 0.005–0.025 mm; account for buildup on fitted features | Aluminum alloys | Corrosion protection, electrical insulation, color, and general wear resistance |
| Type III Hardcoat Anodizing | Gray to dark bronze hard oxide; black available by specification | Typical film thickness 0.025–0.050 mm; tolerance compensation required | Aluminum alloys | Wear surfaces, sliding components, electrical insulation, and demanding environments |
| Chromate Conversion / Chem Film | Clear or iridescent conversion layer with metallic appearance retained | Typically less than 0.001 mm; minimal effect on fitted features | Aluminum alloys | Corrosion protection, conductive interfaces, grounding, and paint preparation |
| Passivation | Clean stainless surface with little or no visual change | No measurable coating buildup | Stainless steels | Remove free iron and support corrosion resistance after machining or fabrication |
| Black Oxide | Matte to semi-gloss black conversion finish, commonly oiled or sealed | Typically less than 0.001 mm | Carbon steel, alloy steel, and selected copper alloys | Reduce reflection, provide mild corrosion protection, and retain dimensional fit |
| Zinc Phosphate | Fine gray crystalline conversion layer | Typical coating buildup 0.002–0.010 mm | Carbon and low-alloy steels | Improve paint adhesion, lubricant retention, and corrosion protection with a topcoat |
| Titanium Anodizing | Voltage-controlled iridescent color without pigment | Typically less than 0.001 mm | Titanium and titanium alloys | Color identification, cosmetic differentiation, and selected medical applications |
| Stainless Steel Pickling | Clean, descaled metallic surface | Controlled surface removal; geometry and condition dependent | Stainless steel parts and weldments | Remove heat tint, scale, and embedded contaminants before passivation or service |
| Finish / Process | Surface Result | Dimensional Consideration | Compatible Materials / Processes | Functional Use |
|---|---|---|---|---|
| Electroless Nickel Plating | Uniform bright or semi-bright nickel-phosphorus layer | Typical added thickness 0.002–0.025 mm; specify allowance and masking | Steel, stainless steel, aluminum, copper, and brass | Corrosion and wear resistance with uniform coverage on complex geometry |
| Zinc Plating | Clear, yellow, black, or specified chromate appearance | Typical added thickness 0.005–0.015 mm | Carbon steel and iron | Sacrificial corrosion protection for brackets, hardware, and general steel components |
| Nickel Plating | Bright, satin, or specified metallic nickel appearance | Typical added thickness 0.005–0.025 mm | Steel, copper alloys, and prepared aluminum | Wear, corrosion, conductivity, and cosmetic requirements |
| Tin Plating | Bright or matte silver-white metallic surface | Typical added thickness 0.002–0.015 mm | Copper, brass, steel, and compatible electrical alloys | Solderability, electrical contact performance, and corrosion protection |
| Copper Plating | Bright or matte copper-colored metallic layer | Typical added thickness 0.005–0.050 mm | Steel, aluminum with preparation, nickel alloys, and plastics with metallization | Electrical or thermal conductivity, plating buildup, and undercoat preparation |
| Powder Coating | Matte, gloss, or textured polymer finish in specified colors | Typical added thickness 0.050–0.150 mm; mask fits, threads, and grounding points | Steel, stainless steel, aluminum, and other heat-tolerant conductive substrates | Color, texture, environmental protection, and impact-resistant enclosure finishes |
| Wet Painting | Matte, satin, gloss, metallic, or soft-touch painted surface | Typical added thickness 0.025–0.075 mm | Metals and prepared plastics | Color matching, UV protection, cosmetic zones, and multi-layer paint systems |
| E-Coating | Uniform black or specified electro-deposited coating | Typical added thickness 0.015–0.035 mm | Steel, cast iron, and compatible conductive metals | Consistent corrosion-resistant coverage on recessed and complex surfaces |
| PTFE Coating | Low-friction matte coating, commonly gray or black | Typical added thickness 0.010–0.030 mm | Prepared aluminum, steel, stainless steel, and compatible metals | Low friction, release behavior, chemical resistance, and reduced adhesion |
| PVD Coating | Thin metallic or ceramic coating in specified colors and compositions | Typical added thickness 0.001–0.005 mm | Tool steels, stainless steels, titanium, and compatible prepared substrates | Surface hardness, wear resistance, low friction, and decorative metallic color |
| Finish / Process | Surface Result | Dimensional Consideration | Compatible Materials / Processes | Functional Use |
|---|---|---|---|---|
| Support Removal & Cleaning | Supports, uncured resin, or attached build structures removed | Local witness marks may remain at support contact points | SLA, FDM, and SLM/DMLS parts | Standard preparation before inspection, assembly, or additional finishing |
| Depowdering & Bead Blasting | Loose powder removed with a consistent matte surface | Negligible material removal; protect critical openings and thin features | SLS, MJF, and SLM/DMLS parts | Clean powder-bed parts and prepare surfaces for dyeing, coating, or use |
| UV Post-Cure | Fully cured resin with process-specific final properties | No coating buildup; shrinkage and distortion depend on resin and geometry | SLA and other photopolymer resin parts | Complete polymerization and establish the specified mechanical and thermal response |
| Vapor Smoothing | Reduced layer texture with a sealed, smoother surface | Controlled surface reflow; review small features and tight tolerances | Compatible SLS, MJF, and FDM thermoplastics | Improve cleanability, tactile feel, appearance, and liquid resistance |
| Dyeing | Color penetrates the porous polymer surface | No measurable coating buildup | SLS and MJF nylon; selected porous polymers | Consistent batch color without a paint film that can chip from the surface |
| Custom Painting | Specified matte, gloss, metallic, or soft-touch painted appearance | Typical added thickness 0.025–0.075 mm | Prepared SLA, SLS, MJF, and FDM polymer parts | Presentation models, color matching, cosmetic prototypes, and end-use housings |
| Clear Part Finishing | Sanded, polished, and optionally clear-coated transparent surface | Material removal and coating buildup are geometry dependent | Clear SLA resins and compatible transparent polymers | Improve transparency for lenses, covers, flow models, and visual prototypes |
| Stress Relief & Heat Treatment | Thermally conditioned metal part with process-specific surface condition | No coating buildup; dimensional movement and scale must be considered | SLM/DMLS metals | Reduce residual stress and establish required metallurgical properties before machining |
| Secondary CNC Machining & Inserts | Machined interfaces, threads, and installed hardware | Local material removal or hardware addition defined by the drawing | Metal and polymer 3D-printed parts | Finish critical bores, sealing faces, threads, datums, and repeat-use fastener locations |
| Finish / Process | Surface Result | Dimensional Consideration | Compatible Materials / Processes | Functional Use |
|---|---|---|---|---|
| SPI A Diamond Polish | High-gloss to mirror molded surface, grades A-1 to A-3 | Transferred from the mold cavity; draft and defect visibility require review | Injection-molded thermoplastics and compatible LSR grades | Optical, transparent, high-gloss, and customer-facing molded surfaces |
| SPI B Semi-Gloss | Smooth semi-gloss molded surface, grades B-1 to B-3 | Transferred from the mold cavity with minimal texture depth | Injection-molded thermoplastics | General cosmetic housings, covers, and controlled semi-gloss surfaces |
| SPI C Matte | Uniform matte molded surface, grades C-1 to C-3 | Transferred from the mold cavity; draft reviewed by geometry and resin | Injection-molded thermoplastics and selected elastomers | Low-gloss consumer, industrial, and handling surfaces |
| SPI D Textured | Dry-blasted molded texture, grades D-1 to D-3 | Texture depth increases draft and release requirements | Injection-molded thermoplastics | Reduce glare, disguise minor marks, and create a tactile molded surface |
| VDI 3400 EDM Texture | Specified EDM texture from fine matte to coarse grain | Texture depth and draft must be confirmed before tool release | Injection-molded thermoplastics and suitable tool steels | Repeatable technical textures tied to an established VDI reference level |
| Mold-Tech Texture | Specified leather, grain, geometric, or custom etched pattern | Texture depth, draw direction, shutoffs, and draft require joint review | Injection-molded thermoplastics and compatible elastomers | Tactile surfaces, brand-specific grain, glare control, and cosmetic differentiation |
| Pad Printing | Localized one- or multi-color printed graphics | Negligible localized ink film; adhesion depends on substrate preparation | Molded plastics, coated metals, and prepared 3D-printed parts | Logos, symbols, controls, and graphics on curved or irregular surfaces |
| Silk Screening | Defined text, symbols, and color fields on flat or gently curved surfaces | Thin localized ink layer; define print boundary and registration tolerance | Sheet metal, molded plastics, and coated panels | Control labels, interface graphics, warnings, and durable part identification |
| Laser Marking | Permanent high-contrast text, code, or graphic | Negligible local surface change; contrast depends on material and finish | Metals, coated metals, and compatible engineering plastics | Serial numbers, data matrix codes, traceability, labels, and durable identification |
Values shown are typical process references. Appearance, thickness, dimensional effect, compatibility, and performance vary by base material, alloy, surface preparation, geometry, color, specification, and supplier process. Final finish callouts, masking boundaries, cosmetic zones, inspection criteria, and documentation are confirmed during quoting.
Evaluate contact pressure, sliding motion, abrasion, lubrication, surface hardness, and dimensional stack-up before selecting a wear-resistant treatment.
Type III Hardcoat Anodizing · Electroless Nickel · PTFE Coating · PVD
Consider the base material, humidity, salt, process fluids, cleaning agents, sterilization, damaged edges, and galvanic contact over the intended service life.
Passivation · Type II Anodizing · Chem Film · Zinc Plating · Powder Coating
Identify grounding points, conductive interfaces, EMI shielding, electrical insulation, heat-transfer surfaces, and areas that must remain free of coating.
Chem Film · Tin Plating · Nickel Plating · As-Machined · Anodizing
Define color, gloss, texture, grain direction, acceptable variation, viewing conditions, touch points, and cosmetic boundaries before production.
Bead Blasting · Brushing · Mechanical Polishing · Powder Coating · Mold Textures
Every sample uses the same machined 6061-T6 aluminum geometry and camera view. Compare how surface preparation and treatment change reflectivity, texture, color, edge definition, and the visibility of tool marks. Final appearance varies with alloy batch, pretreatment, film thickness, sealing, lighting, and viewing angle.
CNC tool paths remain visible. This condition adds no coating thickness and suits internal or non-cosmetic surfaces where machining marks are acceptable.
Fine media creates a uniform, low-gloss texture and reduces directional tool-mark contrast. Media size, pressure, dwell, and alloy influence the final surface.
A transparent Type II oxide layer adds corrosion protection while retaining the natural aluminum tone and visible machining character. Film growth must be considered on close fits.
Type II anodizing with black dye creates a dark metallic surface while preserving edge definition. Alloy, pretreatment, film thickness, sealing, and lighting affect the final color.
Type III anodizing creates a thicker, harder oxide layer for wear and insulation requirements. Its gray-to-dark-bronze appearance and film thickness must be included in tolerance planning.
A cured polymer coating provides color, texture, and environmental protection. Thickness, masking boundaries, hardware interfaces, and grounding points must be defined before processing.
Finishes can add or remove material at bores, threads, sealing faces, datums, electrical contacts, and press-fit interfaces. During DFM, we review coating allowance, masking and plugging boundaries, rack or contact marks, cosmetic zones, and inspection methods so the finished part—not only the base part—meets the drawing.
