Material Selection Guide
Choose the right material—faster. KaiSpeed keeps a broad range of metals and plastics in stock or on demand, backed by engineer-led DFM, compliance options (RoHS/REACH), and material certifications on request.
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CNC Machining Materials
Selecting the right material determines strength, weight, cost, finish quality, and dimensional stability. KaiSpeed machines metals, plastics, and composites for prototypes and production. If you’re unsure, send your CAD + 2D drawing and we’ll recommend the best material/finish for your part’s function and budget.
Metal CNC Machining
Aluminum Alloys
Lightweight, corrosion-resistant, highly machinable; excellent for fast lead times and complex features.
Common grades: 6061-T6, 6063, 6082, 7075-T6, 2024, 5052/5083 (plates), ADC12/A380 (cast).
Best for: Housings, brackets, heat sinks, fixtures, aerospace/robotics components.
Finishes: As-machined, bead-blast, anodize (Type II/Type III hard), chem film (Alodine), powder coat, brushing/polish.
Stainless Steel
Corrosion resistance with good strength and clean cosmetics.
Common grades: 303 (best machinability), 304/304L, 316/316L (marine/medical), 17-4PH (high strength, heat treatable), 430/431/440C (applications vary).
Best for: Food/medical hardware, outdoor parts, shafts, fasteners, tooling.
Finishes: As-machined, passivation, electropolish, bead-blast, brushing.
Carbon & Alloy Steel
High strength, wear resistance; heat treatable for hardness and durability.
Common grades: 1018/1020/1045, 12L14/1215 (free-cutting), 4130/4140/4340, A36, 16MnCr5/42CrMo4.
Best for: Structural parts, bases, tooling, gears, drive components.
Finishes: As-machined, black oxide, zinc/nickel plating, phosphate, powder coat, paint.
Brass
Excellent machinability, tight tolerances, aesthetic surface, good electrical/thermal conductivity.
Common grades: C360 (Ms58 / CuZn39Pb3).
Best for: Fittings, terminals, decorative hardware, fluid components.
Finishes: As-machined, brushing/polish, clear coat, nickel/chrome plating (application-dependent).
Copper
Very high electrical/thermal conductivity; soft and ductile.
Common grades: C110 (ETP), C101 (OFHC). Beryllium copper available on request.
Best for: Bus bars, heat spreaders, EDM electrodes, RF parts.
Finishes: As-machined, polish, tin/nickel plating, anti-tarnish.
Bronze
Good wear characteristics and corrosion resistance; great for bearing applications.
Common grades: C932 (bearing bronze), tin bronzes (per spec).
Best for: Bushings, sleeves, marine hardware, sculptures.
Finishes: As-machined, polish/brushing; oil impregnation or plating as required.
Titanium
Exceptional strength-to-weight, corrosion resistance, biocompatibility.
Common grades: Grade 2, Grade 5 / Ti-6Al-4V.
Best for: Aerospace structures, medical implants/instruments, high-stress parts.
Finishes: As-machined, bead-blast, polish; (note: anodic coloring & surface prep per application).
Magnesium
Ultra-light with good stiffness; careful handling required.
Common grades: AZ31B, AZ91D.
Best for: Weight-critical aerospace/automotive, electronics housings.
Finishes: As-machined, bead-blast, conversion coat, paint/powder.
Zinc & Zinc Alloys
Zinc offers good castability, dimensional stability, damping, and cost efficiency. It’s widely used for die-cast parts that can be CNC post-machined for tight features, threads, and sealing surfaces.
Common alloys: ZAMAK 3 , ZAMAK 5
Best for: Automotive interior hardware, locks/hinges, gears, brackets, consumer electronics housings, decorative hardware, EMI-shielded enclosures.
Plastic CNC Machining
ABS
Tough, impact-resistant, easy to machine; good “as-machined” cosmetics.
Uses: Enclosures, fixtures, automotive interiors, general prototypes.
PC (Polycarbonate)
Transparent, high impact, heat-resistant; can stress-crack—use sharp tools/controlled feeds.
Uses: Guards, lenses, medical/food equipment, packaging components.
PMMA (Acrylic)
Optically clear with hard surface; needs polishing for full transparency after machining.
Uses: Light pipes, displays, windows, fluidic covers.
POM / Delrin (Acetal)
Low friction, dimensionally stable, excellent for precision fits.
Uses: Gears, bushings, pulleys, jigs/fixtures.
PA (Nylon 6/66)
Tough, wear-resistant; absorbs moisture (tolerance planning needed).
Uses: Gears, bearings, sliders, wear plates.
PEEK
High-performance thermoplastic; strong, chemical/heat-resistant, sterilizable.
Uses: Medical implants/instruments, aerospace brackets, seals, bearings.
PP (Polypropylene)
Exceptional strength-to-weight, corrosion resistance, biocompatibility.
Common grades: Grade 2, Grade 5 / Ti-6Al-4V.
Best for: Aerospace structures, medical implants/instruments, high-stress parts.
Finishes: As-machined, bead-blast, polish; (note: anodic coloring & surface prep per application).
HDPE
Impact-resistant, weatherable; great strength-to-density ratio.
Uses: Outdoor parts, containers, spacer blocks.
PTFE (Teflon)
Ultra-low friction, chemical and temperature resistance; softer (fixturing matters).
Uses: Seals, gaskets, chemical-service components, non-stick parts.
FR-4/ GR-10
Glass-reinforced epoxy laminate; strong, flame-retardant, electrical insulator.
Uses: Fixtures, insulating plates, electronic substrates (CNC routing/drilling).
Sheet Metal Materials
Aluminum Alloys
Lightweight, corrosion-resistant, and excellent strength-to-weight—ideal for enclosures, brackets, chassis, and heat-sensitive assemblies. Good formability (grade-dependent) and fast to machine.
Common grades: 5052-H32 · 5083 · 6061-T6
Best for: Aerospace/automotive panels, electronics housings, battery/robotics covers
DFM notes: 5052 bends cleanly; 6061 is stronger but needs larger min bend radius ≈ 1–1.5× t to avoid cracking
Finishes: Anodize (Type II/III), chromate (Alodine), powder coat, bead-blast + dye
Stainless Steel
Strong, hygienic, and corrosion-resistant with good cosmetics; great for medical, food equipment, and marine environments.
Common grades: SUS 304 (304/1.4301) · 316L (on request for higher corrosion resistance)
Best for: Enclosures in harsh/corrosive settings, medical housings, food-contact parts
DFM notes: Higher springback—plan larger bend radii (≥ 1–2× t); deburr for safe handling
Finishes: 2B/BA, brushed #4, bead-blast, passivation, electropolish, laser marking
Steel
High stiffness and durability with strong cost efficiency; broad gauges for structural panels and frames. Needs coating for corrosion protection (unless galvanized/e-coated).
Common grades: SPCC (CRS) · SGCC/SECC (galvanized/electro-galv) · Q235 · 1020
Best for: Chassis, racks, brackets, machine guards, HVAC panels
DFM notes: Account for coating stack-up (powder ~60–100 μm); maintain hole-to-edge ≥ 1× t
Finishes: Powder coat, e-coat, zinc/black oxide, phosphate + paint, silk-screen
Brass
Highly malleable, corrosion-resistant, and naturally “gold-like” in color; great for decorative trims plus functional hardware needing good machinability.
Common grades: C27400 · C28000 (Muntz) · C36000 (free-cutting)
Best for: Nameplates, bezels, aesthetic brackets, valves/fittings
DFM notes: Controls for grain direction on brushed faces; allow clearance for plating thickness
Finishes: Brushed/polished, clear coat, nickel/chrome plating, laser marking
Copper
Outstanding electrical/thermal conductivity with excellent ductility—suited to busbars, RF/EMI shields, terminals, heat spreaders.
Common grades: C101 (OFHC) · C102 (OF) · C110 (ETP) (CN equivalents like T2/TU1/TU2 available)
Best for: Electrical contacts, busbars, heat sinks/straps, shielding cans
DFM notes: Manage springback on formed features; avoid tight emboss near bends
Finishes: Tin/nickel/silver plating, passivation/anti-tarnish, conductive coatings
Injection Molding Materials
Once your tool is approved, we mold functional prototypes and production parts in a wide range of thermoplastics and elastomers. If you need a specific grade (e.g., GF, UV-stabilized, FR UL94, medical/food-contact, ESD), we’ll source it or propose equivalents.
Rigid Thermoplastics (common)
ABS / ASA – General-purpose toughness; ASA adds UV/weather resistance for outdoor use.
PC / PC-ABS / PC-PBT / PC-PET – High impact; blends improve chemical and heat performance.
PA6 / PA66 (Nylon, ±GF) – Strong & wear-resistant; glass-filled grades for stiffness.
POM/Acetal (Copolymer & Homopolymer/Delrin®) – Low friction, great dimensional stability.
PP / PE (HDPE / LDPE / LLDPE / UHMW-PE) – Chemical resistance, ductility; food-grade options available.
PMMA (Acrylic) / PET / PETG – Clear/translucent optics; PMMA has best clarity & scratch resistance; PC is tougher.
PBT / PBT-blends – Electrical & automotive workhorse; good chemical/creep resistance.
SAN / PS – Clear (SAN) or general commodity (PS) for low-load parts.
TPO – Flexible polyolefin with good chemical resistance.
High-Performance Thermoplastics
PEI (ULTEM™) – High heat & flame resistance; stable, medical/industrial.
PEEK – Exceptional strength/heat/chemical resistance; metal-replacement in demanding applications.
PPS / PPA / LCP – Thin-wall, high-temp, electronic connectors, precision parts.
PSU / PES – Rigid, transparent, chemically resistant engineering polymers.
Elastomers (Thermoplastic)
TPU / TPE (Shore A → Shore D) – Soft-touch grips, seals, bellows; abrasion & impact resistant.
TPV (e.g., Santoprene®) – Good compression set & temperature resistance.
PEBA – Lightweight, resilient; medical/sports applications.
Rubbers & Silicone
EPDM – Weather/ozone resistant; seals & gaskets.
FKM (Viton®) – Excellent fuel/oil/chemical resistance; high-temp.
PVC (Shore A) – Flexible, economical elastomer (plasticizer-modified).
LSR (Liquid Silicone Rubber) – Biocompatible, high-temp, excellent flexibility; requires dedicated silicone tooling/process (different from thermoplastic molding).
FAQs
It depends on your priorities:
Fast + economical: Aluminum 6061/6082 (great machinability, anodizing options)
High strength: 7075-T6 (aerospace-grade), 4140 (heat treatable)
Corrosion resistance: Stainless 304/316L
Ultra-machinable & precise small parts: Brass C360
Share your strength/corrosion/weight/cost targets and we’ll recommend the best-fit alloy and temper.
Again, depends on the application:
General & low cost: ABS
Excellent machinability + low friction: POM/Acetal (Delrin®)
Tough & clear: PC (Polycarbonate)
Wear/strength: Nylon PA6/PA66 (±GF)
Optical clarity: PMMA (Acrylic)
High temp/performance: PEI (ULTEM™), PEEK
Tell us your mechanical/thermal/optical needs and environment; we’ll suggest the right resin and finish stack.
Yes. You’ll have engineer-led support from quote to delivery: material selection, DFM feedback, cost/lead-time trade-offs, sampling/first-article checks, and final documentation. We keep you updated at each step.
Yes. We can supply materials with the certifications you require, such as ISO, ASTM/ASME, EN, AMS, JIS, GB/T. On request we provide EN 10204 3.1 MTRs, Certificates of Conformity (CoC), and compliance docs (e.g., RoHS/REACH). Tell us the target standard when you request a quote.
No problem—send your spec anyway. Material names vary by region/standard (ASTM, EN, DIN, JIS, GB/T). We’ll cross-reference equivalents or source the exact grade. Example: the same alloy can appear under different codes across standards. If you share the standard, grade, and key properties, we’ll confirm availability or propose a vetted equivalent.