Engineer's Material Reference
Material Selection
Guide for Engineers
Physical properties, cost rankings, processing parameters, and application guidance for 30+ engineering materials across CNC machining, injection molding, 3D printing, and sheet metal fabrication.
29
Materials
4
Processes
20+
Years Exp.
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Response
Materials by Manufacturing Process
Click "View Full Specs" on any material card to expand physical properties, cost comparison, processing parameters, and engineer tips.
Aluminum 6061-T6
CNC MachiningMost versatile aluminum alloy. Excellent machinability, corrosion resistance, and anodizing response. Default choice for structural parts.
General purposeLow costAnodizable
Density: 2.70 g/cm3Tensile: 310 MPaHardness: 95 HBThermal Cond: 167 W/mK
Relative Cost
Physical Properties
| Property | Value |
|---|---|
| Density | 2.70 g/cm3 |
| Tensile Strength | 310 MPa |
| Yield Strength | 276 MPa |
| Elastic Modulus | 68.9 GPa |
| Hardness | 95 HB |
| Thermal Conductivity | 167 W/mK |
Application Guidance
| Factor | Note |
|---|---|
| Best For | Chassis, brackets, housings, heat sinks |
| Avoid For | High-wear sliding (use 7075 or steel) |
| Corrosion Res. | Excellent (marine OK with anodize) |
| Weldability | Good (4043 filler wire) |
| Surface Finish | Excellent - Anodize Type II/III |
| Cost per kg | $8-12 USD |
Tip: 6061-T6 machines at ~300% the speed of stainless steel. Use climb milling for best surface finish. Minimum wall: 0.5mm. For 50% higher strength, consider 7075-T6 (not weldable).
Stainless Steel 316L
CNC MachiningMarine-grade austenitic stainless. Outstanding corrosion resistance and biocompatibility. Standard for medical devices and marine hardware.
Medical gradeCorrosion resistantHigh machining cost
Density: 8.00 g/cm3Tensile: 485 MPaHardness: 217 HBBiocomp: ASTM F138
Relative Cost
Physical Properties
| Property | Value |
|---|---|
| Density | 8.00 g/cm3 |
| Tensile Strength | 485 MPa |
| Yield Strength | 170 MPa |
| Elastic Modulus | 193 GPa |
| Hardness | 217 HB |
| Corrosion (salt) | Excellent |
Application Guidance
| Factor | Note |
|---|---|
| Best For | Medical implants, marine, food equipment |
| Avoid For | Weight-sensitive apps (use Ti or Al) |
| Weldability | Excellent (low carbon prevents sensitization) |
| Magnetic | No (austenitic, non-magnetic) |
| Surface Finish | Passivate > electropolish for medical |
| Cost per kg | $25-35 USD |
Tip: 316L work-hardens rapidly - use sharp carbide inserts, low cutting speed (60-80 m/min). Passivation in citric acid for 20-30 min restores corrosion resistance. Min wall: 0.8mm.
Titanium Ti-6Al-4V (Gr5)
CNC MachiningAerospace-grade alpha-beta alloy. Best strength-to-weight ratio. Heat treatable to 1100 MPa. Biocompatible for surgical implants.
AerospaceMedicalExpensive
Density: 4.43 g/cm3Tensile: 900 MPaHardness: 334 HBMelt: 1665C
Relative Cost
Physical Properties
| Property | Value |
|---|---|
| Density | 4.43 g/cm3 |
| Tensile Strength | 900 MPa (HT: 1100) |
| Yield Strength | 880 MPa |
| Elastic Modulus | 114 GPa |
| Hardness | 334 HB |
| Melting Point | 1665C |
Application Guidance
| Factor | Note |
|---|---|
| Best For | Aerospace, surgical implants, racing |
| Avoid For | Cost-sensitive consumer goods |
| Corrosion Res. | Excellent (saltwater, body fluid) |
| Weldability | Fair (requires inert atmosphere) |
| Surface | Anodize, PVD coating, passivate |
| Cost per kg | $80-150 USD |
Tip: Titanium has poor thermal conductivity - heat concentrates at the cutting edge. Use rigid setups, high-pressure coolant (70+ bar), sharp carbide. Min wall: 1.0mm. Critical: chip evacuation to avoid fire.
Delrin (POM-C)
CNC Machining - PlasticHigh stiffness, low friction, self-lubricating. The go-to engineering plastic for precision gears, bushings, and sliding parts.
Low frictionDimensionally stable
Density: 1.41 g/cm3Tensile: 70 MPaHDT: 136CFriction: 0.15-0.35
Relative Cost
Physical Properties
| Property | Value |
|---|---|
| Density | 1.41 g/cm3 |
| Tensile Strength | 70 MPa |
| Flexural Modulus | 2.9 GPa |
| HDT @ 1.8MPa | 136C |
| Friction Coeff. | 0.15-0.35 (self-lub) |
| Water Absorption | 0.2% |
Application Guidance
| Factor | Note |
|---|---|
| Best For | Gears, bearings, conveyor components |
| Avoid For | Strong acids/bases (pH <4 or >9) |
| vs Metal | 1/7 weight of steel, 1/3 of Al |
| Adhesion | Difficult to bond (use mechanical) |
| Surface | Polishes to mirror; no coating needed |
| Cost per kg | $6-10 USD |
Tip: POM machines beautifully but chips can be stringy. Use sharp HSS or carbide. Min wall: 0.8mm. Avoid thin walls over large spans - POM creeps under sustained load above 60C. Copolymer (POM-C) is more chemical-resistant than homopolymer (POM-H).
PEEK
CNC Machining - PlasticContinuous use up to 250C. Chemical resistant, biocompatible (ISO 10993). The metal replacement for extreme environments.
High tempExpensiveMedical
Density: 1.32 g/cm3Tensile: 100 MPaHDT: 160CMax Use: 250C
Relative Cost
Physical Properties
| Property | Value |
|---|---|
| Density | 1.32 g/cm3 |
| Tensile Strength | 100 MPa |
| Flexural Modulus | 3.9 GPa |
| HDT @ 1.8MPa | 160C |
| Continuous Use | 250C |
| Flammability | V-0 @ 1.5mm |
Application Guidance
| Factor | Note |
|---|---|
| Best For | Bearings, seals, medical implants, aerospace |
| Avoid For | Cost-sensitive consumer applications |
| Chemical Res. | Excellent (acids, bases, organics) |
| vs 6061 Al | 70% lighter, similar stiffness |
| Sterilization | Gamma stable, autoclavable |
| Cost per kg | $300-600 USD |
Tip: Anneal PEEK before machining to relieve stress. Use carbide or ceramic inserts. Min wall: 1.5mm. 30% glass-filled PEEK improves wear resistance but is more abrasive. Always use coolant - PEEK generates significant heat.
ABS
Injection Molding - RigidHigh impact resistance, excellent surface finish for painting/plating. The workhorse of consumer electronics and automotive interiors.
Low costPaintableMust dry
Density: 1.04 g/cm3Tensile: 45 MPaHDT: 88CShrink: 0.5-0.7%
Relative Cost
Physical Properties
| Property | Value |
|---|---|
| Density | 1.04 g/cm3 |
| Tensile Strength | 45 MPa |
| Flexural Modulus | 2.3 GPa |
| HDT @ 1.8MPa | 88C |
| Impact (Izod) | 200-400 J/m |
| Melt Temp | 200-240C |
Molding Guidance
| Factor | Note |
|---|---|
| Best For | Housings, toys, automotive trim |
| Mold Temp | 50-80C |
| Drying | 2-4 hrs @ 80C (critical!) |
| Gate Design | Edge or submarine gate |
| Surface | Paint, plate, vacuum metalize |
| Cost per kg | $2.50-4 USD |
Tip: ABS must be dried before molding - undried resin causes silver streaks and weak weld lines. Wall: 1.2-3.5mm. Draft: 0.5 min. Avoid sections over 5mm thick to prevent sink. UV-resistant grades available for outdoor use.
Polypropylene (PP)
Injection Molding - RigidLightest commodity plastic. Excellent chemical resistance, living hinge capability, food-safe. Default for packaging and consumer goods.
Lowest costFood safeHigh shrinkage
Density: 0.90 g/cm3Tensile: 35 MPaHDT: 100CShrink: 1.0-2.5%
Relative Cost
Physical Properties
| Property | Value |
|---|---|
| Density | 0.90 g/cm3 |
| Tensile Strength | 35 MPa |
| Flexural Modulus | 1.4 GPa |
| HDT @ 1.8MPa | 100C (homopolymer) |
| Impact (Izod) | 20-60 J/m |
| Melt Temp | 180-230C |
Molding Guidance
| Factor | Note |
|---|---|
| Best For | Packaging, hinges, automotive, medical |
| Mold Temp | 40-80C |
| Warning | High shrink (1-2.5%) - gate carefully |
| Living Hinge | Yes - 0.2-0.5mm flexure |
| Chemical Res. | Excellent (acids, bases) |
| Cost per kg | $1.50-2.50 USD |
Tip: PP's high shrinkage requires careful gate placement and cooling design. Use copolymer PP for better low-temp impact. 20-40% glass-filled PP improves stiffness and reduces shrink to 0.5-1.0%. Min wall: 0.8mm. Draft: 1 minimum.
Polycarbonate (PC)
Injection Molding - RigidHighest impact of any transparent plastic. Optical clarity and heat resistance to 138C. Standard for safety equipment and lighting.
TransparentHigh impactStress cracks
Density: 1.20 g/cm3Tensile: 70 MPaHDT: 138CLT: 88% transparent
Relative Cost
Physical Properties
| Property | Value |
|---|---|
| Density | 1.20 g/cm3 |
| Tensile Strength | 70 MPa |
| Flexural Modulus | 2.3 GPa |
| HDT @ 1.8MPa | 138C |
| Light Transmission | 88-90% |
| Impact (Izod) | 800-900 J/m |
Molding Guidance
| Factor | Note |
|---|---|
| Best For | Safety glasses, medical, lighting |
| Mold Temp | 80-120C (high temp required) |
| Warning | Prone to stress cracking |
| Drying | 3-4 hrs @ 120C |
| vs Acrylic | Stronger impact but lower clarity |
| Cost per kg | $4-7 USD |
Tip: PC requires high mold temps (80-120C) for optical clarity and minimal residual stress. Avoid sharp internal corners - min radius: 0.5mm. Wall: 1.5-4mm. UV-stabilized grades essential for outdoor use.
Nylon 6 (PA6)
Injection Molding - EngineeringExcellent toughness, wear resistance, and fatigue strength. Easier to process than PA66 with lower mold temperatures. Good for gears, bearings, and structural parts.
ToughWear resistantAbsorbs moisture
Density: 1.13 g/cm3Tensile: 80 MPaHDT: 65CShrink: 0.8-1.5%
Relative Cost
Physical Properties
| Property | Value |
|---|---|
| Density | 1.13 g/cm3 |
| Tensile Strength | 80 MPa |
| Flexural Modulus | 2.6 GPa |
| HDT @ 1.8MPa | 65C |
| Impact (Izod) | 50-120 J/m |
| Melt Temp | 220-260C |
Molding Guidance
| Factor | Note |
|---|---|
| Best For | Gears, bearings, structural parts, cable ties |
| Mold Temp | 60-100C |
| vs PA66 | Easier molding, lower HDT, more ductile |
| Moisture | Absorbs 3% (conditions parts at 50% RH) |
| GF Grades | 15-50% glass fiber available |
| Cost per kg | $4-7 USD |
Tip: PA6 is more forgiving than PA66 for molding. Must be dried 4+ hours at 80C. 30% glass-filled PA6 doubles stiffness and halves shrinkage. Min wall: 0.8mm. Excellent for snap-fits due to high elongation.
PBT
Injection Molding - EngineeringExcellent electrical insulation, dimensional stability, and chemical resistance. Low moisture absorption compared to PA. Standard for automotive electrical connectors and switches.
ElectricalLow moistureAutomotive
Density: 1.31 g/cm3Tensile: 55 MPaHDT: 60-150CShrink: 0.5-2.0%
Relative Cost
Physical Properties
| Property | Value |
|---|---|
| Density | 1.31 g/cm3 |
| Tensile Strength | 55 MPa |
| Flexural Modulus | 2.3 GPa |
| HDT @ 1.8MPa | 60-150C (GF dependent) |
| Water Absorption | 0.08% (excellent) |
| Melt Temp | 230-270C |
Molding Guidance
| Factor | Note |
|---|---|
| Best For | Electrical connectors, switches, auto parts |
| Mold Temp | 60-100C |
| vs PA66 | Lower moisture absorption, better electrical |
| Flame Retardant | V-0 grades readily available |
| GF Grades | 10-40% glass fiber common |
| Cost per kg | $5-9 USD |
Tip: PBT crystallizes quickly enabling fast cycle times. Often blended with PET (PBT+PET) for improved surface appearance. Must be dried 2-4 hrs at 120C. Sharp corners stress-crack with certain chemicals. Min wall: 0.8mm.
PMMA (Acrylic)
Injection Molding - TransparentOutstanding optical clarity (92% light transmission) with excellent weather resistance. The standard for transparent display covers, signage, and lighting diffusers.
92% transparentUV stableBrittle
Density: 1.19 g/cm3Tensile: 70 MPaLT: 92%HDT: 95C
Relative Cost
Physical Properties
| Property | Value |
|---|---|
| Density | 1.19 g/cm3 |
| Tensile Strength | 70 MPa |
| Flexural Modulus | 3.2 GPa |
| HDT @ 1.8MPa | 95C |
| Light Transmission | 92% |
| Impact (Izod) | 15-20 J/m (brittle) |
Molding Guidance
| Factor | Note |
|---|---|
| Best For | Displays, signage, lighting diffusers, lenses |
| Mold Temp | 60-80C |
| vs PC | Better clarity, lower impact, cheaper |
| Drying | 3-4 hrs at 80C |
| UV Stability | Excellent - ideal for outdoor use |
| Cost per kg | $3-5 USD |
Tip: PMMA requires highly polished molds for optical clarity. Gate into thickest section to avoid flow marks. Highly notch-sensitive - all corners must have generous radii (>0.5mm). Impact-modified grades available but reduce clarity to 85%.
HDPE / LDPE
Injection Molding / Blow MoldingMost widely used plastic globally. HDPE offers stiffness and chemical resistance. LDPE provides flexibility and impact resistance. Both are FDA-compliant and fully recyclable.
Lowest costFood safeRecyclable
HDPE Density: 0.95 g/cm3LDPE Density: 0.92HDPE Tensile: 32 MPaHDT: 75-120C
Relative Cost
HDPE vs LDPE
| Property | HDPE | LDPE |
|---|---|---|
| Density | 0.95 g/cm3 | 0.92 |
| Tensile | 32 MPa | 10-20 MPa |
| Stiffness | Rigid | Flexible |
| HDT | 75-120C | 40-50C |
| Process | Injection / Blow | Film / Blow |
| Chemical Res. | Excellent | Good |
Molding Guidance
| Factor | Note |
|---|---|
| Best For | Bottles (blow molding), containers, pipes, extrusion profiles, toys |
| Mold Temp | 20-60C |
| Shrinkage | 1.5-4% (high! design for it) |
| Drying | Generally not required |
| UV | Black HDPE has built-in UV stability |
| Cost per kg | $1.20-2 USD |
Tip: HDPE shrinkage is very high (1.5-4%) - parts continue to shrink for days after molding. Design gates at thickest sections with generous draft (2-3 degrees). HDPE is the #1 recycled plastic globally. Min wall: 0.8mm. Blow molding is ideal for bottles and hollow parts.
PS / HIPS
Injection Molding - CommodityCrystal-clear GPPS for disposable packaging. HIPS adds rubber impact modifier for appliance housings and consumer goods. Very easy to process with fast cycles.
Very low costClear (GPPS)Brittle (GPPS)
Density: 1.04-1.06Tensile: 25-45 MPaHDT: 70-95C
Relative Cost
Physical Properties
| Property | GPPS | HIPS |
|---|---|---|
| Density | 1.04 g/cm3 | 1.06 |
| Tensile | 45 MPa | 25 MPa |
| Impact | 15 J/m (brittle) | 100-150 J/m |
| Transparent | Yes (88%) | Opaque |
| HDT | 95C | 70-85C |
| Melt Temp | 180-260C | 180-240C |
Molding Guidance
| Factor | Note |
|---|---|
| Best For | Packaging, cups, appliance housings |
| Mold Temp | 20-60C (low!) |
| vs ABS | Cheaper but lower impact and HDT |
| Flame Retardant | HB rating standard; V-2 possible |
| UV Resistance | Poor - yellows in sunlight |
| Cost per kg | $1.30-2.50 USD |
Tip: PS is one of the easiest plastics to mold with very fast cycle times. GPPS is crystal clear but brittle - do not use for load-bearing parts. HIPS is opaque but much tougher. Both are excellent for thermoforming. Min wall: 0.8mm. Draft: 1-2 degrees.
AS (SAN)
Injection Molding - TransparentTransparent styrene-acrylonitrile copolymer. Better chemical resistance and hardness than PMMA. Good clarity with higher rigidity. Used for cosmetic packaging and household items.
TransparentChemical res.Low cost
Density: 1.08 g/cm3Tensile: 75 MPaLT: 88%HDT: 100C
Relative Cost
Physical Properties
| Property | Value |
|---|---|
| Density | 1.08 g/cm3 |
| Tensile Strength | 75 MPa |
| Flexural Modulus | 3.8 GPa |
| HDT @ 1.8MPa | 100C |
| Light Transmission | 88% |
| Hardness (Rockwell) | 115 M |
Molding Guidance
| Factor | Note |
|---|---|
| Best For | Cosmetic packaging, household items, cups |
| Mold Temp | 40-80C |
| vs PMMA | Better chemical resistance, cheaper |
| vs PC | Lower impact but easier to mold |
| Blending | Often blended with ABS (AS+ABS) |
| Cost per kg | $2-3.50 USD |
Tip: SAN is a cost-effective alternative to PMMA when chemical resistance matters more than maximum clarity. Often used in blends with ABS to improve transparency and surface hardness. Must be dried before molding. Min wall: 0.8mm. Good for thin-wall applications.
PVC (Rigid / Flexible)
Injection Molding / ExtrusionMost versatile construction plastic. Rigid PVC for pipes and fittings. Flexible PVC (with plasticizer) for tubing and seals. Excellent flame retardancy and chemical resistance.
Low costFlame retardantRequires stabilizer
Density: 1.35-1.45Tensile: 40-55 MPaHDT: 55-80CLOI: 45%+
Relative Cost
Physical Properties
| Property | Rigid | Flexible |
|---|---|---|
| Density | 1.35-1.45 | 1.15-1.35 |
| Tensile | 40-55 MPa | 10-25 MPa |
| Hardness | 80-85 Shore D | 50-95 Shore A |
| HDT | 55-80C | <40C |
| LOI | 45%+ | 25-35% |
| Flammability | Self-extinguishing | Slow burning |
Molding Guidance
| Factor | Note |
|---|---|
| Best For | Pipes, fittings, tubing, profiles, wire insulation |
| Mold Temp | 30-60C |
| Decomposition | Releases HCl above 200C - use stabilizer |
| Heat Stabilizer | Required (tin, calcium/zinc based) |
| Plasticizer | Phthalates or bio-based alternatives |
| Cost per kg | $1.20-2.50 USD |
Tip: PVC degrades above 200C releasing hydrochloric acid. Always use heat stabilizers. Rigid PVC has the highest LOI (oxygen index) of commodity plastics making it naturally flame retardant. Corrosive to molds - use chrome-plated or stainless steel molds. Min wall: 1.0mm.
PPS
Injection Molding - High PerformanceSemi-crystalline high-temperature polymer. Continuous use to 220C. Excellent chemical resistance to virtually all solvents. The standard for automotive under-hood electrical components.
220C continuousChemical proofExpensive
Density: 1.35 g/cm3Tensile: 85 MPa (GF40)HDT: 260C (GF40)Max Use: 220C
Relative Cost
Physical Properties
| Property | Value |
|---|---|
| Density | 1.35 g/cm3 (GF40) |
| Tensile Strength | 85 MPa (GF40) |
| Flexural Modulus | 11.5 GPa (GF40) |
| HDT @ 1.8MPa | 260C (GF40) |
| Max Continuous | 220C |
| Flammability | V-0 @ 0.4mm |
Molding Guidance
| Factor | Note |
|---|---|
| Best For | Under-hood electrical, pump housings |
| Mold Temp | 130-150C (high!) |
| Chemical Res. | Excellent - virtually all solvents |
| GF Content | Almost always 30-40% glass filled |
| vs PEEK | Lower cost, lower ductility |
| Cost per kg | $15-30 USD |
Tip: PPS is almost always used with 30-40% glass fiber. Unfilled PPS has limited use. Requires very high mold temperatures (130-150C) for crystallization. Poor weld line strength - design to avoid. Excellent for SMT reflow (260C peak) connectors. Min wall: 0.8mm.
PPSU
Injection Molding - Medical GradeAmber-transparent polyphenylsulfone. Superior impact and hydrolysis resistance vs PEI and PES. Autoclavable 1000+ cycles. The gold standard for reusable surgical instruments and sterilization trays.
AutoclavableImpact resistantVery expensive
Density: 1.29 g/cm3Tensile: 75 MPaHDT: 207CAutoclave: 1000+ cycles
Relative Cost
Physical Properties
| Property | Value |
|---|---|
| Density | 1.29 g/cm3 |
| Tensile Strength | 75 MPa |
| Flexural Modulus | 2.4 GPa |
| HDT @ 1.8MPa | 207C |
| Notched Izod | 690 J/m (exceptional) |
| Steam Sterilization | 1000+ cycles @ 134C |
Molding Guidance
| Factor | Note |
|---|---|
| Best For | Surgical instruments, sterilization trays |
| Mold Temp | 150-180C |
| vs PEI | Better impact and hydrolysis resistance |
| Biocompatible | ISO 10993, USP Class VI |
| Transparent | Amber tint (inherent color) |
| Cost per kg | $50-100 USD |
Tip: PPSU's notch impact strength (690 J/m) is among the highest of any thermoplastic. It survives repeated steam sterilization where PEI and PES would crack. Natural amber color cannot be changed to water-clear. Mold at 150-180C for proper flow. Min wall: 1.0mm.
EVA
Injection / Foam / ExtrusionSoft, flexible, rubber-like copolymer. Shore A 40-95 depending on VA content. Widely used for foam shoe soles, packaging inserts, and flexible tubing. Excellent low-temperature flexibility.
SoftLow costLow temp flex
Density: 0.92-0.95Hardness: Shore A 40-95VA Content: 5-40%
Relative Cost
Physical Properties
| Property | Value |
|---|---|
| Density | 0.92-0.95 g/cm3 |
| Hardness | Shore A 40-95 |
| Tensile Strength | 5-25 MPa |
| Elongation | 500-1000% |
| Service Temp | -70 to 65C |
| VA Content Effect | Higher VA = softer, more flexible |
Molding Guidance
| Factor | Note |
|---|---|
| Best For | Shoe soles, foam, tubing, toys |
| Mold Temp | 20-50C |
| Foam Grades | Cross-linked for foam expansion |
| vs TPE | Cheaper but not as overmoldable |
| UV Resistance | Good - outdoor use OK |
| Cost per kg | $2-4 USD |
Tip: VA (vinyl acetate) content determines properties: 5-10% VA is stiff like LDPE; 18-28% is flexible like rubber; 33-40% is adhesive-grade. Cross-linked EVA foam (by peroxide or radiation) creates the lightweight cushioning in shoe midsoles. Min wall: 1.0mm.
POE
Injection Molding - ToughenerPolyolefin elastomer based on metallocene catalyst technology. Exceptional toughness and impact modifier for PP and PA. Maintains flexibility at very low temperatures. Used for automotive bumpers and impact-modified compounds.
Impact modifierLow tempTough
Density: 0.86-0.91Hardness: Shore A 60-95Tensile: 5-25 MPa
Relative Cost
Physical Properties
| Property | Value |
|---|---|
| Density | 0.86-0.91 g/cm3 (very light) |
| Hardness | Shore A 60-95 |
| Tensile Strength | 5-25 MPa |
| Elongation | 500-1500% |
| Service Temp | -60 to 80C |
| Notched Izod | Does not break (no notch sensitivity) |
Molding Guidance
| Factor | Note |
|---|---|
| Best For | Impact modifier, flexible parts, bumpers |
| Mold Temp | 20-60C |
| Toughening | Add 5-20% to PP/PA for impact |
| vs EPDM | Better flow, no peroxide needed |
| Recycling | Fully recyclable with PO base |
| Cost per kg | $3-6 USD |
Tip: POE is primarily used as an impact modifier rather than a standalone material. Adding 10-20% POE to PP dramatically improves low-temperature impact while maintaining stiffness. Unlike EPDM rubber, POE can be processed on standard thermoplastic equipment without vulcanization. Min wall: 0.8mm.
TPE (SBC/TPV)
Injection Molding - ElastomerRecyclable thermoplastic elastomer. Overmolds onto PP and ABS. Shore A 20-90. Soft-touch grips, seals, vibration dampeners.
RecyclableOvermoldableLow cost
Density: 0.89-1.15Hardness: Shore A 20-90Elongation: 200-500%
Relative Cost
Physical Properties
| Property | Value |
|---|---|
| Density | 0.89-1.15 g/cm3 |
| Hardness | Shore A 20-90 |
| Tensile Strength | 3-25 MPa |
| Elongation @ Break | 200-500% |
| Compression Set | 15-50% |
| Service Temp | -50 to 135C |
Molding Guidance
| Factor | Note |
|---|---|
| Best For | Soft grips, seals, overmolding |
| Overmold Substrates | PP (excellent), ABS (good) |
| Mold Temp | 30-60C |
| vs LSR | Cheaper but lower temp resistance |
| Recycling | Fully recyclable |
| Cost per kg | $4-10 USD |
Tip: For overmolding, substrate must be clean. Bond strength depends on Shore A - softer TPE (<50A) bonds better but is harder to eject. Overmold thickness: 1.0-3.0mm. Include undercuts or mechanical anchors for critical bonds.
Liquid Silicone Rubber (LSR)
Injection Molding - ElastomerHeat resistant to 230C, biocompatible, food-safe. Platinum-cured with fast cycle times. Premium choice for medical and kitchen products.
BiocompatibleHigh tempExpensive
Density: 1.10-1.50Hardness: Shore A 10-80Max Temp: 230C
Relative Cost
Physical Properties
| Property | Value |
|---|---|
| Density | 1.10-1.50 g/cm3 |
| Hardness | Shore A 10-80 |
| Tensile Strength | 5-12 MPa |
| Elongation | 300-800% |
| Compression Set | <15% (excellent) |
| Service Temp | -60 to 230C |
Molding Guidance
| Factor | Note |
|---|---|
| Best For | Medical devices, baby products, seals |
| Cure System | Platinum (addition cure) |
| Equipment | Requires LSR metering system |
| Biocompatible | ISO 10993, USP Class VI |
| Sterilization | Autoclave, gamma, EtO |
| Cost per kg | $20-50 USD |
Tip: LSR molds run cold (10-30C) with heated cavities. Cold runner systems reduce waste by 95% vs traditional runners. Flash is common - design 0.02-0.05mm venting. LSR flows exceptionally well - walls as thin as 0.2mm possible.
SLA Resins
3D Printing - Photopolymer25-100um layer height. Smooth surface, fine details. Multiple formulations: standard, tough, high-temp, flexible, castable.
Smooth surfaceFine detailFast
Layer: 25-100 umTolerance: +/-0.1mmRa: 1-3 um
Relative Cost
Resin Types
| Type | Key Property |
|---|---|
| Standard | Good detail, general purpose |
| Tough/Durable | Impact resistant, PP-like |
| High Temp | HDT 230-290C |
| Flexible | Shore A 30-90 |
| Castable | Zero ash for investment casting |
| Biocompatible | USP Class VI (limited) |
Application Guidance
| Factor | Note |
|---|---|
| Best For | Visual prototypes, fit checks |
| Limitation | UV degradation outdoors |
| Post-Cure | Required for full properties |
| Support Marks | Visible on bottom surfaces |
| Max Dimension | ~300 x 300 x 400mm |
| Cost per liter | $50-200 USD |
Tip: SLA parts require isotropic UV post-cure to achieve datasheet properties. Without post-cure, strength is 40-60% lower. Design supports carefully - they leave witness marks. Min wall: 0.8mm. Holes <1mm may close during printing.
SLS Nylon (PA12)
3D Printing - Powder Bed Fusion100um layer height. Durable functional parts with complex geometries. No support structures needed. Good chemical resistance.
No supportsDurableComplex geometry
Layer: 100 umTensile: 48 MPaElongation: 15-20%
Relative Cost
Physical Properties
| Property | Value |
|---|---|
| Density | 0.98-1.01 g/cm3 |
| Tensile Strength | 48 MPa |
| Flexural Modulus | 1.65 GPa |
| Elongation @ Break | 15-20% |
| Impact (Izod) | 35 J/m |
| Service Temp | Up to 115C |
Application Guidance
| Factor | Note |
|---|---|
| Best For | Functional prototypes, brackets, ducts |
| Supports | None needed (self-supporting) |
| Surface | Slightly grainy (bead blast to improve) |
| Dyeing | Can be dyed various colors |
| vs MJF PA12 | SLS has better surface; MJF faster |
| Cost per kg | $60-100 USD |
Tip: SLS PA12 has a slightly porous surface that absorbs moisture. Seal with epoxy or vapor smoothing for watertight applications. Glass-filled PA12 (PA12-GF) increases stiffness by 40% but reduces impact. Min wall: 0.7mm. Max unsupported overhang: 45 degrees.
Sheet Metal (Al/Steel/SS)
Laser Cutting, Bending, StampingLaser-cut and formed metal parts for enclosures, brackets, chassis. Aluminum 5052, CRS 1018, SS 304. Secondary: welding, PEM, powder coat.
AluminumSteelPowder CoatAnodize
Thickness: 0.5-10mmTolerance: +/-0.1mmMax Size: 1500x3000mm
Relative Cost
Material Options
| Material | Tensile | Cost/kg |
|---|---|---|
| Aluminum 5052-H32 | 228 MPa | $6-10 |
| Cold Rolled Steel 1018 | 440 MPa | $2-4 |
| Stainless Steel 304 | 515 MPa | $8-15 |
| Copper C110 | 220 MPa | $10-18 |
| Galvanized Steel | 270 MPa | $3-5 |
Fabrication Capabilities
| Process | Capability |
|---|---|
| Laser Cutting | +/-0.1mm tolerance, up to 25mm |
| CNC Bending | Up to 8-axis, +/-0.2 deg |
| Stamping | Progressive dies, high volume |
| Welding | TIG, MIG, spot welding |
| Hardware | PEM inserts, rivets |
| Finishing | Anodize, powder coat, plating |
Tip: Minimum bend radius = material thickness (1T) for soft aluminum, 2T for steel. For holes near bends, keep distance > 2 x thickness + bend radius. Standard K-factor: 0.44 for Al, 0.42 for steel. Design bend relief notches to prevent tearing.
Quick Material Comparison
Side-by-side comparison of commonly specified plastics. Hover the table for 3D blueprint view. Use search to filter.
Precision-molded transparent medical components — PC, PMMA, AS (SAN)
29 materials
| Material | Key Benefits | Best Applications | Processing Notes |
|---|---|---|---|
| PP | Inexpensive, chemical resistant, flexible, food-safe | Packaging, hinges, automotive | Shrinks 1-2.5%; warps easily |
| ABS | High impact, low cost, easy finish, paintable | Housings, toys, automotive trim | Must dry 2-4hrs @ 80C |
| PC | Highest impact (transparent), HDT 138C | Safety glasses, medical, lighting | High mold temp 80-120C req. |
| PC-ABS | PC strength + ABS processability | Electronics, handheld devices | Vulnerable to solvents |
| PA66 | Strong, wear/fatigue resistant | Gears, bearings, connectors | Absorbs 2.5% moisture |
| POM | High stiffness, low friction, self-lub | Precision gears, sliding parts | Prone to warping |
| PEEK | Continuous use 250C, biocompatible | Aerospace, medical implants | Very expensive; heated mold >150C |
| PEI (Ultem) | HDT 217C, flame retardant V-0 | Medical, aircraft interiors | Very expensive |
| TPE | Flexible, recyclable, overmoldable | Grips, seals, overmolding | Lower temp resistance |
| TPU | Abrasion resistant, oil resistant | Footwear, tubing, wheels | Hygroscopic; pricey |
| LSR | Heat resistant 230C, biocompatible | Medical, baby products, seals | Requires LSR molding system |
| PA6 | Tough, wear resistant, easier than PA66 | Gears, cable ties, structural | Absorbs 3% moisture |
| PBT | Low moisture, excellent electrical | Connectors, switches, auto | Stress cracks with chemicals |
| PMMA | 92% transparent, UV stable | Displays, signage, lenses | Brittle - notch sensitive |
| HDPE/LDPE | Lowest cost, food safe, recyclable | Bottles, containers, pipes | Very high shrinkage 1.5-4% |
| PS/HIPS | Very low cost, clear (GPPS) | Packaging, cups, appliances | Brittle (GPPS); UV degrades |
| AS (SAN) | Transparent, chemical resistant | Cosmetic packaging, household | Lower impact than PMMA/PC |
| PVC | Flame retardant, chemical resistant | Pipes, fittings, wire insulation | Decomposes >200C (HCl gas) |
| PPS | 220C continuous, chemical proof | Under-hood electrical, pumps | Almost always needs GF |
| PPSU | Autoclavable 1000+, high impact | Surgical instruments, trays | Very expensive; amber color |
| EVA | Soft, flexible, foam capable | Shoe soles, foam, tubing | Low HDT; not for high temps |
| POE | Impact modifier, super tough | Bumper modifiers, flexible parts | Usually blended, not standalone |
Processing Guide & Additives
Critical processing parameters and filler options to optimize your material selection.
Resin Processing Tips
Key parameters every design engineer should understand before committing to tooling.
OK
PP shrinks 1-2.5% - design gates and cooling carefully to minimize warpingOK
ABS is hygroscopic - must dry 2-4 hrs @ 80C before moldingOK
PC requires mold temp 80-120C to avoid stress crackingOK
Nylon absorbs moisture (up to 2.5%) - post-mold conditioning neededOK
PEEK demands heated molds >150C, specialized screws, controlled coolingOK
Glass-filled resins shrink less but increase mold wear 3-5xAdditives, Fillers & Modifiers
Enhance base resin properties with targeted additives for specific performance needs.
Glass Fiber (10-40%)
Increases tensile strength, stiffness and HDT. Makes resin more brittle and abrasive to molds.
Carbon Fiber (10-30%)
Superior stiffness-to-weight. ESD safe. Higher cost than glass. Excellent for structural parts.
Mineral Fillers (Talc, Clay)
Reduces cost, increases hardness and dimensional stability. Lower shrinkage than pure resin.
PTFE / MoS2 (5-15%)
Self-lubricating for bearing/sliding apps. Reduces friction coefficient from 0.4 to 0.1.
UV Stabilizers (1-3%)
Essential for outdoor use. HALS and UV absorbers prevent degradation from sunlight.
Flame Retardants
Brominated or halogen-free phosphorus-based. Achieves UL 94 V-0 at 0.8mm.
Industry Certifications
Material grades matched to your industry requirements and regulatory standards.
Aerospace - AS9100D
PEEK, Ultem, Titanium Gr5, Al 7075. Heat and flame resistance for cabin and engine components.
Medical - ISO 13485
Titanium, PEI, PPSU, LSR. Biocompatible per ISO 10993, sterilizable, chemically resistant.
Electronics - UL / RoHS
ABS-FR, PC-ABS, Copper. EMI shielding, electrical insulation, UL 94 V-0 flame retardancy.
Automotive - IATF 16949
PP, PA66-GF, PBT, TPV. Heat resistant, chemically stable for under-hood and interior.
Food & Beverage - FDA
PP, HDPE, LSR, SS 316L. FDA 21 CFR compliant, chemically resistant, easy to clean.
Marine & Offshore
Titanium Gr2, SS 316L, Cu-Ni 90/10. Outstanding corrosion resistance in saltwater.
Surface Finish Standards
SPI mold finish grades and post-processing options for every application.
SPI Mold Finish Standards
A high-gloss mold finish does not guarantee a glossy part. Final appearance depends on resin type, molding conditions, and geometry. Amorphous materials (PC, ABS) replicate mold texture better than semi-crystalline (PP, PA).
A
SPI A-1 to A-3 - Diamond buff, mirror
Ra < 0.10 um
B
SPI B-1 to B-3 - Fine grit, semi-gloss
Ra 0.10-0.30 um
C
SPI C-1 to C-3 - Matte stone finish
Ra 0.30-0.80 um
D
SPI D-1 to D-3 - Textured/satin
Ra 0.80-3.00 um
M
As-Machined - Tool marks visible
Ra 3.2-6.3 um
Post-Processing Options
Bead blasting · Anodizing (Type II/III) · Electro-polishing · Chrome/Nickel plating · Vapor polishing (PC/acrylic) · Powder coating · Laser marking · PVD coating · Chem film (Alodine) · Passivation
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