The Top Chinese Metal CNC Machining Partner
We Offer a Variety of Injection Molding Materials
Material selection determines whether a part works, lasts, can be made cost-effectively, and meets all functional and regulatory demands. Skipping this step leads to redesigns, production delays, or field failures.
Check out our wide selection of quality materials, those materials meeting the needs of different projects for strength, corrosion resistance, and specialized physical properties for customized parts by CNC machining, injection molding, sheet metal fabrication and 3D printing, vacuum casting, die casting for both prototyping and production stages.
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- RPD Provide 24/7 Engineering Support All Year Round.
- All tools and dies are engineered and produced in house
- More Than 60+ Certified Materials for Choose. Offer CoCs, Material Certifications, Inspection Reports.
- ISO 9001:2015 quality standards.
- Expert DFM & process optimization
Why does material selection matter so much for custom parts?
Choosing the right material for custom parts is critical because it directly impacts performance, cost, manufacturability, and longevity.
Mechanical & Physical Properties
Application Environment
Manufacturing Compatibility
Cost & Lead Time
Surface Finish & Aesthetics
Regulatory & Safety Requirements
Custom Parts with More than 60+ Materials
Provide Various Materials Injection Molding One-Stop Services for Different Industries.
Polyoxymethylene (POM) is a highly crystalline engineering plastic. It has a distinct melting point, and once melted, its viscosity drops rapidly, offering excellent flowability. However, its molding shrinkage is relatively high, typically ranging from 1.5% to 2.5%.
Often call “acetal” or “steel-like plastic,” POM exhibits mechanical properties close to those of metals. It features high strength, high rigidity, and outstanding fatigue resistance, wear resistance, and self-lubricating properties, making it widely used in components such as gears and bearings.
Features of POM CNC Machining Materials
| Content | Description | Content | Description | Content | Description | Features | Typical Application | Cost |
| Density (g/cm³) | 1.41 – 1.42 | Melting temperature (℃) | 190-230 | Hardness (R Scale) | 120 – 127 | High strength / Good rigidity | Precision gears, bearings, valve seats, zippers, conveyor belt parts, clasps | ★★★☆☆ |
| Impact strength (kJ/m²) | 7 – 10 | Shrinkage rate (%) | 1.5-2.5 | Water Absorption | 0.2% – 0.5% |
Bracketing the prohibitive material costs and formidable processing conditions, PEEK injection molding represents the ultimate solution for high-performance precision parts destined for uncompromising environments—those characterized by high temperature, corrosion, and wear.
Features of PEEK Injection Molding Materials
| Content | Description | Content | Description | Content | Description | Features | Typical Application | Cost |
| Density (g/cm³) | 1.30 – 1.32 | Melting temperature (℃) | 360-400 | Hardness (R Scale) | 126 – 132 | High temperature resistant, resistant to chemicals (except concentrated sulfuric acid), high mechanical strength, wear-resistant, radiation-resistant. | Aerospace structural components, medical implants, semiconductor fixtures, high-temperature seals, oilfield parts, etc. | ★★★★★ |
| Impact strength (kJ/m²) | 7 – 10 | Shrinkage rate (%) | 1.0-1.5 | Water Absorption | 0.45% |
PMMA material known as acrylic or Plexiglas, is widely used in optical lenses, display panels, lampshades, and other high-transparency applications due to its excellent transparency, weathering resistance, high hardness, scratch-resistance, light weight and processability, making it suitable for electronics, automotive, medical equipment, architectural decoration industries, meeting the demands for aesthetics, durability and light weight. PMMA CNC machining parts are suitable for electronics, automotive, medical equipment and architectural decoration fields.
Features of PMMA CNC Machining Materials
| Type | Density (g/cm³) | Tensile Strength (MPa） | Tensile Modulus (MPa） | Heat deflection temperature (°C) | Impact strength (kJ/m²) | Hardness (R Scale) | Water Absorption | Thermal Expansion (µm/m°C) | Optical transmittance |
| Casting PMMA | 1.18 – 1.20 | 65 – 75 | 3100 – 3300 | 95 – 105 | 1.5 – 2.0 | 95 – 105 | 0.3% – 0.4% | 6.0 – 8.0 | 92%-93% |
| Extruded PMMA | 1.17 – 1.19 | 60 – 70 | 3000 – 3200 | 85 – 95 | 1.0 – 1.8 | 90 – 100 | 0.3% – 0.4% | 7.0 – 9.0 | 90%-92% |
| High Impact PMMA | 1.18-1.20 | 55-65 | 2800-3100 | 80-95 | 8.0 – 25.0+ | 85-100 | 0.3% – 0.5% | 7.0 – 10.0 | 85%-91% |
| UV Stabilized PMMA | 1.19-1.20 | 60-70 | 3000-3300 | 85-100 | 1.5 – 2.5 | 90-105 | 0.3% – 0.4% | 6.0 – 8.0 | 91%-92% |
ABS material is suitable for the manufacture of complex geometric parts as its excellent mechanical properties, impact resistance, toughness, and heat resistance. ABS material is easy to cut, has a smooth surface, easy to color and paint. ABS CNC machining parts commonly used in automotive parts, electronic housings & home appliances. Its insulating properties also make it suitable for electrical equipment.
Features of ABS CNC Machining Materials
| Type | Density (g/cm³) | Tensile Strength (MPa） | Tensile Modulus (MPa） | Heat deflection temperature (°C) | Impact strength (kJ/m²) | Hardness (R Scale) | Water Absorption | Thermal Expansion (µm/m°C) |
| General-purpose ABS | 1.04 – 1.06 | 40 – 47 | 2200 – 2500 | 85 – 95 | 20 – 30 | 105 – 115 | 0.20% – 0.45% | 6.5 – 9.5 |
| High-impact ABS | 1.03 – 1.05 | 35 – 42 | 1900 – 2200 | 85 – 95 | 35 – 50 | 100 – 110 | 0.25% – 0.50% | 7.0 – 10.0 |
| ABS Flame Retardant Grade | 1.08-1.10 | 30- 40 | 1400-1900 | 80-95 | 10-20 | 80-95 | 0.15% – 0.35% | 7.5 – 11 |
| Heat-resistant/electroplated grade ABS | 1.03 – 1.07 | 45 – 52 | 2300 – 2600 | 95 – 105 | 15 – 25 | 110 – 118 | 0.10% – 0.25% | 6.0 – 8.5 |
Provided that moisture is tightly controlled and the high shrinkage is acceptable, PA is well-suited for precision moving components that demand high strength, wear resistance, and oil tolerance.
Features of Nylon/PA Injection Molding Materials
| Content | Description | Content | Description | Content | Description | Features | Typical Application | Cost |
| Density (g/cm³) | 1.20 – 1.22 | Melting temperature (℃) | 260-310 | Hardness (R Scale) | 118 – 123 | Ultra-high impact strength, high transparency, good dimensional stability, and excellent electrical insulation properties. | Headlights lenses, safety helmets, mobile phone casings, etc. | ★★★☆☆ |
| Impact strength (kJ/m²) | 15 – 25 | Shrinkage rate (%) | 0.5-0.7 | Water Absorption | 0.20% |
PP injection molding is ideal for low-cost, high-volume general-purpose parts that demand chemical resistance — though trade-offs include high shrinkage and low rigidity.
Features of PP Injection Molding Materials
| Content | Description | Content | Description | Content | Description | Features | Typical Application | Cost |
| Density (g/cm³) | 0.90 – 0.91 | Melting temperature (℃) | 200-260 | Hardness (R Scale) | 60-70 | The lightest general-purpose plastic, with excellent fatigue resistance. | Car bumpers, instrument panels, food containers, medical devices, household appliance components, etc. | ★★☆☆☆ |
| Impact strength (kJ/m²) | 3-6 | Shrinkage rate (%) | 1.0-2.5 | Water Absorption | < 0.01 |
PE injection molding is ideal for parts demanding low cost, high throughput, chemical resistance, and good flexibility — though the trade-offs include significant shrinkage and poor thermal stability.
Features of HDPE Injection Molding Materials
| Content | Description | Content | Description | Content | Description | Features | Typical Application | Cost |
| Density (g/cm³) | 0.945 – 0.955 | Melting temperature (℃) | 180-240 | Hardness (R Scale) | 60-70 | Resistant to chemical corrosion, good toughness, excellent low-temperature impact resistance (-50℃ maintains toughness), and low cost | Household items, chemical containers, toys, etc. | ★★☆☆☆ |
| Impact strength (kJ/m²) | High | Shrinkage rate (%) | 1.5-3.0 | Water Absorption | < 0.01 |
PC injection molding is ideal for precision components demanding optical clarity, impact strength, and dimensional stability, provided that strict pre-drying and management of high melt viscosity are enforced.
Features of PC Injection Molding Materials
| Content | Description | Content | Description | Content | Description | Features | Typical Application | Cost |
| Density (g/cm³) | 1.20 – 1.22 | Melting temperature (℃) | 260-310 | Hardness (R Scale) | 118 – 123 | Ultra-high impact strength, high transparency, good dimensional stability, and excellent electrical insulation properties. | Headlights lenses, safety helmets, mobile phone casings, etc. | ★★★☆☆ |
| Impact strength (kJ/m²) | 15 – 25 | Shrinkage rate (%) | 0.5-0.7 | Water Absorption | 0.20% |
PPS injection molding is ideal for precision components that demand high heat resistance (up to 260°C), chemical resistance, and excellent rigidity. However, it requires a high mold temperature (130-150°C), and the material itself is relatively brittle.
Features of PPS Injection Molding Materials
| Content | Description | Content | Description | Content | Description | Features | Typical Application | Cost |
| Density (g/cm³) | 1.35 – 1.42 | Melting temperature (℃) | 300-340 | Hardness (R Scale) | 85-90 | High rigidity, with excellent heat resistance up to 200℃, and extremely strong chemical resistance. | Automobile sensors, electronic and electrical components, chemical-resistant pump bodies, high-temperature connectors, etc. | ★★★☆☆ |
| Impact strength (kJ/m²) | medium | Shrinkage rate (%) | 0.5-1.4 | Water Absorption | ＜0.05% |
PEI injection molding is ideal for precision components that demand high-temperature resistance (up to 170°C), high strength, and inherent flame retardancy. However, it necessitates high mold temperatures (130-180°C) and rigorous drying.
Features of PEI Injection Molding Materials
| Content | Description | Content | Description | Content | Description | Features | Typical Application | Cost |
| Density (g/cm³) | 1.27 | Melting temperature (℃) | 340-400 | Hardness (R Scale) | 85-90 | Amorphous high-temperature material, naturally flame-retardant | Medical/electronic enclosures, aircraft interior components, high-temperature resistant connectors, etc. | ★★★★☆ |
| Impact strength (kJ/m²) | Extremely high | Shrinkage rate (%) | 0.5-0.7 | Water Absorption | 0.25% |
PVC is an ideal material for applications that demand low cost, chemical resistance, and natural flame retardancy, despite its challenging processing characteristics and limited heat resistance.
Features of PVC Injection Molding Materials
| Content | Description | Content | Description | Content | Description | Features | Typical Application | Cost |
| Density (g/cm³) | 1.38 – 1.45 | Melting temperature (℃) | 170-210 | Hardness (R Scale) | 74 – 81 | Flame-retardant, inexpensive, corrosion-resistant | Corrosion-resistant pipe fittings, electrical insulation components, commercial machine enclosures, and medical device enclosures, etc. | ★★☆☆☆ |
| Impact strength (kJ/m²) | 3-10 | Shrinkage rate (%) | 0.2-0.6 | Water Absorption | 0.2-0.6% |
PS injection molding is ideal for low-cost, easy-to-mold, and high-rigidity parts (both transparent and opaque). However, the material is brittle and has poor heat resistance.
Features of PS Injection Molding Materials
| Content | Description | Content | Description | Content | Description | Features | Typical Application | Cost |
| Density (g/cm³) | 1.04 – 1.09 | Melting temperature (℃) | 180-240 | Hardness (R Scale) | 65-75 | Transparent, hard, easy to process, low in price | Stationery, toys, cosmetic packaging, etc. | ★★☆☆☆ |
| Impact strength (kJ/m²) | Low | Shrinkage rate (%) | 0.4-0.7 | Water Absorption | ＜0.2% |
PBT (Polybutylene Terephthalate) is suitable for electronic/automotive parts requiring chemical resistance, good electrical insulation, and high rigidity, but it requires strict pre-drying and has a high shrinkage rate.
Features of PBT Injection Molding Materials
| Content | Description | Content | Description | Content | Description | Features | Typical Application | Cost |
| Density (g/cm³) | 1.27 | Melting temperature (℃) | 230-260 | Hardness (R Scale) | 75-85 | Excellent electrical insulation properties, standard material for the connector industry | Automobile electrical connectors, relays, ignition coil casings, optical fiber sheaths, electric tool casings, etc. | ★★★☆☆ |
| Impact strength (kJ/m²) | Medium | Shrinkage rate (%) | 1.3-2.4 | Water Absorption | High |
TPU (Thermoplastic Polyurethane) is suitable for overmolding or shock-absorbing parts requiring high elasticity, wear resistance, and softness, but it requires strict pre-drying and has a narrow processing window.
Features of TPU Injection Molding Materials
| Content | Description | Content | Description | Content | Description | Features | Typical Application | Cost |
| Density (g/cm³) | 1.27 | Melting temperature (℃) | 190-230 | Hardness (R Scale) | 60-95 | Rubber elastomer, with the best wear resistance | Mobile phone cases, air cushions, hoses, cable sheaths, sealing rings, mechanical shock-absorbing pads, etc. | ★★★☆☆ |
| Impact strength (kJ/m²) | Extremely high | Shrinkage rate (%) | 0.5-1.5 | Water Absorption | High |
Blog & News
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What is CNC Machining?
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FAQs About Our NPI Solutions Services
Why Tooling?
Tooling is the foundation of high-volume, repeatable manufacturing. Tooling turns a slow, manual process into a fast, automated, high-volume production system. If you need mass production, you must be choose tooling and molding production.
What kind of equipment do you use?
The molding workshop includes EDM, wire EDM, 50+CNC machining center, 50+injection machines ranging from 80 to 1000 tons, ect to meet different production requirements. Request equipment list, contact our team: ashely@rpdmfg.com.
Do you support export mold or production?
Yes, exactly. We support both. You can either for use at your own facility or leave it with us for long-term molding production.
What is your quality control system?
We operate under a rigorous Quality Management System (QMS) aligned with ISO standards. Our 5 Steps QC process is including IQC (Incoming Quality Control) , FQC (Final Quality Control) , OQC (Outgoing Quality Control) for routine production.
QE (Quality Engineering) / CAPA (Corrective and Preventive Actions) implemented throughout the entire product lifecycle, especially during the post-sale stage, to drive continuous improvement. Simply speaking 100% inspection before shipment to ensure zero defects.
What kind of quality assurance or warranty do you offer on orders?
One of the reasons engineers purchase from RPD is that we take on all the risks for you. We guarantee you’ll love what you get. Not happy with it? We’ll either redo it or give you a full refund. Your purchase is completely risk-free.
Why injection tooling is so expensive?
Material – Hardened steel (costly but durable for high volume)
Complexity – CNC, EDM, polishing; multi-cavity, undercuts add cost
Precision – Tight tolerances require advanced equipment & skilled labor
Customization – Every mold is custom-built for a specific part
Engineering – Significant design time for cooling, ejection, and geometry
Which kind of file formats can I send for tooling& production?
We accept STEP, IGES, STL, DWG, DXF, and other common CAD formats.
What Factors will Influence Tooling Design?
1. Part Geometry – Shape, size, and complexity drive mold design. Thin walls, intricate details, and complex geometries require specialized features like additional cooling or advanced gating systems.
2. Material Selection – The plastic type affects cooling rates, shrinkage, and flow. Polypropylene shrinks more; polycarbonate needs higher mold temperatures. Abrasive or corrosive plastics also demand wear-resistant mold materials.
3. Tolerances & Precision – High-precision parts (automotive, medical) require tighter mold tolerances — which complicates design and increases cost.
4. Ejection System – Ejector pins, air blasts, or stripper plates must be carefully integrated to remove parts without damage — affecting both design and cycle time.
5. Gate Design – Gate type and location (direct, pin, edge) control how molten plastic enters the mold, impacting part quality, surface finish, and cycle time.
6. Undercuts & Parting Lines – Undercuts or complex shapes may require side actions or lifters to release the part, increasing mold complexity and cost.
Can we store the mold at your facility for future production orders? Do you provide free maintenance for the mold?
Yes, we offer two key benefits for molds set up at our facility: free storage and free maintenance.