ISO 9001 & AS9100 Certified Plastic Machining & Molding
Plastic Materials: Properties, Types & Machining
Plastic materials are synthetic or semi-synthetic polymers that can be molded, extruded, or machined into finished parts. They range from low-cost commodity resins such as polypropylene and polystyrene to high-performance polymers such as PEEK and PTFE that withstand extreme temperatures and aggressive chemicals.
At Baetro, we help engineers select the right plastic material and manufacture custom parts to ±0.001 inch, with instant quotes, no minimum order quantity, and 3–7 day lead times. Whether you are designing a lightweight housing, a wear-resistant bearing, or a medical-grade component, understanding plastic material properties and categories helps you balance performance, cost, and manufacturability.
±0.001″
Machining tolerance
3–7 days
Standard lead time
Free DFM
On every quote
MOQ 1
Prototype to production
Plastic Materials Fundamentals
What Are Plastic Materials?
Plastic materials are made from long-chain molecules called polymers. Most engineering plastics are produced from petrochemical feedstocks, although bio-based and recycled options are growing. The molecular structure of a polymer determines its mechanical, thermal, and chemical properties, which is why material selection matters so much for part performance.
Unlike metals, plastics are generally lightweight, electrically insulating, and resistant to corrosion. They can be softened and reshaped repeatedly if they are thermoplastics, or permanently set if they are thermosets. The vast majority of machined and molded parts use thermoplastics because they can be recycled, reprocessed, and repaired more easily.
Lightweight
Up to 60% lighter than aluminum, 80% lighter than steel
Corrosion Resistant
Withstands chemicals, moisture, and outdoor exposure
Electrically Insulating
Ideal for housings, connectors, and safety barriers
Design Freedom
Complex geometries in one part via molding or machining
Versatile Engineering Materials
From commodity resins to high-performance polymers that replace metals.
Plastic Types
Types of Plastic Materials
Plastic materials fall into three main performance categories, plus a fundamental division between thermoplastics and thermosets. Understanding these classifications is the first step toward choosing a material that will survive your application environment.
Low-cost, high-volume
Commodity Plastics
High-volume, low-cost materials used in packaging, consumer goods, and disposable products. Easy to process but with limited mechanical properties and temperature resistance.
- Examples: PE, PP, PS, PVC
- Key properties: Low cost, easy to process, limited heat resistance
- Typical uses: Packaging, bottles, tubing, disposable parts
Good strength & machinability
Engineering Plastics
Better mechanical strength, thermal stability, and chemical resistance than commodity plastics. Designed to replace metals in structural, wear, and electrical applications.
- Examples: ABS, Nylon, PC, POM, PBT
- Key properties: Good strength, wear resistance, machinability
- Typical uses: Gears, housings, bearings, connectors
Extreme conditions
High-Performance Plastics
Maintain properties under extreme conditions. Resist high temperatures, aggressive chemicals, and mechanical stress that would destroy most engineering plastics.
- Examples: PEEK, PTFE, PPS, PEI
- Key properties: Extreme temperature and chemical resistance
- Typical uses: Medical implants, aerospace, semiconductors
Why Choose Baetro
Why Source Plastic Parts from Baetro
Choosing a supplier is about more than material availability. Engineers need precision, speed, and transparency from quote to delivery.
Instant Online Quotes
Upload your CAD file and receive a quote in under 60 seconds. Our system analyzes geometry, material, and tolerances to give you live pricing and lead times.
No Minimum Order Quantity
Order one prototype or ten thousand production parts. We do not impose minimum order quantities, so you can validate designs before committing to high-volume tooling.
3–7 Day Lead Times
Standard plastic parts ship in 3–7 days. Expedited options are available when your project timeline demands it.
Precision Tolerances to ±0.001 Inch
Our CNC machining centers hold tight tolerances consistently. Whether you need a single prototype or a full production run, every part meets the same quality standard.
Free DFM Feedback
Before we machine or mold your first part, our engineers review your CAD files for manufacturability. We often suggest design improvements or material substitutions that reduce cost without compromising function.
ISO 9001 & AS9100 Certified
Our Qingdao facility operates under ISO 9001:2015 and AS9100D quality systems. Material traceability, inspection reports, and certificates are available for mission-critical applications.
Material grades
Common Plastic Materials
Selecting the right plastic material means matching polymer properties to part function, operating environment, and manufacturing process. Here are the materials Baetro machines and molds most often.
ABS (Acrylonitrile Butadiene Styrene)
Tough, impact-resistant engineering plastic with a good surface finish. Machines easily, accepts paints and adhesives. Tensile strength ~40–50 MPa, service temperature up to ~100°C.
Applications: enclosures, toys, automotive trim, low-load structural parts.
Nylon (Polyamide / PA) — Strong, wear-resistant engineering plastic with excellent fatigue properties. Nylon 6 and Nylon 6/6 are most common. Absorbs moisture, requiring consideration for tight tolerances.
Applications: gears, bearings, bushings, sliding components.
POM / Acetal / Delrin — Rigid, low-friction engineering plastic with excellent dimensional stability. Low moisture absorption, good chemical resistance. Machines to tight tolerances.
Applications: precision gears, bearings, cam followers, clock mechanisms.
Polycarbonate (PC)
Transparent engineering plastic with exceptional impact strength. Virtually unbreakable compared to acrylic and glass. Tensile strength 55–75 MPa, service temperature ~115–135°C.
Applications: safety shields, lenses, electronic housings, medical device components.
Learn more about Polycarbonate
PEEK (Polyetheretherketone) — High-performance thermoplastic with outstanding mechanical properties, chemical resistance, and thermal stability. Maintains strength up to 260°C. Biocompatible for medical implants.
Applications: aerospace, oil and gas, medical, semiconductor.
PTFE (Teflon) — Extremely low coefficient of friction and near-universal chemical resistance. Soft, cannot support high loads. Compression-molded or machined from stock shapes.
Applications: seals, gaskets, bearings, linings, electrical insulation.
Material properties
Plastic Material Properties
Plastic material properties vary widely across polymer families. The most important properties for engineers to evaluate are mechanical strength, thermal behavior, chemical resistance, and electrical insulation.
| Property | ABS | Nylon 6/6 | POM / Acetal | Polycarbonate | PEEK |
|---|---|---|---|---|---|
| Tensile strength (MPa) | 40–50 | 70–90 | 60–70 | 55–75 | 90–100 |
| Max service temp (°C) | ~100 | 120–150 | 100–120 | 115–135 | 240–260 |
| Density (g/cm³) | 1.04–1.06 | 1.14 | 1.41 | 1.20 | 1.30 |
| Water absorption (%) | 0.3 | 2.5–3.0 | 0.2–0.8 | 0.15–0.35 | 0.1 |
| Relative cost | $ | $$ | $$ | $$ | $$$$ |
| Machinability | Excellent | Good | Excellent | Good | Fair |
Heat deflection temperature and continuous service temperature define how hot a plastic part can get before it loses stiffness or degrades. Plastics expand and contract more than metals with temperature changes, affecting tolerance stack-ups in assemblies that combine plastic and metal components.
Material comparison
Plastic vs. Metal: When to Choose Each
Choosing between plastic and metal depends on load, temperature, environment, cost, and manufacturing volume.
Comparison Table
| Factor | Plastic | Metal |
|---|---|---|
| Weight | Lightweight | Heavy |
| Corrosion resistance | Excellent | Varies; often needs protection |
| Electrical insulation | Excellent | Conductive |
| Machinability | Fast, low tool wear | Slower, harder on tools |
| Strength | Moderate to high | High |
| Heat resistance | Lower, except high-performance grades | High |
| Cost at low volume | Lower for CNC | Higher for machining |
| Cost at high volume | Very low for molding | Higher per part |
Plastic is the better choice when weight matters, corrosion resistance is required, electrical insulation is needed, or complex geometries must be produced economically at high volume. Metal is the better choice for high stress, extreme temperatures, or applications requiring electrical or thermal conductivity.
When to Choose Each
- Choose plastic when: weight reduction is critical, corrosion resistance is required, electrical insulation is needed, complex geometries are required, or high-volume production with low per-part cost is desired.
- Choose metal when: high stress or extreme temperatures are expected, tight tolerance over wide temperature ranges is required, electrical or thermal conductivity is needed, or impact resistance and long-term creep resistance are critical.
- Hybrid designs: Many products use metal for load-bearing structures and plastic for insulation, wear surfaces, or cosmetic covers.
Machinability
Plastic Materials for CNC Machining
Many plastic materials are well suited to CNC machining, but each polymer has its own behavior, tooling requirements, and surface finish expectations.
Best Plastics for CNC Machining
- POM/Acetal: Easiest to machine, holds tight tolerances, excellent surface finish.
- ABS: Produces clean chips, good surface finish, economical.
- Polycarbonate: Machines well, good surface finish, impact-resistant.
- Nylon: Machines well but requires attention to moisture content and heat buildup.
- PEEK: Machinable with specialized tooling and conservative speeds.
- PTFE: Soft, can deform under clamping pressure, requires experienced setup.
Key machining considerations:
- Use sharp carbide tools and moderate speeds to prevent melting
- Proper chip evacuation prevents chip wrapping
- Soft plastics require gentle clamping to avoid deformation
- Avoid sharp internal corners to reduce stress concentration
Tolerances and Surface Finish
Baetro holds tolerances to ±0.001 inch on most machined plastic parts, with tighter tolerances available on select features.
- POM and ABS can achieve Ra 0.4–0.8 μm with proper machining
- Polycarbonate achieves good surface finish with polished tooling
- Post-machining polishing, vapor polishing, or coating available
- Full CMM inspection and surface roughness testing on every production run
- First article inspection reports available for production approval
Applications
Plastic Material Applications
Plastic materials appear in nearly every industry because of their versatility and design freedom.
Industry
Automotive & EV
Plastics reduce vehicle weight and improve efficiency. Under-hood components use heat-resistant grades such as PPS and PEEK. Interior trim uses ABS and polypropylene. Battery housings and charging connectors use flame-retardant engineering plastics.
Industry
Electronics
Housings, connectors, switches, and insulators rely on plastics for electrical insulation and impact protection. ABS, polycarbonate, and PBT are common choices. Transparent polycarbonate is used for lenses and displays.
Industry
Medical Devices
PEEK, PEI, and certain grades of polycarbonate are used for surgical instruments, implantable devices, and diagnostic equipment. Biocompatibility, sterilization resistance, and dimensional stability are critical selection criteria.
Industry
Industrial Machinery
Gears, bearings, bushings, rollers, and wear pads are often made from Nylon, POM, UHMW, or PTFE. These materials reduce friction, resist chemicals, and operate without lubrication in many environments.
Industry
Consumer Products
Everything from phone cases to kitchen appliances to sporting goods uses plastic materials. ABS, polypropylene, and polycarbonate dominate this space because of their balance of cost, appearance, and durability.
Industry
Aerospace
PEEK, PEI, and other high-performance plastics are used for interior components, structural brackets, insulators, and lightweight assemblies where weight savings and fire resistance are critical.
Manufacturing options
Plastic Materials for Injection Molding
Injection molding is the most cost-effective way to produce high-volume plastic parts. Material selection for molding balances flow behavior, shrinkage, cycle time, and end-use performance.
Mold-Friendly Materials
ABS, polypropylene, polyethylene, and polystyrene are among the easiest materials to injection mold. They flow well, shrink predictably, and are available in many grades and colors.
- Nylon, POM, and polycarbonate are common but require precise drying and process control
- PEEK can be injection molded with high barrel temperatures and heated molds
- High-performance plastics usually reserved for applications justifying additional processing cost
Design Considerations
Successful injection molded parts follow design-for-manufacturability guidelines:
- Wall thickness: Keep walls uniform and within recommended ranges
- Draft angles: Add draft to vertical walls for easy release
- Ribs and fillets: Use ribs for stiffness, add fillets to reduce stress
- Gate location: Position gates to minimize weld lines and fill defects
- Shrinkage: Account for material shrinkage in mold design and tolerance analysis
Volume and Cost Trade-offs
Injection molding has high upfront tooling cost but very low per-part cost at volume.
- For prototypes or low volumes, CNC machining is usually more economical
- Baetro offers both processes to help you choose the right route
- Selection based on quantity, timeline, and part complexity
- No minimum order quantity for machining; tooling required for molding
Material selection
How to Select the Right Plastic Material
Material selection is a decision tree. Start with operating conditions, then match manufacturing process and cost constraints.
Define Operating Conditions
Identify the maximum temperature, chemical exposure, mechanical loads, and environmental conditions the part will face. A gear in a cleanroom has very different requirements from a valve seal exposed to hot oil.
Consider Manufacturing Process
CNC machining favors materials that hold tolerances and produce clean chips. Injection molding favors materials that flow well and shrink predictably. 3D printing has its own material compatibility rules.
Balance Cost and Performance
It is easy to over-specify material. PEEK may solve every problem, but if ABS or Nylon meets the requirements, the cost savings can be substantial. Our engineers review every quote and suggest material substitutions that maintain function while reducing cost.
Upload Your CAD File
Send your design in STEP, IGES, SolidWorks, or Parasolid format. STEP files are preferred for plastic machining quotes.
Receive Quote + DFM Feedback
In under 60 seconds, review pricing, lead time, and manufacturability notes. Our engineers recommend the best plastic material for your application.
Approve and Place Order
Select material, finish, quantity, and shipping method. Your project manager confirms the order and production schedule.
Cost considerations
Plastic Material Cost Factors
Understanding what drives plastic part costs helps you make informed design and material decisions.
- Material grade: Commodity plastics cost a few dollars per kilogram; PEEK can cost 10–50 times more.
- Part complexity: Deep pockets, thin walls, and intricate features increase machining time and cost.
- Tolerances: Tighter tolerances (±0.001″) require slower feeds, sharper tools, and more inspection.
- Surface finish: Polished or vapor-smoothed finishes increase cost; “as machined” is cheapest.
- Order quantity: Low volumes have higher per-part cost due to setup; high volumes reduce per-part cost.
- Manufacturing process: CNC machining has no tooling cost but higher per-part cost; injection molding has high tooling cost but very low per-part cost at volume.
FAQ
Plastic Materials FAQs
Answers to common questions about plastic materials, types, properties, and machining.
What are plastic materials?
Plastic materials are synthetic or semi-synthetic polymers made from long-chain molecules. They can be molded, extruded, or machined into parts and are valued for being lightweight, corrosion resistant, electrically insulating, and cost-effective.
What are the main types of plastic materials?
Plastic materials are commonly classified as commodity plastics, engineering plastics, and high-performance plastics. They can also be divided into thermoplastics, which can be remelted, and thermosets, which cure permanently.
What is the strongest plastic material?
PEEK is one of the strongest unfilled thermoplastics, with tensile strength around 90–100 MPa and continuous use temperatures up to 260°C. Glass-filled or carbon-filled grades of Nylon and PEEK can achieve even higher strength and stiffness.
What plastic is easiest to machine?
POM/Acetal, ABS, and polycarbonate are among the easiest plastics to machine. They produce clean chips, hold tight tolerances, and achieve good surface finishes with standard carbide tooling.
Can plastic materials replace metal?
Yes, in many applications. Engineering plastics such as Nylon, POM, and PEEK can replace metal in gears, bearings, housings, and structural brackets when loads, temperatures, and chemical exposure are within the plastic’s capability range.
What is the best plastic for high temperatures?
PEEK, PTFE, PPS, and PEI are the best choices for high-temperature applications. PEEK offers the best combination of strength and heat resistance, with continuous service temperatures up to 260°C.
How much do plastic materials cost?
Commodity plastics cost a few dollars per kilogram, while engineering plastics such as Nylon and polycarbonate cost more. High-performance plastics such as PEEK can cost 10–50 times more than commodity plastics. Upload your CAD file for an instant quote that breaks down pricing by material and process.
Ready to start
Get Started with Plastic Parts
Whether you need a single prototype or 10,000 production parts, Baetro delivers plastic machining and molding services that combine precision, speed, and engineering expertise.
Upload your CAD file for an instant quote with live pricing, lead times, and free DFM feedback. Our engineers review every design — not just price it — helping you reduce machining costs, improve manufacturability, and achieve better performance.
Parts ship in 3–7 days. No minimum order quantity. ISO 9001 & AS9100 certified.
Not ready to upload a file? Contact our engineers to discuss your project, review material options, or get guidance on material selection.