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Plastic CNC Machining Materials Handbook

Cnc plastic materials
Last updated: May 23, 2026

Plastic CNC Machining Materials Handbook

CNC machining of plastics (also called engineering plastic cutting/machining) has wide applications across electronics, medical, semiconductor, automotive, and industrial sectors. This handbook organizes plastics by performance grade, provides a standardized datasheet for every common material, and collects the process, quality, and reference data you need on the shop floor.

💡 How to use this handbook — Browse materials by grade in Section 1, jump straight to a material datasheet from the navigation map, or start from a requirement in the selection guide.

🗂️ Handbook Navigation

Part 1 — Introduction

  • This overview page (classification, plastic vs. metal, selection guide)

Part 2 — Material Datasheets ⭐ Core

Grade Materials
🟢 Commodity PMMA / Acrylic · ABS · PP · PE / HDPE / UHMW · PVC
🟡 Engineering POM / Acetal ⭐ · PA / Nylon · PC · PET
🔴 Specialty PEEK ⭐ · PTFE / Teflon · PEI / Ultem · PI / Vespel · PSU / PPSU · PPS

Part 3 — Process & Technology

Part 4 — Quality & Reference

📊 1. Classification by Performance Grade

🟢 Commodity Plastics (low cost, easy to machine)

Material English/Abbreviation Characteristics Typical Applications
Acrylic PMMA / Plexiglass Highly transparent, easy to machine, brittle Transparent covers, display parts, light guides
ABS ABS Good toughness, easy to machine, low cost Housings, prototypes, mock-ups
Polypropylene PP Chemical resistant, fatigue resistant, relatively soft Chemical containers, medical parts
Polyethylene PE / HDPE / UHMW-PE Wear resistant, self-lubricating, impact resistant Sliders, liner plates, wear parts
PVC PVC Corrosion resistant, flame retardant, cheap Chemical piping, insulating parts

🟡 Engineering Plastics (excellent performance, most commonly used) ⭐

Material English/Abbreviation Characteristics Typical Applications
Polyoxymethylene / Acetal POM (Delrin) ⭐ High rigidity, wear resistant, dimensionally stable, easy to machine Gears, bearings, precision parts
Nylon PA / Nylon Wear resistant, good toughness, self-lubricating Gears, pulleys, bushings
Polycarbonate PC Highly transparent, extremely high impact resistance Protective covers, transparent parts
PET / PETP PET Good rigidity, dimensionally stable, wear resistant Precision mechanical parts

💡 POM (Acetal) is the most popular plastic for CNC machining — its cutting performance rivals metal, with high dimensional accuracy.

🔴 Specialty Engineering Plastics (high-end, heat resistant)

Material English/Abbreviation Characteristics Typical Applications
Polytetrafluoroethylene / Teflon PTFE (Teflon) Extremely heat resistant, corrosion resistant, ultra-low friction Seals, insulating parts, corrosion-resistant parts
Polyether Ether Ketone PEEK ⭐ Top-tier heat resistance (260℃), high strength, corrosion resistant Aerospace, medical, semiconductor
Polyetherimide PEI (Ultem) Heat resistant, flame retardant, high strength Aerospace, electronics
Polyimide PI (Vespel) Extremely heat resistant, wear resistant Aerospace, semiconductor
Polysulfone PSU / PPSU Heat resistant, sterilizable Medical devices
Polyphenylene Sulfide PPS Heat resistant, chemical resistant, flame retardant Industrial, automotive

💡 PEEK is the “aristocrat” of plastics — expensive but with performance approaching that of metal, often used in high-end applications as a metal replacement.

📋 2. Common Challenges in CNC Plastic Machining

Challenge Cause Solution
Thermal deformation/melting Poor thermal conductivity, concentrated cutting heat Reduce speed, ample cooling, air blast
Dimensional instability Internal stress, moisture absorption (e.g., nylon) Anneal before machining, drying treatment
Excessive burring High material toughness Sharp tools, proper toolpaths
Cracking (brittle materials) e.g., acrylic, PC Sharp tools, low feed rate
Tool sticking Soft materials Sharp cutting edges, increase rake angle

📌 For detailed defect diagnosis and fixes, see Quality, Defects & Surface Treatment; for process settings, see the Process Guide and Cutting Parameters.

🎯 3. Plastic vs. Metal CNC Machining Comparison

Item Plastic Metal
Weight Light Heavy
Machining Difficulty Relatively easy but requires heat control Medium~Hard
Insulation Excellent Conductive
Corrosion Resistance Mostly excellent Depends on material
Strength Relatively low (except PEEK) High
Cost Low for commodity, high for specialty Medium~High

📌 4. Material Selection Quick Reference

Requirement Recommended Materials
Transparency PMMA, PC
Wear resistance/Gears POM, Nylon, UHMW-PE, PET
Heat resistance PEEK, PTFE, PI, PPS
Corrosion resistance PTFE, PP, PVC
Insulation PTFE, PEI, PVC
High-strength metal replacement PEEK, PEI, PI
Low-cost prototyping ABS, PMMA
Medical/sterilizable PEEK, PSU/PPSU

📌 For a full property comparison table and requirement-based decision matrix, see the Appendix & Reference Data.

⭐ Recommended Starter Set

If you are building familiarity with CNC plastics, we recommend prioritizing these 5 most widely used materials:

  1. POM (Acetal) ⭐ — The king of CNC plastics
  2. Nylon (PA) — The most common wear-resistant material
  3. PEEK — The high-end representative
  4. PMMA (Acrylic) — The transparency representative
  5. PTFE (Teflon) — The corrosion/heat resistance representative

📐 Rating System

All material datasheets in this handbook use a consistent five-star scale for easy comparison:

Machinability : ★★★★★  (5 stars = easiest to machine)
Wear resistance: ★★★★☆
Heat resistance: ★★★☆☆
Cost          : ★★☆☆☆  (FEWER stars = cheaper)

⚠️ Note that cost is inverted — fewer stars means lower cost. All cutting parameters in this handbook are starting points for reference only; always validate on scrap and adjust to your machine, tooling, and part geometry.