CNC Machining Materials Guide: Metals & Plastics for Precision Parts
Explore the wide range of metals and plastics we use for CNC machining. Understand the properties, surface finish options, advantages, and suitable applications to help you choose the right material for your custom parts.
Metal Materials
Metal materials are ideal for applications requiring strength, heat resistance, or high load-bearing capacity. Below is a comparison of commonly used metals.
| Material | Key Properties | Surface Finishes | Advantages | Disadvantages | Price Level |
|---|---|---|---|---|---|
| 6061 Aluminum | Lightweight, medium strength, easy to machine | Anodizing, sandblasting, polishing | Affordable, corrosion resistant, good for general use | Lower strength compared to steel | ** |
| 7075 Aluminum | High strength aerospace-grade alloy | Anodizing, sandblasting, polishing | Very strong, good wear resistance | Poor weldability, higher cost | *** |
| 2024 Aluminum | Excellent fatigue resistance | Anodizing, painting | Strong and lightweight, great for structures | Poor corrosion resistance | *** |
| 304 Stainless Steel | General-purpose stainless, corrosion-resistant | Polishing, passivation, sandblasting | Good corrosion resistance, widely available | Hard to machine, heavier | *** |
| 316 Stainless Steel | Marine-grade stainless steel | Polishing, passivation, sandblasting | Excellent corrosion resistance, biocompatible | Expensive, harder to process | **** |
| 17-4PH Stainless | Precipitation hardened, high strength | Heat treatment, polishing | High strength + corrosion resistance | May deform after heat treatment | **** |
| Carbon Steel (45#) | High strength, good machinability | Heat treatment, plating, painting | Strong and affordable | Rusts easily, requires surface protection | * |
| Tool Steel D2 | High hardness and wear resistance | Heat treatment, nitriding, polishing | Ideal for molds, wear parts | Difficult to machine, costly | ***** |
| Titanium Grade 2 | Commercially pure, excellent corrosion resistance | Polishing, anodizing | Lightweight, strong, biocompatible | High cost, harder to machine | ***** |
| Titanium Grade 5 | Aerospace-grade (Ti-6Al-4V) alloy | Polishing, anodizing | Strong and light, excellent strength-to-weight | Very expensive, complex to machine | ***** |
| Brass (C360) | Easy machining, good conductivity | Polishing, electroplating, chrome plating | Beautiful finish, good for decorative parts | Softer material, moderate strength | *** |
| Copper (C110) | Excellent thermal and electrical conductivity | Polishing, electroplating | Best electrical properties | Expensive, soft, deforms easily | **** |
| Inconel 718 | High-temperature alloy, extreme corrosion resistance | Heat treatment, polishing | Ideal for aerospace & heat-resistant parts | Very hard to machine, very costly | ***** |
Plastic Materials
Plastic materials offer excellent chemical resistance, low weight, and are ideal for electrical insulation and consumer-facing applications. See the comparison below.
| Material | Key Properties | Surface Finishes | Advantages | Disadvantages | Price Level |
|---|---|---|---|---|---|
| ABS | Good strength and impact resistance | Painting, silk screen | Easy to machine, affordable, general-purpose | Not heat-resistant, ages under sunlight | * |
| Nylon (PA6) | High wear resistance, strong, tough | Dyeing, polishing | Good chemical resistance, ideal for sliders | High moisture absorption, dimensional shift | ** |
| POM (Delrin) | High rigidity, low friction, stable | Polishing | Dimensionally stable, wear-resistant | Brittle under impact, limited temp range | ** |
| PTFE (Teflon) | Chemically inert, very low friction | Rarely treated | Extremely corrosion-resistant, high-temp | Low mechanical strength, soft | *** |
| PEEK | High-performance, thermally stable | Polishing, coating | Metal replacement, heat + chemical resistant | Very expensive | ***** |
| Polycarbonate (PC) | Transparent, high impact resistance | Polishing, painting | Strong and clear | Scratches easily, not solvent-resistant | *** |
| PVC | Chemical-resistant, rigid | Painting | Low-cost, corrosion-resistant | Low strength, degrades under UV | * |
| Acrylic (PMMA) | Optical clarity, rigid | Polishing, dyeing | Beautiful look, good for displays | Brittle, impact resistance is low | ** |
| HDPE | High impact strength, water-resistant | Dyeing | Lightweight, affordable, chemical-resistant | Poor machining accuracy, low temp tolerance | * |
| UHMW-PE | Extremely low friction, excellent wear | Polishing | Great for wear parts, self-lubricating | Hard to machine, absorbs moisture | *** |
FAQ
Which material is best for mechanical strength?
Steel and titanium alloys are ideal for high strength applications. Tool steel (D2) is also suitable for wear parts.
What’s the best option for corrosion resistance?
316 stainless steel and titanium alloys provide excellent corrosion resistance, especially in marine or medical environments.
Need help with material selection or prototype development?
Our engineering team offers complete support from material consultation to drawing analysis, prototyping, and small-batch production.
We also provide surface finish recommendations based on functional and aesthetic requirements.
📩 Send us your drawing or project details to get expert feedback within 24 hours.
