How to Choose the Right Material for Your CNC Machined Parts
Introduction
Selecting the right material is one of the most important decisions in any CNC machining project. The material you choose affects strength, weight, durability, corrosion resistance, visual appearance, machining time, and of course—cost. With so many metals and plastics available, understanding their differences can help engineers, designers, and buyers make smart, cost-effective choices.
This guide breaks down the most commonly used machining materials, their ideal applications, and how to choose the best one for your project.
1. Aluminum: The Most Versatile Machining Material
Best for: Prototypes, aerospace parts, automotive components, housings, brackets
Aluminum is lightweight, corrosion-resistant, and easy to machine, making it one of the most economical options.
Popular grades:
6061: Excellent general-purpose choice
7075: High-strength aerospace grade
Why choose aluminum:
Fast machining = lower cost
Strong yet lightweight
Great for tight tolerances
2. Stainless Steel: Strength + Corrosion Resistance
Best for: Industrial parts, shafts, medical components, high-wear environments
Stainless steel is harder to machine than aluminum but offers superior strength and corrosion resistance.
Common grades:
304: Corrosion resistance
316: Marine & medical applications
17-4 PH: High strength and excellent durability
Why choose stainless steel:
Withstands harsh environments
Great for functional, long-lasting parts
3. Carbon Steel: Strong & Cost-Effective
Best for: Structural parts, fasteners, mechanical components
Carbon steels offer excellent strength and are often chosen for parts that need durability without a premium price.
Considerations:
Requires coatings or plating to prevent rust
Machining cost varies by hardness level
4. Titanium: High Performance for Demanding Applications
Best for: Aerospace, medical implants, high-performance mechanical parts
Titanium is extremely strong and lightweight, offering the best strength-to-weight ratio of any machining material.
However, it is slow and expensive to machine.
Why choose titanium:
Exceptional strength
Lightweight
Resistant to heat and corrosion
5. Plastics: Lightweight, Affordable & Easy to Machine
Best for: Enclosures, low-load components, food-grade and chemical-resistant parts
Plastics are excellent for rapid prototyping and specific applications requiring low friction or chemical resistance.
Popular machining plastics:
Delrin (Acetal): High strength, very stable
Nylon: Strong, flexible
PTFE (Teflon): Chemical resistant
Polycarbonate: Impact-resistant
Why choose plastics:
Fastest machining time
Excellent for low-cost prototypes
Lightweight and corrosion-proof
6. Consider Your Application Requirements
When choosing materials, evaluate:
Strength requirements
Operating temperature
Corrosion or chemical exposure
Weight limitations
Budget
Surface finish needs
Working backward from the application helps narrow the ideal choices quickly.
7. Ask Your Machinist for Material Guidance
Material selection affects toolpaths, speeds, and machining strategy. Speaking with your machining team early ensures you choose a material that meets functional needs while keeping production efficient and cost-effective.
At Universal Machining & Engineering, we help customers identify the right materials for prototypes, one-off parts, and high-volume production.
Conclusion
Choosing the right CNC material is essential for balancing performance, durability, and budget. With the right guidance and understanding, you can achieve better results and smoother production.
If you're unsure which material is best for your part, our engineers and machinists are here to help.
Get Expert Material Guidance for Your Next Project
Reach out today to discuss your design and find the best material for strength, cost, and performance.
