Choosing the right material is one of the most important decisions in CNC milling. The material affects how strong the part will be, how long it will last, how smooth the finish looks, and even how much the project will cost. When you understand how each material behaves, it becomes much easier to pick the right one for your design.

In this guide, you’ll find simple explanations of the top 10 CNC milling materials that manufacturers rely on for precision, quality, and dependable performance.

1. Aluminum

Aluminum is one of the go-to materials for CNC milling because it checks almost every box—easy to machine, lightweight, strong, and resistant to corrosion. It also cuts quickly, which helps reduce machining time and cost.

Why Aluminum Works Well:

• Strong but not heavy
• Smooth finish after milling
• Good resistance to rust
• Friendly for high-speed machining
• 
  

Where It’s Used:

Aerospace parts, automotive parts, electronic casings, consumer products, and general mechanical components.

Common grades: 6061 for all-purpose use and 7075 for parts that need higher strength.

2. Stainless Steel

Stainless steel is chosen when strength and durability are the top priorities. It performs well in harsh conditions and stays strong even when exposed to moisture, heat, or chemicals.

Why Stainless Steel Works Well:

• Very strong and long-lasting
• Resists corrosion and rust
• Good performance in high temperatures
• 
  

Where It’s Used:

Medical equipment, marine parts, kitchen and food-processing machinery, tools, and industrial components.

Popular grades: 304, 316, and 17-4 PH.

3. Mild Steel (Carbon Steel)

Mild steel is a great choice when you want something strong but still affordable. It machines easily, can be welded without much trouble, and offers excellent durability for many types of parts.

Why Mild Steel Works Well:

• Strong and reliable
• Cost-effective
• Easy to cut and shape
• Good for everyday mechanical components
• 
  

Where It’s Used:

Brackets, industrial equipment, structural parts, jigs, fixtures, and automotive components.

Common grades include 1018 and 1045.

4. Brass

Brass is known for its exceptional machinability. It cuts very cleanly, allowing for sharp detail and a polished finish. Its gold-like appearance also makes it a popular choice for parts that will be visible.

Why Brass Works Well:

• Extremely easy to machine
• Low friction
• Naturally attractive finish
• Great for precise and detailed parts
• 
  

Where It’s Used:

Valves, fittings, gears, connectors, decorative products, and electronic parts.

Most common grade: C360 brass.

5. Copper

Copper is softer than brass but offers excellent heat and electrical conductivity. It requires experience to machine because it can stick to cutting tools, but it’s essential for certain industries.

Why Copper Works Well:

• One of the best electrical conductors
• Great heat transfer
• Naturally resistant to corrosion
• 
  

Where It’s Used:

Electrical components, heat exchangers, electrical contacts, and cooling or heating parts.

6. Titanium

Titanium is known for its incredible strength while still being much lighter than steel. It performs well under stress and handles high heat with ease. However, it is more difficult and slower to machine, which increases cost.

Why Titanium Works Well:

• Very strong but lightweight
• Excellent corrosion resistance
• Safe for the human body (biocompatible)
• 
  

Where It’s Used:

Aerospace parts, medical implants, high-performance automotive components, military applications.

Most used grade: Grade 5 (Ti-6Al-4V).

7. ABS Plastic

ABS is one of the most common plastics used for CNC machining. It’s low-cost, light, durable, and machines smoothly. This makes it great for prototypes and parts that don’t need metal strength.

Why ABS Works Well:

• Easy to machine
• Tough and lightweight
• Affordable
• Great impact resistance
• 
  

Where It’s Used:

Prototypes, enclosures, consumer products, and early design models.

8. POM (Acetal/Delrin)

POM is an engineering plastic known for its stiffness and smooth movement. Because it has low friction and excellent dimensional stability, it’s often used as a substitute for metal in moving parts.

Why POM Works Well:

• Very smooth and stable
• Resistant to wear
• Holds shape extremely well
• Great for tight tolerances
• 
  

Where It’s Used:

Gears, rollers, bearings, bushings, and precision mechanical parts.

9. Nylon

Nylon is a flexible yet strong plastic that works well in applications where shock absorption and durability are important. It’s commonly used in moving parts and mechanical assemblies.

Why Nylon Works Well:

• Strong but flexible
• Good wear resistance
• Lightweight
• Long-lasting in industrial environments
• 
  

Where It’s Used:

Automotive components, consumer goods, industrial machine parts, and moving assemblies.

10. Acrylic (PMMA)

Acrylic is a clear plastic that mills nicely and has a glass-like finish. It’s often used for display items or transparent parts because it looks clean and attractive.

Why Acrylic Works Well:

• Clear and visually appealing
• Weather-resistant
• Machines cleanly and polishes well
• Great for decorative or visible parts
• 
  

Where It’s Used:

Panels, display stands, signs, lenses, and covers.

How to Choose the Right CNC Milling Material

Material selection depends on how the final part will be used. Here’s a simple breakdown to help make the decision easier:

1. Need Strength or Durability?

Choose steel, stainless steel, titanium, or aluminum.

2. Need Lightweight Parts?

Go for aluminum, titanium, or engineering plastics like ABS or POM.

3. Need Resistance to Heat or Corrosion?

Use stainless steel, titanium, or brass.

4. Need High Precision?

Aluminum, brass, and POM are excellent for tight tolerances.

5. Need to Control Costs?

ABS, nylon, and mild steel are budget-friendly options.

Why the Right Material Matters in CNC Milling

Using the proper material leads to:

• Better accuracy
• A smoother finish
• Longer tool life
• Faster production
• Fewer machining issues
• A stronger and more reliable final part

A poor material choice can lead to warping, rough surfaces, overheating, or even failed machining runs—costing extra time and money.

Beyond Milling: Other Fabrication Options

Many projects require more than one manufacturing method. For example, sheet metal parts often need bending after cutting or machining.

If your project includes formed or folded metal parts, check out CNC Metal Bending for precise and clean bends in brackets, enclosures, housings, and custom metal structures.

Final Thoughts

Every CNC material has its own strengths, weaknesses, and best use cases. By understanding these differences, you can choose the right material for your project and get better results from your machining process. When you pick a material that matches your design and performance needs, you improve accuracy, reduce machining time, and create parts that last longer.

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