CNC Machining Materials, Everything You Need to Know

CNC machining is popular for its automation feature. It does not only speed up the speed. But also promote high precision and accuracy. Besides this, it is used in many applications across many industries. So, when we talk about CNC machining and its output products. We also consider the materials we use for the CNC machining process. So, here is a detailed guide on CNC machining materials and their applications.

Factors for Selecting the Suitable CNC Machining Material

So, let’s discuss what factors can help us select the best material for making metal parts using CNC machining. These factors will not only give us better options. But also increase the effectiveness of the whole process.

1. Machining Environment

You must consider the operating conditions of the CNC machining. They may include temperature, humidity, and exposure to chemicals. These all factors will eventually affect material performance and longevity.

2. Part Weight

It is also very important to consider the weight of your metal part. Because the material density affects the final product quality. Besides this, it also influences its suitability for a particular application.

Metal	Density (g/cm³)
Aluminum	2.70
Magnesium	1.74
Titanium	4.51
Stainless Steel	7.75 – 8.05
Carbon Steel	7.85
Brass	8.40 – 8.73
Copper	8.94

3. Heat Resistance

When CNC machining cuts the material, it produces heat. So, you must consider that your selected materials can bear this heat. So, it can withstand the operational environment and prevent deformation or failure. 

Metal	Max Operating Temperature (°C)
Aluminum	150 – 200
Magnesium	120 – 150
Titanium	400 – 600
Stainless Steel	600 – 900
Carbon Steel	500 – 750
Brass	200 – 300
Copper	200 – 300

 

4. Electrical Conductivity and Magnetic Needs

Sometimes industries require metal parts that have high electric conductivity and magnetic properties. So, in such cases, materials like aluminum, iron, and copper are more suitable. They are electric and magnetic conductors.

5. Hardness

It is an important point to consider while choosing material. Because it is responsible for both machinability and the wear on cutting tools. Additionally, it affects the production efficiency and costs of over all process. So, here are some hardness ranges for different materials

Metal	Hardness (HV)
Aluminum	15 – 95 HV
Magnesium	32 – 52 HV
Titanium	70 – 440 HV
Stainless Steel	150 – 300 HV (varies by grade)
Carbon Steel	120 – 200 HV
Brass	60 – 120 HV (varies by alloy)
Copper	35 – 110 HV (varies by alloy)

 

6. Surface Finish and Aesthetics

Some applications demand optimal surface finishing and aesthetics. So, it is important to consider these factors while choosing the material

7. Application and Budget

Some applications demand mechanical, thermal, and chemical requirements So, it is important to consider what materials suit more. Besides this, budgeting is also crucial to consider. If you have a lower budget, you can opt for the less-expensive material for metal parts

What are the Best Materials for CNC Machining Projects

Let’s discuss the best materials for CNC Machining projects and their properties. These will help us understand their applications in the different fields

Metal CNC Materials

1. Aluminum (6061, 7075):
   • 6061: Versatile, good strength-to-weight ratio, corrosion-resistant.
   • 7075: High strength, suitable for aerospace applications.Widely used for its machinability and strength-to-weight ratio. Suitable for automotive, aerospace, and consumer products.
2. Stainless Steel (316, 303, 304):
   • 316: Excellent corrosion resistance, used in marine environments.
   • 303: Easy to machine, suitable for intricate parts.
   • 304: General-purpose, good corrosion resistance.
3. Carbon Steel and Alloy Steel: Strong, wear-resistant, used in high-stress applications.
4. Brass: Easy to machine, good electrical conductivity, used in fittings and instruments.
5. Copper: Excellent electrical conductivity, used in electrical components.
6. Titanium: High strength-to-weight ratio, corrosion-resistant, used in aerospace and medical applications.
7. Magnesium: Lightweight, used in automotive and aerospace industries.

CNC Plastic Materials

1. Acetal (POM): Low friction, high stability, used in gears and bearings.
2. Acrylic (PMMA): Transparent, good optical properties, used in lenses and displays.
3. Polycarbonate (PC): Impact-resistant, used in safety equipment.
4. Polypropylene (PP): Chemical-resistant, used in chemical and medical components.
5. ABS: Strong, impact-resistant, used in consumer electronics.
6. Nylon: Tough, wear-resistant, used in mechanical parts.
7. UHMW-PE: Ultra-high molecular weight polyethylene, extremely durable, used in high-wear applications.

Other Materials

1. Foam: Lightweight, used in prototypes and packaging.
2. Wood: Used in furniture and artistic projects.
3. Composites: Combines multiple materials for enhanced properties, used in high-performance applications.

CNC Material List and their Common Applications

So, after discussing all the materials, here is a summary of all materials along with their applications in CNC machining.

Material	Key Properties	Common Applications
Aluminum 6061	Versatile, corrosion-resistant	Automotive, consumer products
Aluminum 7075	High strength	Aerospace
Stainless Steel 316	Corrosion-resistant	Marine, Medical
Stainless Steel 303	Easy to machine	Complex parts
Stainless Steel 304	General-purpose	Household items
Carbon Steel	Strong, wear-resistant	Machinery parts
Brass	Easy to machine, conductive	Fittings, instruments
Copper	Excellent conductivity	Electrical components
Titanium	High strength-to-weight ratio, corrosion-resistant	Aerospace, medical implants
Magnesium	Lightweight	Automotive, aerospace

 

Considerations for Choosing CNC Materials

Here are some considerations, you must keep in your mind while choosing the materials for CNC machining

1. Non-Metallic Materials as Substitutes:Sometimes, you may be concerned about weight, corrosion resistance, or cost. So, you can replace Plastics with composite metals.
2. Potential of Phenolics: Phenolic materials are also known for electrical insulation and heat resistance. So, you can use phenolic materials in electronics and high-temperature environments.
3. Importance of Knowing Different Plastics: As we know every plastic has a unique composition. So, each plastic has unique properties. It makes them suitable for certain applications. So, if you have a better understanding of these differences. You can select the right material and maximize performance and cost-efficiency.
4. Selection Between Different Foams:When it comes to insulation, packaging, or model making. We often deal with less dense materials and high resilience. So, foam materials can be a good option. However, they vary in density and resilience. So, you must go with their suitability with certain applications. 

Conclusion

In conclusion CNC machining materials. Multiple factors may participate in selecting the most suitable material concerning an application. These factors may include operating environment, mechanical properties, and cost. So, many materials, offer unique benefits for certain applications. So, it is important to know every detail and properties of the material. You can go with the right option and increase the efficiency of the process at low costs.

Frequently Asked Questions

Q1. Which is the Most Commonly Used Material in CNC Machining?

It’s Aluminum.  It is widely used because of its excellent machinability and versatile properties. 

Q2. What Materials Can a CNC Machine Cut?

It depends on the CNC machine’s capabilities and tooling. Otherwise, it can deal with and cut different materials like plastics, wood, foam, and composites. 

Q3. Why Plastic is More Suitable Than Metal for CNC Machining?

Plastics are more suitable. Because they are lightweight and have high corrosion resistance. Besides this, they have relatively low cost.