A Guide on Picking the Best CNC Material for Machining

Posted on : By

Home / Blog / Article
A Guide on Picking the Best CNC Material for Machining

Have you decided on using CNC machining for your part production? If you did, you’ve probably made a great choice, considering the number of CNC material options you have at your disposal to bring your custom product to life. To start with, CNC machining is a highly accurate and repeatable manufacturing process used for prototypes and production parts. Also, it is a subtractive process that involves cutting material away from a solid block using computer-controlled cutting tools like drills and lathes. As a result, you have a professional-quality part suitable for mechanical use.

One of the biggest advantages of CNC machining is its material versatility. This is because the process can use aluminum and steel alloys as raw materials as well as a wide range of engineering metals. Also, it is used to cut high-quality plastics. You can treat many of these CNC machining materials with a variety of finishing options after machining. In most cases, such a wide range of options offers such flexibility. However, there is also that added dilemma that comes with having so many CNC machining materials at your disposal.

To make your CNC machining project worthwhile, you must know about most, if not all, of the CNC materials at your disposal. This article will discuss the different CNC machining material properties you should consider and the factors to consider before choosing a particular CNC material. Read to the end to find out a stress-free way of selecting the best materials for your CNC project.

Questions Checklist to Consider when Picking CNC Materials

Given the vast array of material options for CNC machining, it is highly likely that there will be more than one suitable material for your prototyping or production job.

However, finding that one CNC cutting material depends on your priorities: do you need a metal with exceptional mechanical properties, such as a titanium alloy? Or is speed a priority, leading you to more machinable materials like Aluminum 6061 or plastic like Delrin? Do you simply want a machined prototype at the lowest possible price?

Here are examples of a checklist of questions you should answer before picking a CNC material for your project:

1. What Will You Use the Part For?

Just as CNC machining can be used to machine different materials, it is also applicable in manufacturing different parts. Due to this reason, the application of the part is definitely a question that should be foremost when picking a CNC material. This is because the application would help determine the properties the CNC material used must have. For example, a part needed for insulating functions would favor plastic as the CNC material for production. However, a metal may be more favorable to choose in cases of tensile strength.

cnc machined part made from metal
CNC machined part for automotive

While this example seems oversimplified, most CNC materials needed for part production would need to have a bunch of properties. To know more about the CNC cutting material with the best properties for your part production, it’s best to ask experts like RapidDirect.

2. What are the Operating Temperatures of the Part’s Environment?

The operating temperature of the environment in which the part will be functioning is another important factor to consider before making a final choice. This is because the melting point of the CNC material used has to be greater than the operating temperature. If not, there might be a change in the part’s structure. Also, you have to ensure the CNC machining material can withstand extreme temperature changes. While some materials might be able to resist these temperature changes, some could show structure changes over a period of use.

Another reason to know the material’s resistance to its operating temperature is to know if it can withstand the heat that comes from the CNC machining operations.

3. Will You Use the Part Outdoors or Indoors?

The conditions a part will face varies depending on the location of its use. You can accurately determine the temperature or moisture they’ll face in their operating environments for those used indoors. However, in outdoor environments where the weather cannot be controlled, it is advisable to use a material that can withstand moisture and rusting while maintaining its structure. Also, extreme weather changes in outdoor environments could cause structure warping of particular CNC materials.

Of course, it won’t always be possible to find a material that meets all of your criteria to the highest possible degree. The very strongest machining materials are rarely the cheapest. Also, choosing added strength may lead to a reduction in chemical resistance or some other property.

However, after answering these questions, you should be able to identify the essential properties your CNC cutting material of choice must possess. After this, the next step is to identify possible CNC materials that can fit into your ideal. From this list, you’ll have to compromise on the most important properties and pick the material that has these properties.

Upload your files and get started with RapidDirect today!

An Overview of Various CNC Materials

The best and easiest way to determine the best and most suitable CNC machining material is to consult an expert like RapidDirect. Once we know the outline of your project, we can help you decide on materials, finishing processes, and much more, depending on your goals, budget, and timeframe.

However, if you want to draw up a shortlist of potential CNC machining materials in advance, it is worth getting acquainted with the options out there.

From versatile aluminum alloys to specialist engineering plastics, here are some of the materials which are compatible with CNC machining:


aluminum 6061 sheet: a cnc material
Aluminum 6061 sheet

This metal possesses properties like good corrosion resistance, excellent machinability, and electroplating properties. Hence, it is one of the most popular CNC materials used in machining. It has a good strength-to-weight ratio, and its sheer variety means there is a suitable alloy for most machining projects. Machinists use aluminum for making parts for industries such as the aerospace, construction, automotive, and defense industries.

Common aluminum grades include:

various grades of cnc machinable aluminum material
Various aluminium grades

RapidDirect also offers aluminum machining in grades 1060, 1100, 2024, 3004, 5083, 5754, 6082, 6063, 6083, 7050, 5A12 and 5A02.

Stainless Steel

stainless steel pipes: a cnc material
Stainless steel pipes

Machinists widely use stainless steel in several industries due to its corrosion resistance and other desirable properties. Due to its wide applications, stainless steel comes in a variety of grades, many of which are suitable for CNC machining.

Common stainless steel grades include:

various grades of cnc machinable stainless steel material
Various steel grades

RapidDirect also offers stainless machining in 410 stainless steel, 416 stainless steel, and 440C stainless steel.


steel sheets
A36 Steel sheets

Steel is well known for its low costs and high tensile strength. Hence, it is suitable for use in industries such as machinery, construction, and aerospace. However, its use in these various industries will require various machinable variants. Hence, steel comes in quite a few variants.

various grades of cnc machinable steel material
Steel Grades

RapidDirect also offers steel machining in Alloy Steel 4140, 1045 Carbon Steel, and Alloy Steel 4340.

Other Metals

copper sheets: a cnc material
Copper sheets

Beyond aluminum and steel, it is also possible to machine metals such as brass, copper, titanium, and zinc, offering engineers a wider range of physical properties for their parts. Copper, for example, is an excellent conductor. This property makes it suitable for the production of electrical parts.

different cnc machinable metal materials
Different CNC machinable metals

RapidDirect also offers metal machining in other brass, copper, and titanium grades, as well as Zinc Sheet Alloy 500.


pom plastic
POM plastic

CNC machines are equally capable of cutting plastics. In most cases, these plastics may be preferred for cost, electrical insulation, or other reasons. Plastics are often a suitable prototyping material when the final part is made with injection molding.

different cnc machinable plastic materials
Various Plastic Grades

RapidDirect also offers plastic machining in Acrylic, G-10 Garolite, Nylon, PEEK, Polycarbonate, and Polypropylene.


RapidDirect CNC Machining Services

Going through this article, it is clear that CNC machining is a manufacturing process that is adaptable to many manufacturing processes. Due to this versatility, it could be hard for you to handle all the aspects of your production process all by yourself.

However, with experts like RapidDirect to guide you every step of the way, it makes every single step of the production process (from design to material selection to the actual manufacturing) easier.

With our machinists and designers possessing years of manufacturing experience, we can analyze your design file, evaluate its feasibility for manufacturing, and make cost-effective suggestions that can make your CNC machining process a success. Reach out to us immediately to get started.

Try RapidDirect now,
for free

All information and uploads are secure and confidential.