Material selection in CNC manufacturing: Why machinability is crucial

Selecting the right material is a key success factor in CNC machining. In addition to mechanical properties such as strength, corrosion resistance or weight, one criterion in particular plays a decisive role in economic efficiency: machinability. This describes how well a material can be machined using cutting processes such as turning, milling, drilling or grinding.

Materials with good machinability can be machined faster and more precisely, cause less tool wear and result in smooth surfaces – which not only reduces production costs, but also shortens production times. Conversely, materials that are difficult to machine require more effort: longer machining times, more frequent tool changes and potentially higher reject rates.

Machinability depends, among other things, on the hardness, thermal conductivity, chip breaking behavior and chemical composition of the material. Aluminum alloys such as EN AW-6082 or free-cutting steels such as 1.0715 are considered to have very good machinability and are ideal for series and prototype production. Stainless steels, titanium or high-strength alloys, on the other hand, place higher demands on machines, tools and process parameters.

Especially for components with tight tolerances, complex geometries or short delivery times, a well-thought-out choice of material can make all the difference. In practice, high machinability means higher precision, lower costs and shorter delivery times.

Our team at CNC24 will be happy to support you in selecting the right material – tailored to function, availability and machinability. This allows you to get the most out of your component – both technically and economically.

What is the best material for CNC machining?

The answer depends heavily on the application. Aluminum alloys such as EN AW-6082 are very easy to machine and ideal for prototypes or lightweight components. Stainless steels such as 1.4301 are suitable for durable, corrosion-resistant components. Titanium is used for highly stressed applications, but is difficult to machine and more cost-intensive. Plastic solutions such as POM-C are ideal for lightweight, low-wear designs.

Aluminum vs. steel – which is better for your project?

Aluminum offers advantages in terms of weight, machinability and corrosion resistance – especially in aerospace and automotive engineering. Steel scores with high strength, wear resistance and lower material costs for large quantities. Free-cutting steels are often the first choice for series production with an economic focus.

How does machinability affect CNC costs?

The better the machinability of a material, the shorter the machine run times, the lower the tool wear and the higher the reproducibility. This reduces both direct production costs and indirect costs due to rejects or reworking.

Material selection for milling, turning and drilling in comparison

Not every material is equally suitable for every CNC process. Soft plastics can be milled well, but can melt during drilling. Titanium requires special parameters for all processes. Steel is an all-rounder, while aluminum is particularly advantageous for milling.

Glossary of important terms

Machinability – Machinability of a material using cutting processes.
Tolerance behavior – Measure of how well precise dimensions can be maintained.
Material number – Standardized designation of technical materials (DIN EN ISO).
Corrosion resistance – Resistance to environmental influences such as moisture, chemicals, etc.
Free-cutting steel – Special steel for high cutting speeds with short chips.

Selected materials in comparison

Materiaḷgroup	Material designation	Material no.	Machinability	Tolerance behavior	Corrosion resistance	Typical applications
Aluminum	EN AW-6082	3.2315	⭐⭐⭐⭐☆	Very good	Medium	Lightweight construction, prototyping
	EN AW-7075	3.4365	⭐⭐☆☆☆	Good	Medium	Aviation, motor sports
	EN AW-2011	3.1655	⭐⭐⭐⭐⭐	Very good	Low	Series parts, threads
	EN AW-6061	3.3211	⭐⭐⭐⭐☆	Good	Medium	Mechanical engineering, devices
	EN AW-5083	3.3547	⭐⭐☆☆☆	Medium	High	Marine, vehicle construction
Free-cutting steels	11SMn30	1.0715	⭐⭐⭐⭐⭐	Very good	Low	Turned parts, connecting parts
	9SMn28K	1.0718	⭐⭐⭐⭐☆	Good	Low	Machine parts, shafts
	36SMn14	1.0762	⭐⭐⭐⭐☆	Good	Low	Serial turned parts
Structural steels	S235JR	1.0038	⭐⭐⭐☆☆	Good	Low	Frames, carriers, laser parts
	C45E	1.1191	⭐⭐☆☆☆	Medium	Low	Gear wheels, shafts
	42CrMo4	1.7225	⭐⭐☆☆☆	Medium	Medium	Gear parts, tools
Stainless steels	X5CrNi18-10	1.4301	⭐⭐☆☆☆	Medium	High	Medical technology, housing
	X10CrNiMoTi18-10	1.4571	⭐⭐☆☆☆	Medium	Very high	Chemical plants, outdoor areas
	X6CrNiTi18-10	1.4541	⭐⭐☆☆☆	Medium	High	Food industry
Titanium	Ti6Al4V	3.7164	⭐☆☆☆☆	Medium	Very high	Implants, aviation
	Titanium Grade 2	3.7035	⭐⭐☆☆☆	Medium	High	Plant engineering, chemistry
Plastics	POM-C	–	⭐⭐⭐⭐⭐	Very good	Medium	Sliding parts, guides
	PA6	–	⭐⭐⭐☆☆	Good	Medium	Technical plastic parts
	PTFE	–	⭐⭐☆☆☆	Medium	Very high	Seals, chemical applications
	PE-HD	–	⭐⭐☆☆☆	Medium	High	Devices, covers

About CNC24

CNC24 is the transparent manufacturing cloud for the global procurement of components. With just one contract and contact partner, CNC24 provides access to more than 500 selected manufacturers from all over the world.

CNC24 specializes in plastic and metal components using the production methods of milling, turning, sheet metal processing, die casting, injection moulding and 3D printing.

For quality control, all parts undergo an additional test process in the in-house measuring center before they are delivered. CNC24 was founded in 2019 by co-founders Willi Ruopp and Marlon Gerat. The start-up serves all industrial sectors with a need for production parts – from special machinery and plant engineering to IOT and medical, testing and measurement technology.