In the precision production of mechanical components, the selection of the right material is a key stage of the process. CNC machining – whether turning, milling or 5-axis machining – requires materials that not only meet strength requirements, but also work well with tools and cutting technology.
At SIM Gdynia, we have specialized in CNC services for over 45 years and know how important the quality and type of raw material is. In this article, we present an overview of the materials we use most often in our production.
Materials most commonly used in CNC machining
Three main material groups dominate our machinery: carbon steel, stainless steel and aluminum. These raw materials form the basis for the production of precision components for industries such as the automotive, energy and mechanical engineering sectors.
Carbon steel – versatile and robust
Structural steel (e.g. S235JR, S355J2) and quenched and tempered steels such as C45, 42CrMo4, 16MnCr5 are the basic materials from which we produce a wide range of parts. Their availability, the possibility of precise CNC machining and excellent mechanical properties make them a reliable choice for many projects.
Stainless steel – corrosion resistance
Stainless steel is a material that is used in environments requiring increased chemical resistance. At SIM Gdynia, we often machine austenitic and ferritic steels, which require the appropriate selection of cutting parameters due to their hardness and tendency to harden during machining.
Aluminum – lightness and versatility
Thanks to its low weight and good conductive properties, aluminum is often used in industries such as aviation, automotive and electronics. In the CNC milling process, it allows for very high accuracy and short cycle times.
Less typical, but equally important materials
Although the vast majority of parts produced in our hall are made of metals, there is no shortage of projects using plastics and non-ferrous metals.
Plastics
At SIM Gdynia, we process engineering plastics such as POM, PA and PTFE. These materials are characterized by a low coefficient of friction, good chemical resistance and ease of processing, although they require precise tool alignment and thermal deformation control.
Non-ferrous metals: copper, brass, bronze
These materials are used less frequently but are still important, especially for the production of electrically conductive or wear-resistant components. They require special tool geometries because they are relatively soft and can stick to the cutting edge.
How do the physical properties of materials affect CNC machining?
Each material reacts differently to the cutting process. Hardness affects tool wear, ductility determines the type of chip, and thermal conductivity affects dimensional stability during machining.
Machinability of materials – a key technological parameter
Machinability is a collective term for how easily a material can be processed. Grades such as 11SMn30 (free-cutting steel) have very good machinability and are ideal for mass-produced parts. Stainless steel or copper, on the other hand, require sharper tools, lower feed rates and more efficient cooling.
Quality control and material conformity
Every material used in our production undergoes a quality control process. The certification of the material and the possibility of verifying its chemical composition are crucial. Thanks to the SPECTROMAXx spectrometer, we are able to quickly and precisely confirm the material’s conformity with the specification – before it even reaches the CNC machine.
We work with renowned suppliers who offer a wide range of steel bars (drawn and rolled) in grades such as 11SMn30, C35, ETG88 and 20MnCr5. These grades provide different mechanical properties, such as hardness, machinability or fatigue strength, depending on the final application of the workpiece.
Summary
Choosing the right material for CNC machining is not just a question of availability – it is a decision that affects the entire production cycle, the service life of the tools, the quality of the finished component and its compliance with technical requirements. At SIM Gdynia, we attach great importance to the quality of raw materials, precise control and matching of machining technology to a specific material.If you are looking for a partner who not only produces custom-made mechanical components but also advises you on the best raw material, please contact us. Our services CNC guarantee quality, experience and technological know-how.
