What are the processing methods of CNC machining?

we commonly encounter are usually made from such as 303, 304, 316, 420, etc. Stainless steel parts possess good formability, compatibility, corrosion resistance, and strong rigidity, making them ubiquitous in both industrial and everyday life.

 

The precision Turning stainless steel parts we commonly encounter are usually made from such as 303, 304, 316, 420, etc. Stainless steel parts possess good formability, compatibility, corrosion resistance, and strong rigidity, making them ubiquitous in both industrial and everyday life. These products find extensive applications in medical, aerospace, automotive, communication, optoelectronics, kitchenware, and other fields.

 

Different grades of stainless steel have different hardness and slightly varying characteristics. In the CNC machining, are there challenges in machining stainless steel?

 

Ningbo LEKE Precision Technology Co.,Ltd. specializes in precision CNC turning-milling/turned parts machining, and we have compiled a list of the machining challenges associated with stainless steel.

 

A. High cutting force: Stainless steel undergoes significant plastic deformation during cutting, leading to increased cutting forces. Severe work hardening of stainless steel, high thermal strength, further increases cutting resistance, and curling and breaking of chips also appear relatively difficult.

 

B. Severe work hardening: Stainless steel has high plasticity, causing distortion during plastic deformation, with a high strengthening coefficient. Additionally, the austenite is not stable enough, and under the action of cutting stress, some austenite will transform into martensite. Furthermore, compound impurities are easily decomposed and dispersed under the effect of cutting heat, resulting in the formation of a hardened layer during cutting. The work hardening phenomenon generated in the previous feed or previous process significantly affects the smooth progress of subsequent processes.

 

C. Chips are not easily broken and prone to adhesion: Stainless steel has high plasticity and toughness. During CNC machining, chips are continuous, not only affecting smooth operation but also squeezing and damaging the already machined surface. At high temperatures and pressures, stainless steel has strong affinity with other metals, easily leading to adhesion and forming chip lumps, exacerbating tool wear and causing tearing phenomena, thus deteriorating the machined surface.

 

D. High cutting temperature: Plastic deformation and friction between the workpiece and the tool during cutting are significant, resulting in a large amount of cutting heat generation. A considerable amount of cutting heat is concentrated at the interface between the cutting zone and the tool-chip contact, with poor heat dissipation conditions.

 

E. High coefficient of linear expansion: The coefficient of linear expansion of stainless steel is approximately 1.5 times that of carbon steel. Under the action of cutting temperature, the workpiece is prone to thermal deformation, making it difficult to control dimensional accuracy.

 

F. Tool wear is easy: Affinity during stainless steel cutting leads to bonding and diffusion between the tool and the chip, causing adhesive wear and diffusion wear of the tool, resulting in crescent-shaped depressions on the tool front face, and the cutting edge may also experience minor flaking and notching. Additionally, carbides in stainless steel (such as TiC) have high hardness, directly contacting and rubbing against the tool during cutting, scratching the tool. Moreover, there is work hardening during machining, all of which exacerbate tool wear.

 

Through the above analysis, we understand that the machining challenges of precision stainless steel parts mainly manifest as high cutting force, severe work hardening, high adhesiveness, high temperature, large coefficient of linear expansion, and easy tool wear. When we understand the characteristics of stainless steel machining, corresponding measures can be taken, such as selecting machine tools, choosing cutting tools, selecting tool paths, determining cutting parameters, and using cutting fluids, to ensure the quality of product machining

Welcome to contact with us Ningbo LEKE Precision Technology Co.,Ltd for any question and would like to discuss with you.