CNC machining is particularly rough will have any impact on the parts

Particularly rough CNC machining will have a negative impact on parts in many aspects, including reduced wear resistance, reduced fit stability, weakened fatigue strength, reduced corrosion resistance, poor sealing, reduced contact stiffness and reduced measurement accuracy.?

Wear resistance reduction

Rough CNC machining surfaces will cause the effective contact area between the mating surfaces to decrease, thereby increasing the pressure and friction resistance, making the part wear faster. For example, rough surfaces may only have an effective contact area of 15% to 20%, while the surface of precision machined parts can have an effective contact area of 85% to 90%, significantly improving the wear resistance.

Loss of fit stability

For the parts with clearance fit, the surface roughness is easy to form wear, which makes the clearance increase rapidly, and even destroys the compatibility. Especially in the case of small size and high precision, the surface roughness has a greater impact on the fit. For interference fit, the actual effective interference is reduced because the microscopic convex peak is flattened during assembly, thus reducing the connection strength.

Decreased fatigue strength

There are large troughs and unevenness on the surface of rough parts. These unevenness areas are easy to cause stress concentration under alternating load, accelerate the generation and expansion of fatigue cracks, and thus reduce the fatigue strength of parts.

Reduced corrosion resistance

Parts with high surface roughness are more likely to accumulate corrosive gases or liquids, which penetrate into the inner layer of the metal through the microscopic concave of the surface, resulting in surface corrosion. Reducing the surface roughness can reduce the accumulation and penetration of corrosive substances on the surface and improve the corrosion resistance of parts.

Poor sealing

Rough surfaces do not fit tightly to each other, causing gas or liquid to leak through the gap between contact surfaces. Reducing the surface roughness can improve the tightness of the part, ensuring its sealing effect under high pressure, high speed or corrosive environment.

Contact stiffness reduction

Rough surface will reduce the actual contact area, thereby reducing the contact stiffness, affecting the machining accuracy of the machine tool and the overall performance of the part.

Loss of measurement accuracy

The surface roughness of the measured surface of the part and the measuring tool will directly affect the accuracy of the measurement. Especially in the precision measurement process, the impact of surface roughness on the measurement accuracy is more significant.

Cause and solution

The causes of surface roughness in CNC machining include the friction between the tool and the surface of the part, the plastic deformation of the surface layer metal when the chip is separated, and the high-frequency vibration in the process system. Solutions include selection of suitable cutting parameters, optimization of tool design and reduction of vibration in the process system.