Defects and improvement measures of CNC turning machining bearing

This article mainly talks about the reasons and solutions for CNC turning machining bearing to have turning chatter lines or rib retention at assembly chamfers.

CNC turning machining bearing has turning chatter

The outer diameter of the bearing ring after CNC turning machining has obvious turning vibration lines (see the figure below), the surface shows fine lines, and the appearance surface roughness value is about Ra=25um. The main reason for this defect is that the rigidity of the turning tool is insufficient during the turning process, and the cutting force is too large, which causes the turning tool to "vibrate" and causes vibration lines on the surface of the workpiece; in addition, the blank allowance is too large or uneven (may be Ovality is out of tolerance), which will cause the tool to vibrate due to the impact of the alternating cutting force; improper selection of the cutting amount in the turning process, excessive cutting amount, resulting in turning vibration lines.

The improvement measures for this problem are as follows.

1) Strictly control the elliptical deformation of the CNC turning machining bearing ring forging blank. Before turning, carry out a full inspection of the ellipse of the bearing ring forging blank, and pick out unqualified products with excessive ovality.

2) Select a reasonable amount of turning for unqualified ovality products, increase the number of turnings if necessary, and change from one pass to two passes.

3) After turning, pick out the workpiece with vibration pattern on the outer diameter of the bearing ring, and process it separately in the subsequent grinding process.

CNC turning machining bearing has turning chatter

Retaining ribs at the assembly chamfer of CNC turning machining bearing

The rib (obvious turning tool pattern) at the chamfered part of the bearing ring assembly after CNC turning is shown in the figure below. The main reasons for this defect are the large amount of turning of the chamfered part and the poor chip removal; the excessive runout of the machine tool spindle and the excessive clearance of the spindle bearing, resulting in the processing of chamfering ribs.

The improvement measures for this problem are as follows.

1) When compiling the chamfering machining program, add a finishing pass and leave a machining allowance of 0.05~0.10mm to reduce the surface roughness value of the chamfering.

2) Regularly test the accuracy of the machine tool equipment to ensure that the machine tool accuracy is qualified.

3) After finding the rib in the chamfering part of the bearing ring assembly (obvious turning tool pattern), use the CNC lathe to rework and remove the rib in the chamfering part by turning.

Retaining ribs at the assembly chamfer of CNC turning machining bearing

CNC Turning Machining Bearing Supplier - Malante

Suzhou Malante Precision Machinery Co., Ltd. is a production-oriented enterprise specializing in the processing and assembly of mechanical parts, such as CNC Turning Machining Bearing parts. If you have POM, PA, PE, UHNW and other engineering plastics; carbon steel, stainless steel, die steel, titanium alloy, copper, aluminum and other metal materials that need CNC turning into parts, feel free to contact us. Our products are exported to various countries, welcome you to be our partner.