Processing basic knowledge that few people know in CNC precision parts processing [(attached) elimination method-on]

In the mass production of CNC precision parts processing, due to the high precision of the workpieces and short delivery time, the operation efficiency of the equipment is the top priority of production and processing. Being able to master simple basic knowledge can not only improve production efficiency, but also reduce the failure rate of the machine.

The following is the basic knowledge of processing:

1. Chip Control

Long continuous cutting around the tool or workpiece. Usually caused by low feed, low and/or shallow cutting depth.

the reason:

1. The feed for the selected geometry is too low.

Solution: Increase feed.

2. The cutting depth is too shallow for the selected geometry.

Solution: Choose a blade geometry with stronger chip breaking capability. Increase the coolant flow.

3. The radius of the tool tip is too large.

Solution: Increase the cutting depth or select a groove shape with stronger chip breaking ability.

4. Inappropriate lead angle.

Solution: Choose a smaller tool nose radius.

2. Surface quality

The surface looks and feels "hairy" and does not meet tolerance requirements.

        the reason:

        1. Chip breaking by hitting the parts and leaving traces on the processed surface.

        Solution: Select the groove shape that guides the chip removal. Change the main declination angle, reduce the cutting depth, and select a positive rake angle tool system with a centered blade inclination.

        2. The reason for the appearance of the hairy surface is that the groove on the cutting edge wears too much.

        Solution: Choose a brand with better resistance to oxidation and wear, such as a metal-ceramic brand, to reduce cutting speed.

        3. The combination of too high feed and too small fillet of the tip will produce a rough surface.

        Solution: Choose a larger tool nose radius and lower the feed.

3. Burr formation

When cutting away from the workpiece, burrs are formed at the cutting end.

        the reason:

        1. The cutting edge is not sharp enough.

        Solution: Use inserts with sharp cutting edges:-Fine-grinding inserts with small feed rates (<0.1mm/r).

        2. The feed is too low for the cutting edge roundness.

        Solution: Use a toolholder with a small lead angle.

        3. Groove wear or chipping at the cutting depth of CNC precision parts.

        Solution: When leaving the workpiece, end the cutting with a chamfer or radius.

4. Vibration

High radial cutting force, cause: vibration or tremor scratches caused by the tool or tool installation. Usually occurs when using boring bars for internal machining.

        the reason:

        1. Inappropriate lead angle.

        Solution: Choose a larger lead angle (kr=90°).

        2. The radius of the tool tip is too large.

        Solution: Choose a small tip radius.

        3. Inappropriate cutting edge roundness, or negative chamfer.

        Solution: Choose a grade with a thin coating or an uncoated grade.

        4. Excessive flank wear on the cutting edge.

        Solution: Choose a more wear-resistant grade or reduce the cutting speed.