Basic knowledge of machining that few people know in CNC precision parts machining

Basic knowledge of machining that few people know in CNC precision parts machining

In the mass production of CNC precision parts processing, because the workpiece requires high precision and short delivery time, the operation efficiency of the equipment is the top priority of the 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.

1. Chip control

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

 

the reason:

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

Solution: Increase the feed.

2. The cutting depth of the selected groove is too shallow.

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

3. The tool nose radius is too large.

Solution: Increase the depth of cut or choose a geometry with stronger chip breaking ability.

4. Inappropriate entering angle.

Solution: Choose a smaller nose radius.

2. Surface quality
The surface looks and feels “hairy” and does not meet the tolerance requirements.

the reason:

1. The chip breaks by hitting the part and leaving marks on the machined surface.

Solution: Choose the groove shape that guides chip removal. Change the entering angle, reduce the depth of cut, and choose a positive rake angle tool system with a central cutting edge inclination.

2. The reason for the hairy surface is that the grooves on the cutting edge are too worn.

Solution: Choose a brand with better oxidation and wear resistance, such as a cermet brand, and reduce the cutting speed.

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

Solution: Choose a larger tool nose radius and reduce 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 blades with sharp cutting edges:-Fine grinding blades with a small feed rate (<0.1mm/r).

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

Solution: Use a tool holder with a small entering angle.

3. The grooves at the cutting depth of CNC precision parts are worn or chipped.

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

4. Vibration

High radial cutting force, cause: vibration or chatter scratches caused by the tool or tool installation. It usually occurs when the boring bar is used for internal machining.

the reason:

1. Inappropriate entering angle.

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

2. The tool nose radius is too large.

Solution: Choose a small tool nose radius.

3. Inappropriate cutting edge roundness, or negative chamfering.

Solution: Choose a grade with a thin coating, or a non-coated grade.

4. Excessive flank wear on the cutting edge.

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

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