Trouble Shooting for Threading

TROUBLE SHOOTING

Problems Observation Causes Solutions
Low thread precision. Threads do not mesh with each other. Incorrect tool installation.
Set the insert center height at 0".
Check holder inclination (Lateral).
Shallow thread. Incorrect depth of cut. Modify the depth of cut.
Lack of insert wear or plastic deformation resistance.
Refer to "Quickly generated flank wear." and "Large plastic deformation." below.
Poor surface finish. Surface damage. Chips wrap around or clog the workpieces. Change to flank infeed and control the chip discharge direction.
Change to an M-class insert with a 3-D chip breaker.
The side of the insert cutting edge interferes with the workpiece. Check the lead angle and select an appropriate shim.
Surface tears. Built-up edge (Welding). Increase cutting speed.
Increase coolant pressure and volume.
Cutting resistance too high. Decrease depth of cut per pass.
Surface vibrations. Cutting speed too high. Decrease the cutting speed.
Insufficient work piece or tool clamping. Re-check work piece and tool clamping.
(Chuck pressure, clamping allowance)
Incorrect tool installation. Set the insert center height at 0".
Short tool life. Flank wear quickly generated. Cutting speed too high. Decrease the cutting speed.
Too many passes causes abrasive wear. Reduce the number of passes.
Small depth of cut for the finishing pass. Do not re-cut at 0" depth of cut, larger than .002" is recommended.
Non-uniform wear of the right and left sides of the cutting edge. The work piece lead angle and the tool lead angle do not match. Check the work piece lead angle and select an appropriate shim.
Chipping and fracture. Cutting speed too low. Increase cutting speed.
Cutting resistance too high. Increase the number of passes and decrease the cutting resistance per pass.
Unstable clamping. Check work piece deflection.
Shorten tool overhang.
Recheck work piece and tool clamping.
(Chuck pressure, clamping allowance)
Chip packing. Increase coolant pressure to blow away chips.
Change the tool pass to control chips. (Lengthen each pass to allow the coolant to clear the chips.
Change from standard internal cutting to back turning to prevent chip jamming.
Non-chamfered work pieces causes high resistance at the start of each pass. Chamfer the workpiece entry and exit faces.
Large plastic deformation. High cutting speed and large heat generation. Decrease the cutting speed.
Lack of coolant supply. Check coolant is supply is sufficient.
Increase coolant pressure and volume.
Cutting resistance too high. Increase the number of passes and decrease the cutting resistance per pass.



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