BIG DAISHOWA High Performance Tooling Solutions Vol 3

ROUGH BORING HEADS

ROUGH BORING TROUBLESHOOTING Under certain conditions, it may be necessary to modify or adapt recommended cutting data and/or tooling configurations of the application. Below are general solutions to common problems.

Problem

Possible Cause

Remedy

Feed rate too low

Increase feed rate

Excessive height variation of inserts Width of chip excessive (D.O.C.)

Preset tool to max. .0002" variation of both inserts

Poor Chip Control

Preset tool for stepped cutting method

Excessive stock allowance

Consult cutting data tables

Excessive speed

Reduce SFM, check cutting data tables Shorten tool to increase stiffness Increase boring bar diameter to larger size Change boring bar to carbide or heavy metal

Extreme length/diameter ratio

Chatter & Vibration

Insert radius too large Unstable workpiece

Reduce nose radius of insert

Improve fixture and clamping support

Lead angle on insert holders

Change to 90 degree insert holders (type CC) Change to tougher grade of carbide insert Use larger radius if available

Wrong insert

Inserts Chipping or Breaking

Severe interruption

Increase speed, decrease feed

Check for boring bar/bore diameter clearance Improve chip control, increase feed

Chips packing and re-cutting

Wrong insert

Change to higher wear resistant grade

Excessive cutting speed

Reduce speed

Poor Tool Life

Inserts chipping

Check stock allowance and feed rate Increase through tool coolant pressure Adjust coolant ports of head if available

Coolant pressure too low

Boring bar diameter too large Excessive stock allowance Inadequate space below bore

Reduce to smaller head and extended range holder

Re-set tool for stepped cutting Elevate workpiece from table more

Chips Not Evacuating

Poor chip control Excessive feed rate

See above problem

Reduce feed; minimum 25% of insert radius Reset tool for stepped cutting method RPM in area of low spindle torque; increase speed RPM in area of gear change; adjust RPM Change insert to higher rake angle Reduce depth of cut

Stock allowance excessive

Insufficient Machine Power

Low machine torque

Excessive feed rate CC type insert holders

Reduce feed rate

Use square insert holders with 6 degree lead

Excessive Exit Burr

Reduce depth of cut Reduce insert radius

Cutting forces too high

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