CNC Lathe Chucks: Troubleshooting common problems

Possible causes and solutions for common chuck problems such as:

1. Component slippage 
2. Excessive Vibration
3. Master Jaw not moving
4. Poor Accuracy
5. Base Jaw Breakage

Troubleshooting: Component slippage

1. Lack of lubrication on master jaws & moving parts -Lubricate master jaws through the grease nipple
2. Component Clamping at end of the stroke -Clamp the component at the middle of the Jaw stroke to avoid slippage.
3. Speed is excessively high -Reduce the speed level to obtain necessary chucking
4. Cutting forces too high -Calculate cutting force & check against chuck specifications
5. Insufficient chucking force -Check hydraulic pressure setting

Troubleshooting: Excessive Vibration

1. Run out on chuck body beyond permissible value-True the chuck body within permissible value as specified
2. Top jaws holding the job not symmetric with the rotation axis and therefore causes imbalance -Chuck with the special jaws and component to be dynamically balanced
3. Draw tube / Draw bar may be out of centre or out of alignment -Check and correct the alignment

Troubleshooting: Master Jaw not moving

1. Chuck with dirt from burrs & chips - Dismantle & do periodic maintenance.
2. Internal parts of Chuck broken/ jammed -Replace broken parts & do periodic maintenance.
3. Check cylinder for malfunction.

Troubleshooting: Poor Accuracy

1. Excessive height of top jaws -Reduce the height of top jaws as recommended by GMT
2. Guide ways of the internal parts of the chuck could be worn out -Recondition the chuck /Replace the chuck with new.
3. Too much chucking force - Reduce the chucking force to optimum level

Troubleshooting: Base Jaw Breakage

1. Component  Clamping at end of the stroke -Clamp the component at the middle of the Jaw stroke.
2. Excess Draw Bar pull (causing breakage of Master Jaw & Wedge) - Select suitable cylinder from ‘Selection Chart’ specified in GMT Instruction Manual and maintain the Draw Bar pull as specified.