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5.7 TROUBLE SHOOTING FOR SURFACE GRINDING
5.7.1 TWO FACTORS THAT CAUSE GRINDING PROBLEM
There are many factors that may affect the final grinding result. A machine operator must
understand wheat items should be noted. In addition, the operator should understand the
cause of problem, and then try to find the solutions for solving the problem. There are two
major factors that cause grinding problem:
A. MACHINE PROBLEMS: Such as the spindle bearings must be precise. All moving
parts require proper lubrication for smooth movement. The machine structure should be
rigid enough to produce fine finish on surface. The machine installation location must
be kept away from external vibrating sources, such as railway or punch press.
B. MACHINE OPERATION PROBLEMS: Such as the correct selection of grinding wheel.
If grinding wheel dressing method is correct or not. If coolant contains dusts or not. If
the grinding wheel face is clogged or smooth or not. If the operator fully understands
the machine construction, cross movement and feed and operation method, etc.
5.7.2 FREQUENTLY OCCURRED PROBLEMS, CAUSES AND
CORRECTION FOR SURFACE GRINDING
PROBLEM: Intermittent grinding caused by unbalanced grinding wheel or external vibration.
The grinding wheel is clogged, smooth and chattering. REMEDY: To balance, true and sharpen
the grinding wheel. The machine installation location should be isolated from the external
vibrating source.
IRREGULAR SCRATCH MARKING OR FISHTAIL MARKING
CAUSES: Dusts contained in coolant. Dusts drop from the grinding wheel guard. Insufficient
coolant. Dusts drop from the chuck when removing the workpiece.
REMEDY: Clean inside and outside of the grinding wheel guard. Clean coolant. Clean chuck
before removing workpiece. Fill proper amount of coolant.
BURNING DAMAGE AND COLOR CHANGE ON WORKPIECE
CAUSES: Insufficient grinding amount. Grinding wheel is too hard or too fine. Too heavy grinding
on a small area causes heat concentration.
REMEDY: Increase table feed speed. Reduce grinding depth. Increase coolant flow speed and
flow rate to cool down workpiece.
WORKPIECE IS NOT PARALLEL
CAUSES: Partial over-heat. Internal stress relieved. Workpiece is bending or twisting.
REMEDY: Reduce holding force on the chuck. Place the bento side of workpiece on the chuck.
Turn over workpiece then pad it with a sheet of paper. Light grinding several times, then turn over
workpiece for continued grinding to achieve a flat surface.
WORKPIECE IS NOT EVEN
CAUSES: Partial over-heat. Internal stress. Workpiece is bent or twisted.
REMEDY: Use low clamping force on the chuck. Place workpiece on the chuck with bent side
facing upward. Place a sheet of paper under workpiece. Slightly grinding several times then turn
over workpiece and grinding again. Repeat grinding until a plain surface is obtained.
5-16
818~2040 PD
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