The two most common grinding problems are often caused by the incorrect bond for the surface being ground.
Glazing
This is the most common diamond segment problem, often caused by a bond that is too hard.
As a diamond segment wears down, the bond wears, exposing more diamond that continue cutting.
If the bond does not wear back, then eventually there is no diamond exposed, so the segment will slow down and stop grinding.
The cutting surface of the segment will feel smooth.
This is known as glazing or polishing.
See table below for tips on how to rectify.
Short Segment Life
Generally caused by using a bond which is too soft for the material being cut. It usually occurs when grinding more abrasive materials such as green concrete. Sometimes concrete looks cured but is not fully.
Use a harder bond for the application.
Increasing the number of shoes reduces the weight per shoe, and can reduce wear. Or reduce the pressure on the grinder.
When wet grinding , ensure correct amount of water or coolant is used (too much can be just as bad as too little).
Operating RPM may be too low or too high (if adjustable)
Common Problems and remedies:
|
Problem |
Probable Causes |
Solutions |
| Grinding too slow | Too much contact. |
Cups - try a cup wheel with less segments. Shoes - Change from double segment to single segment, or reduce number of shoes. |
| Bond too hard for material. |
Use a softer bond |
|
| Segment glazed up. |
Dress with abrasive material until diamond becomes exposed again (see more below) |
|
|
Overheating. |
Wet concrete (without causing puddles) to cool. Or use cutting lubricants. |
|
|
Glazing |
Too high RPM for the selected grinding shoe. | Reduce RPM speed or less friction and heat. |
| Mismatched aggregate and bonds (bond too hard for material). | Change to a softer bond which will wear down, exposing more diamonds. | |
| Not enough diamonds to cope with given condition. | Increase diamond quantity by adding more shoes or switching to double segmented shoes. | |
| Material too hard. | Dress your tool on some soft concrete or with an abrasive wheel to expose diamonds. | |
| Overheating. | Saturate concrete (without water puddling) to cool segments. Or use cutting lubricants or clean builders sand. |
|
| Too much coolant when grinding wet. | Reduce amount of coolant. | |
|
Segments knocked off tool |
Floor areas 'above grade' (raised above the surface level). | Hand grind surface to level. Spot grind if area is less than 10mm high. |
|
Deep scratches |
Wrong grit. | Select a finer grit or take more time when grinding. |
| Concrete can be softer in one area than another. | Go back a step and use coarser grit. | |
|
Discolouration of floor |
An adhesive may have discoloured the matrix. |
Unfortunately unfixable. |
|
Short segment life |
Bond is too soft for the material being ground |
Select a harder bond for the application |
|
Increase the number of shoes. |
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When wet grinding , ensure correct amount of water or coolant (too much can be just as bad as too little). |
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Operating RPM too low or too high (if adjustable) |
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Too much weight or force on grinder |
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Insufficient dust extraction |
