Diamonds
Diamonds
Background
Diamond abrasives usually consist of 2 components:
1.Diamond powder (also known as diamond crystals or grit). By changing the size of the diamond powder or grit, we can change how coarse or fine the scratches will be that are left behind from the grinding process.
2.A binding agent (metal or resin). Diamond powder
is mixed and suspended in either a metal or resin binding agent. When suspended in a metal binding agent, the finished product is referred to as a Metal Bond or Sintered diamond segment. When suspend-
ed
in a resin binding agent, the finished product is referred to as a Resin Bond diamond segment or pad. By changing the hardness of the binding agent, we can change how fast or slow the diamond abra-
sive
will wear.
General Principles
The following are general rules regarding diamond seg- ments in grinding applications. As with all general rules there are exceptions or cases when it is not the case.
DIAMOND GRIT SIZE
Changing the size of the diamond grit to a smaller par- ticle/grit size will effect the performance of the diamond tool in the following ways:
•Create a finer scratch pattern.
•Increase the life of the diamond tool.
The opposite will occur when changing to a larger
particle/grit size.
BINDING
•Increase life of diamond tool.
•Decrease production rate.
•Cause diamond tool to leave finer scratches in dry - grinding applications (when compared to a softer bond diamond tool with the same diamond grit size).
The opposite will occur when making the metal or resin bond softer.
NUMBER OF DIAMOND SEGMENTS/PADS UNDER THE MACHINE
Increasing the number of segments under the machine will:
•Reduce pressure on each individual diamond seg- ment.- Reduce wear rate on diamond segments.
•Reduce load on the machine and cause the grinder to draw less current.
•Create a smoother scratch pattern (particularly on soft floors).
The opposite will occur when decreasing the number of segments under the machine.
WET AND DRY GRINDING
When using diamond segments wet, the following principles apply:
•Production rates will be higher than dry grinding.
•Diamond segments will wear faster (due to pres- ence of slurry) and therefore, harder bonds can be used (when comparing with dry grinding).
•Scratches from diamond grit will be deeper.
When using diamond segments dry, the following prin- ciples apply:
•Production rates will be slower on harder materials than if wet grinding.
•Softer bond segments will be required in order to encourage segment wear (as there will be not slurry to help diamond segments to wear).
•Scratches from diamond grit will not be as deep compared to if it were also used for wet grinding.
•There will be more heat generated by the diamond segment.
Summary of diamond principles
Diamond segments need to wear in order to achieve productivity. Diamond segment wear can be influenced by the following factors:
•Pressure.
•Hardness of bond.
•Diamond grit size.
•Presence of water.
•Number of segments under the machine.
•Adding an additional abrasive (e.g. sand, silicone carbide) on the floor will increase wear.
18- English