Husqvarna PG820 - Manual (Page 16)

18 - English
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 fi ne 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 fi nished product is referred to as a Metal
Bond or Sintered diamond segment. When suspend-
ed
in a resin binding agent, the fi nished 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 fi ner scratch pattern.
Increase the life of the diamond tool.
The opposite will occur when changing to a larger
particle/grit size.
BINDING AGENT—METAL BOND OR RESIN BOND
Increasing hardness of bond will:
Increase life of diamond tool.
Decrease production rate.
Cause diamond tool to leave fi ner 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.
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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 fl oors).
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 infl uenced
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 fl oor will increase wear.
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Diamonds