Grinding Guide - Husqvarna PG820 RC Operator's Manual

Grinding guide Diamonds
The following are guidelines regarding diamond
segments grinding applications. As with all guide lines
there are always exceptions to the rule.
General
The diamond segment comprises usually of two
components:
• Diamonds (also called diamond crystals or corn).
Changing the size of the diamonds or corn will change
the coarseness or fineness of the scratches after the
grinding process.
• A bonding agent (metal or plastic). Powder is mixed
and suspended in a metal or plastic bonding agent. If
metal is used as a bonding agent, the finished product
is called metal-bonded or sintered diamond segment.
If plastic is used as a bonding agent, the finished
product is called plastic-bonded diamonds or
polishing disc. By changing the hardness of the
bonding agent, you can change how quickly or slowly
the diamond abrasive is worn down.
Diamond grit size
The following are general rules regarding diamond
segments in grinding applications. As with all general
rules there are exceptions or cases when it is not the
case.
Changing the size of the diamond grit to a smaller
particle/grit size will effect the performance of the
diamond tool in the following ways:
• Create a finer scratch pattern.
• Increase life of diamond tool.
The opposite will occur when changing to a larger
particle/grit size.
Binding agent
Increasing hardness of bond will:
• Create a finer scratch pattern.
• Increase life of diamond tool.
• Decrease production rate.
The opposite will occur when making the metal or resin
bond softer.
Number of diamond tools under the
machine
An increased number of tools under the machine leads to:
• Less pressure on each individual tool – less wear on
the diamond tools.
• Reduce load on the machine and cause the grinder to
draw less current.
• Create a smoother scratch pattern (particularly on soft
floors).
The reverse happens if you reduce the number of tools
under the machine.
OPERATING
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 presence
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
principles 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
The diamond tools must be worn in order to give a high
grinding efficiency. The wear on diamond tools can be
affected by the following factors:
• Pressure.
• Hardness of bond.
• Diamond grit size.
• Presence of water.
• Number of tools under the machine
• Adding an additional abrasive (e.g. sand, silicone
carbide) on the floor will increase wear.
Generally, the faster a diamond tool is worn down, the
better the grinding efficiency. Changing the factors above
can also change the following results:
• Scratch pattern.
• Current draw of machine.
• Flatness of floor (see next section).
• Ease of operation.
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