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Introduction : Blade
dressers are basically conceived from the multi - point wheel
dressing concept -as an extension to the areas with a stringent
control demand on quality & economy. The basic advantages
which have lead to the extensive used of blade dressers are
:
- They are very economical
in comparison with single-point dressers.
- Higher form retention
capability compared to single point dressers.
- Minimum in-process
service attention compared to any other dressers due to
their self-wearing property.
- They are ideally suited
for optimum dressing condition and in turn for optimum grinding
conditions.
- Greater flexibility
in selection from a wide range of varities of dressers to
suit different grinding wheel specifications and grinding
conditions.
The following paragraphs
offer in-depth study and detailed analysis of the above attributes.
Economic considerations:
Blade diamonds are composed of thin natural diamond needles
which are much cheaper than larger single point diamonds in
direct consideration of weight basis. The impact of this economy
will be felt to a greater extend when we try to replace the
costlier chisel points, precisions single point and indexable
crowns and blade dressers.
Form retention capability
: A single point or a chisel point has a limitation that in
certain special applications like dressing of wheels, within
15 to 20 hours of running. The condition of the dresser tips
deteriorate to such a degree that the repeatability of form
& related tolerances on the components are adversely affected.
This results in the necessity to reset the dressers with fresh
cutting points.
Blade dressers are designed to utilize their full life span
with minimum deterioration of form and tolerances. It gives
certain typical examples or areas where certain steep angles
and sharp internal corners are effectively traced with precision
blades in comparison to ordinary single point dressers and
ordinary blade dressers.
Minimum in-process service attention
: Normally, when a single point or a chisel point dresser
is mounted, the machinist has to "watch" for a number
of defects on the component.
1. "Glazing" of the wheel due to
"blunting" of diamonds.
2. Loss of form & profiles.
3. "Breaking of wheel corners:
4. Appearance of "unstraightness" due to varying
load conditions on the dressers.
Blade dressers have been developed on the "fix and forget"
principal -a concept of the right choice of dresser for an
operation -when the next attention of the machines is warranted
only when the dresser is fully used up.
Optimised Conditions of the grinding wheel : Modern
grinding technology has facilities to optimise a grinding
process to the barest minimum operational cost-provided, the
very starting point of the operation, namely dressing, is
optimised. A proper dressing demands the following conditions
on the grinding wheel surface.
1. A pure abrasive action - no "rubbing" action.
2. Proper fracture of individual grains to expose maximum
abrasive area for grinding.
3. Minimum "filling" of bonding cavities on the
wheel surface to minimise friction during grinding operation.
4. Minimum "grain pullout"
Flexibility in selection : Unlike single
point dressers which are more or less independent of the grinding
wheel specifications or conditions (except for the weight
in carats), blade dressers need to be selected with due considerations
to the grinding wheel specification and conditions of dressing.
Conclusion : Blade dressers have been
developed over the last decade through extensive field trials
with renowed engineering industries. The benefits derived
have been passed on to the several companies, through substantial
reduction in their manufacturing costs.
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