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Ways for grinding hard material ?
Grinding hard materials like carbides & ceramics
Grinding hard materials-various materials to be grinded
Grinding hard materials Wet and dry like cemented carbides
Grinding hard materials-Diamond wheel
For the Grinding hard materials difficult to machine ferrous metals
Cubic Boron Nitride (CBN) wheels are used. Grinding hard materials ratio often
written as GR is a ratio of the volume of workpiece material removed to the
volume of wheel wear. Grinding hard materials like ceramics is almost exclusively
performed with manufactured diamonds. Because of the lower grinding heat generated
by the CBN wheels, there is little or no thermal damage occuring to the surface
of the workpiece. Therefore cutting tools and parts ground with CBN wheels generally
have a longer useful life. Diamond wheels are universally used and perform best
while grinding hard materials.
How can you ensure low cost grinding hard materials with Diamond Wheels ?
There is no clearly defined technique or method of increasing material removal rate (mrr) that will guarantee the most effective utilization of the diamond grinding wheel. Laboratory tests have indicated that both in wet and dry grinding of cemented carbides, the life of the wheel is shortened in some direct relationship to the increase in mrr, irrespective of the technique employed for increasing the removal rate. There is some indication however, that in case of wet grinding the use of heavy cross-feeds will take a somewhat lesser toll in the wheel life than will downfeed or the table speed. However a very important factor to consider is that the wheel is only removing carbide while the wheel and the workpiece are in contact. Any technique which increases the noncontact time between the wheel and the workpiece diminishes the effective mrr and increases cost.
Because these hard and abrasion resistant materials are often
used in applications where tolerance and surface finish are critical, diamond
superabrasives are the only means for cost effective grinding.
As shown in the chart below, superabrasives tool cost normally represents less
than 10 percent of total manufacturing expenditures while the benefits of superabrasives
usage can have a major impact on the total cost equation.
-Extremely long intervals between dressing and overall wheel life results in
more consistent part-to-part geometries.
-Fewer dressing cycles and infrequent wheel changes mean more productive machine
up-time.
-Improved ground surface and subsurface integrity means reduced tensile stresses
and overall higher quality finished parts.
-Shorter gring cycle times and reduced part inspection requirements mean greater
productivity and lower overall grinding costs.
In short, superabrasives reduce the cost of achieving high quality. And they're
versatile enough to be used effectively in the most simple tool room grinding
operations as well as in the most complex CNC production grinding operations.
