Wheel tests on the fly

Dear Doc: There’s lots of discussion at my company about the best diamond fluting wheel for grinding tungsten carbide. Is there a quick test to determine which wheel is best?

The Doc Replies: Few companies perform even a basic wheel test. In most cases, operators stick on the new wheel, grind a few parts, make some adjustments, finish out the wheel and then form a half-baked opinion. They don’t measure anything, so they have nothing to go on. Unless there are huge differences in wheel wear or heat generation, they’ll never know which wheel is better.

Although a solid test can take several days, you can conduct one for three wheels in just a few hours and make a reasonable assessment. First, true the candidate wheels with the same truing parameters. Next, grind a few parts at about half your standard feed rate. Then increase the feed rate in increments of 25 percent nominal and grind a few more.

Image courtesy of J. Badger.

Measure the change in part dimension after every part to estimate wheel wear. Measure power, preferably with a real power meter, although the ammeter on the machine will also work. (Remember to subtract wheel-idle power.) Either measure or eyeball the surface finish. Do this for all three wheels, and plot the results on a spreadsheet.