By Mark Albert

Synthetic-diamond dressing tools are often a superior alternative to natural-diamond dressing tools for conditioning a grinding wheel. The reason is the consistency that the synthetic-diamond tools bring to the process. That is a key point in the case for synthetic diamond dressing tools made by William D. James, a product engineer in the stationary tool group at Saint-Gobain Abrasives (Worcester, Massachusetts).

According to Mr. James, synthetic tool stones start out as more consistent products because the manufacturing process that creates them is tightly controlled and predictable. Synthetic stones are available in a variety of close-tolerance sizes, are longer than most elongated natural stones and have a uniform rectangular shape through their entire length. As he explains, all dressing tool diamonds (natural or synthetic) develop wear flats over time. With natural diamonds, problems begin as wear flats increase in size and eventually become too big to sharpen the wheel. Instead of opening the wheel’s grain structure, the dressing tool closes it, leaving the wheel dull. Synthetic diamonds are consistently shaped so that their wear flats never get large enough for this to happen.

This “non-dulling” property means that synthetic stones never need indexing as natural stones do. Likewise, the longer synthetic stones simply outlast the shorter natural diamonds. For these reasons, using synthetic-diamond dressing tools avoids two causes of machine downtime—interruptions for indexing the tool or replacing it outright.
three- and five-stone 'uniform synthetic blade' tools
These three- and five-stone “uniform synthetic blade” tools are shown with CVD diamonds. The tools have straight or angled diamond section configurations.

Mr. James identifies six steps for transitioning to synthetic-diamond dressing tools:

1. Choose between monocrystalline and CVD (chemical vapor deposition) diamonds. Both types work well, but the monocrystalline stones tend to be more durable (and a little more expensive).
2. Specify the correct diamond size and shape. These must be matched to the specific grinding application.
3. Decide how many stones to use. Unlike single-point natural-diamond tools, an equivalent synthetic-diamond tool may have as many as five stones or more mounted in a blade-like configuration. Generally, the larger the wheel size, the more stones are needed to dress it.
4. Be sure the individual diamond stones are oriented correctly. They must be angled up for general use and straight on for heavy-duty applications.
5. Configure the tool properly. Blade configurations with multiple stones must be mounted vertically so that the wheel sees only one diamond width as the tool moves across the wheel.
6. Use appropriate dressing parameters and stick to them. Synthetic tools use the same parameters as those for natural-diamond tools, but synthetic tools weaken faster if overheated because recommended speeds and feeds are exceeded.

Mr. James concludes that whether you’re considering the use of synthetic diamonds to improve wheel-conditioning consistency or to eliminate downtime associated with having operators interrupt production to index the diamonds, synthetic dressing tools have much to offer.

Labels: Machinery Tool