Monocrystalline diamonds make the coating question “moot.”
Was asked a question “Why all the fuss about tool coatings? The base material and the tool geometry do the work.”
We agree that the tool material and geometry are important determinants of success in production machining. See our original post here. But tool coatings can play a critical role in assuring successful machining by
- Significantly increasing tool life by minimizing wear;
- Control built up edge (BUE);
- Contol heat build up;
- Increase the edge hardness.
To me, and I hope to you, ‘successful machining’ means “more parts produced per day at lower cost per part.” Coatings help achieve this by increasing tool life (reducing tool cost component per part); by keeping machines running longer between changes (more parts per shift because more uptime per shift); and reducing variability of parts produced (BUE and thermal variation requiring machine adjustments).
Advancing the idea from Diamond Coatings (polycrystalline) to a Monocrsytalline Tool Insert, the folks at Paul Horn and H10 worldwide make the coating material into the tool material- to make the impossible possible. The photo above shows an aluminum workpiece machined to a maximum surface deviation of Ra 0.010 μm; Rz 0.014 μm. It is an optical component machined from a single piece of aluminum, that I photographed at Paul Horn Technology Days last month.
Or how about this plastic workpiece- absolutely no tool marks or ‘frosting’:
Polycrystalline diamond coatings are widely available. This monocrystalline diamond tooling was first shown to us by Horn USA at our 2010 National Technical Conference. While diamonds are a non-starter for ferrous workpieces, they can be your key for ‘brilliant machining’ on other workpiece materials such as aluminum, copper, brass and bronze, nickel, precious metals, and plastics like PVC, polycarbonate, acrylic.
But I guess it isn’t quite correct to call it a coating.