ABRASIVES
The wheel can be delivered with either diamond or CBN abrasives in grain sizes from 40 to 1000 µm. AeroMetal diamond wheels target carbide, ceramic, sapphire, quartz, and similar ap- plications, while the CBN variant is best used for rough grinding of hardened steel and cast iron. In one test, an AeroMetal ax- ial face grinding diamond wheel (30-mm diameter, 3-mm bond width, 80-µm grit), ground a circular pocket (60-mm diameter × 0.7-mm deep) into a block of polycrystalline silicon carbide (SiC). The wheel rotated at 2500 rpm, moving helically at a 600 mm/min feed rate, under cool- ant. At a depth of cut of 0.01
more porous BRS5 version is so elastic you can bend the wheel in your hands, though you’ll want to keep it on your grinder where it can achieve a mirror-like fi nish in carbide and other hard materials.
In one test on carbide with a surface grinder, a 175-m diameter, 1000 grit, 1A1 Bright Star wheel operating at 1540 rpm at a feed rate of 2 m/min and 0.001 mm/pass achieved an Ra
of 0.012 µm and Rmax
The Radiac/Tyrolit Genis CF wheel features a carbon fi ber core to reduce weight up to 80% and improve vibration dampening. It’s a vitrifi ed CBN product capable of running at 100 m/sec for fi nishing crankshafts and other high- volume components.
mm per helical pass the wheel achieved a surface fi nish of 1.4 µm with wheel wear of 0.06 mm. At a 0.03-mm depth of cut the surface fi nish was 2.2 µm with 0.08 mm of wheel wear.
A Resin Bonded Wheel You Can Bend Asahi has also just introduced Bright Star, an elastic resin bond wheel for super fi nishing and polishing. The
of
0.10 µm, versus 0.08 µm and 0.17 µm, respectively, for a standard resin bond wheel with the same specs. Running the same test on ceramic (Al2
O3 ), the Bright Star achieved an Ra of 0.03 µm and Rmax of 0.41 µm versus 0.1 μm and 0.87
μm, respectively, for a standard resin bond. In another test, a Bright Star 1500 grit wheel ground carbide inserts with a surface fi nish of Ra
0.01 μm and Rmax of 0.01 μm.
Asahi says the wheel should be perfect for applica- tions like semiconductors, glass, optics, carbide tools, and medical devices. Bright Star can be shaped and trued like any resin bond wheel, so that would add to the possibilities. Smith says his fi rst success has been with D2 steel in a mold shop, where the Bright Star wheel replaced labor intensive hand polishing using loose abrasives.
Asahi’s resin bonded diamond Bright Star BRS5 wheel is so elastic you can bend it in your hands. It can achieve a mirror-like fi nish in carbide and other hard materials.
66
AdvancedManufacturing.org | November 2016
Dressing with 2 µm accuracy In-process wheel dressing or tru- ing necessarily changes the profi le of the wheel. And unless you’re using a fl at wheel and can rely on an acoustic sensor or probe to locate the precise location of the wheel in space, how do you know exactly what you’re doing to your wheel profi le when you dress? The solution is to dress with a very precise roll, with a certifi ed diameter and radius, and to ask your machine control to
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76 |
Page 77 |
Page 78 |
Page 79 |
Page 80 |
Page 81 |
Page 82 |
Page 83 |
Page 84 |
Page 85 |
Page 86 |
Page 87 |
Page 88 |
Page 89 |
Page 90 |
Page 91 |
Page 92 |
Page 93 |
Page 94