FREZY TRZPIENIOWE Z WĘGLIKÓW SPIEKANYCH MOULD AND DIE INDUSTRY NORTON WINTER PRECISION TECHNOLOGY TOOL GRINDING / 135 151 181 213 126 46 54 64 76 91 107 *25 *20 *7 *15 Ra 1) [µm] 1.6 10.9 9.5 8.2 6.8 6.1 5.4 4.8 4.25 3.4 2.7 2.1 1.7 1.4 1.02 0.85 0.7 0.54 0.43 12.8 11.2 9.6 8 7.2 6.4 5.6 4 3.2 2.4 2 1.6 1.2 1 0.8 0.64 0.5 5 1.2 1 0.9 0.8 0.7 0.63 0.5 0.4 0.3 0.25 0.15 0.13 0.1 0.08 0.063 0.2 1.4 Rz 1) [µm] Rt 1) [µm] GG HB 180 - 250 Stahl HRC 1 58 Stahl weich Grain sizes according to FEPA *Norton Winter Grain Sizes 1) Calculation basis 1Ra = 8Rt = 0.85 Rz Rauheitswert WORKING DATA AND GRIT SIZES HONING SPEED The cutting speed (vc) is based on the speed at the circumference of the honing tool (VA) and its stroke speed (VH). SUGGESTED VALUES MEDIAN PRACTICAL VALUES vc = 30-70 m/min 52 m/min vA = 20-60 m/min 49 m/min vH = 10-30 m/min 16 m/min INTERSECTION ANGLE The ratio of stroke speed (vH) and speed at the circumference (VA) gives the characteristic angle of intersection (α) of the honing pattern. Usually the two speeds are selected so that the intersection angle lies between 25° and 60°, with a median value in practice of 36°. CONTACT PRESSURE RANGE 20–200 N/cm² (exceptions up to 600 N/cm²) COOLANT In honing, mineral oil-based honing oils and water-soluble emulsions are used. Typical fluid use is 30–150 l/min per bore. GRIT SIZES The abrasive grit sizes specified for this process are classified according to FEPA standards, starting with B46 / D46. It is possible to manufacture tools different from those shown in the programmes. Please do not hesitate to contact us if you require assistance. Customers’ own tools can also be coated. With regard to the determination of the nominal size, the undersizes which depend on the coating must be specified based on the grit size. Grit size tables can be found in the Service section of this catalogue. ACHIEVABLE SURFACE FINISH VALUES WHEN HONING WITH METAL BOND HONING TOOLS The practical values listed in the adjoining diagram serve as a quick reference. Accurate surface finish values always depend on the bond, grit size and concentration of the honing tool as well as the workpiece material, coolant and the process parameters. It is especially important to maintain a balanced ratio between grit size and concentration in order to prevent excessive levels of contact pressure. Concentration levels should be between C35 and C100 or V120 and V240 respectively, depending on grit size.
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