247 Каталог HOFFMANN GROUP 2016 Станочный режущий и вспомогательный инструмент Вер. 47 Стр.247

Каталог HOFFMANN GROUP 2016 Режущий инструмент и оснастка Стр. 247 0247 ENG Lab2u

Hoffmann Group 47 < R ) RflNTGEN 1 HOLEJf. Band-saw blades Releasing the material Clamp the material so that the band saw blade cuts with as little vibration as possible. When cutting material bundles, tack weld the ends together if necessary. This increases the cutting performance and the blade life. K i 1 i \ \ c AVAVX /I i Jil ni m Running in new blades At normal feed rates the sharp teeth of a new blade dig very aggressively into the material. Therefore reduce the feed rate by 50 % and the cutting speed by 70 % for the first cuts. After the blade has cut an area of about 400 cm2, slowly increase the feed rate to the optimum value. The working life of a band-saw blade is to a large extent dependant on controlled running in Coolant The coolant helps to prevent the overheating of the saw tooth and component and transports the chips away from the cutting point. It is usual to supply coolant when sawing all steels. Cast iron on the other hand is usually sawn dry. Cutting oil gives good results when sawing case-hardening steels, higher alloyed tool steels, heat-treatable steels, stainless steels and titanium. Micro-spray systems give good results when sawing pipes and profiles. In this connection, note the need for a good chip clearance brush. Cutting speed and feed rate The cutting speed (blade speed) depends on the tensile strength, type and cross-section of the material to be sawn. The greater the tensile strength, the lower the cutting speed should be. Smaller cross-sections can be sawn at higher speeds than larger cross-sections. Thin-walled pipes and profiles, and sharp edges, are sawn at low feed rates; the feed rate (pressure) should be kept as constant as possible. Material Cutting speed in m/min for bi-alfa cobalt (M42) General purpose steels / machining steels 80-90 Case-hardening steels / heat-treatable steels 45-75 Unalloyed tool steels / roller bearing steels 40-60 Alloyed tool steels / high speed steels 30-40 Stainless steels 20-35 Heat-resistant steels, high-tem perature alloys 15-25 If vibration occurs adjust the cutting speed (m/min) to marginally faster or slower. As the blade becomes blunter increase the feed rate slightly. Recognising a cracked weld on the blade Polished areas on the weld after a short period of use indicate a manufacturing fault. The weld will break after it has run longer and the crack propagates as a zigzag, causing the blade to break in overload. Tooth pitches Tooth pitch recommendations for solid materials: Recommendation: also state the rake angle. Tooth pitch recommendations for pipes: for material thickneaes Variable pitch teeth Clamping angle <25 mm 10/14 0" U-i 1 3 3 8/12 0” 25 - 50 mm 6/10 0° 35-70 mm 5/8 0° 40 - 90 mm 5/6 10" 50-120 mm 4/6 0"/5"/10“ 50-150 mm 4/5 10’ 80-180 mm 3/4 0710” 130 - 350 mm 2/3 10" 150 - 400 mm 1,5/2 10" 200 - 600 mm 1,1/1,6 10" >500 mm 0,75/1,25 10" Wall thidmess S(mm) Outer pipe 0D (mm) Tooth pitch Z (TPI) Variable pitch teeth 3/4 0° and 4/6 0° are suitable only for pipes, profiles and girders, not for solid material. For sawing solid material of high-alloy and long-chipping materials, the band qualities bi-alfa Master No. 174050 and bi-alfa Master RP No. 174100 are recommended in addition to 10° variable pitch teeth. 20 40 60 80 100 120 150 200 300 500 2 14 10/14 10/14 10/14 10/14 8/12 8/12 8/12 8/12 5/8 3 14 10/14 10/14 8/12 8/12 8/12 8/12 6/10 6/10 5/8 4 10/14 10/14 8/12 8/12 8/12 6/10 6/10 5/8 5/8 4/6 5 10/14 10/14 8/12 8/12 6/10 6/10 5/8 4/6 4/6 4/6 6 10/14 8/12 8/12 6/10 6/10 5/8 5/8 4/6 4/6 4/6 8 10/14 8/12 8/12 6/10 5/8 5/8 4/6 4/6 4/6 4/6 10 8/12 6/10 5/8 4/6 4/6 4/6 4/6 4/6 4/5 12 8/12 6/10 4/6 4/6 4/6 4/6 4/6 4/6 4/5 15 8/12 6/10 4/6 4/6 4/6 4/5 4/5 4/5 4/5 20 4/6 4/6 4/6 4/6 4/5 4/5 4/5 3/4 30 4/6 4/6 4/5 4/5 4/5 4/5 2/3 50 4/5 3/4 2/3 2/3 80 3/4 2/3 2/3 >100 2/3 1,5/2 For thin-walled pipes (up to approx. 8 mm wall thickness) use preferably tooth pitches with 0” rake. Rule of thumb: There should be at least 3 teeth in contact with the component. Tape width The largest blade width permissible on the machine should be selected, in order to achieve sufficient stability at higher feed rate forces. When sawing curves, the blade width is depending on the smallest radius to be cut (see table). Radius (mm) 3 8 15 30 38 65 100 140 Blade width (mm) 3 5 6 8 10 13 16 20 247