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Machine sawing tools \ Processing and machining technology - Sawing

                     Work regulations for metal circular saw blades


         ƒ Use the correct tooth shape and tooth pitch for the different
          materials and applications.
         ƒ For pipe diameters and contact lengths smaller than 50 mm, use
          tooth shape A (finely toothed).
         ƒ Saw blades must be sawn-in due to the sharpness of the teeth.   t
          When doing so, the cutting speed must be reduced by up to 50%
          until the teeth have lost their initial sharpness.  Too fine        Correct           Too coarse
         ƒ Use coolants to avoid overheating and ensure chips are removed.
         ƒ Clamp the material at as short a distance as possible to avoid
          vibrations.
         ƒ The cutting speed and feed rate must be adjusted to match the
          material and geometry (see cutting value table).

                     Guide to eliminating faults with metal saw blades

         Wear on teeth                                     Tool breakage
         ƒ Larger tooth pitch if the saw blade clogs with chips  ƒ Re-sharpen tool
         ƒ Improve coolant feed or use correct coolant     ƒ Reduce cutting speed
         Teeth break off                                   Clogging and material adhesion to saw blade
         ƒ Improve poor chip removal                       ƒ Optimise feed
         ƒ Use appropriate tooth pitch                     ƒ Optimise saw blade shape
         ƒ Optimise workpiece clamping                     ƒ Coolant optimisation

                     Retraction of bandsaw blades


         A new saw band has very sharp tooth tips due to the manufacturing method. In order to withstand the
         cutting pressure when band sawing, the tooth tips should be circularly ground. Without this fine grinding
         step, the high cutting pressure will lead to microscopic damage to the tooth tips and consequently to a
         shorter service life of the entire saw band. Saw blades should be retracted to significantly increase the
         service life. The following steps describe proper retraction:
         ƒ The correct band speed must be used for the material to be cut.
         ƒ Reduction of the feed speed or feed power of the saw to reach a cutting speed of 20% to 50% of the   1  2  3
          normal cutting speed. Mild steels require a greater reduction in velocity than materials that are more
          difficult to machine.                                           ① New saw band   ② With retraction   ③ Without
         ƒ The first cut should be initiated at reduced speed with care taken to ensure the teeth form a shaving. As  retraction
          soon as the blade is fully submerged in the workpiece, the feed can be increased slightly.
         ƒ The feed speed should be successively increased across several cuts until the normal cutting speed is
          reached (total cutting area 60 to 118 inch /150 to 300 cm ) 2
                                   2
         It is important to note that slight adjustments must be made to the band speed during insertion in the
         case of excessive noise or vibration. As soon as the saw blade has been retracted, the recommended
         band speed should be used.


                     Rules for working with metal circular saws

         ƒ Where contact length is less than 50 mm or in the case of thin-walled pipes and profiles, only tooth pitches with 0° chip angle may be used.
         ƒ The lifespan of a saw blade depends on controlled sawing-in: Reduce cutting pressure (feed) by 50% for the first cuts, then increase feed to the optimal value
          after approx. 300 cm surface has been cut.
         ƒ As a general rule, the cutting speed is determined by the strength, type and cross-section of the sawn material. The higher the strength, the lower the speed that
          must be selected. A higher speed can be used with smaller cross sections than with larger cross sections. The chip shape indicates whether the speed and feed
          rate are selected correctly. The chips should be loosely coiled. If the chips are thin, the feed should be increased; thick chips are a sign of the speed being too
          high.
         ƒ The material should be clamped in order to help the saw blade work with as little vibration as possible.
         ƒ Use of coolant prevents overheating and aids faster chip removal.
         ƒ Use of the highest permitted band width for the machine ensures sufficient stability at higher feed forces. When cutting curves, the blade width depends on the
          smallest radius which is to be cut (see cutting value table).
         Radius (mm)            3        8        15        30        38        65        100        140
         Band width (mm)        3        5        6          8        10        13         16        20














       Source: Hahn+Kolb Werkzeuge GmbH
       Technical data subject to change.             www.iconridge.com
       Availability subject to country specific rules and regulations.                          169

   0335_EN_2018_KERN[21846968]-i.indd  335                                                            12/17/2018  3:32:17 PM
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