Page 9 - Centerdrill Produktkatalog 2020 English
P. 9

Short introduction

      Machines and tools
      The precondition for a professional  flow drilling process is working  with a suitable machine  that provides
      the required RPM  and kW-power. This  can  be either a  column  drilling  machine,  a  CNC  machining  center, or  a  milling
      machine. The required spindle RPM and kW powers can be found online and as well as in the catalogue. If the RPM is too
      low, the tool may overheat and decrease the quality of the flow-forming hole. However, if the kW power is too low, your
      machine may stop working and there is a possibility that the Centerdrill tool may crack.

      Basic equipment
      The Centerdrill should be first fixed in a collet, and then, in a collet chuck with an aluminum cooling ring, as this is the
      only way to ensure the concentricity, a proper hold of the Centerdrill flow punch former, and to prevent it from
      overheating of the machine spindle. It should be noted that the Centerdrill tool is always fully clamped with the entire
      shaft in the collet and the union nut is tightened with a hook wrench. However, it is recommended to retighten it regularly.
      To reduce the build-up of the metal on the outside of the Centerdrill, our white Centerdrill parting paste should be applied
      thinly on the Centerdrill flow punch  former. During  the thread forming  process,  it is essential to apply a  good
      lubricant to the thread former. We also offer all the required products, combined in our Centerdrill Beginner Set.
      You can find them in the catalogue on pages 56-59.

      Machine settings
      It must be ensured that at the very beginning of the flow drilling process, the Centerdrill tool is smoothly placed on the
      workpiece surface and penetrates the metal at a feed rate of approx. 50-150 mm/min, provided that the RPM is set correctly.
      With this feed rate, the Centerdrill tool will move down with approx. 2.5 mm per second. The depth-stop of the machine
      regarding the workpiece surface depends on the fact whether the collar should be preserved or removed. If you require
      the collar on the surface, the flow drilling process ends at about 0.5 - 3.0 mm above the workpiece surface. It depends on
      the thickness of the material and the size of the core hole diameter. When the collar on the surface is to be removed,
      the cutting edges of the Centerdrill tool must be flush with the workpiece surface. In this case, the feed rate should be also
      min. 900 mm/min. In this way, the cutters of the Centerdrill are spared. The workpiece to be machined must be firmly clamped
      so that it does not move horizontally or vertically. Otherwise, the Centerdrill tool may crack. The workpiece should never
      be held by hand.

      Flow drilling process
      Once the  Centerdrill  tool  and  your workpiece  are firmly clamped,  the  machine starts working at  the  appropriate
      rotational speed  and thus,  the  machine achieves the  required  kW power.  Then, the  tip  of the  Centerdrill  tool can be
      placed smoothly on the workpiece surface and the corresponding axial pressure must be applied, whereby the material is
      heated and melted until it becomes red-hot. The Centerdrill tool can  now quickly penetrate the material  and form
      the bush downwards and the collar  upwards. The Centerdrill tool should be moved out quickly once reaching  the
      corresponding  depth-stop.  If the Centerdrill tool turns too long  on the spot, the material  overheats. On average,
      the flow-forming process takes only a few seconds. If the collar is to be removed to obtain a flat surface, the feed rate
      must be increased significantly at the end of the process. The removed chips may  fly off randomly.
      Therefore, suitable protective clothing  should be worn or a protective shield must be installed at the machine.
      The hot workpiece should be allowed to cool down at the end of the flow drilling process, or it may only be handled with
      appropriate tools or gloves. Afterwards, we recommend to form the thread and not to cut it. Our Centerdrill
      standard core hole diameters are also  intended  for thread forming  only. As a result, you can  obtain a stable,
      turning-free and wobble-free connection from your own material in just two operations.

      Parting paste
      It is recommended to apply our white parting paste to the Centerdrill flow punch former  in order to avoid the
      build-up of metals on  the Centerdrill tool (depending on  a  material  and material  thickness, every 1-5 holes).
      The application of the parting paste can be done manually, for example with a brush. It is important that the
      parting paste is applied from the beginning and from the top to the bottom of the band of the Centerdrill. A thin film
      is sufficient.  However,  too  much white  paste  reduces  the  required  heat  of the  process and has a negative  effect
      on the quality of the formed bush and collar. The release agent is water-soluble and oil-free, so  it is also  optimally
      suitable for components to be coated subsequently where no residues may remain on the surface. Read more on page 60.

      During  thread forming,  our lubricants  should always  be applied, i.e. in every threading  process,  otherwise  the
      lifetime of the thread former  may  be significantly  reduced because of the high  friction and the  high torque.
      Likewise, we also offer easily washable oils, and oils for spraying in the catalogue, page 61.

   4   5   6   7   8   9   10   11   12   13   14