Техническая информация Sumitomo - страница 6

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Basics of Threading

  • Thread Cutting Methods

Cutting Method Characteristics

Radial Infeed

  • Most common threading technique, used mainly for small pitch threads.

Leading Trailing Edge Easy to change cutting conditions such as depth of cut, etc. Edge

  • Longer contact points lead to more chatter.
  • Difficult to control chip evacuation.
  • Damage on the trailing edge gets larger faster.

Feed Dir. Direction of Cut Flank Infeed

  • Effective for large pitch threads and blemish-prone work material surfaces.
  • Chips evacuate from one side for good chip control.
  • The trailing edge side is worn, and therefore the flank is easily worn.

Corrected Flank Infeed

  • Effective for large pitch threads and blemish-prone work material surfaces.
  • Chips evacuate from one side for good chip control.
  • Inhibits flank wear on trailing edge side.

Alternating Flank Infeed

  • Effective for large pitch threads and blemish-prone work material surfaces.
  • Wears evenly on right and left cut edges.
  • Since both edges are used alternatively, chip control is sometimes difficult.
  • Troubleshooting for Threading
FailureCauseCountermeasures
Excessive Cutting Edge Wear· Tool material· Select a more wear-resistant grade
· Cutting condition· Decrease the cutting speed · Optimise coolant flow and density · Change the number of passes.
e FailureUneven Wear on Right and Left Sides· Insert attachment· Check whether the cutting edge inclination angle is appropriate for the screw lead angle. · Check whether the tool is mounted properly.
g Edg· Cutting condition· Change to corrected flank infeed or alternating flank infeed
CuttinChipping· Cutting condition· If caused by a built-up edge, increase cutting speed
Breakage· Packing of chips· Supply enough amount of coolant to the cutting edge.
· Cutting condition·Increase the number of passes while decreasing the depth of cut per pass. ·Use different tools for roughing and finishing applications.
Poor Surface Roughness· Cutting condition·If blemished due to low-speed machining, increase the cutting speed. · If chattering occurs, decrease the cutting speed. ·If the depth of cut of the final pass is small, make it larger.
racy· Tool material· Select a more wear-resistant grade
d Accu· Inappropriate cutting edge inclination angle· Select a correct shim to secure relief on the side of the insert.
pe anInappropriate Thread Shape· Insert attachment· Check whether the tool is mounted properly.
Sha· Small depth of cut· Check cutting depth
Shallow Thread Depth
· Tool wear· Check damage to the cutting edge.