Техническая информация Sumitomo - страница 6

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

Failure Cause Countermeasures

Excessive Cutting Edge Wear Tool material Select a more wear-resistant grade

• Decrease the cutting speed
• Cutting condition
• Optimise coolant flow and density
• Change the number of passes.
• Check whether the cutting edge inclination angle is

Uneven Wear on Right and Left

• Insert attachment appropriate for the screw lead angle.

Sides

• Check whether the tool is mounted properly.
• Change to corrected flank infeed or alternating flank
• Cutting condition

infeed

Chipping Cutting condition If caused by a built-up edge, increase cutting speed

• Supply enough amount of coolant to the cutting

Breakage Packing of chips edge.

• Increase the number of passes while decreasing the depth of cut per pass.
• Cutting condition
• Use different tools for roughing and finishing applications.
• If blemished due to low-speed machining, increase the cutting speed.

Poor Surface Roughness Cutting condition If chattering occurs, decrease the cutting speed.

• If the depth of cut of the final pass is small, make it larger.

N Tool material Select a more wear-resistant grade

• Inappropriate cutting
• Select a correct shim to secure relief on the side of

edge inclination angle the insert.

Inappropriate Thread Shape Insert attachment Check whether the tool is mounted properly.

• Small depth of cut
• Check cutting depth

Shallow Thread Depth

• Tool wear
• Check damage to the cutting edge.