Page 1045 - Tungaloy Catalog

Technical Reference
Drilling Tools

Problem Cause Countermeasure
Misalignment of workpiece rotation • Set the misalignment to 0 ~ .008 in.
Scratch marks on the tool The tool periphery Offset direction reduced diameter of workpiece • Set offset direction extended diameter of workpiece
Offset machining in excess of allowable range
• Use the tool in the allowable offset range.
• Flatten the entry surface in pre-machining.
No flatness of the entry surface
• Set the feed rate for lower than .001'' ipr in rough surface area.
• Exchange the insert.
Chipping of peripheral cutting edge
Bend of workpiece
• Change to the clamp method with rigidity.
• Increase the cutting speed by 20 % and lower the feed rate by 20 % within standard conditions.
Chip packing
• Raise the fluid pressure (for higher than 1.5 MPa).
Misalignment for workpiece rotation • Set the misalignment to 0 ~ .008 in.
Inappropriate offset contents • Adjust offset contents.
Hole diameter No flatness of the entry surface • Flatten the entry surface in pre-machining.
Inappropriate hole accuracy Roughness Varieties and supply of cutting fluid • The concentration of cutting fluid must be higher than 5 %.
• Set the feed rate for lower than .001'' ipr at rough surface area.
Bend of workpiece
• Change to the clamp method with rigidity.
• Use cutting fluid superior in lubricity.
• Change to internal cutting fluid supply from external one.
• Increase the cutting speed by 20 % within standard conditions.
Inappropriate cutting conditions
• Lower the feed rate by 20 % within standard conditions.
• Exchange the insert.
Failures of inserts
• Increase the cutting speed by 20 % and lower the feed rate by 20 % within standard conditions.
Common Chip packing
• Raise the fluid pressure (for higher than 1.5 MPa).
Looseness of screws • Tighten the screw.
• Work within standard conditions.
Inappropriate cutting conditions • Increase the cutting speed by 10 % within standard conditions.
• Increase the feed rate by 10 % within standard conditions.
Failures of inserts • Exchange inserts.
Prolonged and • Change to internal cutting fluid supply from external one.
twisted of chips Machining by external fluid supply • Step feed.
• Use dwell function for approximately 0.1 sec.
Chip control Chips around the central cutting edge • Shorten the chips by shifting to higher speed and feed.

• Change to internal cutting fluid supply from external one.
• Raise the fluid pressure (for higher than 1.5 MPa).
Fluid supply
Chip packing • Increase the cutting speed by 20 % and lower the feed rate by 20 % within standard conditions.
• Raise the fluid pressure (for higher than 1.5 MPa).
Inappropriate cutting conditions
• Exchange the drill holder.
Large failure of drill holders • Tighten the screw. Technical Reference
Common
Looseness of screws • Lower the cutting speed by 20 % within standard conditions.
• Increase the feed rate by 10 % within standard conditions.
Inappropriate cutting conditionss
• Exchange the insert.
Large wear of inserts • Change to the machine with higher torque rigidity.
Chatter • Change to a clamp method with rigidity.
Vibration in drilling • Change the drill setting method. 14
• Tighten the screw.
Others Looseness of screws • Use the range of number of revolutions suited machine spec. Lower the feed rate by 20 ~ 50 %.
• Exchange inserts before the failure becomes larger.
Insufficient machine power and torque
• Check the oil hole plug screw is tightly screwed in place.
Machine stop • Check that the fluid flows powerfully from the drill.
Burned inserts
• Lower the cutting speed and the feed rate by 20 % within standard conditions.
• Exchange the insert.
Failures of inserts • Lower the feed rate by 20 ~ 50 % just before leaving the workpiece.
Large burr
Inappropriate cutting conditions

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