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Taps on SUS tool life Measures against degradation What are the precautions for pre-hole processing?
Pay attention to work hardening.
Stainless steel is a material that is easy to work and harden.
Stainless steel is a material that is easy to work and harden.
The work hardening of the pilot hole reduces the tool life of the tap, which is the subsequent machining process.
Here are some common causes and countermeasures.
Common cause (1) General-purpose carbide drills for general steel are used for pilot hole drilling.
Lack of sharpness for stainless steel. In addition, the high-speed rotation, which is a processing condition for carbide drills, causes work hardening of stainless steel.
We recommend internal coolant supply -type carbide drills for stainless steel and high-speed drills for stainless steel with sharp sharpness.
・ internal coolant supply -type carbide drills for stainless steel ADO-SUS-3D, ADO-SUS-5D, etc.
・High speed drills for stainless steel NEXUS-GDS, EX-SUS-GDS, EX-SUS-GDR, etc.
We recommend internal coolant supply -type carbide drills for stainless steel and high-speed drills for stainless steel with sharp sharpness.
・ internal coolant supply -type carbide drills for stainless steel ADO-SUS-3D, ADO-SUS-5D, etc.
・High speed drills for stainless steel NEXUS-GDS, EX-SUS-GDS, EX-SUS-GDR, etc.
Common cause (2) Too many steps
When stainless steel is rubbed, the molecular arrangement changes, and work hardening occurs.
When step processing is performed for chip discharge, be careful not to make it finer than necessary.
The appropriate step amount is 0.5 times the drill diameter (0.25 times for deep holes and small diameter ).
When stainless steel is rubbed, the molecular arrangement changes, and work hardening occurs.
When step processing is performed for chip discharge, be careful not to make it finer than necessary.
The appropriate step amount is 0.5 times the drill diameter (0.25 times for deep holes and small diameter ).
Common causes (3) Extremely low feed per revolution
If the feed amount per revolution is low, it is necessary to rotate a lot to process one hole, and the drill rubs a lot of the wall surface of the hole, which leads to work hardening.
Guidelines for the appropriate amount of feed per revolution in stainless steel processing
・ internal coolant supply type carbide drill for stainless steel 2%~3% of drill diameter (φ10→0.02~0.03mm/rev)
・High speed drill for stainless steel 1.5%~2% of drill diameter (φ10→0.015~0.02mm/rev)
* The condition range varies depending on the size and material type. For processing, please refer to the cutting condition table for each product.
If the feed amount per revolution is low, it is necessary to rotate a lot to process one hole, and the drill rubs a lot of the wall surface of the hole, which leads to work hardening.
Guidelines for the appropriate amount of feed per revolution in stainless steel processing
・ internal coolant supply type carbide drill for stainless steel 2%~3% of drill diameter (φ10→0.02~0.03mm/rev)
・High speed drill for stainless steel 1.5%~2% of drill diameter (φ10→0.015~0.02mm/rev)
* The condition range varies depending on the size and material type. For processing, please refer to the cutting condition table for each product.
Common cause (4) The pilot hole diameter is small.
regrinding The diameter of the drill is smaller than that of a new one.
In addition, compared to high-speed drills, carbide drills have less hole expansion allowance, and drills of the same diameter tend to be smaller.
In order to extend the tool life of the tap, it is effective to set the pilot hole diameter aiming for the maximum value of minor diameter within the standard.
Pay attention not only to the drill diameter, but also to the actual size after drilling.
regrinding The diameter of the drill is smaller than that of a new one.
In addition, compared to high-speed drills, carbide drills have less hole expansion allowance, and drills of the same diameter tend to be smaller.
In order to extend the tool life of the tap, it is effective to set the pilot hole diameter aiming for the maximum value of minor diameter within the standard.
Pay attention not only to the drill diameter, but also to the actual size after drilling.