Endmill specification design method, cutting condition detecting method, and processing method

Abstract

Provided is an endmill ( 5 ). The maximum spindle speed, per one minute, of a main spindle to which the endmill is attached is Smax. The number of teeth of the endmill ( 5 ) is N. The outer shape of the endmill ( 5 ) is Da. The natural frequency at which vibrations at the end of the endmill ( 5 ) reach a maximum level is ω 1. ω1 and/or N are set so that when the diameter-direction infeed amount of the endmill ( 5 ) is set to Rd: i) ω 1 ×60/N×6<Smax, if Rd is at least 4% of Da; and ii) ω 1 ×60/N×3<Smax, if Rd is less than 4% of Da.

1 . An endmill specification design method, comprising:
 setting ω 1  and/or N so as to satisfy the following,   wherein when a maximum spindle speed per one minute of a main spindle having an endmill attached thereto is defined as Smax,   the number of teeth of the endmill is defined as N,   an outer shape of the endmill is defined as Da,   a natural frequency at which a vibration is maximized in a tool tip of the endmill is defined as ω 1 , and   a radial depth of cut of the endmill is defined as Rd,   i) in a case where Rd is equal to or greater than 4% of Da,   ω 1 ×60/N×6<Smax is satisfied, and   ii) in a case where Rd is smaller than 4% of Da,   ω 1 ×60/N×3<Smax is satisfied.   
     
     
         2 . The endmill specification design method according to  claim 1 ,
 wherein bottom surface machining is performed in a case of i), and side surface machining is performed in a case of ii).   
     
     
         3 . A cutting condition detecting method, comprising:
 setting a rotation speed of a main spindle having an endmill attached thereto so as to satisfy the following,   wherein when a maximum spindle speed per one minute of the main spindle is defined as Smax,   the number of teeth of the endmill is defined as N,   an outer shape of the endmill is defined as Da,   a natural frequency at which a vibration is maximized in a tool tip of the endmill is defined as ω 1 , and   a radial depth of cut of the endmill is defined as Rd,   i) in a case where Rd is equal to or greater than 4% of Da,   a range of ω 1 ×60/N×6 to Smax is satisfied, and   ii) in a case where Rd is smaller than 4% of Da,   a range of ω 1 ×60/N×3 to Smax is satisfied.   
     
     
         4 . The cutting condition detecting method according to  claim 3 ,
 wherein bottom surface machining is performed in a case of i), and side surface machining is performed in a case of ii).   
     
     
         5 . The cutting condition detecting method according to  claim 3 ,
 wherein the rotation speed of the main spindle is set to a rotation speed so as to avoid ω′×60/N(m−0.5) (m is a natural number), when the natural frequency that is a frequency higher than oil serving as the natural frequency at which the vibration is maximized in the tool tip of the endmill, that has a vibration peak independent of ω 1 , and that has a peak value of the vibration which is equal to or greater than 1/10 of a peak value of ω 1  is defined as ω′.   
     
     
         6 . A processing method comprising:
 performing machining on a workpiece by using the cutting condition detecting method according to  claim 3 .