Hard-carbon coated machine tool and cutting oil composition therefor

Abstract

A machine tool is used for machining a workpiece in the presence of a cutting oil composition. The machine tool includes a tool base and a hard carbon coating formed on the tool base. The hard carbon coating has 1 atomic % or less of hydrogen. The cutting oil composition contains a base oil and at least one of an ashless fatty-ester friction modifier and an ashless aliphatic-amine friction modifier.

What is claimed is:  
     
         1 . A cutting oil composition for a hard-carbon coated machine tool, comprising: a base oil and at least one of an ashless fatty-ester friction modifier and an ashless aliphatic-amine friction modifier.  
     
     
         2 . A cutting oil composition according to  claim 1 , wherein said at lease one of the ashless fatty-ester friction modifier and the ashless aliphatic-amine friction modifier has a C 6 -C 30  hydrocarbon group, and is contained in an amount of 0.05 to 3.0% by mass based on the total mass of the cutting oil composition.  
     
     
         3 . A cutting oil composition according to  claim 1 , further comprising a polybutenyl succinimide and/or a derivative thereof.  
     
     
         4 . A cutting oil composition according to  claim 3 , wherein the polybutenyl succinimide and/or the derivative thereof is contained in an amount of 0.1 to 15% by mass based on the total mass of the cutting oil composition.  
     
     
         5 . A cutting oil composition according to  claim 1 , further comprising 0.1% or less by mass of zinc dithiophosphate in terms of phosphorus based on the total mass of the cutting oil composition.  
     
     
         6 . A cutting oil composition according to  claim 1 , wherein the oil is supplied in mist form.  
     
     
         7 . A machine tool for machining a workpiece in the presence of a cutting oil composition, the cutting oil composition containing at least one of an ashless fatty-ester friction modifier and an ashless aliphatic-amine friction modifier, the machine tool comprising: 
 a tool base; and    a hard carbon coating formed on the tool base, the hard carbon coating having 1 atomic % or less of hydrogen.    
     
     
         8 . A machine tool according to  claim 7 , wherein the hard carbon coating has 0.5 atomic % or less of hydrogen.  
     
     
         9 . A machine tool according to  claim 7 , wherein the hard carbon coating is formed by physical vapor deposition.  
     
     
         10 . A machine tool according to  claim 7 , wherein the tool base has a surface roughness Ra of 0.03 μm or lower.  
     
     
         11 . A machine tool unit, comprising: 
 a machine tool including a tool base and a hard carbon coating formed on the tool base, the hard carbon coating having 1 atomic % or less of hydrogen; and    a cutting oil composition to lubricate the machine tool, the cutting oil composition containing at least one of an ashless fatty-ester friction modifier and an ashless aliphatic-amine friction modifier.    
     
     
         12 . A machine tool unit according to  claim 11 , wherein the hard carbon coating has 0.5 atomic % or less of hydrogen.  
     
     
         13 . A machine tool unit according to  claim 11 , wherein the hard carbon coating is formed by physical vapor deposition.  
     
     
         14 . A machine tool unit according to  claim 11 , wherein the tool base has a surface roughness Ra of 0.03 μm or lower.  
     
     
         15 . A machine tool unit according to  claim 11 , wherein said at lease one of the ashless fatty-ester friction modifier and the ashless aliphatic-amine friction modifier has a C 6 -C 30  hydrocarbon group, and is contained in an amount of 0.05 to 3.0% by mass based on the total mass of the cutting oil composition.  
     
     
         16 . A machine tool unit according to  claim 11 , wherein the cutting oil composition further contains a polybutenyl succinimide and/or a derivative thereof.  
     
     
         17 . A machine tool unit according to  claim 16 , wherein the polybutenyl succinimide and/or the derivative thereof is contained in an amount of 0.1 to 15% by mass based on the total mass of the cutting oil composition.  
     
     
         18 . A machine tool unit according to  claim 11 , wherein the cutting oil composition further contains 0.1% or less by mass of zinc dithiophosphate in terms of phosphorus based on the total mass of the cutting oil composition.  
     
     
         19 . A machine tool unit according to  claim 11 , wherein the cutting oil composition is supplied in mist form.