Method of machining metallic tubes

Abstract

A method of machining a tube includes performing an obverse drawing process to the tube, where the obverse drawing process draws the tube in an obverse drawing direction from a first end toward a second end of the tube. The tube is turned around to perform a reverse drawing process, where the reverse drawing process draws the tube in a reverse drawing direction from the second end toward the first end of the tube. The obverse and the reverse drawing processes are alternately performed until the tube is thinned to a desired thickness.

1 . A method of machining a tube, and the method comprising:
 a) providing a metallic tube having a first end and a second end;   b) performing an obverse drawing process for the metallic tube, where the obverse drawing process draws the metallic tube in an obverse drawing direction from the first end toward the second end;   c) performing a reverse drawing process for the metallic tube, where the reverse drawing process draws the metallic tube in a reverse drawing direction from the second end toward the first end; and   d) repeating step b) to step c) until the metallic tube has a predetermined thickness.   
   
   
       2 . The method as claimed in  claim 1 , further comprising:
 annealing the metallic tube before step b) or step c).   
   
   
       3 . The method as claimed in  claim 1 , further comprising:
 coating a layer of lubricant on a surface of the metallic tube before step b) or step c).   
   
   
       4 . The method as claimed in  claim 3 , wherein the layer of lubricant is a solid soap substance. 
   
   
       5 . The method as claimed in  claim 1 , wherein the metallic tube is a circular tube. 
   
   
       6 . The method as claimed in  claim 1 , wherein the metallic tube is an angular tube. 
   
   
       7 . The method as claimed in  claim 1 , wherein the metallic tube is an Al—Zn—Mg tube. 
   
   
       8 . A method of machining a tube, and the method comprising:
 a) providing a metallic tube having a first end and a second end;   b) passing the metallic tube through a first eye hole from the first end, and drawing out the metallic tube from the first eye hole where the first eye hole has a diameter smaller than an external diameter of the metallic tube;   c) passing the metallic tube through a second eye hole from the second end, and drawing out the metallic tube from the second eye hole where the second eye hole has a diameter smaller than an external diameter of the metallic tube; and   d) repeating step b) to step c) until the metallic tube meet a predetermined thickness.   
   
   
       9 . The method as claimed in  claim 8 , further comprising:
 annealing the metallic tube before step b) or step c).   
   
   
       10 . The method as claimed in  claim 8 , further comprising:
 coating a layer of lubricant on an exterior surface of the metallic tube before step b) or step c).   
   
   
       11 . The method as claimed in  claim 10 , wherein the layer of lubricant is a solid soap substance. 
   
   
       12 . The method as claimed in  claim 8 , wherein the metallic tube is a circular tube. 
   
   
       13 . The method as claimed in  claim 8 , wherein the metallic tube is an angular tube. 
   
   
       14 . A method of machining a tube, and the method comprising:
 a) providing a metallic tube having a first end and a second end;   b) forming a first pressing portion at the first end;   c) inserting a first plug into the metallic tube from the second end until the first plug abuts against the first pressing portion, and drawing the metallic tube out of an eye hole after the first plug pushes the metallic tube passing through the eye hole where the first plug has an external diameter larger than an internal diameter of the metallic tube;   d) removing the first pressing portion;   e) forming a second pressing portion at the second end;   f) inserting a second plug into the metallic tube from the first end until the second plug abuts against the second pressing portion, and drawing the metallic tube out of the eye hole after the second plug pushes the metallic tube passing through the eye hole where the second plug has an external diameter larger than the internal diameter of the metallic tube;   g) removing the second pressing portion; and   h) repeating step b) to step g) until the metallic tube meet a predetermined thickness.   
   
   
       15 . The method as claimed in  claim 14 , further comprising:
 annealing the metallic tube before step c) or step f).   
   
   
       16 . The method as claimed in  claim 14 , further comprising:
 coating a layer of lubricant on an interior surface of the metallic tube before step c) or step f).   
   
   
       17 . The method as claimed in  claim 16 , wherein the layer of lubricant is a solid soap substance. 
   
   
       18 . The method as claimed in  claim 14 , wherein the eye hole has a diameter equal to an external diameter of the metallic tube. 
   
   
       19 . The method as claimed in  claim 14 , wherein the metallic tube is a circular tube. 
   
   
       20 . The method as claimed in  claim 14 , wherein the metallic tube is an angular tube.