Method and apparatus for manipulating metal workpieces

Abstract

A method of forming a duct section from a web of material includes the steps of forming a series of perforations in a web of material, the series of perforations defining an outline of one of a hole or notch in a finished duct section, forming a male lock bend and a female lock seam in first opposed edges of the web of material, forming flanges in second opposed edges of the web of material, removing the portion of material interior to the series of perforations to form the hole or notch, and bending the web of material to form the finished duct section.

What is claimed is: 
     
         1 . A method of manipulating a sheet of material, said method comprising the steps of:
 loading cutting parameter data into a controller, said cutting parameter data defining an architecture of at least one feature to be formed in a sheet of material; and   forming a series of perforations in said sheet of material in accordance with said cutting parameter data, said series of perforations forming an outline of said at least one feature.   
     
     
         2 . The method according to  claim 1 , further comprising the steps of:
 subsequent to forming said series of perforations, forming at least one of a lock seam and a flange in said sheet of material; and   subsequent to forming said at least one of said lock seam and said flange in said sheet of material, removing the portion of material interior to said series of perforations to produce said at least one feature.   
     
     
         3 . The method according to  claim 2 , further comprising the step of:
 bending said sheet of material to form a duct section.   
     
     
         4 . The method according to  claim 2 , wherein:
 said series of perforations are formed using a plasma cutter.   
     
     
         5 . The method according to  claim 3 , wherein:
 said at least one feature is a hole, a notch, a tap or an access door.   
     
     
         6 . The method according to  claim 4 , further comprising the steps of:
 unwinding said sheet of material from a roll;   straightening said sheet of material; and   subsequent to forming said series of perforations in said sheet of material;   shearing said sheet of material from said roll using said plasma cutter.   
     
     
         7 . The method according to  claim 1 , wherein:
 said sheet of material is sheet metal.   
     
     
         8 . The method according to  claim 4 , wherein:
 said plasma cutter is operable in a continuous cutting mode and a perforation cutting mode.   
     
     
         9 . A method of forming a duct section from a web of material, comprising the steps of:
 forming a series of perforations in a web of material, said series of perforations defining an outline of one of a hole or notch in a finished duct section;   forming a male lock bend and a female lock seam in first opposed edges of said web of material;   forming flanges in second opposed edges of said web of material;   removing the portion of material interior to said series of perforations to form said hole or said notch; and   bending said web of material to form said finished duct section.   
     
     
         10 . The method according to  claim 9 , wherein:
 said series of perforations are formed using a plasma cutter.   
     
     
         11 . The method according to  claim 10 , further comprising the steps of:
 unwinding said web of material from a roll;   straightening said web of material; and   shearing said web of material from said roll using said plasma cutter.   
     
     
         12 . The method according to  claim 10 , wherein:
 said plasma cutter is operable in a continuous cutting mode and a perforation cutting mode.