Method for biopsy device needle tip

Abstract

A biopsy device having a cannula with a distal tip is disclosed. The distal tip includes a blade, and can be a unitary metal injection molded component including a base and a blade. The blade can have a hardness of at least 40 HRC. The blade can be hardened, polished, and then honed to provide a sharp leading edge.

1 . A method of forming blade for attachment to a biopsy device cannula, the method comprising the steps of:
 providing a distal tip comprising a generally flat blade portion extending from a base portion adapted for attachment to the cannula;   hardening the blade portion to have a hardness of at least about 40 HRC; and   forming a blade leading edge.   
     
     
         2 . The method of  claim 1  wherein the step of hardening comprises heat treating the blade portion. 
     
     
         3 . The method of  claim 1  wherein the step of forming the blade leading edge comprises honing the blade portion. 
     
     
         4 . The method of  claim 1  wherein the step of forming the blade leading edge is performed after the step of hardening the blade. 
     
     
         5 . The method of  claim 4  further comprising the step of polishing the blade prior to forming the blade leading edge and after the step of hardening the blade. 
     
     
         6 . The method of  claim 1  comprising forming serrations extending from the leading edge of the blade on at least one side of the blade, wherein substantially all of the serrations on the side of the blade are generally parallel to one another. 
     
     
         7 . The method of  claim 1  comprising forming serrations on first and second sides of the blade, wherein substantially all the serrations on the first side of the blade are generally parallel to one another, and where substantially all the serration on the second side of the blade are generally parallel to one another. 
     
     
         8 . The method of  claim 1  wherein the step of forming the leading edge comprises honing first and second sides of the blade portion substantially simultaneously. 
     
     
         9 . The method of  claim 1  comprising:
 attaching the distal tip to a cannula; and   with the distal tip attached to the cannula, forming the blade leading edge.