Method and Apparatus for Forming Cutting Blades

Abstract

There is provided a method of forming cutting blades using selective laser melting comprising positioning a first part of an elongate strip with pre-formed teeth within a powder bed, forming coating layers layer-by-layer to create a cutting surface on each pre-formed tooth by repeatedly depositing a layer of powder on the powder bed and scanning a laser beam over the deposited powder to fuse powder to the pre-formed teeth.

What is claimed is: 
     
         1 . A cutting blade, comprising:
 an elongate strip formed from a first material;   a plurality of pre-formed teeth formed from the first material, the plurality of pre-formed teeth extending from the elongate strip; and   at least one coating layer of a second material, the at least one coating layer comprising a first coating layer fused to the plurality of pre-formed teeth, the second material being harder than the first material;   wherein the at least one coating layer defines a cutting edge of the cutting blade.   
     
     
         2 . The cutting blade of  claim 1 , wherein the first material is a steel. 
     
     
         3 . The cutting blade of  claim 1 , wherein each of the plurality of pre-formed teeth comprise a rectangular profile. 
     
     
         4 . The cutting blade of  claim 1 , wherein the at least one coating layer comprises a second coating layer fused to the first coating layer. 
     
     
         5 . The cutting blade of  claim 1 , wherein each of the at least one cutting layer has a thickness in a range from 0.05 mm to 0.10 mm. 
     
     
         6 . The cutting blade of  claim 1 , wherein the second material comprises a mixture of tungsten carbide and cobalt. 
     
     
         7 . The cutting blade of  claim 6 , wherein the mixture comprises 80% tungsten carbide and 20% cobalt. 
     
     
         8 . The cutting blade of  claim 1 , wherein the at least one coating layer comprises a substantially two-dimensional extension of the plurality of pre-formed teeth. 
     
     
         9 . The cutting blade of  claim 1 , wherein the at least one coating layer comprises a three-dimensional shape extending from the plurality of pre-formed teeth. 
     
     
         10 . The cutting blade of  claim 9 , wherein the three-dimensional shape comprises an inverted frusto-conical cone. 
     
     
         11 . The cutting blade of  claim 9 , wherein the three-dimensional shape comprises a pentagonal cross-section. 
     
     
         12 . The cutting blade of  claim 9 , wherein the three-dimensional shape comprises a bifurcated shape with a substantially V-shaped cross-section. 
     
     
         13 . The cutting blade of  claim 9 , wherein the three-dimensional shape comprises a stack of multiple frusto-conical sections. 
     
     
         14 . The cutting blade of  claim 1 , wherein the second material comprises particles of tungsten carbide, aluminum oxide, a boride, or combinations thereof and a matrix of cobalt, chromium, titanium, or mixtures thereof. 
     
     
         15 . The cutting blade of  claim 1 , wherein the elongate strip comprises a first edge extending along a length of the elongate strip and a second edge extending along a length of the elongate strip, wherein the first edge and the second edge are separated across a width of the elongate strip, and wherein the first edge defines the plurality of pre-formed teeth. 
     
     
         16 . An apparatus for forming cutting blades using selective laser melting, the apparatus comprising:
 a laser; and   a powder bed;   wherein first and second opposing walls of the powder bed are provided with at least one pair of opposing slits with a sealing element located around each slit so as to prevent loss of powder from the powder bed whilst allowing passage of a cutting blade through the slits.   
     
     
         17 . The apparatus for forming cutting blades according to  claim 16 , wherein a plurality of pairs of opposing slits are provided so as to allow processing of a plurality of cutting blades at once, with each slit sealed against powder loss by a sealing element. 
     
     
         18 . The apparatus for forming cutting blades according to  claim 16 , further comprising a galvanometer canner configured to move a beam emitted by the laser across the powder bed. 
     
     
         19 . The apparatus for forming cutting blades according to  claim 16 , further comprising a powder dispenser configured to spread a layer of powder across the powder bed. 
     
     
         20 . The apparatus for forming cutting blades according to  claim 16 , further comprising a processor programmed with a plurality of profiles for scanning the laser over the powder bed to form two-dimensional and three-dimensional shapes of a cutting edge of the cutting blade.