Additive manufacturing method and system

Abstract

A method builds a workpiece using an additive manufacturing process, wherein the workpiece is built up by consolidating material in a layer-by-layer manner. The method includes receiving an initial geometric model defining surface geometry of the workpiece, determining workpiece slices to be consolidated as layers of the workpiece during the additive manufacturing process from the initial geometric model, determining adjusted positions of the workpiece slices adjusted from initial positions of the workpiece slices as determined from the initial geometric model, the determination of the adjusted positions based upon warping of the workpiece expected to occur during or after the additive manufacturing process, and building the workpiece using the additive manufacturing process, wherein the workpiece slices are formed in the adjusted positions.

1 . A method of building a workpiece using an additive manufacturing process, wherein the workpiece is built up by consolidating material in a layer-by-layer manner, the method comprising:
 receiving an initial model defining surface geometry of the workpiece,   determining initial workpiece slices to be consolidated as layers of the workpiece during the additive manufacturing process from the initial geometric model,   building a test workpiece in accordance with the initial workpiece slices using the additive manufacturing process,   determining a degree of warping by measuring the test workpiece after an end of the build of the test workpiece,   determining an adjusted surface geometry of the workpiece adjusted from the initial workpiece model such that warping of the workpiece with the adjusted surface geometry expected to occur during or after the additive manufacturing process returns the workpiece to or towards the surface geometry as defined in the initial geometric model, and   building the workpiece with the adjusted surface geometry using the additive manufacturing process.   
     
     
         2 . A method according to  claim 1 , wherein the test workpiece is built on a build plate and the degree of warping is determined by measuring the test workpiece after an end of the build of the test workpiece with the test workpiece attached to the build plate. 
     
     
         3 . A method according to  claim 2 , wherein the build plate is used to establish a datum for measuring the test workpiece. 
     
     
         4 . A method according to  claim 3 , where the datum is a surface of the build plate. 
     
     
         5 . A method according to  claim 4 , wherein the datum is an upper surface of the build plate. 
     
     
         6 . A method according to  claim 2  comprising carrying out heat treatment on the test workpiece and the degree of warping is determined by measuring the test workpiece after the heat treatment. 
     
     
         7 . A method according to  claim 1 , wherein the test workpiece is built on a build plate and the degree of warping is determined by measuring the test workpiece after the test workpiece is released from the build plate. 
     
     
         8 . A method according to  claim 7  comprising carrying out heat treatment on the test workpiece and the degree of warping is determined by measuring the test workpiece after the heat treatment. 
     
     
         9 . A method according to  claim 1  comprising carrying out heat treatment on the test workpiece and the degree of warping is determined by measuring the test workpiece after the heat treatment. 
     
     
         10 . A method according to  claim 1 , wherein measuring the test workpiece is carried out on a coordinate positioning machine. 
     
     
         11 . A method according to  claim 10 , wherein the coordinate positioning machine is a coordinate measuring machine. 
     
     
         12 . A method according to  claim 11 , wherein the coordinate measuring machine is non-Cartesian coordinate positioning machine. 
     
     
         13 . A method according to  claim 10 , wherein the coordinate positioning machine is a machine tool. 
     
     
         14 . A method according to  claim 1 , wherein measuring the test workpiece is carried out using a non-contact measurement probe. 
     
     
         15 . A method according to  claim 14 , wherein the non-contact probe is an optical non-contact probe. 
     
     
         16 . A method according to  claim 1 , wherein measuring the test workpiece is carried out using a contact measurement probe. 
     
     
         17 . A method according to  claim 16 , wherein the contact measurement probe is a touch trigger or scanning contact probe. 
     
     
         18 . A method according to  claim 1  wherein the workpiece is built in the same orientation in a build volume as the test workpiece. 
     
     
         19 . A method according to  claim 1 , wherein the workpiece is built with the same supports as the test workpiece. 
     
     
         20 . A method according to  claim 1 , wherein the workpiece is built in the same position within a build volume as the test workpiece. 
     
     
         21 . A method according to  claim 1 , wherein the adjusted surface geometry takes into account a difference in a build of the workpiece and a build of the test workpiece. 
     
     
         22 . A method according to  claim 21 , comprising determining the adjusted surface geometry using a mapping describing how the adjusted surface geometry should be modified based upon the difference between the builds. 
     
     
         23 . A method according to  claim 21 , wherein the difference comprises a difference in a first position of the test workpiece in a build volume in which the test workpiece is built and a second position of the workpiece in the build volume. 
     
     
         24 . A method according to  claim 1 , comprising building a series of test workpieces each based upon the adjusted surface geometry slices determined from the distortion that occurred for a previous one of the test workpieces until surface geometry of one of the test workpieces of the series, after warping, matches that of the initial geometric model within a predefined tolerance.