Additive manufacturing

Abstract

In one example, a non-transitory processor readable medium with instructions thereon that when executed cause an additive manufacturing machine to inhibit build material in an overlying layer of build material from fusing with a first slice formed in an underlying layer of build material.

1 - 4 . (canceled) 
     
     
         5 . A non-transitory processor readable medium having instructions thereon that when executed cause an additive manufacturing machine to form a physical barrier on an underlying object slice to overlying build material fusing with the underlying object slice. 
     
     
         6 - 7 . (canceled) 
     
     
         8 . The medium of  claim 5 , where the instructions to form a physical barrier include instructions to dispense a liquid coalescence modifier agent on to the underlying object slice bordering an area where an overlying object slice in the overlying build material will cover the underlying object slice. 
     
     
         9 . A computer program product that includes the processor readable medium of  claim 5 . 
     
     
         10 . An additive manufacturing machine controller that includes the processor readable medium of  claim 5 . 
     
     
         11 - 14 . (canceled) 
     
     
         15 . The medium of  claim 5 , where the instructions to form a physical barrier include instructions to dry the modifier agent dispensed on to the underlying object slice before forming the overlying build material. 
     
     
         16 . An additive manufacturing machine, comprising:
 an apparatus for form slices of an object; and   a controller having instructions thereon that when executed:
 cause the apparatus to form an underlying object slice; 
 cause the apparatus to form a physical barrier on the underlying object slice to overlying build material fusing with the underlying object slice; and 
 cause the apparatus to, in the overlying build material, form an overlying object slice on the underlying object slice. 
   
     
     
         17 . The machine of  claim 16 , wherein:
 the apparatus comprises:
 a first device to layer powdered build material; 
 a second device to dispense a liquid, light absorbing coalescing agent on to build material; 
 a third device to dispense a liquid coalescence modifier agent on to build material; 
 a light source to apply light energy to build material; 
   the instructions to cause the apparatus to form the underlying object slice include instructions to:
 cause the first device to layer build material in a first layer; 
 cause the second device to dispense a liquid, light absorbing coalescing agent on to build material in the first layer in a first pattern of the underlying object slice; and 
 cause the light source to apply light energy to build material in the first layer patterned with coalescing agent to generate heat to melt patterned build material in the first layer, to form the underlying object slice; 
   the instructions to cause the apparatus to form the physical barrier include instructions to cause the third device to dispense a liquid coalescence modifier agent on to the underlying object slice bordering an area where the overlying object slice will cover the underlying object slice; and   the instructions to cause the apparatus to form the overlying object slice include instructions to:
 cause the first device to layer build material in a second layer over the underlying object slice; 
 cause the second device to dispense a liquid, light absorbing coalescing agent on to build material in the second layer in a second pattern of the overlying object slice; and 
 cause the light source to apply light energy to build material in the second layer patterned with coalescing agent to generate heat to melt patterned build material in the second layer, to form the overlying object slice on the underlying object slice. 
   
     
     
         18 . The machine of  claim 17 , wherein the instructions to cause the apparatus form the barrier include instructions to dry the modifier agent dispensed on to the underlying object slice before layering build material over the underlying object slice. 
     
     
         19 . A non-transitory processor readable medium having instructions thereon that when executed cause an additive manufacturing machine to:
 form a first layer of build material;   dispense a liquid, light absorbing coalescing agent on to build material in the first layer in a pattern of a first slice of an object;   expose build material in the first layer patterned with coalescing agent to light to generate heat to melt patterned build material in the first layer to form the first slice;   dispense a liquid coalescence modifier agent on to the first slice covering an area where the first slice will underhang a second slice of the object;   form a second layer of build material on the first slice;   dispense a liquid, light absorbing coalescing agent on to build material in the second layer in a pattern of the second slice; and   expose build material in the second layer patterned with coalescing agent to light to generate heat to melt patterned build material in the second layer to form the second slice on the first slice.   
     
     
         20 . The medium of  claim 19 , having instructions to dry the modifier agent on the first slice before forming the second layer of build material. 
     
     
         21 . The medium of  claim 20 , wherein the instructions to dry the modifier agent include instructions to heat the modifier agent.