Techniques for mixing in additive fabrication and related systems and methods

Abstract

According to some aspects, a mixer for detection and/or removal of material in an undesired location of an additive fabrication device is provided. For instance, in an inverse stereolithography device, liquid photopolymer may adhere and cure or partially cure to a surface of the additive fabrication device in a location that may interfere with the additive fabrication process and/or cause the additive fabrication process to be unsuccessful. The mixer may be coupled to a movable structure within the additive fabrication device so that the mixer, when coupled to the movable structure, may be moved along at least one axis within the additive fabrication device. The mixer may be configured to detect and/or remove undesired material from a surface within the additive fabrication device.

What is claimed is: 
     
         1 . An additive fabrication device configured to form layers of solid material on a build surface by directing light onto a liquid photopolymer, the additive fabrication device comprising:
 a container configured to hold liquid photopolymer;   a mixer disposed within the container and comprising a first magnetic component; and   a movable structure disposed below the container and configured to move along a first axis, wherein the movable structure comprises a second magnetic coupling component configured to couple to the first magnetic component, and wherein motion of the moveable structure along the first axis causes motion of the mixer along the first axis as a result of said coupling.   
     
     
         2 . The additive fabrication device of  claim 1 , wherein the second magnetic component is configured to move toward and away from the container and thereby couple and decouple, respectively, to the first magnetic component. 
     
     
         3 . The additive fabrication device of  claim 1 , wherein the movable structure comprises an optical unit. 
     
     
         4 . The additive fabrication device of  claim 1 , wherein the mixer further comprises an elongated body with a first end and a second end and at least one edge member extending along the elongated body from the first end to the second end. 
     
     
         5 . The additive fabrication device of  claim 4 , wherein the at least one edge member is configured to remove debris from a surface proximate to the at least one edge member. 
     
     
         6 . The additive fabrication device of  claim 4 , wherein the at least one edge member is configured to spread an even layer of liquid photopolymer. 
     
     
         7 . The additive fabrication device of  claim 1 , wherein the mixer further comprises housings configured to house the at least one magnetic component, and wherein the housings are disposed at the first end and the second end of the elongated body. 
     
     
         8 . The additive fabrication device of  claim 1 , wherein the mixer further comprises at least one retaining arm configured to maintain the position of the mixer in the container when the mixer is not in use. 
     
     
         9 . The additive fabrication device of  claim 1 , wherein the mixer further comprises a filter element. 
     
     
         10 . The additive fabrication device of  claim 9 , wherein the filter element comprises an array of holes in an upper surface of the elongated body. 
     
     
         11 . An additive fabrication device configured to form layers of solid material on a build platform, the additive fabrication device comprising:
 a container;   a mixer disposed within the container and comprising a first magnetic component;   a movable structure disposed below the container and configured to move along a first axis, wherein the movable structure comprises a second magnetic component configured to couple to the first magnetic component;   a sensor configured to produce sensor data indicative of a state of the mixer;   at least one processor; and   at least one computer readable medium comprising instructions that, when executed by the at least one processor:
 operate one or more actuators to move the movable structure and the mixer along the first axis whilst the first and second magnetic components are coupled; and 
 detect a failure of an additive fabrication process based at least in part on the sensor data produced by the sensor during movement of the mixer along the first axis. 
   
     
     
         12 . The additive fabrication device of  claim 11 , wherein the second magnetic component is configured to move toward and away from the container and thereby couple and decouple, respectively, to the first magnetic component. 
     
     
         13 . The additive fabrication device of  claim 11 , wherein the movable structure comprises an optical unit. 
     
     
         14 . The additive fabrication device of  claim 13 , wherein the sensor is a Hall sensor configured to monitor the coupling state of the mixer and the movable structure. 
     
     
         15 . The additive fabrication device of  claim 11 , wherein the sensor is a force sensor configured to monitor forces experienced by the mixer whilst the mixer is coupled to the movable structure and moved along at least one axis. 
     
     
         16 . The additive fabrication device of  claim 11 , wherein the instructions, when executed by the at least one processor, further comprise alerting the user upon detection of a failure. 
     
     
         17 . The additive fabrication device of  claim 16 , wherein the instructions, when executed by the at least one processor, further comprise recoupling the mixer and the movable structure upon detection of a failure prior to alerting the user. 
     
     
         18 . An additive fabrication device configured to form layers of solid material on a build platform, the additive fabrication device comprising:
 a build platform;   a mixer disposed below the build platform and comprising at least one magnetic component;   a movable structure disposed below the mixer and configured to move along a first axis, wherein the movable structure comprises a second magnetic component configured to couple to the first magnetic component;   a sensor configured to produce sensor data indicative of a state of the mixer;   at least one processor; and   at least one computer readable medium comprising instructions that, when executed by the at least one processor:
 lower the build platform iteratively whilst moving the movable structure along the first axis underneath the build platform whilst the first and second magnetic components are coupled until the build platform contacts the mixer; 
 detect a failure of an additive fabrication process based at least in part on sensor data produced by the sensor; and 
 move the movable structure along the first axis while the build platform is in contact with the mixer to remove the detected failure. 
   
     
     
         19 . The additive fabrication device of  claim 18 , wherein the second magnetic component is configured to move toward and away from the container and thereby couple and decouple, respectively, to the first magnetic component. 
     
     
         20 . The additive fabrication device of  claim 18 , wherein the movable structure comprises an optical unit. 
     
     
         21 . The additive fabrication device of  claim 18 , wherein the sensor is a Hall sensor configured to monitor the coupling state of the mixer and the movable structure. 
     
     
         22 . The additive fabrication device of  claim 18 , wherein the sensor is a force sensor configured to monitor forces experienced by the mixer whilst the mixer is coupled to the movable structure and moved along the first axis. 
     
     
         23 . The additive fabrication device of  claim 18 , wherein the instructions, when executed by the at least one processor, further comprise alerting the user upon detection of a failure. 
     
     
         24 . The additive fabrication device of  claim 23 , wherein the instructions, when executed by the at least one processor, further comprise recoupling the mixer and the movable structure upon detection of a failure prior to alerting the user.