Additive manufacturing system with heater configured for improved interlayer adhesion in a part formed by the system

Abstract

A three-dimensional object printing system improves the interlayer adhesion of an object. The printing system includes a platform on which a three-dimensional object is built. A material applicator in the printing system expels material to form layers of the object on the platform. The material applicator also includes a heater mounted to an arm that is configured to rotate about the material applicator to position the heater so the heater heats the layer of the object ahead of the material applicator as the material applicator moves relative to the platform.

What is claimed is: 
     
         1 . A three-dimensional (3D) object manufacturing system comprising:
 a platform defining a planar surface;   a material applicator configured to expel material to form a layer of an object on the platform;   a first actuator operatively connected to one of the platform and the material applicator to move the platform and material applicator relative to one another in at least a first direction and a second direction that are orthogonal to one another in a plane that is parallel to the planar surface; and   a heater mounted to an arm that is configured to rotate about the material applicator to position the heater relative to the material applicator so the heater heats a portion of the layer of the object before the material applicator expels material onto the portion of the layer of the object as the material applicator moves in the first and second directions.   
     
     
         2 . The 3D object manufacturing system of  claim 1  wherein the heater is further configured to heat the expelled material ahead of the material applicator to a temperature greater than a transition temperature of the material forming the object on the platform but less than a temperature at which the material becomes liquid. 
     
     
         3 . The 3D object manufacturing system of  claim 2  further comprising:
 a second actuator operatively connected to the arm to which the heater is mounted, the actuator being configured to rotate the arm about the material applicator. 
 
     
     
         4 . The 3D object manufacturing system of  claim 3  further comprising:
 a controller operatively connected to the first actuator and the second actuator, the controller being configured to operate the second actuator to rotate the arm and position the heater to lead the material applicator as the material application moves relative to the platform. 
 
     
     
         5 . The 3D object manufacturing system of  claim 4  wherein the controller is further configured to adjust an electrical power delivered to the heater with reference to a speed at which the material applicator moves. 
     
     
         6 . The 3D object manufacturing system of  claim 4  wherein the controller is further configured to adjust an electrical power delivered to the heater with reference to a size of an area over which the material applicator moves while expelling material. 
     
     
         7 . The 3D object manufacturing system of  claim 4  wherein the controller is further configured to adjust an electrical power delivered to the heater with reference to an elapsed time since the heater heated the area in which the material applicator is expelling material. 
     
     
         8 . The 3D object manufacturing system of  claim 4  further comprising:
 a sensor for generating a signal indicative of a temperature of an area opposite the sensor, the sensor being mounted proximate to the heater; and 
 the controller is operatively connected to the sensor, the controller being further configured to adjust an electrical power delivered to the heater with reference to the temperature indicated by the signal received from the sensor. 
 
     
     
         9 . The 3D object manufacturing system of  claim 8  wherein the sensor is mounted to precede the heater as the material applicator moves relative to the platform. 
     
     
         10 . The 3D object manufacturing system of  claim 9  wherein the sensor is an infrared thermocouple. 
     
     
         11 . The 3D object manufacturing system of  claim 4  wherein the material applicator is an extruder. 
     
     
         12 . The 3D object manufacturing system of  claim 4  wherein the material applicator is a printhead. 
     
     
         13 . The 3D object manufacturing system of  claim 4  wherein the heater is a single heating element. 
     
     
         14 . The 3D object manufacturing system of  claim 14 , the heater further comprising:
 a source of pressurized air positioned to direct air heated by the single heating element away from the heating element.   
     
     
         15 . The 3D object manufacturing system of  claim 4 , the material applicator further comprising:
 a heater within the material applicator to heat material to be expelled from the material applicator to a transition temperature of the material before expelling the material.   
     
     
         16 . A three-dimensional (3D) object manufacturing system comprising:
 a platform defining a planar surface;   a material applicator configured to expel material to form a layer of an object on the platform;   a first actuator operatively connected to one of the platform and the material applicator to move the platform and material applicator relative to one another in at least a first direction and a second direction that are orthogonal to one another in a plane that is parallel to the planar surface;   a heater mounted to an arm that is configured to rotate about the material applicator to position the heater relative to the material applicator so the heater heats a portion of the layer of the object before the material applicator expels material onto the portion of the layer of the object as the material applicator moves in the first and second directions, the heater being further configured to heat the expelled material ahead of the material applicator to a temperature greater than a transition temperature of the material forming the object on the platform but less than a temperature at which the material becomes liquid; and   a second actuator operatively connected to the arm to which the heater is mounted, the actuator being configured to rotate the arm about the material applicator.   
     
     
         17 . The 3D object manufacturing system of  claim 16  further comprising:
 a controller operatively connected to the first actuator and the second actuator, the controller being configured to operate the second actuator to rotate the arm and position the heater to lead the material applicator as the material application moves relative to the platform. 
 
     
     
         18 . The 3D object manufacturing system of  claim 17  wherein the controller is further configured to adjust an electrical power delivered to the heater with reference to a speed at which the material applicator moves. 
     
     
         19 . The 3D object manufacturing system of  claim 18  further comprising:
 a sensor for generating a signal indicative of a temperature of an area opposite the sensor, the sensor being mounted proximate to the heater; and 
 the controller is operatively connected to the sensor, the controller being further configured to adjust an electrical power delivered to the heater with reference to the temperature indicated by the signal received from the sensor. 
 
     
     
         20 . The 3D object manufacturing system of  claim 19 , the material applicator further comprising:
 a heater within the material applicator to heat material to be expelled from the material applicator to a transition temperature of the material before expelling the material.