Spatial light modulation of powder-based additive manufacturing with temperature control including by sensor feedback

1. A powder-based additive manufacturing system for producing 3D objects from powder material, the system comprising:

a supply of powder;

a recoater for applying powder on a powder bed, wherein a top surface of the powder bed defines an image plane;

a radiation source comprising a light source and a spatial light modulator adapted to simultaneously apply radiation to an entire image plane or to selectively apply radiation to a portion of the entire image plane;

a temperature measurement device for measuring a temperature of powder at one or more locations of the image plane; and

a controller configured to:

preheat the powder in the powder supply to a first temperature below a flow temperature to provide preheated powder in the powder supply;

after preheating the powder in the powder supply, operate the recoater to apply a layer of the preheated powder upon the powder bed;

after operating the recoater to apply the layer of the preheated powder, operate the light source and the spatial light modulator to apply radiation to the entire image plane simultaneously to heat the preheated powder along the entire image plane to a process temperature to provide a process temperature powder layer; and

after operating the light source and the spatial light modulator to apply radiation to the entire image plane simultaneously, operate the light source and the spatial light modulator to selectively apply radiation to portions of the entire image plane but not to the entire image plane and to heat portions of the powder under the entire image plane but not all of the powder under the entire image plane to a fusing temperature;

wherein the fusing temperature is higher than the process temperature; and the process temperature is higher than the first temperature.

2. A powder-based additive manufacturing system according to claim 1 further comprising at least one of a heated gas supply and a chamber heater for heating the powder to the first temperature.

3. A powder-based additive manufacturing system according to claim 1 , wherein the recoater comprises at least one of a roller and a doctor blade.

4. A powder-based additive manufacturing system according to claim 1 , wherein the spatial light modulator comprises at least one of a digital light processor (DLP), liquid crystal display (LCD), liquid crystal on silicon (LCOS), and grating light valve (GLV).

5. A powder-based additive manufacturing system according to claim 1 , wherein the radiation source applies visible light radiation.

6. A powder-based additive manufacturing system according to claim 1 , wherein the radiation source applies IR radiation.

7. A powder-based additive manufacturing system according to claim 1 , wherein the controller is further configured to scan a laser to define an outer surface of the cross-sectional areas fused by the radiation source.

8. A powder-based additive manufacturing system according to claim 1 , wherein the radiation source is stationary.

9. A powder-based additive manufacturing system according to claim 1 , wherein the radiation source comprises at least one of an LED, an LED array, a near IR fiber laser, and a diode laser.

10. A powder-based additive manufacturing system according to claim 1 , wherein the supply of powder comprises at least one of the following materials: polyamide (PA), polyaryletherketone (PAEK), polyether ether ketone (PEEK), polyphenylene sulfide (PPS) and polycarbonate (PC).

11. A powder-based additive manufacturing system according to claim 1 , wherein the supply of powder comprises at least one of the following materials: carbon black and a pigment or dye defining a non-black color.

12. A powder-based additive manufacturing system for producing 3D objects from powder material, the system comprising:

a supply of polymeric powder;

a recoater for applying the polymeric powder on a powder bed, wherein a top surface of the powder bed defines an image plane;

a radiation source comprising a light source and a spatial light modulator adapted to selectively apply radiation to the image plane;

a temperature measurement device for measuring a temperature of powder at one or more locations of the image plane and providing powder temperature data to a controller; wherein,

the controller is configured to:

preheat the polymeric powder in the powder supply to a first temperature below a flow temperature to provide preheated polymeric powder in the powder supply;

operate the recoater to apply a layer of the preheated polymeric powder upon the powder bed;

operate the light source and the spatial light modulator to heat the preheated powder in the image plane to a process temperature;

operate the light source and the spatial light modulator to selectively heat portions but not all of the powder in the image plane to a fusing temperature; and

receive the powder temperature data from the temperature measurement device to operate the light source and spatial light modulator to maintain the powder in the image plane at the process temperature outside of the selectively heated portions,

wherein the fusing temperature is higher than the process temperature; and the process temperature is higher than the first temperature.