Three-Dimensional Printing System with Improved Motion and Imaging Control
A three-dimensional printing system includes a resin vessel, a build tray, a movement mechanism, a sensor, a light engine, and a controller. The resin vessel is configured to contain photocurable (radiation curable) resin and includes a transparent sheet. The transparent sheet has an upper surface that defines a lower bound for the photocurable resin. The build tray has a lower surface configured to support the 3D article. A lower face is defined by either the build tray or the 3D article. The sensor is configured to output a signal indicative of a vertical position of the transparent sheet. The light engine is configured to image a build plane that is proximate to the upper surface of the transparent sheet. The controller is configured to control motion of the movement mechanism based upon analyzing a signal from the sensor including determining a maximum deflection of the transparent sheet during motion.
1 . A three-dimensional (3D) printing system comprising:
a resin vessel configured to contain photocurable resin and including a transparent sheet, the transparent sheet having an upper surface defining a lower bound for the photocurable resin;
a build tray to support a 3D article, the build tray or the 3D article defining a lower face;
a movement mechanism coupled to the build tray;
a sensor configured to output a signal indicative of a vertical position of the transparent sheet;
a light engine configured to image a build plane that is proximate the upper surface of the transparent sheet;
a controller configured to:
(a) operate the movement mechanism to position the lower face at the build plane;
(b) operate the light engine to selectively harden a layer of the photocurable resin onto the lower face;
(c) operate the movement mechanism to begin raising the lower face at a specified velocity;
(d) concurrent with (c), receive the signal to monitor the vertical position of the transparent sheet;
(e) determine when the transparent sheet has reached a maximum upward vertical deflection;
(f) determine a magnitude of the maximum upward vertical deflection;
(g) based upon reaching the maximum deflection, lower the lower face by a vertical distance based upon a magnitude of the maximum upward vertical deflection;
(h) repeat step (b); and
(i) continue monitoring the signal and operating the movement mechanism and light engine to complete fabrication of the 3D article.
2 . The three-dimensional (3D) printing system of claim 1 wherein the controller is further configured to determine the specified velocity based at least in part upon a mechanical property of a cured state of the photocurable resin, the mechanical property is based upon one or more of an elastic modulus and a yield strength.
3 . The three-dimensional (3D) printing system of claim 2 wherein the controller is further configured to receive a signal indicative of a viscous force being exerted by the lower face upon the transparent sheet, the specified velocity is based at least in part upon the viscous force.
4 . The three-dimensional (3D) printing system of claim 1 wherein between steps (c) and (g) the controller is configured to operate the movement mechanism to halt vertical motion when the transparent sheet has reached a maximum upward deflection.
5 . The three-dimensional (3D) printing system of claim 1 wherein the light engine is activated in step (h) in less than 500 milliseconds after vertical motion of step (g) has stopped.
6 . The three-dimensional (3D) printing system of claim 1 wherein the light engine is activated in step (h) in less than 200 milliseconds after vertical motion of step (g) has stopped.
7 . The three-dimensional (3D) printing system of claim 1 wherein the light engine includes a light source and a spatial light modulator, a vertical position of the build tray is specified by an encoded coordinate LZ and the controller is further configured to:
store a plurality of data frames individually and uniquely correlated with a single value of LZ;
read LZ when the lower face is positioned at the build plane; and
load a data frame associated with LZ into the spatial light modulator.
8 . A method of manufacturing a three-dimensional (3D) article comprising:
providing a three-dimensional (3D) printing system including:
a resin vessel configured to contain photocurable resin and including a transparent sheet, the transparent sheet having an upper surface defining a lower bound for the photocurable resin;
a build tray to support a 3D article, the build tray or the 3D article defining a lower face;
a movement mechanism coupled to the build tray;
a sensor configured to output a signal indicative of a vertical position of the transparent sheet; and
a light engine configured to image a build plane that is proximate the upper surface of the transparent sheet;
operating the movement mechanism to position the lower face at the build plane;
operating the light engine to selectively harden a layer of the photocurable resin onto the lower face;
operating the movement mechanism to begin raising the lower face at a specified velocity;
concurrent with operating the movement mechanism, receiving the signal to monitor the vertical position of the transparent sheet;
concurrent with receiving the signal, determining when the transparent sheet has reached a maximum upward vertical deflection;
determining a magnitude of the maximum upward vertical deflection;
lower the lower face by a vertical distance based upon a magnitude of the maximum upward vertical deflection;
operate the light engine to selectively harden a layer of the photocurable resin onto the lower face; and
repeat operating the movement mechanism and light engine until the 3D article fabrication is completed.
9 . The method of claim 8 further including determining the specified velocity based at least in part upon a mechanical property of a cured state of the photocurable resin, the mechanical property is based upon one or more of an elastic modulus and a yield strength.
10 . The method of claim 9 further including receiving a signal indicative of a viscous force being exerted by the lower face upon the transparent sheet, the specified velocity is based at least in part upon the viscous force.
11 . The method of claim 8 further including operating the movement mechanism to halt vertical motion when the transparent sheet has reached a maximum upward deflection.
12 . The method of claim 8 wherein the light engine is activated in less than 500 milliseconds after lowering the lower face by a vertical distance based upon a magnitude of the maximum upward vertical deflection.
13 . The method of claim 8 wherein the light engine is activated in less than 200 milliseconds after lowering the lower face by a vertical distance based upon a magnitude of the maximum upward vertical deflection.
14 . The method of claim 8 wherein the light engine includes a light source and a spatial light modulator, a vertical position of the build tray is specified by an encoded coordinate LZ and further including:
storing a plurality of data frames individually and uniquely correlated with a single value of LZ;
reading LZ when the lower face is positioned at the build plane; and
loading a data frame associated with LZ into the spatial light modulator.
15 . A non-volatile storage media for a three dimensional (3D) printing system, the 3 D printing system including:
a resin vessel configured to contain photocurable resin and including a transparent sheet, the transparent sheet having an upper surface defining a lower bound for the photocurable resin;
a build tray to support a 3D article, the build tray or the 3D article defining a lower face;
a movement mechanism coupled to the build tray;
a sensor configured to output a signal indicative of a vertical position of the transparent sheet; and
a light engine configured to image a build plane that is proximate the upper surface of the transparent sheet;
the non-volatile storage medium storing software instructions that when executed cause a controller to:
(a) operate the movement mechanism to position the lower face at the build plane;
(b) operate the light engine to selectively harden a layer of the photocurable resin onto the lower face;
(c) operate the movement mechanism to begin raising the lower face at a specified velocity;
(d) concurrent with (c), receive the signal to monitor the vertical position of the transparent sheet;
(e) determine when the transparent sheet has reached a maximum upward vertical deflection;
(f) determine a magnitude of the maximum upward vertical deflection;
(g) based upon reaching the maximum deflection, lower the lower face by a vertical distance based upon a magnitude of the maximum upward vertical deflection;
(h) repeat step (b); and
(i) continue repetition of steps among steps (b) to (h) until the 3D article fabrication is completed.
16 . The non-volatile storage media of claim 15 , wherein the controller is further configured to determine the specified velocity based at least in part upon a mechanical property of a cured state of the photocurable resin, the mechanical property is based upon one or more of an elastic modulus and a yield strength.
17 . The non-volatile storage media of claim 16 , wherein the controller is further configured to receive a signal indicative of a viscous force being exerted by the lower face upon the transparent sheet, the specified velocity is based at least in part upon the viscous force.
18 . The non-volatile storage media of claim 15 , wherein between steps (c) and (g) the controller is configured to operate the movement mechanism to halt vertical motion when the transparent sheet has reached a maximum upward deflection.
19 . The non-volatile storage media of claim 15 , wherein the light engine is activated in step (h) in less than 500 milliseconds after vertical motion of step (g) has stopped.
20 . The non-volatile storage media of claim 15 , wherein the light engine includes a light source and a spatial light modulator, a vertical position of the build tray is specified by an encoded coordinate LZ and the controller is further configured to:
store a plurality of data frames individually and uniquely correlated with a single value of LZ;
read LZ when the lower face is positioned at the build plane; and
load a data frame associated with LZ into the spatial light modulator.