Rapid prototyping and manufacturing system and method

• US 20070075458A1
• Filed: 09/30/2005
• Published: 04/05/2007
• Est. Priority Date: 09/30/2005
• Status: Active Grant

• Current Assignee: 3D Systems, Inc. (3D Systems Corporation)
• Original Assignee: 3D Systems, Inc. (3D Systems Corporation)
• Inventors: Wahlstrom, Ben, Hunter, Don
• Granted Patent: US 7,585,450 B2
• Time in Patent Office: Days
• US Class Current: 264/401
• CPC Class Codes: B22F 10/12 by photopolymerisation, e.g. stereolithography [SLA] or digital light processing [DLP]
• CPC Class Codes: B22F 10/36 of energy beam parameters
• CPC Class Codes: B22F 12/38 Housings, e.g. machine housings
• CPC Class Codes: B22F 12/44 characterised by the configuration of the radiation means
• CPC Class Codes: B22F 12/49 Scanners
• CPC Class Codes: B22F 12/67 Blades
• CPC Class Codes: B22F 12/84 Parallel processing within single device
• CPC Class Codes: B22F 12/90 Means for process control, e.g. cameras or sensors
• CPC Class Codes: B29C 64/135 the energy source being concentrated, e.g. scanning lasers or focused light sources
• CPC Class Codes: B29C 64/182 in parallel batches
• CPC Class Codes: B33Y 30/00 Apparatus for additive manufacturing; Details thereof or accessories therefor
• CPC Class Codes: B33Y 40/00 Auxiliary operations or equipment, e.g. for material handling
• CPC Class Codes: B33Y 50/02 for controlling or regulating additive manufacturing processes
• CPC Class Codes: Y02P 10/25 Process efficiency

Abstract

A stereolithography apparatus having a resin vat with resupply containers in one-way flow communication and a leveling container in two-way flow communication, an automatic offload cart to remove and replace build support platforms, an elevator assembly for supporting and releasably retaining a build platform removably attached to the stereolithography apparatus frame such that elevator forks supporting the build platform can be released into the vat and removed from the stereolithography apparatus with the vat, and a recoater assembly and recoater blade for mapping the resin surface in the vat and applying a fresh coating of resin to a cross-section being built in the vat.

Claims

1. A stereolithography apparatus comprising a longitudinally extending recoater and a carrier for said recoater, and wherein said recoater has a blade body with front and back surfaces and top and bottom surfaces, a foot for sensing blade gap at each end of said blade body extending laterally outward from said front surface thereof and having a flat bottom surface level with the bottom surface of said blade body and a top surface tapering distally from said blade to a thinned-down blade gap sensing portion of said top surface of said foot, whereby a sensor in sensing communication with said sensing portion of said foot can sense the distance of the top of said foot from a liquid resin surface.

2. Stereolithography apparatus according to claim 1 wherein said recoater is a vacuum assisted recoater and further comprises a vacuum channel extending longitudinally along said bottom surface of said blade body for contact with a resin surface, a sight window on said back surface of said blade for viewing resin pulled by vacuum into said vacuum channel, and a vacuum port for engaging a source of vacuum.

3. Stereolithography apparatus according to claim 2 wherein said vacuum port is a flexible vacuum cup for receiving a vacuum connection.

4. Stereolithography apparatus according to claim 1 wherein said recoater is adapted for attachment by hand and in the absence of tools to a carrier for said recoater, one or both of said recoater blade body and carrier further comprising at least two magnets spaced along the front surface thereof for attachment of the recoater to said carrier, at least two handles extending laterally outward from said back surface of said recoater blade body for hand attachment to said carrier, and alignment pins and corresponding channels located one on said recoater blade body and one on said carrier for aligning engagement of said recoater and carrier.

5. Stereolithography apparatus according to claim 1 wherein said carrier comprises contacts for said recoater and a proximity switch cooperating with said contacts for confirming positional alignment of said recoater on said carrier.

6. Stereolithography apparatus according to claim 1 further comprising a first sensor translatably secured to said carrier for transport along the length of said recoater blade to determine the distance of said blade gap sensing feet from the surface of the resin at a plurality of points in the direction of travel of said recoater.

7. A method for stereolithography by which three-dimensional objects are produced from liquid resin by alternately applying laser energy to the uncured resin surface to at least partially cure the resin surface, recoating the at least partially cured resin surface with uncured resin, and repeating alternately applying energy and recoating to build the objects layer-by-layer in accordance with a predetermined object representation, said method comprising, prior to applying laser energy to the uncured resin surface, establishing a predetermined blade gap for a recoater and storing the predetermined blade gap in a controller, determining the distance between the bottom of the recoater and the resin surface at each end of the recoater at a plurality of points throughout the length of travel of the recoater and storing the determined distances in a controller, and during recoating, controlling the blade gap in response to the stored predetermined blade gap throughout the length of travel of the recoater and maintaining the recoater parallel to the resin surface throughout its length of travel at the predetermined blade gap.

8. A method according to claim 7 wherein the step of determining the distance between the bottom of the recoater and the resin surface at each end of the recoater at a plurality of points throughout the length of travel of the recoater comprises sensing the distance of a sensor from a first sensing location adjacent an end of the recoater to the resin surface, sensing the distance of the sensor from an adjacent second sensing location to a top surface of the recoater, determining the distance from the top surface to the bottom surface of the recoater, determining the distance between the bottom surface of the recoater and the surface of the resin, and repeating the sensing and determining steps at each end of the recoater at a plurality of points throughout the length of travel of the recoater.

9. A method according to claim 8 wherein the first and second sensing locations are immediately adjacent each other and wherein the top surface of the recoater is the top surface of a thinned down portion of a blade gap sensing foot extending laterally from the recoater at each end thereof and the bottom surface is the bottom of the foot.

10. A method for recoating a layer of at least partially cured resin in a stereolithography apparatus having a recoater, said method comprising the step of adjusting the height of each end of the recoater above the resin surface throughout the length of travel of the recoater at the predetermined blade gap, thereby to maintain the recoater parallel throughout its length of travel across the resin surface.

11. A method for keeping a recoater parallel with a resin surface in a stereolithography apparatus, said method comprising the step of rotating the recoater about a central axis thereof along the direction of travel of the recoater across the resin surface.