CARTRIDGE FOR SOLID IMAGING APPARATUS AND METHOD

• US 20080179786A1
• Filed: 09/17/2007
• Published: 07/31/2008
• Est. Priority Date: 01/17/2007
• Status: Active Grant

• Current Assignee: 3D Systems, Inc. (3D Systems Corporation)
• Original Assignee: 3D Systems, Inc. (3D Systems Corporation)
• Inventors: Hull, Charles W., Sperry, Charles R., Scott, Suzanne M., Mojdeh, Mehdi, Mcnamara, Dennis F., Rittenhour, Jason A.
• Granted Patent: US 8,105,066 B2
• Time in Patent Office: Days
• US Class Current: 264/308
• CPC Class Codes: B29C 64/112 using individual droplets, e.g. from jetting heads
• CPC Class Codes: B29C 64/124 using layers of liquid which are selectively solidified
• CPC Class Codes: B29C 64/35 Cleaning
• CPC Class Codes: B29C 64/357 Recycling
• 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

Abstract

A solid imaging apparatus is provided that includes a replaceable cartridge containing a source of build material and an extendable and retractable flexible transport film for transporting the build material layer-by-layer from the cartridge to the surface of a build in an image plane. An operator using the device needs merely to remove a spent cartridge and replace it with a fresh cartridge to continue solid imaging virtually uninterrupted. The apparatus also includes the capability of withdrawing and inserting an imager without the operator having to perform a separate alignment step. A brush attached to the transport film and forming part of the cartridge provides for intra-layer removal of excess uncured build material. If desired, the apparatus can produce a fully reacted build. A high intensity UV source cures the build between layers. An injection molded build pad is designed to hold a build in an inverted position for improving the build. The invention also provides for tilting the build elevator to reduce air entrainment and for releasing the build from the image plane.

Claims

1. Apparatus for supplying build material to an image plane in a solid imaging device, said apparatus comprising a cartridge containing a source of build material, a reciprocating build material transport surface in said cartridge and alternately extendable and retractable therefrom, said transport surface in coating communication with said source for receiving a layer of build material thereon and conveying the build material layer-by-layer to an image plane exterior of said cartridge;

and an alternately sealed opening in said cartridge through which said transport surface alternately extends and retracts.

2. The apparatus of claim 1 further comprising a scraper located in said cartridge in scraping contact with said transport surface for removing excess uncured build material therefrom and returning it to said source in said cartridge for reuse.

3. The apparatus of claim 1 further comprising a cleaning assembly fixed to said transport surface at a leading edge thereof and alternately extendable and retractable with said transport surface.

4. The apparatus of claim 3 wherein said cartridge further comprises a cartridge housing sealed against solid imaging radiation ingress and build material egress.

5. The apparatus of claim 3 wherein said cleaning assembly comprises a housing mounted to said transport surface at a leading edge thereof, said housing containing a brush for removing excess uncured build material from the surface of a build, said brush housing further comprising one or more seals for engaging said cartridge housing substantially to preclude solid imaging radiation ingress upon retraction of said brush housing and transport surface into said cartridge.

6. The apparatus of claim 5 wherein said brush is a rotary brush for spinning contact with the surface of a build to remove excess uncured build material.

7. The apparatus of claim 6 wherein said brush is a rotary brush for spinning inside the cartridge to propel from the brush excess uncured build material and said brush housing comprises splash guards to contain said propelled excess uncured build material and a seal to preclude ultraviolet radiation from entering said cartridge.

8. The apparatus of claim 1 wherein said transport surface is a flexible film transmissive to solid imaging radiation.

9. The apparatus of claim 1 wherein said transport surface comprises a film selected from the group of films prepared from silicone, poly (propylene), poly (carbonate), fluorinated ethylene propylene, polytetrafluorethylene, and mixtures and co-polymers thereof.

10. The apparatus of claim 1 wherein said alternately extendable and retractable transport surface comprises a flexible film and said apparatus further comprises a chassis frame and a contact roller carried by said chassis frame about which said film alternately extends and retracts.

11. The apparatus of claim 10 further comprising an applicator carried by said chassis frame adjacent said contact roller for applying a layer of build material to said transport surface.

12. The apparatus of claim 11 wherein said applicator comprises a reservoir for build material and a coating roller in coating contact with said reservoir, said reservoir and said coating roller carried by said chassis frame adjacent said contact roller for applying a layer of build material to said transport surface.

13. The apparatus of claim 11 wherein said cartridge comprises a cartridge housing defining an upper section for said chassis, said contact roller, and said applicator, and said cartridge housing defines a lower section comprising a first wetted chamber for storage of build material, a second dry chamber for storage of said transport surface in a retracted condition, and a third chamber for a pump for pumping build material from said first wetted chamber to said applicator.

14. The apparatus of claim 13 further comprising a plurality of passages between said upper section and said wetted first chamber for build material and a rotary gate valve for controlling flow of build material.

15. The apparatus of claim 14 further comprising a filter in said wetted first chamber adjacent said pump for removing solids from the build material.

16. Apparatus of claim 13 further comprising a coupling mounted to said contact roller for engaging a retraction motor in a solid imaging device and another coupling mounted to said coating roller for engaging a coating motor in a solid imaging device when said cartridge is inserted into said device.

17. Apparatus of claim 13 wherein said pump is a diaphragm pump and said apparatus further comprises a fitting for said pump adapted to engage a source of air in a solid imaging device.

18. Apparatus for supplying build material to an image plane in a solid imaging device, said apparatus comprising:

a) a housing having a lid and upper and lower sections, wherein said lower section comprises a first wetted chamber containing flowable build material, a second dry chamber, and a third pumping chamber containing a diaphragm pump in flow communication with said first wetted chamber, and wherein said upper section comprises an elongate lateral slot through which build material is supplied to an image plane layer-by-layer;

b) a build material applicator in said upper section of said housing in flow communication with said diaphragm pump, said applicator comprising a reservoir into which said pump pumps the build material from said first wetted chamber and a roller in coating communication with said reservoir for receiving the build material on said coating roller;

c) a conveyor adjacent said build material applicator for receiving a layer of build material from said applicator and conveying said build material layer-by-layer to an image plane in a solid imaging device through said elongate lateral slot, said conveyor comprising;

i) an extendable and retractable flexible transport film,

ii) a roller over which said film passes in contact with said roller; and

iii) a drive coupling mounted axially on said contact roller axial shaft at one end of said shaft for driving said contact roller to retract said film from an extended position;

d) a frame for mounting said contact roller, said reservoir, and said coating roller, said frame comprising a pair of laterally opposed and longitudinally extending legs extending into said second dry chamber of said lower section of said housing and having said contact roller mounted to said legs at an end of said legs located in said upper section of said housing, said contact roller having an axial shaft extending at opposite ends thereof through each of said legs for mounting said contact roller in said frame in said upper section, said frame further comprising a follower rod for providing tension to said film for extending and retracting said film, wherein said film is fixedly attached at one end thereof to said frame adjacent said roller opposite said film contact of said roller, said film extending from said fixed attachment around said follower rod to said contact roller and over said contact roller to said elongate lateral housing slot, said frame providing an elongate longitudinal frame slot in each leg for supporting said follower rod and retract straps adjacent each said frame slot mounted at one end to said follower rod and at the other to said contact roller axial shaft and traveling therebetween about an idler rod for providing travel of said rod in said slot as said contact roller extends and retracts said film, and wherein said film is attached at its end opposite said fixed end to a cleaning assembly for removing excess uncured build material from a build between layers, said cleaning assembly comprising;

i) a roller brush mounted in a housing for rotating contact with an imaged build surface,

ii) an actuatable seal for sealing said cleaning assembly in said housing lateral slot, thereby precluding ingress of ultraviolet and visible radiation and egress of build material, and

iii) a motor mount fixed to said housing for attachment to drives in an imaging device for rotating said brush and extending said cleaning assembly and said film across an image plane, whereby when retracted said film extends in said first dry chamber of said housing substantially coextensive with said frame legs and said cleaning assembly seals against said housing, and when extended said film travels through said upper section of said housing and out said elongate lateral housing slot.

19. A method for solid imaging comprising the steps of:

a) inserting a cartridge containing a transport surface and a source of solid imaging build material into a solid imaging apparatus

b) engaging the cartridge and apparatus in cooperating relation for extending the transport surface, applying a layer of solid imaging build material to the transport surface, retracting the transport surface, and removing and reusing excess uncured build material remaining on the transport surface; and

b) performing solid imaging with the cooperating cartridge and apparatus.

20. The method of claim 19 wherein the step of engaging the cartridge and apparatus in cooperating relation comprises:

a) attaching drive couplings in the cartridge with drive motors in the apparatus for extending the transport surface and applying a layer of solid imaging build material to the transport surface;

b) attaching an air supply in the apparatus to a diaphragm pump in the cartridge;

c) attaching the transport surface to a drive motor in the apparatus for extending the transport surface; and

d) turning a valve on the cartridge for pumping of the build material.

21. The method of claim 20 further comprising the step of continually pumping and filtering build material within the cartridge when the cartridge is inserted into the apparatus to provide a homogeneous build material.

22. A method for removing and recovering excess uncured build material from the surface of a build having a layer of solid image build material solidified thereon, said method comprising the steps of contacting the surface of the build with a cleaning assembly to remove excess uncured build material, removing the excess uncured build material from the cleaning assembly, and recovering the excess uncured build material from the cleaning assembly for reuse.

23. The method of claim 22 wherein the step of removing excess uncured build material from the build surface with a cleaning assembly comprises contacting the surface of the build with a rotating brush.

24. The method of claim 23 wherein the step of removing the excess uncured build material from the cleaning assembly comprises spinning the brush at from about 3,000 to 6,000 rpm'"'"'s.

25. The method of claim 24 wherein the step of recovering the excess uncured build material from the cleaning assembly for reuse comprises introducing the excess uncured build material into a source thereof and filtering the source containing the excess.