Method and apparatus for rapid freezing prototyping

• US 6,253,116 B1
• Filed: 08/04/1998
• Issued: 06/26/2001
• Est. Priority Date: 08/04/1998
• Status: Expired due to Fees

• Current Assignee: New Jersey Institute of Technology
• Original Assignee: New Jersey Institute of Technology
• Inventors: Zhang, Wei, Yan, Yongnian, Ji, Zhiming, Leu, Ming C.
• Primary Examiner(s): Grant, William
• Assistant Examiner(s): Rapp, Chad
• Application Number:
  US09/128,805
• Time in Patent Office: 1,057 Days
• Field of Search: 700/123, 700/119, 700/182
• US Class Current: 700/119
• CPC Class Codes: B29C 33/3857 by making impressions of one or more parts of models, e.g. shaped articles and including possible subsequent assembly of the parts
• CPC Class Codes: B29C 64/106 using only liquids or viscous materials, e.g. depositing a continuous bead of viscous material
• CPC Class Codes: B29C 64/40 Structures for supporting 3D objects during manufacture and intended to be sacrificed after completion thereof
• CPC Class Codes: B33Y 10/00 Processes of additive manufacturing
• 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 40/20 Post-treatment, e.g. curing, coating or polishing
• CPC Class Codes: B33Y 50/02 for controlling or regulating additive manufacturing processes

Abstract

A method and apparatus for forming three-dimensional patterns by depositing a crystalloid material onto substrate in a layer by layer fashion. The apparatus includes a computer responsive for controlling the material depositing rate and the three-dimensional relative movement between the depositing head and the substrate. The controlling information comes from the sliced CAD model of the part. For each cross-section, the depositing head plots the boundary and the interior while the building material comes out of the head. The crystalloid material deposited on the substrate or previous layer of the part rapidly freezes forming a new layer of the part. The material can be deposited by a continuous extruding device or a drop-on-demand device. Where necessary, support structure is built in the same way but with material of a different melting point. The ambient temperature is accurately controlled to a certain low point in order to make the deposited material flow to a certain extent and freeze after a short time. The preferred crystalloid material is water or brine which does not pollute the environment. However, the invention encompasses the use of other crystalloid materials.

Claims

1. A system for use in rapid freezing prototyping, using at least two crystalloid materials capable of transitioning between liquid and solid states at a threshold temperature, said system comprising:

a material supply subsystem and a material deposition subsystem in fluid communication with said supply subsystem;

a three-dimensional spatial positioning subsystem connected to said material deposition subsystem and operative to position said material deposition subsystem at a plurality of points within a predetermined region; and

a freezing chamber having an interior region defining said predetermined region;

whereby said material supply subsystem directs said material in said liquid state to said material deposition subsystem;

said positioning subsystem adapted to position said material deposition subsystem at one of said points;

said material deposition subsystem adapted to maintain said material at least one liquid state temperature proximate to said threshold temperature and depositing said material within said freezing chamber;

said chamber causing said material to have a solid state temperature by lowering the temperature of said material from said liquid state through said threshold temperature to said solid state temperature; and

said material supply subsystem is adapted to supply a first and second crystalloid material having a first and second threshold temperatures respective; and

said material deposition subsystem is adapted to maintain said first material at a first liquid state temperature and said second material at a second liquid state temperature;

such that said two crystalloid materials form first and second layers respectively.

2. The system of claim 1 including a computer having a computer-aided-design program operatively connected to control said material supply and deposition subsystems;

said positioning subsystem and said freezing chamber thereby automatically forming said at least one layer.

3. The system of claim 2 wherein said computer causes sufficient material to be deposed to form a prototype.

4. The system of claim 1 including a support removal subsystem for removing at least one layer from said freezing chamber.

5. The system of claim 1 for use with first and second materials having first and second colors wherein:

said spatial positioning subsystem cooperates with said material deposition subsystem to form a first layer of said first color and a second layer of said second color.

6. The system of claim 1 for use with said first and second materials having said first and second threshold temperatures respectively where said first threshold temperature is greater than said second threshold temperature said system including:

a support removal subsystem for removing said at least one layer from said freezing chamber by raising said solid state temperature to be greater than said second threshold temperature and less than said first threshold temperature;

such that said second material is returned to said liquid state.

7. A method of rapid freezing prototyping using a system having a material supply subsystem, a spatial positioning subsystem, a freezing chamber, a material deposition subsystem in fluid communication with said material extrusion subsystem with at least one crystalloid material capable of transitioning between liquid and solid states at a threshold temperature, said method comprising the steps of:

directing said material in said liquid state through said material supply subsystem to said material deposition subsystem;

maintaining said material in said material deposition subsystem at least one liquid state temperature proximate to said threshold temperature positioning said material deposition subsystem with said material using said spatial positioning system;

depositioning said material within said freezing chamber;

lowering said material in said chamber from said liquid states temperature through said threshold temperature to a solid state temperature thereby forming said material into at least one layer of material;

wherein said material supply subsystem is adapted to supply a first and second crystalloid material having a first and second threshold temperatures respective; and

said material deposition subsystem is adapted to maintain said first material at a first liquid state temperature and said second material at a second liquid state temperature;

such that said two crystalloid materials form first and second layers respectively.

8. The method of claim 7 including the steps of:

removing said at least one layer from said freezing chamber by means of a support removal subsystem

casting a mold from said at least one layer by means of a cold casting assembly.

9. The method of claim 7 wherein said steps of directing, maintaining, positioning, depositing and lowering are repeated sequentially in a predetermined number of cycles;

and

said positioning step includes moving incrementally said material deposition subsystem a predetermined distance during each of said cycles to form a plurality of layers;

such that said layers in combination form a prototype.

10. The method of claim 9 wherein said moving step moves said material deposition subsystem in a continuous manner with said depositioning step so as to cause said plurality of layers to be a continuous extrusion which over many cycles forms said prototype.

11. The method of claim 9 including the step of assembling said plurality of layers to form said prototype.

12. The method of claim 9 wherein said moving step moves said material deposition subsystem in discrete increments in sequence with said depositioning step so as to cause said plurality of layers to be formed from discrete droplets which over many cycles forms said prototype.