Method and apparatus for producing a stepless 3-dimensional object by stereolithography

• US 5,217,653 A
• Filed: 02/13/1992
• Issued: 06/08/1993
• Est. Priority Date: 02/18/1991
• Status: Expired due to Fees

• Current Assignee: Gleb A. Abakumov, Jackov Tuchinsky, Leonid Mashinsky, Sergei A. Chesnokov, Sergey L. Novoshilov, Vadim N. Dzegilenok, Valery A. Zaitsev, Vladimir A. Murayev, Vladimir D. Tihonov, Vladimir K. Cherkasov
• Original Assignee: Gleb A. Abakumov, Jackov Tuchinsky, Leonid Mashinsky, Sergei A. Chesnokov, Sergey L. Novoshilov, Vadim N. Dzegilenok, Valery A. Zaitsev, Vladimir A. Murayev, Vladimir D. Tihonov, Vladimir K. Cherkasov
• Inventors: Abakumov, Gleb A., Murayev, Vladimir A., Cherkasov, Vladimir K., Dzegilenok, Vadim N., Novoshilov, Sergey L., Chesnokov, Sergei A., Tihonov, Vladimir D., Mashinsky, Leonid, Zaitsev, Valery A., Tuchinsky, Jackov
• Primary Examiner(s): HEITBRINK, JILL LYNNE
• Application Number:
  US07/834,699
• Time in Patent Office: 481 Days
• Field of Search: 264/22, 264/40.1, 264/25, 264/308, 425/174, 425/174.4, 219/121.25, 219/121.28, 219/121.29, 219/121.79, 219/121.8, 156/273.3, 156/273.5, 156/275.5
• US Class Current: 264/401
• CPC Class Codes: B29C 64/135 the energy source being concentrated, e.g. scanning lasers or focused light sources
• 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

Abstract

A method and apparatus for producing a stepless 3-dimensional object by stereolithography, wherein a mathematical representation of the object is stored and dissected so as to generate a mathematical representation of a first laminate thereof, and a representative slope of the side wall surface of the first laminate at a plurality of different coordinates along the side wall surface is determined. The height of the first laminate is optimized by increasing the height whilst minimizing any deviation between the representative slope and the mathematical representation of the side wall surface. The liquid medium is irradiated with a beam of radiation at an angle representative of the uniform slope, and the irradiated liquid medium is allowed to polymerize and harden. The cured laminate is displaced relative to a surface of the liquid, and the process is repeated as required in respect of subsequent contiguous laminates. The apparatus includes a carriage having four degrees of freedom of movement for directing an optical fiber towards the liquid medium at a predetermined angle equal to the representative slope of the side wall.

Claims

1. A method for producing a stepless 3-dimensional object formed of a plurality of contiguous laminates each having a respective height and side wall surface and produced by stereolithographically polymerizing a liquid medium, said method comprising the steps of:

(a) storing a mathematical representation of said object,

(b) dissecting the mathematical representation so as to generate a mathematical representation of a first laminate thereof having an upper and lower base bound by an interconnecting side wall surface formed by a generatrix having a predetermined angle to said base for each point along a periphery of said base,

(c) determining a representative slope of the side wall surface of the first laminate for each of said points,

(d) optimizing the height of said first laminate by increasing the height whilst minimizing any deviation between the representative slope determined in (c) and the mathematical representation of the side wall surface,

(e) irradiating said liquid medium with a beam of radiation at an angle equal to said representative slope,

(f) allowing the irradiated liquid medium to polymerize and harden,

(g) displacing the first laminate relative to a surface of the liquid, and

(h) repeating steps (b) to (g) as required in respect of subsequent contiguous laminates.

2. The method according to claim 1, wherein at least one of said laminates is polymerized along its side wall surface only whereby said at least one laminate is rendered hollow thereby decreasing the resulting mass of said 3-dimensional object.

3. The method according to claim 2, further including the step of forming at least one reinforcing rib integral with said at least one laminate so as to render the 3-dimensional object more rigid.

4. The method according to claim 1, further including the step of irradiating the liquid medium normal to a base of each laminate with a flux of parallel space modulated radiation.

5. The method according to claim 1, wherein step (g) comprises:

displacing the first laminate relative to a lower inside surface of a vessel containing therein a volume of said liquid medium so as to maintain a distance between said lower inside surface and a lower surface of the first laminate equal to the height of a successive laminate, and

adjusting the volume of the liquid medium in said vessel such that an upper surface of the liquid medium is level with the lower surface of said first laminate.

6. An apparatus for producing a stepless 3-dimensional object formed of a plurality of contiguous laminates each having a respective height and side wall surface inclined in respect to a vertical and being produced by stereolithographically polymerizing a liquid medium, the system comprising:

storage means for storing therein a geometrical model of said 3-dimensional object,

a vessel for storing therein said liquid medium,

a source of radiation for producing a beam of radiation,

laminate generating means coupled to the storage means for generating laminates each having upper and lower bases bound by an interconnecting side wall surface inclined in respect to a vertical and being formed by a generatrix having a predetermined angle to said bases for each point along a periphery of said bases,

directing means coupled to the laminate generating means for directing said beam of radiation towards said vessel so as to strike the liquid medium at said predetermined angle for each of said points,

supporting means for supporting said object, and

displacing means for displacing the object relative to the vessel so that a lowermost surface of the object is contiguous with each successively irradiated laminate.

7. The apparatus according to claim 6, wherein the directing means has four degrees of freedom.

8. The system according to claim 7, wherein the directing means comprises:

a carriage,

independent drive means coupled to the carriage for effective translational movement thereof in two mutually perpendicular directions in a predetermined plane,

a platform mounted on the carriage and rotatable about a first axis perpendicular to said plane,

a drive shaft mounted on the platform and rotatable about a second axis perpendicular to said first axis, and

flexible waveguide means secured to said drive shaft for directing said beam of irradiation from a first end of the waveguide means proximate said source of irradiation to a second end of the waveguide means proximate said vessel.

9. The apparatus according to claim 8, wherein said beam of irradiation is visible light and said waveguide means is an optical fiber.

10. The apparatus according to claim 6, further including a subsidiary source of radiation for producing space-modulated parallel irradiation which is directed normal to a lower surface of the vessel within the periphery of said lower base.

11. The apparatus according to claim 6, wherein the liquid medium has a depth equal to a height of said laminate between the lower and upper bases thereof, said lowermost surface of the object being contiguous with an upper surface of the liquid medium.

12. An apparatus for producing a stepless 3-dimensional object formed of a plurality of contiguous laminates each having a respective height and side wall surface and produced by stereolithographically polymerizing a liquid medium, the system comprising:

storage means for storing therein a geometrical model of said 3-dimensional object,

a vessel for storing therein said liquid medium,

a source of radiation for producing a beam of radiation,

laminate generating means coupled to the storage means for generating said laminates each having upper and lower bases bound by an interconnecting side wall surface formed by a generatrix having a predetermined angle to said bases for each point along a periphery of said bases,

directing means coupled to the laminate generating means for directing said beam of radiation towards said vessel so as to strike the liquid medium at said predetermined angle for each of said points,

supporting means for supporting said object, and

displacing means for displacing the object relative to the vessel so that a lowermost surface of the object is contiguous with each successively irradiated laminate, wherein the directing means has four degrees of freedom.

13. The apparatus according to claim 12, wherein the directing means comprises:

a carriage,

independent drive means coupled to the carriage for effective translational movement thereof in two mutually perpendicular directions in a predetermined plane,

a platform mounted on the carriage and rotatable about a first axis perpendicular to said plane,

a drive shaft mounted on the platform and rotatable about a second axis perpendicular to said first axis, and

flexible waveguide means secured to said drive shaft for directing said beam of irradiation from a first end of the waveguide means proximate said source of irradiation to a second end of the waveguide means proximate said vessel.

14. The apparatus according to claim 13, wherein said beam of irradiation is visible light and said waveguide means is an optical fiber.

15. The apparatus according to claim 12, further including a subsidiary source of radiation for producing space-modulated parallel irradiation which is directed normal to a lower surface of the vessel within the periphery of said lower base.

16. The apparatus according to claim 12, wherein the liquid medium has a depth equal to a height of said laminate between the lower and upper bases thereof, said lowermost surface of the object being contiguous with an upper surface of the liquid medium.