Systems and methods for resin recovery in additive manufacturing

Patent metadata

Field	Value
Publication number	US-11731345-B2
Application number	US-202217569641-A
Country	US
Kind code	B2
Filing date	Jan 6, 2022
Priority date	Jan 7, 2019
Publication date	Aug 22, 2023
Grant date	Aug 22, 2023

Abstract

A method of producing multiple batches of objects by stereolithography, includes the steps of: (a) dispensing an initial or subsequent batch of dual cure resin into a stereolithography apparatus, the resin including a light polymerizable component and a heat polymerizable component; (b) producing an intermediate object by light polymerization of the resin in the apparatus, wherein the intermediate object retains excess resin on a surface thereof; then (c) separating excess resin from the intermediate object; (d) blending the excess resin with additional dual cure resin to produce a subsequent batch of dual cure resin; (e) repeating steps (a) through (c), and optionally repeating step (d), to produce additional object(s); and (f) baking the objects, together or separately, to produce multiple batches of objects.

First claim

We claim:

1. A method of producing multiple batches of objects by stereolithography, comprising the steps of:
(a) dispensing an initial or subsequent batch of dual cure resin into a stereolithography apparatus, said resin comprising a light polymerizable component and a heat polymerizable component;
(b) producing an intermediate object by light polymerization of said resin in said apparatus, wherein said intermediate object retains excess resin on a surface thereof after said producing said intermediate object, and wherein said stereolithography apparatus is a bottom up stereolithography apparatus; then
(c) separating excess resin from said intermediate object, wherein said separating step is carried out by centrifugal separation;
(d) blending said excess resin with additional dual cure resin to produce a subsequent batch of dual cure resin, said blending carried out in a blender;
(e) repeating steps (a) through (c), and optionally repeating step (d), to produce additional object(s); and
(f) baking said objects, together or separately, to produce multiple batches of objects, wherein said repeating step (e) comprises transferring said subsequent batch of dual cure resin from said blender to a resin dispenser for said dispensing step (a).

2. The method of claim 1 , wherein said polymerizing or light polymerization is exothermic.

3. The method of claim 1 , wherein steps (a) through (c) are repeated at least twice and step (d) is repeated at least once.

4. The method of claim 1 , wherein said objects comprise an open lattice.

5. The method of claim 1 , wherein said objects comprise dental models.

6. The method of claim 1 , wherein excess resin is retained on said intermediate object in an amount by weight of at least 40 percent as compared to the weight of said intermediate object.

7. The method of claim 1 , wherein excess resin is blended with additional dual cure resin in a volume ratio of from 10:90 up to 60:40 (excess resin:additional dual cure resin).

8. The method of claim 1 , wherein said excess resin is free of wash liquid in said blending step.

9. The method of claim 1 , said excess resin of step (b) having a viscosity greater than that of said dual cure resin of step (a), and said subsequent batch of dual cure resin of step (d) having a viscosity less than that of said excess resin.

10. The method of claim 1 , wherein said initial batch and subsequent batches of dual cure resin have a viscosity of from 1,000 to 100,000 centipoise at 25 degrees centigrade.

11. The method of claim 1 , wherein said excess dual cure resin of step (b) has a viscosity at least 1,000 centipoise greater (or 10 percent greater) than that of said dual cure resin of step (a).

12. The method of claim 1 , wherein said resin comprises a polyurethane, cyanate ester, epoxy, or silicone dual cure resins.

13. The method of claim 1 , wherein:
said initial batch of dual cure resin has a unique identifier assigned thereto;
said blending step further comprises assigning a unique identifier to each subsequent batch of dual cure resin; and
said producing step further comprises: (i) assigning a unique identifier to each object;
and (ii) recording the unique identifier of the batch of resin from which each object is produced.

14. The method of claim 13 , further comprising the step of:
(g) determining and comparing at least one physical property of objects produced from different batches of resin (for example, to ensure uniformity or consistency of objects within a given tolerance even though produced from different resin batches).

15. The method of claim 14 , wherein said determining and comparing step further comprises: (i) determining the unique identity of each said object, and (ii) retrieving the unique identity of the resin batch recorded for said object.

16. The method of claim 1 , further comprising, before the separating step, mounting a build platform on which said intermediate object is retained on a rotor in a chamber or securing said intermediate object to retention members in the chamber.

Assignees

• Carbon Inc

Inventors

• Converse Courtney F
• Light Allison
• Powell W Ryan
• Wojtaszek Mateusz Marek

Classifications

• B29C64/124 Primary

  using layers of liquid which are selectively solidified · CPC title

• B29C64/176

  Sequentially · CPC title

• B29C64/357 Primary

  Recycling · CPC title

• B29C64/393

  for controlling or regulating additive manufacturing processes · CPC title

• B33Y10/00

  Processes of additive manufacturing · CPC title