# US 12,214,553 B2 · System for window separation in an additive manufacturing process

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- Number: US 12,214,553 B2
- Document ID: US12214553B2
- Status: Granted
- Kind: B2
- Application number: 17/965,699
- Filed: 2022-10-13
- Published: 2023-02-02
- Granted: 2025-02-04
- Earliest claimed: 2018-11-01
- Assignees: Stratasys, Inc.
- Applicants: Stratasys, Inc.
- Inventors: Christopher Prucha; Joel Ong; John Paton
- Web page: https://patentgrep.com/patent/US12214553B2

## CPC

- B29C 64/364: Conditioning of environment
- B01D 63/081: {Manufacturing thereof}
- B01D 71/32: containing fluorine atoms
- B29C 64/135: the energy source being concentrated, e.g. scanning lasers or focused light sources
- B29C 64/245: Platforms or substrates (support structures intended to be sacrificed after manufacture B29C64/40)
- B29C 64/25: Housings, e.g. machine housings
- B29C 64/255: Enclosures for the building material, e.g. powder containers
- B29C 64/379: Handling of additively manufactured objects, e.g. using robots
- B33Y 10/00: Processes of additive manufacturing
- B33Y 30/00: Apparatus for additive manufacturing; Details thereof or accessories therefor
- B01D 2313/203: Open housings
- B29C: SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING (making preforms B29B11/00; making laminated products by combining previously unconnected layers which become one product whose layers will remain together B32B37/00 - B32B41/00)
- B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28)
- B33Y: ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING

## Abstract

An additive manufacturing system including a base assembly and a tray assembly. The base assembly includes a build window, substantially transparent to electromagnetic radiation; a projection system configured to project electromagnetic radiation toward an upper surface of the build window; and a tray seat arranged around a perimeter of the build window. The tray assembly is configured to engage with the base assembly in an engaged configuration and includes: a tray structure defining a registration feature configured to engage the tray seat to locate an aperture proximal to the upper surface of the build window in the engaged configuration; and a separation membrane that is configured to laminate across the upper surface of the build window in response to an evacuation of gas from an interstitial region and configured to separate from the build window in response to injection of gas into the interstitial region.

## Claims

### Claim 1

An additive manufacturing system comprising:
a build window:
facing a projection system;
defining a lamination surface opposite the projection system; and
configured to pass radiation, emitted by the projection system, through the lamination surface; and
a tray assembly comprising:
a tray:
comprising a perimeter support edge inwardly offset from an outer edge of the tray and defining an aperture; and
configured to locate over and engage the build window with the aperture arranged about the build window and with the perimeter support edge offset above the lamination surface; and
a separation membrane:
extending across the aperture;
tensioned over and against the perimeter support edge;
operable in:
a laminated position, the separation membrane laminated against the lamination surface, below the perimeter support edge, in the laminated position, responsive to evacuation of fluid from an interstitial region between the separation membrane and the lamination surface, to form a build surface offset below the perimeter support edge, and the perimeter support edge offset above the lamination surface by a first height in the laminated position; and
an expanded position, the separation membrane forming a convex geometry offset above the perimeter support edge and offset above the lamination surface, in the expanded position to promote separation of the separation membrane from a layer of a resin polymerized over the build surface via radiation emitted by the projection system, and the perimeter support edge offset above the lamination surface by the first height in the expanded position;
a fluid distribution port fluidly coupled to the interstitial region; and
a fluid distribution channel circumscribing the build window and intersecting the fluid distribution port.

### Claim 2 (depends on 1)

The additive manufacturing system of claim 1:
wherein the separation membrane forms the convex geometry offset above the lamination surface in the expanded position responsive to pumping of fluid into the interstitial region between the separation membrane and the lamination surface.

### Claim 3 (depends on 1)

The additive manufacturing system of claim 1:
further comprising a second tray assembly comprising:
a second tray:
comprising a second perimeter support edge defining a second aperture; and
configured to locate over the build window, in replacement of the tray assembly, with the second aperture arranged about the build window and with the second perimeter support edge approximately coplanar the lamination surface; and
a second separation membrane:
extending across the aperture;
tensioned against the second perimeter support edge of the second tray; and
operable in:
a second laminated position, the second separation membrane laminated against the lamination surface in the second laminated position, responsive to evacuation of fluid from a second interstitial region between the second separation membrane and the lamination surface, to form a second build surface approximately coplanar with the second perimeter support edge; and
a second expanded position, the second separation membrane forming a second convex geometry above the second perimeter support edge and offset above the lamination surface in the second expanded position to promote separation of the second separation membrane from a second layer of a second resin polymerized over the second build surface via radiation emitted by the projection system.

### Claim 4 (depends on 1)

The additive manufacturing system of claim 1:
wherein the separation membrane is laminated against the lamination surface to form the build surface comprising a planar build surface in the laminated position.

### Claim 5 (depends on 1)

The additive manufacturing system of claim 1:
wherein the separation membrane is operable in the laminated position responsive to evacuation of fluid comprising air from the interstitial region; and
wherein the separation membrane is operable in the expanded position responsive to pumping of fluid comprising air into the interstitial region.

### Claim 6 (depends on 1)

The additive manufacturing system of claim 1:
wherein the tray further comprises:
a lower member defining:
the perimeter support edge; and
a perimeter relief encircling and inwardly offset from the perimeter support edge; and
an upper member:
comprising a perimeter tongue; and
configured to assemble over the lower member:
with the separation membrane located between the lower member and the upper member, a portion of the separation membrane interposed between the perimeter relief and the perimeter tongue;
with the perimeter tongue inserted into the perimeter relief; and
with the perimeter tongue cooperating with the perimeter support edge to tension the separation membrane across the aperture.

### Claim 7 (depends on 1)

The additive manufacturing system of claim 1:
wherein the tray further defines a parapet:
extending above and encircling the aperture; and
cooperating with the separation membrane to form a vessel configured to store a volume of the resin.

### Claim 8 (depends on 1)

The additive manufacturing system of claim 1, further comprising:
a pressure regulation system configured to:
pump fluid into the interstitial region, via the fluid distribution port, to transition the separation membrane into the expanded position; and
evacuate fluid from the interstitial region, via the fluid distribution port, to transition the separation membrane into the laminated position.

### Claim 9 (depends on 1)

The additive manufacturing system of claim 1, wherein the tray defines the fluid distribution port proximal the perimeter support edge.

### Claim 10 (depends on 1)

The additive manufacturing system of claim 1:
wherein the separation membrane comprises a copolymerized tetrafluoroethylene film transparent to radiation, emitted by the projection system, at wavelengths within a wavelength range corresponding to initiation of polymerization of the resin; and
wherein the build window comprises a rigid structure transparent to radiation, emitted by the projection system, at wavelengths within the wavelength range.

### Claim 11 (depends on 1)

The additive manufacturing system of claim 1:
wherein the separation membrane is characterized by a first elasticity; and
further comprising a second tray assembly comprising:
a second tray:
comprising a second perimeter support edge inwardly offset from a second outer edge of the second tray and defining a second aperture; and
configured to locate over and engage the build window, in replacement of the tray assembly, with the second aperture arranged about the build window; and
a second separation membrane:
characterized by a second elasticity greater than the first elasticity;
extending across the aperture;
tensioned against the second perimeter support edge; and
operable in:
a second laminated position, the second separation membrane laminated against the lamination surface, below the perimeter support edge, in the second laminated position, responsive to evacuation of fluid from a second interstitial region between the second separation membrane and the lamination surface, to form a second build surface offset below the second perimeter support edge, and the second perimeter support edge offset above the lamination surface by a second height in the second laminated position; and
a second expanded position, the second separation membrane forming a second convex geometry offset above the build window and the second perimeter support edge in the second expanded position to promote separation of the second separation membrane from a second layer of a second resin polymerized over the second build surface via radiation emitted by the projection system, and the second perimeter support edge offset above the lamination surface by the second height in the second expanded position.

### Claim 12

A tray assembly configured to interface with a build window arranged in an additive manufacturing system, facing a projection system, and defining a lamination surface opposite the projection system, the tray assembly comprising:
a tray:
comprising a perimeter support edge defining an aperture inwardly offset from an outer edge of the tray and; and
configured to locate over and engage the build window with the aperture arranged about the build window and with the perimeter support edge offset above the lamination surface of the build window; and
a separation membrane:
extending across the aperture;
tensioned against the perimeter support edge of the tray; and
operable in:
a laminated position, the separation membrane laminated against the lamination surface in the laminated position, responsive to evacuation of fluid from an interstitial region between the separation membrane and the lamination surface, to form a build surface offset below the perimeter support edge, and the perimeter support edge offset above the lamination surface by a first height in the laminated position; and
an expanded position, the separation membrane forming a convex geometry offset above the perimeter support edge and offset above the lamination surface in the expanded position to promote separation of the separation membrane from a layer of a resin polymerized over the build surface via radiation emitted by the projection system, and the perimeter support edge offset above the lamination surface by the first height in the expanded position;
a fluid distribution port fluidly coupled to the interstitial region; and
a fluid distribution channel circumscribing the build window and intersecting the fluid distribution port.

### Claim 13 (depends on 12)

The tray assembly of claim 12:
wherein the separation membrane forms the convex geometry offset above the lamination surface in the expanded position responsive to pumping of fluid into the interstitial region between the separation membrane and the lamination surface.

### Claim 14 (depends on 12)

The tray assembly of claim 12:
wherein the tray defines the fluid distribution port arranged proximal the perimeter support edge and configured to couple to a pressure regulation system, the pressure regulation system arranged in the additive manufacturing system and configured to:
pump fluid into the interstitial region, via the fluid distribution port, to transition the separation membrane into the expanded position; and
evacuate fluid from the interstitial region, via the fluid distribution port, to transition the separation membrane into the laminated position.

### Claim 15 (depends on 12)

The tray assembly of claim 12, wherein the tray further comprises:
a lower member defining:
the perimeter support edge; and
a perimeter relief encircling and inwardly offset from the perimeter support edge; and
an upper member:
comprising a perimeter tongue; and
configured to assemble over the lower member:
with the separation membrane located between the lower member and the upper member;
with the perimeter tongue inserted into the perimeter relief, extending below the perimeter support edge, and outwardly offset from the perimeter support edge; and
with the perimeter tongue cooperating with the perimeter support edge to tension the separation membrane across the aperture.

### Claim 16

A tray assembly comprising:
a tray:
configured to locate over and engage a build window of an additive manufacturing system, the additive manufacturing system comprising a projection system configured to project radiation through the build window, the build window defining a lamination surface opposite the projection system; and
comprising:
a lower member defining:
an aperture;
a perimeter support edge facing the aperture and configured to seat offset above the lamination surface; and
a perimeter relief encircling and inwardly offset from the perimeter support edge; and
an upper member:
comprising a perimeter tongue; and
configured to assemble over the lower member with the perimeter tongue inserted into the perimeter relief and extending below the perimeter support edge; and
a separation membrane:
extending across the aperture, the perimeter support edge, and the perimeter relief, a portion of the separation membrane interposed between the perimeter relief and the perimeter tongue;
tensioned across the aperture by the perimeter support edge and the perimeter relief via assembly of the upper member onto the lower member; and
operable in:
a laminated position, the separation membrane laminated against the lamination surface in the laminated position, responsive to evacuation of fluid from an interstitial region between the separation membrane and the lamination surface, to form a build surface offset below the perimeter support edge, and the perimeter support edge offset above the lamination surface by a first height in the laminated position; and
an expanded position, the separation membrane forming a convex geometry above the lamination surface and the perimeter support edge in the expanded position to promote separation of the separation membrane from a layer of a resin polymerized over the build surface via radiation emitted by the projection system and transmitted through the build window and the separation membrane, and the perimeter support edge offset above the lamination surface by the first height in the expanded position;
a fluid distribution port fluidly coupled to the interstitial region; and
a fluid distribution channel circumscribing the build window and intersecting the fluid distribution port.

### Claim 17 (depends on 16)

The tray assembly of claim 16:
wherein the tray defines the fluid distribution port extending proximal the perimeter support edge and configured to couple to a pressure regulation system, the pressure regulation system arranged in the additive manufacturing system and configured to:
pump fluid into the interstitial region, via the fluid distribution port, to transition the separation membrane into the expanded position; and
evacuate fluid from the interstitial region, via the fluid distribution port, to transition the separation membrane into the laminated position.

### Claim 18 (depends on 16)

The additive manufacturing system of claim 16:
wherein the separation membrane defines:
a membrane perimeter; and
a set of perforations proximal and inset from the membrane perimeter; and
wherein the tray assembly further comprises a set of tensioning posts:
extending between the lower member and the upper member;
outwardly offset from the perimeter tongue and the perimeter relief;
configured to receive the set of perforations to position the separation membrane between the lower member and upper member; and
configured to:
laterally retain the separation membrane via the set of perforations during assembly of the upper member onto the lower member; and
tension the separation membrane across the aperture.

### Claim 19 (depends on 16)

The additive manufacturing system of claim 16, wherein the perimeter support edge comprises a radiused edge in contact with the separation membrane in the laminated position.

### Claim 20 (depends on 16)

The additive manufacturing system of claim 16:
wherein the separation membrane forms the convex geometry above the perimeter support edge and offset above the lamination surface in the expanded position responsive to pumping of fluid into the interstitial region between the separation membrane and the lamination surface.