# US 12,005,499 B2 · Three-dimensional printing with melting point suppression agents

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- Number: US 12,005,499 B2
- Document ID: US12005499B2
- Status: Granted
- Kind: B2
- Application number: 17/637,644
- Filed: 2019-10-15
- Published: 2022-09-01
- Granted: 2024-06-11
- Earliest claimed: 2019-10-15
- Assignees: Hewlett-Packard Development Company, L.P.
- Applicants: Hewlett-Packard Development Company, L.P.
- Inventors: Vladek Kasperchik; Mohammed S. Shaarawi; Mackensie C. Smith
- Web page: https://patentgrep.com/patent/US12005499B2

## CPC

- B22F 10/14: by jetting of binder onto a bed of metal powder
- B22F 10/30: Process control
- B22F 10/64: by thermal means (control of energy beam parameters for post heating B22F10/364)
- B22F 12/58: for changing the material composition, e.g. by mixing
- B33Y 10/00: Processes of additive manufacturing
- B33Y 30/00: Apparatus for additive manufacturing; Details thereof or accessories therefor
- B33Y 80/00: Products made by additive manufacturing
- B22F 2203/11: temperature, temperature profile
- B22F 2304/10: Micron size particles, i.e. above 1 micrometer up to 500 micrometer
- B22F 2998/10: Processes characterised by the sequence of their steps
- B33Y 70/00: Materials specially adapted for additive manufacturing
- Y02P 10/25: Process efficiency
- B22F: WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER (making alloys by powder metallurgy C22C); APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- 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
- Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS

## Abstract

A three-dimensional printing system can include a particulate build material including metal particles. The three-dimensional printing system can include a binding agent applicator fluidly coupled or coupleable to a binding agent. The three-dimensional printing system can include a suppression agent applicator fluidly coupled or coupleable to a melting point suppression agent, the melting point suppression agent including a dispersion of melting point suppression particles. The three-dimensional printing system can include a hardware controller to generate a command to direct the binding agent applicator to iteratively apply the binding agent to the particulate build material to form individually patterned object layers of a green body object, and direct the suppression agent applicator to iteratively apply the melting point suppression agent to a discrete location of the individually patterned object layers. The discrete location can include a discrete surface region of the green body object.

## Claims

### Claim 1

A method of three-dimensional printing comprising:
iteratively applying individual build material layers of a particulate build material onto a powder bed, wherein the particulate build material includes from about 80 wt % to 100 wt % metal particles;
based on a 3D object model, iteratively and selectively applying a binding agent to individual build material layers to define individually patterned object layers that become adhered to one another to form a layered green body object;
based on the 3D object model, iteratively and selectively applying a melting point suppression agent to individual build material layers at a discrete location of the individually patterned object layers, wherein the melting point suppression agent is a dispersion of a melting point suppression particles, and wherein the discrete location is inclusive of a discrete surface region of the layered green body object; and
heating the layered green body object to fuse the metal particles together to form a fused three-dimensional object, wherein the melting point suppression agent interacts with the metal particles during the heating and creates a visible mark having increased optical reflectivity at the discrete surface region on the fused three-dimensional object.

### Claim 2 (depends on 1)

The method of claim 1, wherein the melting point suppression agent, at the location applied, reduces a local melting temperature of the metal particles in an area containing the melting point suppression agent, and localized melting at the discrete surface region during heating creates the visible mark having the increased optical reflectivity.

### Claim 3 (depends on 1)

The method of claim 1, wherein the melting point suppression particles include:
pigment selected from carbon black pigment, or pigments producing element carbon when heated above a corresponding pyrolysis temperature;
a carbon precursor to produce elemental carbon via pyrolysis when heated above its thermal decomposition temperature;
metal selected from iron, cobalt, nickel, chromium, manganese, vanadium, tin, zinc, copper, tool steels, ferrous alloys, stainless steels, or an alloy thereof; or
any combination of pigment, carbon precursor, metal, or pigment and metal thereof.

### Claim 4 (depends on 1)

The method of claim 1, wherein dispersion of the melting point suppression particles includes a liquid vehicle, wherein the liquid vehicle comprises water, organic co-solvent, and surfactant.

### Claim 5 (depends on 1)

The method of claim 1, wherein the discrete location is further defined as having a depth beyond the discrete surface region from about 30 μm to about 500 μm.

### Claim 6 (depends on 1)

The method of claim 1, wherein the melting point suppression particles are present within the green body object at the discrete location at an average melting point suppression particle to metal particle weight ratio from about 0.05:100 to about 1:10.

### Claim 7 (depends on 1)

The method of claim 1, wherein the layered green body object is heated to a temperature from about 600° C. to about 3,500° C. to fuse the metal particles together and form the fused three-dimensional object.

### Claim 8 (depends on 1)

The method of claim 1, wherein the metal particles have a D50 particle size from about 3 μm to about 150 μm, and the melting point fusing particles have a D50 particle size from about 2 nm to about 1,000 nm.

### Claim 9 (depends on 1)

The method of claim 1, wherein the metal particles include iron, aluminum, titanium, copper, cobalt, chromium, nickel, vanadium, tungsten, tungsten carbide, tantalum, molybdenum, magnesium, tool steels, ferrous alloys, stainless steels, an alloy thereof, or a mixture thereof.

### Claim 10

A three-dimensional printing system comprising:
a particulate build material including from about 80 wt % to 100 wt % metal particles having a particle size from about 3 μm to about 150 μm;
a binding agent applicator fluidly coupled or coupleable to a binding agent, wherein the binding agent includes a binder in an aqueous binder vehicle;
a suppression agent applicator fluidly coupled or coupleable to a melting point suppression agent, the melting point suppression agent including a dispersion of melting point suppression particles; and
a hardware controller to generate a command to:
direct the binding agent applicator to iteratively apply the binding agent to the particulate build material to form individually patterned object layers of a green body object, and
direct the suppression agent applicator to iteratively apply the melting point suppression agent to a discrete location of the individually patterned object layers, wherein the discrete location corresponds to include a discrete surface region of the green body object.

### Claim 11 (depends on 10)

The system of claim 10, wherein the discrete location of the individually patterned object layers extends beyond the discrete surface region to within a bulk of the green body object to a depth from about 30 μm to about 500 μm.

### Claim 12 (depends on 10)

The system of claim 10, further comprising a fusing oven to heat the layered green body object and form a fused three-dimensional object, wherein the melting point suppression agent interacts with the metal particles during heating to form visible mark at a surface of the fused three-dimensional object having increased optical reflectivity compared to other surface locations where the melting point suppression agent was not applied while forming the green body object.

### Claim 13 (depends on 10)

The system of claim 10, wherein the metal particles include stainless steel and the melting point suppression particles include carbon black pigment.

### Claim 14

A metal article comprising:
a sintered metal particle body of a first metal material; and
a metal surface of the sintered metal particle body, wherein the metal surface includes:
a first sintered surface portion of the first metal material; and
a second sintered surface portion including a melting point suppressed-sintered alloy of the first metal material and melting point suppression particles, wherein the second sintered surface portion has a higher optical reflectivity than the first surface portion.

### Claim 15 (depends on 14)

The metal article of claim 14, wherein the sintered metal particle body further includes a discrete location with the melting point suppressed-sintered alloy therein, wherein the melting point suppressed-sintered alloy is positioned directly adjacent to the second sintered surface portion and has a depth therefrom ranging from 30 μm to 500 μm.