Cleaning fluids for use in additive manufacturing apparatuses and methods for monitoring status and performance of the same

Patent metadata

Field	Value
Publication number	US-2022242130-A1
Application number	US-202017612452-A
Country	US
Kind code	A1
Filing date	May 22, 2020
Priority date	May 23, 2019
Publication date	Aug 4, 2022
Grant date	—

Abstract

Embodiments of the present disclosure are directed to additive manufacturing apparatuses, cleaning stations incorporated therein, and methods of cleaning using the cleaning stations.

First claim

1 . A method of cleaning a print head comprising:
applying a cleaning fluid comprising from 70 wt % to 99.9 wt % water and 0.1 wt % to 30 wt % of one or more organic solvents selected from the group consisting of dimethyl formamide (DMF), N-methyl-2-pyrrolidone (NMP), dimethyl sulfoxide (DMSO), N,N-dimethylacetamide (DMAc), 1,3-dimethyl-2-imidazolidinone (DMI), 1,3-dimethyl-3,4,5,6-tetrahydro-2(1H)-pyrimidinone (DMPU), ethylene glycol, diethyl glycol, dipropylene glycol dimethyl ether, cyrene, dimethyl isosorbide, and propylene glycol to a surface of the print head having precipitant from a binder fluid comprising polyvinyl alcohol or a derivative thereof thereon; and removing used cleaning fluid from the surface of the print head after the cleaning fluid at least partially dissolves the precipitant from the surface.

2 . The method of claim 1 , wherein the cleaning fluid comprises from 0.5 wt % to 10 wt % of the one or more organic solvents.

3 . The method of claim 1 , wherein the organic solvent comprises DMF, NMP, DMSO, dipropylene glycol dimethyl ether, cyrene, dimethyl isosorbide, ethylene glycol, and combinations thereof.

4 . The method of claim 1 , wherein the cleaning fluid has a viscosity of less than 10 cP at 25° C.

5 . The method of claim 1 , wherein the cleaning fluid has a boiling point that is greater than or equal to 100° C. at 1 atm.

6 . The method of claim 1 , wherein the density of the cleaning fluid is from 0.900 to 1.400 g/cm 3 .

7 . The method of claim 1 , further comprising:
passing at least a portion of the cleaning fluid through the print head having the precipitant from a binder fluid comprising polyvinyl alcohol (PVA), polyvinyl pyrrolidone (PVP), polyacrylic acid (PAA), or derivatives thereof therein.

8 . The method of claim 7 , further comprising:
removing the used cleaning fluid from the print head after the cleaning fluid at least partially dissolves the precipitant from within the print head.

9 . A method for monitoring a status of a cleaning fluid in a cleaning fluid system, the method comprising:
obtaining an initial value corresponding to at least one physical property selected from the group consisting of a density of the cleaning fluid, a viscosity of the cleaning fluid, a haze measurement, a surface tension, a color, a pH, a conductivity, and fluorescence of the cleaning fluid; obtaining a subsequent value corresponding to the at least one physical property of the cleaning fluid after a predetermined period of time of usage of the cleaning fluid to clean a print head; estimating one of an amount of contaminant in the cleaning fluid and an amount of evaporation of the cleaning fluid based on the difference between the subsequent value and the initial value of the physical property; selecting a cleaning fluid maintenance process is selected from a plurality of available maintenance processes based on the estimated one of the amount of contaminant and the amount of evaporation in the cleaning fluid; and performing the cleaning fluid maintenance process selected.

10 . The method of claim 9 , wherein performing the cleaning fluid maintenance process selected comprising adding water to the cleaning fluid.

11 . The method of claim 9 , wherein performing the cleaning fluid maintenance process selected comprises replacing a portion of the cleaning fluid containing contaminants with fresh cleaning fluid.

12 . The method of claim 9 , wherein performing the cleaning fluid maintenance process selected comprises replacing a majority of a volume of the cleaning fluid with fresh cleaning fluid.

13 . The method of claim 9 , wherein performing the cleaning fluid maintenance process selected comprises returning the cleaning fluid containing contaminants to a cleaning fluid reservoir in the cleaning fluid system.

14 . The method of claim 9 , wherein the at least one physical property is the density of the cleaning fluid, and wherein selecting the cleaning fluid maintenance process is further based on a viscosity, a surface tension, or both, of the cleaning fluid after the predetermined period of time.

15 . The method of claim 9 , wherein the cleaning fluid initially comprises from 70 wt % to 99.9 wt % water and 0.1 wt % to 30 wt % of one or more organic solvents selected from the group consisting of dimethyl formamide (DMF), N-methyl-2-pyrrolidone (NMP), dimethyl sulfoxide (DMSO), N,N-dimethylacetamide (DMAc), 1,3-dimethyl-2-imidazolidinone (DMI), 1,3-dimethyle-3,4,5,6-tetrahydro-2(1H)-pyrimidinone (DMPU), ethylene glycol, diethyl glycol, dipropylene glycol dimethyl ether, cyrene, dimethyl isosorbide, and propylene glycol.

16 . The method of claim 9 , wherein the contaminants comprise polyvinyl alcohol (PVA), polyvinyl pyrrolidone (PVP), polyacrylic acid (PAA), or derivatives thereof.

17 . A method for monitoring the performance of an additive manufacturing device using a fluorescent binder, the method comprising:
exposing at least one layer comprising the fluorescent binder to electromagnetic radiation wherein the fluorescent binder includes fluorescent material which emits light in response to the electromagnetic radiation; sensing the emitted light intensity of the at least one layer after exposure; and computing a level of binder, solvent, or both within the layer versus time by utilizing a control system which correlates the sensed emitted light intensity to the level of binder, solvent, or both in the layer.

18 . The method of claim 17 , further comprising locating defects in the layer when the recorded emitted light intensity deviates from expected emitted light intensity values, or when the level of binder, solvent, or both deviates from expected levels.

19 . The method of claim 18 , further comprising performing diagnostic checks on the additive manufacturing device when defects are located.

20 . The method of claim 17 , wherein the electromagnetic radiation is UV radiation.

Assignees

• Gen Electric

Inventors

• Alberts William C
• Bromberg Vadim
• Chan Kwok Pong
• Estes Robert Edgar
• Mayer Jacob
• Mook Joshua Tyler
• Mekker Janet
• Murphy William Cosmo
• Natarjan Arunkumar
• Thompson Mary Kathryn
• Yang Xi
• Sands Travis

Classifications

• B22F10/70

  Recycling · CPC title

• B22F12/90

  Means for process control, e.g. cameras or sensors · CPC title

• B22F10/38

  to achieve specific product aspects, e.g. surface smoothness, density, porosity or hollow structures · CPC title

• B22F10/14

  by jetting of binder onto a bed of metal powder · CPC title

• B41J2/16538

  with brushes or wiper blades perpendicular to the nozzle plate · CPC title