US-12617152-B2 - Three-dimensional printer apparatus having electro-osmotic lubricant flow

US12617152B2US 12617152 B2US12617152 B2US 12617152B2US-12617152-B2

Abstract

A three-dimensional printing system is provided that includes a tank, a textured substrate connected to the tank, and at least one electrode. The tank contains a liquid photopolymer resin and a lubricant. The textured substrate is configured to allow light to pass through into the liquid photopolymer resin. The at least one electrode is configured to control a flow of the lubricant on the textured substrate.

Inventors

Sandeep Patil
Nanzhu Zhao

Assignees

NISSAN NORTH AMERICA, INC.

Dates

Publication Date: 20260505
Application Date: 20230626

Claims (16)

1 . A three-dimensional printing system comprising: a tank containing a liquid photopolymer resin and a lubricant; a textured substrate connected to the tank, the textured substrate being configured to allow light to pass through into the liquid photopolymer resin; and at least one electrode, the at least one electrode being optically transparent and being configured to control a flow of the lubricant on the textured substrate.
2 . The three-dimensional printing system according to claim 1 , wherein: the textured substrate comprises a first substrate that is optically transparent and a second substrate formed on a surface of the first substrate, and the second substrate includes a textured surface facing the liquid photopolymer resin.
3 . The three-dimensional printing system according to claim 2 , wherein the textured substrate includes at least one pillar.
4 . The three-dimensional printing system according to claim 3 , wherein each of the at least one pillar is formed directly on the surface of the first substrate.
5 . The three-dimensional printing system according to claim 3 , wherein: the at least one electrode includes a plurality of electrodes, and each of the at least one pillar is one of the plurality of electrodes.
6 . The three-dimensional printing system according to claim 2 , wherein the first substrate is formed of a glass material.
7 . The three-dimensional printing system according to claim 2 , wherein the second substrate is formed of polydimethylsiloxane.
8 . The three-dimensional printing system according to claim 2 , wherein: the at least one electrode includes at least one positive electrode and at least one negative electrode, and the at least one positive electrode and the at least one negative electrode each overlay the surface of the first substrate on opposite sides of the second substrate.
9 . The three-dimensional printing system according to claim 1 , further comprising at least one of a pump and a reservoir configured to supply the lubricant to the tank.
10 . The three-dimensional printing system according to claim 1 , further comprising at least one sensor configured to detect an amount of the lubricant in a portion of the textured substrate.
11 . The three-dimensional printing system according to claim 1 , wherein the lubricant is an oil that includes an additive with a higher sensitivity to electroosmosis than the oil.
12 . The three-dimensional printing system according to claim 1 , wherein the at least one electrode includes electrodes disposed on opposite sides of the textured substrate.
13 . The three-dimensional printing system according to claim 1 , wherein the lubricant is in contact with the at least one electrode.
14 . The three-dimensional printing system according to claim 1 , wherein the at least one electrode is provided on the first substrate and is spaced apart from the second substrate.
15 . A three-dimensional printing system comprising: a tank containing a liquid photopolymer resin and a lubricant; a textured substrate connected to the tank, the textured substrate being configured to allow light to pass through into the liquid photopolymer resin; at least one electrode; and at least one of a pump and a reservoir configured to supply the lubricant to the tank, the at least one electrode being configured to control a flow of the lubricant on the textured substrate.
16 . A three-dimensional printing system comprising: a tank containing a liquid photopolymer resin and a lubricant; a textured substrate connected to the tank, the textured substrate being configured to allow light to pass through into the liquid photopolymer resin; at least one electrode; and at least one sensor configured to detect an amount of the lubricant in a portion of the textured substrate, the at least one electrode being configured to control a flow of the lubricant on the textured substrate.

Description

BACKGROUND Field of the Invention The present invention generally relates to a three-dimensional printing system having electro-osmotic lubricant flow, and a textured window for such a system. The three-dimensional printing system includes a tank containing a liquid photopolymer resin and a lubricant, a textured substrate connected to the tank, and at least one electrode. The textured substrate is configured to allow light to pass through into the liquid photopolymer resin. The at least one electrode is configured to control a flow of the lubricant on the textured substrate. The textured window includes a textured substrate configured to allow light to pass through into a liquid photopolymer resin and at least one electrode. The textured substrate includes pillars projecting from a surface of the textured substrate. Each of the at least one electrode comprises an electrode material formed in one of the pillars. Background Information Three-dimensional (“3D”) printers have been used to print a wide variety of three-dimensional products. Objects are printed layer by layer by the 3D printer by curing portions of a light curable photopolymer resin layer by layer, one layer at a time, within a printing area of a tank filled with the photopolymer resin. A curing device, such as an ultraviolet light source, is projected through a transparent substrate or bottom wall of the tank curing each layer of the object on a carrier surface that is at least partially submerged within the photopolymer. The carrier surface is incrementally raised upward as each layer is cured thereon. One problem with such conventional arrangement is that portions of the photopolymer resin can adhere to the transparent substrate (bottom wall of the tank). This adhesion slows and/or delays the printing process, thereby decreasing productivity. It is therefore advantageous to prevent adhesion of the photopolymer to the transparent substrate. In order to address this problem of adhesion, textured windows have been developed that include a textured surface in contact with the photopolymer resin. The textured surface includes grooves that are configured to hold lubricant. The textured windows are substantially transparent and can be used as the transparent substrate. By providing a layer of the lubricant between the photopolymer resin and the transparent substrate, adhesion between the photopolymer and transparent substrate can be reduced. Although these lubricant-infused textured windows can improve the printing speed by increasing the slip length along the textured window in the print area, when the lubricant is filled in the grooves of the textured substrate, bubbles may be generated. The bubbles undesirably reduce the transparency of the textured window and thereby increase both the energy consumption of the printer apparatus and the loss of light emitted to cure the photopolymer resin. Furthermore, the amount of lubricant along the surface of the textured window is depleted over time. Therefore, adhesion between the photopolymer and the transparent substrate can still become a problem when the amount of lubricant lost reaches a certain level. For example, a 20% loss in lubricant can render the textured window useless for printing due to adhesion problems. In addition, adhesion of the photopolymer to the transparent substrate can damage the textured window. Therefore, further improvement is needed to increase the transparency of the textured substrate and reduce the adhesion of the photopolymer to the transparent substrate during operation. In particular, it is desirable to improve the flow of lubricant on the surface of the textured window and to thereby improve the energy efficiency of the 3D printer and extend the time which the 3D printer can continuously print. SUMMARY It has been discovered that the amount of bubbles in the lubricant filled in the grooves of the textured substrate can be reduced by providing a system in which transparent electrodes are disposed on the textured window to cause an electro-osmotic flow of the lubricant across and within the grooves of the textured substrate. The system includes a textured window including at least one transparent electrode configured to control a flow of the lubricant on the textured substrate. In particular, by providing the transparent electrode(s) on the textured substrate, the electrode(s) cause an electro-osmotic flow of the lubricant across and within the grooves of the textured substrate, thereby preventing undesirable bubbles that reduce the transparency of the textured window. Furthermore, by providing the electrode(s) on the transparent substrate, the flow of lubricant into specific areas or grooves of the textured window can be more precisely controlled such that electro-osmotic flow of the lubricant can be caused only in areas of the textured substrate where the amount of lubricant is low. Therefore, it is desirable to provide a three-dimensional printing system that includes suc