CN108930054B

CN108930054B - Metal micro 3D printing method based on self-assembly molecular membrane control technology

Info

Publication number: CN108930054B
Application number: CN201811041502.3A
Authority: CN
Inventors: 张彦振; 刘永红; 李德格
Original assignee: China University of Petroleum East China
Current assignee: China University of Petroleum East China
Priority date: 2018-09-07
Filing date: 2018-09-07
Publication date: 2020-06-09
Anticipated expiration: 2038-09-07
Also published as: CN108930054A

Abstract

The invention relates to a novel 3D metal printing method based on a self-assembly molecular membrane control technology, and belongs to the field of 3D metal printing and micro-nano manufacturing. The novel 3D metal printing method needs to add a special organic molecule into the electroplating solution, and the organic molecule can form a layer of compact self-assembled molecular film with good insulation on the whole surface of the printed metal. The molecular film can effectively isolate the printed piece from the electrolyte and can block all electrochemical reactions on the surface of the printed piece. During printing, a certain range of reduction potential is applied to the printed object to enable metal ions in the electroplating solution to perform reduction reaction. The laser is used for removing the self-assembled molecular film adsorbed on the surface of the metal, so that the metal is directly contacted with the electrolyte, and the electrodeposition is only carried out in a laser irradiation area, thereby realizing the metal additive manufacturing at a specified position.

Description

Metal micro 3D printing method based on self-assembly molecular membrane control technology

Technical Field

The invention belongs to the field of additive manufacturing and micro-nano manufacturing, and relates to a novel metal additive manufacturing method based on a self-assembly molecular membrane control technology, a laser technology and an electrochemical technology.

Technical Field

The additive manufacturing technology is a forming technology based on a discrete stacking forming idea. The technology uses a computer, a CAD and other workpieces to slice and layer a three-dimensional entity, and builds a three-dimensional body layer by using section which changes layer by layer. This technique does not require dies and fixtures and has the ability to build complex shapes. 3D printing of non-metallic materials such as plastics has now substantially reached the level of commercial application. But for 3D printing of metals, it is still in the laboratory stage at present.

The principle of the current metal 3D printing technology is mainly a metal powder sintering technology, and in addition, a droplet printing technology, an ultrasonic 3D metal printing technology and the like are also available. The metal powder sintering technology can be classified into an electron beam melting technology, an electron beam welding technology, a selective laser melting technology, and the like according to the difference of the heat source used. The principles of the above techniques are very similar and can be collectively classified as thermophysical method-based 3D metal printing; it is necessary to melt the metal powder at a high temperature at a designated position and then solidify it to form a 3D metal body. The melting and solidifying process usually causes the problems of rough surface, stress concentration, coarse grains, uneven structure, pores, low mechanical strength and the like of the printed metal part. The above problems are difficult to overcome by the 3D metal printing technique using the thermophysical method. In addition, the above-described techniques are limited by the size of the heat source and the size of the metal powder, and generally cannot print metal components having a feature size of less than one millimeter.

Electroplating and electroforming techniques are electrochemical-based metal additive manufacturing processes and have been widely used in the industry. Current electroplating techniques are commonly used for surface treatment of metal parts, with coating thicknesses typically on the order of microns. The reason why the electroplating technique cannot be used for 3D metal printing is that metal deposition at a specific position cannot be achieved. Similar to electroplating techniques, electroforming is another metal additive manufacturing technique based on electrochemical principles. Electroforming techniques require the use of a mandrel to electrochemically deposit metal onto the mandrel and then separate from the mandrel to produce or replicate the metal product.

Disclosure of Invention

The invention aims to provide an additive manufacturing technology suitable for tiny metal parts.

The principle of the invention is as follows: organic molecules capable of forming an insulating and dense self-assembled molecular film on the surface of a metal are added into a plating solution, so that the surface of a printed metal part soaked in the plating solution is completely covered by the self-assembled molecular film. When a potential is applied to the metal component, which can reduce the metal ions in the electroplating solution, the insulating self-assembled molecular film can prevent the electrochemical reaction of the metal ions on the surface of the metal component, so that the whole surface of the metal component can not be subjected to electrodeposition. The technique irradiates the surface of a metal part with a laser beam having a specific energy or a two-dimensional laser pattern to remove a self-assembled molecular film adsorbed on the surface thereof. After the self-assembled molecular film is removed, electrochemical deposition can be carried out on the laser irradiation area. By controlling the movement track of the laser beam or the shape of the two-dimensional laser pattern, the three-dimensional metal structure can be printed.

The invention has the following characteristics:

1. the metal additive manufacturing is based on the electrochemical principle, and the growth speed of metal per minute in the laser direction is in the micron order, so that the metal additive manufacturing is very suitable for the production and the manufacture of tiny metal parts.

2. The metal additive principle of the invention is consistent with electroplating, so that the metal part printed and manufactured by the metal additive principle has no thermal stress, the mechanical strength of the workpiece is high, and the surface is smooth.

3. By controlling the change of the laser pattern, the tiny metal parts with complex structures can be printed and manufactured.

Drawings

FIG. 1 is a schematic diagram of 3D metal printing principle based on self-assembly molecular membrane control technology

Detailed Description

See fig. 1. The invention relates to a novel 3D metal printing method based on a self-assembly molecular film control technology, in particular to a method for forming a self-assembly molecular film with good compactness and good insulativity on the surface of a printed metal by adding a special organic molecule into electroplating solution. The molecular film can effectively separate the printed piece from the electrolyte and can block the electrochemical reaction on the surface of the printed piece. During printing, a certain range of reduction potential is applied to the printed object to enable metal ions in the electroplating solution to perform reduction reaction. The laser is used for removing the self-assembled molecular film adsorbed on the surface of the metal, so that the metal is directly contacted with the electrolyte, and the electrodeposition is only carried out in a laser irradiation area, thereby realizing the metal additive manufacturing at a specified position. The energy density of the laser used during printing is preferably such that the self-assembled molecular film is just removed. Too much laser energy density can cause thermal melting of the workpiece and damage to the workpiece.

When a laser beam with a smaller diameter is adopted, the laser beam needs to be scanned two-dimensionally point by point and line by line in the printing process so as to realize metal deposition in a larger area.

It is also possible to directly project and print the surface of the workpiece using a two-dimensional laser pattern with an editable pattern shape. In the printing process, the three-dimensional metal component can be printed by adjusting the geometric shape of the two-dimensional pattern.

Claims

1. A metal micro 3D printing method based on a self-assembly molecular membrane control technology is characterized in that: the electroplating solution contains an organic molecule, the organic molecule can be spontaneously adsorbed on the surface of the printed metal to form a compact and insulated self-assembled molecular film, and the molecular film can effectively realize the physical isolation of the workpiece from the electroplating solution and block all electrochemical reactions generated on the surface of the metal; in the printing process, a potential capable of enabling metal ions in electroplating solution to generate reduction reaction on the surface of the workpiece is applied, and meanwhile, laser with proper energy density is adopted to remove the self-assembled molecular film adsorbed on the metal surface, so that the metal surface is directly contacted with the electroplating solution, and the electrochemical deposition is controlled to be only generated in a laser irradiation area.

2. The metallic micro 3D printing method according to claim 1, wherein: the laser may be a laser beam with a small diameter or a laser pattern with an editable two-dimensional shape.

3. The metallic micro 3D printing method according to claim 1, wherein: the energy density of the laser is preferably just enough to remove the self-assembled molecular film.