CN108356270A - A kind of metal 3D printing method based on contact resistance heating - Google Patents

Abstract

A metal 3D printing method based on contact resistance heating, relating to a metal 3D printing method. After the cathode and anode are electrically heated, they are respectively connected to the positive and negative electrodes of the power supply. The cathode and anode are made of graphite material, and the cathode and anode are kept in contact with the graphite head to heat up the cathode and anode; the metal printing material enters the graphite head through the wire feeding system, and prints Before, the energized cathode and anode are clamped directly above the 3D printing workbench, and energized to heat; the filamentous metal printing material is put into the graphite head, and after reaching the fusion printing standard, it is extruded by the wire feeding system for printing. The metal 3D printing device based on contact resistance is equipped with power supply, metal printing material, electric heating anode, graphite head, 3D printing table, electric heating cathode and wire feeding system; the positive and negative electrodes of the power supply are connected with the electric heating anode and cathode, and the electric heating The anode and cathode are respectively in contact with the graphite head, the metal printing material enters the graphite head through the wire feeding system, and the working table is set under the graphite head.

Description

A metal 3D printing method based on contact resistance heating

technical field

The invention relates to a metal 3D printing method, in particular to a metal 3D printing method based on contact resistance heating.

Background technique

In recent years, metal 3D printing has become a hot spot, but most metal 3D printing uses lasers, electron beams, etc. ] Li Zhiyong, Yang Bin, Wang Pengcheng, Li Qiao, Mo Yumei. Research status and trends of metal 3D printing technology [J]. New technology and new technology, 2017 (04): 25-28.), the progress is slow and difficult to popularize. Therefore, in order to promote the progress of metal 3D printing and save costs, people have used many other thermal printing methods, such as ceramic sintering ([2] Zhu Lijuan, Tang Meng, Yu Baohai, Liu Yue, Tian Yanwen, Zhai Yuchun 3 Northeastern University Department of Materials Chemistry, School of Materials and Metallurgy. Research on Sintering Process of TiC/NiCrMoAlTi Cermet [J]. Materials Engineering, 2001(06): 10-12.), Resistance Wire Heating ([3] Xia Jiewen. Composition of Resistance Wire Heating Group heat treatment technology and application [J]. Chemical construction technology, 1994 (3): 23-25.) and so on. But there are more or less some problems, such as the temperature is too low, the temperature is difficult to control, and the quality of the printed product is poor.

The metal 3D printing method based on contact resistance is to use a DC stabilized current power supply to connect special material graphite to heat. The idea of this patent is to use the point contact between two conductors, which will produce the characteristics of contact resistance ([4] Xu Jun, Li Kun. Research on contact resistance of electrical contact[J]. Electrical Materials, 2011(01):10-13.), this contact resistance is much larger than the resistance of the conductor itself, and applying a DC voltage of several volts to it can be Generating dozens or even hundreds of amperes of current can make the contact point reach a very high temperature locally, and the temperature can be controlled. It can melt metal materials with different melting points. By controlling the heating temperature, the metallographic structure characteristics can also be improved. The head is equipped with a CNC system for metal 3D printing processing.

At present, relatively mature metal 3D printing technologies generally use lasers, electron beams, plasma arcs, etc. as heat sources. On the one hand, traditional metal 3D printing cannot adjust the heating temperature during the heating process, and can only melt the metal first and then shape it. , and the metal 3D printing technology based on contact resistance can solve this problem and provide the possibility of metal printing in more directions. On the other hand, the current metal 3D printers are extremely expensive, and the cost is too high, while the metal 3D printing system based on contact resistance heating does not exceed 10,000 yuan, and the cost is low, which can meet the consumption level of ordinary people.

Contents of the invention

The purpose of the present invention is to provide a metal 3D printing method based on contact resistance heating.

The metal 3D printing method based on contact resistance heating adopts a metal 3D printing device based on contact resistance, and the method includes the following steps:

1) After electrically heating the cathode and the anode, respectively connect the positive pole and the negative pole of the DC stabilized current power supply, the cathode and the anode are made of graphite material, and the cathode and the anode are kept in contact with the graphite head, so that the cathode and the anode are heated up;

2) The metal printing material enters the graphite head through the wire feeding system. Before printing, the energized cathode and anode are clamped directly above the 3D printing workbench, and energized for heating;

3) Put the filamentary metal printing material into the graphite head, and after reaching the fusion printing standard, it will be driven and extruded by the wire feeding system for printing.

In step 1), the cathode and anode are kept in point contact with the graphite head and can be reinforced with springs or screws. The contact resistance generated by the point contact is about 0.1Ω, and the voltage only needs a few volts to generate a large power, so that a large amount of local Joule heat, rise to high temperature.

In step 2), the wire feeding system can use the motor gear to drive the wire, and the wire feeding speed can be regulated by the motor controller; the heating by electricity can use the principle of contact resistance heating to rapidly heat up.

The metal 3D printing device based on contact resistance is provided with a power supply, a metal printing material, an electric heating anode, a graphite head, a 3D printing workbench, an electric heating cathode and a wire feeding system; the positive pole of the power supply is connected to the electric heating anode, and the power supply The negative electrode of the electrode is connected to the electric heating cathode, the electric heating anode and the electric heating cathode are respectively in contact with the graphite head, the metal printing material enters the graphite head through the wire feeding system, and the 3D printing workbench is set under the graphite head.

The present invention has the following advantages:

1) Low cost and high efficiency

Since the cost of the metal 3D printing method based on contact resistance is relatively small compared with laser and other metal 3D printing methods, the present invention has low cost and high heating efficiency, and can reach the required temperature within a few minutes and perform subsequent printing Work.

2) Adjustable temperature

The temperature of metal 3D printing methods such as laser and electron beam cannot be adjusted, while the method based on contact resistance heating adjusts the temperature through voltage and current control, and the temperature is adjustable, which makes metal 3D printing a step forward.

3) High quality finished product

The invention is carried out in a closed environment, which strictly guarantees the quality of metal melting and printing.

Description of drawings

FIG. 1 is a schematic structural diagram of a metal 3D printing device based on contact resistance according to an embodiment of the present invention.

Fig. 2 is a schematic diagram of a metal 3D printed circular aluminum product based on contact resistance according to an embodiment of the present invention.

FIG. 3 is a schematic diagram of a pyramid-shaped aluminum product printed by metal 3D printing based on contact resistance according to an embodiment of the present invention.

Detailed ways

The following embodiments will further illustrate the present invention in conjunction with the accompanying drawings.

The present invention adopts a metal 3D printing device based on contact resistance (as shown in Figure 1), and the metal 3D printing device based on contact resistance is provided with a power supply 1, a metal printing material 2, an electric heating anode 3, a graphite head 4, and a 3D printing Workbench 5, electric heating cathode 6 and wire feeding system 7; the positive pole of the power supply 1 is connected to the electric heating anode 3, the negative pole of the power supply 1 is connected to the electric heating cathode 6, and the electric heating anode 3 and the electric heating cathode 6 are respectively connected to graphite The metal printing material 2 enters the graphite head 4 through the wire feeding system 7 , and the 3D printing workbench 5 is set under the graphite head 4 . The metal 3D printing method based on contact resistance heating is as follows: electrically heat the cathode and anode (graphite material, which is easy to oxidize when other metal materials are used at high temperature), and after connecting the positive and negative electrodes of the DC stabilized current power supply respectively, they are kept in contact with the graphite head. Point contact, in order to ensure continuous point contact between the cathode and anode and the graphite head, it can be reinforced with springs or screws. The point contact between the graphite head and the graphite cathode and anode will generate contact resistance, which is the key of the present invention. Through the existing experiments, it can be obtained that the contact resistance generated by point contact is about 0.1Ω, and the voltage only needs a few volts to generate a large power, so that a large amount of Joule heat is generated locally and rises to a high temperature.

The cathode and anode of the graphite material are connected with the graphite head, and the temperature can be rapidly raised in a short time to reach the required temperature, which can reach more than 1400°C and can melt stainless steel. The metal printing material enters the graphite head through the wire feeding system. Before printing, the energized cathode and anode are clamped directly above the 3D printing workbench, and the energized heating is used to heat up rapidly based on the contact resistance heating principle, and then the filamentous metal printing material enters the graphite. In the head, after reaching the fusion printing standard, the extrusion is driven by the wire feeding system for printing.

The feasibility experiment results and conclusions of the present invention are given below.

In order to verify the feasibility and effectiveness of the method adopted by the present invention, the circuit is connected according to Fig. 1, and the melting points of different metal materials can be reached by adjusting the voltage and current. During the experiment, the graphite head became red in just a few minutes, reached the melting point required by the metal, and melted the metal, flowing to the 3D printing workbench. As the voltage and current increase, the temperature will also increase. At present, the melting points of aluminum, copper, and silver can be met. Metal 3D printing devices based on contact resistance are low-cost, easy to put into production, realize consumer-grade metal 3D printing, and can control temperature and be optimized. Refer to Fig. 2 and Fig. 3 for schematic diagrams of metal 3D printing circular and pyramid-shaped aluminum products based on the contact resistance of the embodiment of the present invention.

Claims (4)

1. a kind of metal 3D printing method based on contact resistance heating, it is characterised in that use the metal 3D based on contact resistance Printing equipment the described method comprises the following steps：

1) anode and cathode of DC current regulator power supply are connect after electrical heating cathode and anode respectively, the cathode and anode use Graphite material, cathode and anode are kept and graphite head point contact, and cathode and anode is made to heat up；

2) metallic print material is entered into graphite head by wire feed system, before being printed, the surface of 3D printing workbench fills Press from both sides energization cathode and anode, electrified regulation；

3) Filamentous metallic print material is entered in graphite head, after reaching melting printing standard, is driven and squeezed by wire feed system, It is printed.

2. a kind of metal 3D printing method based on contact resistance heating as described in claim 1, it is characterised in that in step 1) In, the cathode and anode keep reinforcing with graphite head point contact spring or screw, and the contact resistance that point contact generates is 0.1 Ω。

3. a kind of metal 3D printing method based on contact resistance heating as described in claim 1, it is characterised in that in step 2) In, the wire feed system drives wire using motor gear, and regulates and controls wire feed rate by electric machine controller.

4. a kind of metal 3D printing method based on contact resistance heating as described in claim 1, it is characterised in that described to be based on The metal 3D printing device of contact resistance be equipped with power supply, metallic print material, electrical heating anode, graphite head, 3D printing workbench, Electrical heating cathode and wire feed system；The anode of the power supply is connect with electrical heating anode, and cathode and the electrical heating cathode of power supply connect It connecing, electrical heating anode and electrical heating cathode are contacted with graphite head respectively, and metallic print material enters graphite head by wire feed system, The 3D printing workbench is located at below graphite head.