CN109047768B

CN109047768B - Low-melting-point metal wire for 3D printing

Info

Publication number: CN109047768B
Application number: CN201811002583.6A
Authority: CN
Inventors: 耿家维; 郭文波; 张俊; 蔡昌礼; 邓中山
Original assignee: Yunnan Kewei Liquid Metal Valley R&D Co Ltd
Current assignee: Yunnan Kewei Liquid Metal Valley R&D Co Ltd
Priority date: 2018-08-30
Filing date: 2018-08-30
Publication date: 2021-07-13
Anticipated expiration: 2038-08-30
Also published as: CN109047768A

Abstract

The invention relates to a low-melting-point metal wire for 3D printing, which is prepared from the following raw materials in percentage by weight: 20-45% of Bi, 25-40% of Sn and the balance of In to 100%. The melting point of the metal wire is 75-100 ℃, the hardness and the tensile strength of the metal wire can be effectively improved by adjusting the relative content of Bi, Sn and In, the requirements of circuit printing, three-dimensional metal structural part printing and plastic-combined functional structural part printing can be met, and the metal wire has wide application prospect and higher commercial popularization value.

Description

Low-melting-point metal wire for 3D printing

Technical Field

The invention relates to the technical field of 3D printing of metal raw materials, in particular to a low-melting-point metal wire for 3D printing.

Background

3D printing is a technique for building objects by layer-by-layer printing using bondable materials such as powdered metals or plastics based on digital model files. The printing machine is basically the same as the common printing working principle, wire materials or printing materials such as liquid or powder are arranged in the printer, and after the printing materials are connected with a computer, the printing materials are overlapped layer by layer under the control of the computer, and finally, a blueprint on the computer is changed into a real object. The method is more and more widely applied to the fields of mold manufacturing, industrial design, automotive electronics, aerospace and the like.

At present, the 3D printing of metal materials generally adopts a laser rapid prototyping method, that is, a high-power laser is used to irradiate the surface of a test piece, melt metal powder to form a liquid molten pool, and then a laser beam is moved to melt the front powder and cool and solidify the rear metal. During the printing process, measures such as inert gas protection, spray head control and the like need to be applied. The difficulty of the 3D printing manufacturing technology of metal materials is due to the high melting point of metal (up to thousands degrees), which involves various physical processes such as solid-liquid phase change, surface diffusion, heat conduction, etc. of metal. Rapid heating and cooling will also cause large residual stresses in the test piece. In addition, metal powder with a high melting point such as titanium alloy, nickel-based superalloy, tungsten alloy and stainless steel is mostly used as a raw material for metal 3D printing, and the powder manufacturing cost is high.

Different from the 3D printing route of high-temperature metal, in the current low-cost popular 3D printer, Fused Deposition (FDM) is mainly adopted, that is, the printer feeds a wire into an extrusion type nozzle controlled by computer-aided manufacturing software, the nozzle heats and melts a linear printing material and then extrudes the linear printing material, and the extruded liquid raw material is rapidly cooled and solidified, thereby forming the linear printing material. Currently, the most commonly used fuse wires are mainly PLA, ABS, elastomer, cast wax, polyester thermoplastic, etc., but these wires cannot realize a device having a conductive function because they do not have metallic characteristics such as conductivity, high strength, etc. In the prior art, a related scheme for 3D metal printing at room temperature already exists, but the device printed by the low-melting-point metal has small hardness, tensile strength and other ratios and poor comprehensive performance, so that the application of the low-melting-point metal printing is limited. In recent years, feeding printing and metal combined printing are one of the research directions in the industry, and metal and nonmetal mixed printing enables the whole manufacturing process to be alternately printed with nonmetal materials, so that various electronic circuit functional devices are realized, and full-automatic manufacturing and assembling of target terminal equipment are possible. However, the metal in the prior art cannot realize simultaneous combined printing with materials such as plastics.

Disclosure of Invention

The invention aims to provide a low-melting-point metal wire for 3D printing, which is prepared from the following raw materials in percentage by weight: 20-45% of Bi, 25-40% of Sn and the balance of In to 100%;

preferably, the percentage content of Bi is 2-8% higher than that of Sn, and the percentage content of Sn is 6-12% higher than that of In.

The invention discovers that the solidus line and the liquidus line of the Bi-Sn-In low-melting-point metal wire rod are improved along with the increase of the Bi content, and the hardness is linearly increased along with the increase of the Bi content ratio; but decreases significantly as the content of Sn and In increases. However, increasing the Sn content of the low melting point metal improves the shear strength and tensile strength of the low melting point metal wire rod, and particularly when the amounts of the respective components are within the above ranges, the metal wire rod is more desirable in various properties.

Preferably, the wire rod comprises a mechanical property improving agent. The mechanical property improver can further improve the bonding property and fatigue resistance of the metal.

Preferably, a metal antioxidant is added to the wire rod. The addition of the metal antioxidant can further improve the oxidation resistance of the metal and improve the printing reliability.

Preferably, the mechanical property improver is one or more of Ag, Cu or Zn. Ag can improve the yield limit and tensile strength of the wire rod and can improve the wettability of the material; zn and Cu can improve the wettability of the material, the mechanical property of the material and the reliability of the wire rod.

Preferably, the metal antioxidant is one or more of Ga, P or Al. The addition of the trace elements Ga and P can effectively improve the oxidation resistance of the wire, and can generate an enriched oxide film on the surface layer of the oxide film, so that the concentration of oxygen element is reduced, the oxidation of the wire is inhibited, and the effect of improving the wettability of the metal surface is also achieved; and the trace element Al is also added, so that a compact oxide film can be formed on the surface of the wire rod by the aluminum element to form a 'barrier layer', the oxidation of the wire rod is inhibited, and the effect of improving the oxidation resistance of the wire rod can be achieved.

Preferably, the addition amount of the mechanical property improver is 0.1-1%.

Preferably, the addition amount of the metal antioxidant is 0.1-0.5%.

Preferably, the metal wire rod of the present invention is prepared from the following raw materials in parts by weight: 38-40% of Bi, 78-36% of Sn34, and the balance of In to 100%; the use amount of each raw material is within the range, so that the strength and toughness of the metal wire can be ensured, and a better printing effect can be obtained.

Or 38-40% of Bi, 34-36% of Sn, 0.1-0.7% of a mechanical property improver, 0.1-0.35% of a metal antioxidant, and the balance of In to 100%.

The use amount of each raw material is in the range, so that the strength, toughness, oxidation resistance, wettability and the like of the metal wire can be ensured, and a better printing effect is obtained.

As a specific preferred scheme, the metal wire rod of the present invention is prepared from the following raw materials by weight:

40% of Bi, 35% of Sn and 100% of In;

or 40% of Bi, 35% of Sn, 0.2% of Zn, 0.15% of Al, 0.1% of Cu, 0.15% of P and the balance of In to 100%;

or 40% of Bi, 34% of Sn, 0.1% of Ag, 0.5% of Zn, 0.1% of Al, 0.1% of Cu and the balance of In to 100%;

or, Bi 39.5%, Sn 34.5%, Ag 0.1%, Al 0.1%, Ga 0.05%, In complement to 100%;

or 38.5% of Bi, 36% of Sn, 0.5% of Zn, 0.2% of Al, 0.1% of P, 0.05% of Ga and the balance of In to 100%;

or Bi 38%, Sn 35%, Ag 0.1%, Cu 0.1%, P0.1%, In to 100%.

Another object of the present invention is to protect the method for preparing the metal wire of the present invention, comprising the steps of:

1) adding the raw materials in parts by weight into a smelting furnace, and then adding a smelting covering agent ZnCl₂Heating to 600-680 ℃ to melt all the raw materials, and keeping the temperature for 20-40 min;

2) and stirring the melted raw materials for 25-35 min, removing the melting covering agent, pouring the mixture into a mold to prepare a low-temperature metal ingot blank, and extruding the low-temperature metal ingot blank into strips or threads to obtain the alloy.

Preferably, the raw materials are heated to 650 ℃ to be melted and the temperature is kept for 30 min;

preferably, the ZnCl is₂The addition amount of the melting covering agent was 0.1% of the total mass of each raw material.

A final object of the invention is to protect the use of the wire according to the invention in circuit printing, printing of three-dimensional metallic structures and printing of three-dimensional functional structures incorporating plastics.

Preferably, in the printing of the three-dimensional functional structure in combination with a plastic, the plastic is polylactic acid or acrylonitrile-styrene-butadiene copolymer.

Preferably, the printing of the functional structural member incorporating plastic is performed by FDM melt jet printing technology.

Preferably, the surface precision of the plastic substrate in the printing process is 0.1 mm-0.2 mm.

The application the metal wire can print the adhesion better on plastic substrate such as polylactic acid (PLA), acrylonitrile-styrene-butadiene copolymer (ABS) etc. realizes the direct production of various electronic circuit function devices, simultaneously because this metal wire belongs to low melting point metal wire, the melting point is low (75 ℃ -100 ℃) between, can easily heat at heating shower nozzle and melt. Generally, PLA and ABS have a melting point of between 180 and 220 ℃, and the low-melting-point metal wire can be easily matched with a plastic printing material such as PLA and ABS for printing operation by an FDM fusion jet printing technology, and the effect is better especially when the printing surface precision of a plastic substrate is between 0.1 and 0.2 mm. Other metal wires such as aluminum wires (melting point 660 ℃), copper wires (melting point 1083 ℃), have too high melting points, cannot be melted by the FDM technology, cannot achieve the purpose of printing, and are seriously oxidized after being melted in air, so that the printing operation is more difficult. The low-melting-point metal does not have the problems and is one of ideal materials for mixed printing of metal and nonmetal.

The metal wire has the following beneficial effects:

1) this 3D prints low melting point metal wire, through the relative content of adjustment bismuth indium tin, compare with traditional low melting point material, for example tin (fusing point 232 ℃) or tin bismuth alloy (138 ℃), greatly reduced printing temperature, cooling speed is also faster, prints the in-process, and the power consumption is still less, has reduced the printing cost, and the while temperature is low, and the operation is got up and is more difficult to scald, prints the security performance and increases substantially.

2) When the traditional low-melting-point metal wire is used for mixed printing with a plastic material, the plastic material is softened due to the fact that part of the plastic material is sensitive to temperature and the plastic material is softened due to overhigh temperature, and the problem that the plastic material is softened due to the fact that the traditional low-melting-point metal wire is high in melting temperature cannot be effectively solved. Due to the fact that the melting point of the wire is low, the 3D printing low-melting-point metal wire greatly reduces the influence on the printed plastic material in the printing process, and can effectively avoid the problem of softening of the plastic material. Meanwhile, the 3D printed low-melting-point metal wire has larger heat enthalpy and a period of heat absorption buffering time, is not melted at once due to high temperature of the plastic after being mixed with the plastic for printing, and has higher stability after being printed.

Drawings

FIG. 1 is a diagram of several external specifications of a low melting point metal wire;

FIG. 2 is a schematic view of a metal wire and a plastic wire being combined for 3D printing;

in fig. 2, 1 is a metal wire, 2 is a plastic wire, 3 is a metal wire nozzle, 4 is a plastic wire nozzle, 5 is a tray, 6 is a plastic structure, and 7 is a metal structure.

Detailed Description

Example 1

The embodiment relates to a low-melting-point metal wire for 3D printing, which is prepared from the following raw materials in percentage by mass: 40% of Bi, 35% of Sn and the balance of In.

The embodiment also relates to a preparation method of the metal wire, which comprises the following steps:

1) adding weighed raw materials of 40kg of pure Bi, 35kg of pure Sn and 25kg of pure In into a 200kg smelting furnace, adding 100g of ZnCl2 smelting covering agent In total to 100kg, heating to 350 ℃, and keeping the temperature for 30 min.

2) Stirring the obtained melt for 30min, removing the surface covering agent, and pouring the mixture into a mold to prepare a low-temperature metal ingot blank.

3) Extruding the ingot obtained in the step (2) into strips and filaments on an extruder.

The metal wire prepared by the embodiment can ensure that the mechanical properties such as the strength, the toughness and the like of the wire are relatively good, and is beneficial to the printing operation of the wire.

Example 2

The embodiment relates to a low-melting-point metal wire for 3D printing, which is prepared from the following raw materials in percentage by mass: 40% of Bi, 35% of Sn, 0.2% of Zn, 0.15% of Al, 0.1% of Cu, 0.15% of P and the balance of In.

1) adding weighed raw materials of 40kg of pure Bi, 35kg of pure Sn, 200g of pure Zn, 150g of pure Al, 100g of pure Cu, 150g of pure P and 24.4kg of pure In into a 200kg smelting furnace, adding 100g of ZnCl2 smelting covering agent In total to 100kg, heating to 650 ℃, and preserving heat for 30 min.

3) Extruding the ingot obtained in step (2) into strips and filaments on an extruder, wherein the structure of the strip and the filaments is shown in figure 1.

The metal wire prepared by the embodiment can ensure that the mechanical properties such as the strength, the toughness and the like of the wire are relatively good, and is beneficial to the printing operation of the wire. Meanwhile, when 0.2% of Zn is added and 0.1% of Cu is added, the wettability of the wire rod obtained in the proportion is enhanced; when 0.15% of Al is added and 0.15% of P is added, the oxidation resistance of the wire rod is effectively improved, and the long-term storage of the metal wire rod is facilitated.

Example 3

The embodiment relates to a low-melting-point metal wire for 3D printing, which is prepared from the following raw materials in percentage by mass: 40% of Bi, 34% of Sn, 0.1% of Ag, 0.5% of Zn, 0.1% of Al, 0.1% of Cu and the balance of In.

1) adding weighed raw materials of 40kg of pure Bi, 34kg of pure Sn, 100g of pure Ag, 500g of pure Zn, 100g of pure Al, 100g of pure copper and 25.2kg of pure In into a 200kg smelting furnace, adding 100g of ZnCl2 smelting covering agent In total to obtain 100kg of pure Sn, pure Ag, pure Zn, pure Al, pure Cu and pure In, heating to 650 ℃, and keeping the temperature for 30 min.

The metal wire prepared by the embodiment can ensure that the mechanical properties such as the strength, the toughness and the like of the wire are relatively good, and is beneficial to the printing operation of the wire. Meanwhile, the yield limit and tensile strength of the wire can be improved by adding 0.1% of Ags, and the wettability of the wire can be effectively enhanced by adding 0.5% of Zn and 0.1% of Cu in a matching manner; 0.1 percent of Al is added, so that the oxidation resistance of the wire rod is effectively improved, and the long-term storage of the metal wire rod is facilitated.

Example 4

The embodiment relates to a low-melting-point metal wire for 3D printing, which is prepared from the following raw materials in percentage by mass: 39.5% of Bi, 34.5% of Sn, 0.1% of Ag, 0.1% of Al, 0.05% of Ga and the balance of In.

1) the weighed raw materials of 39.5kg of pure Bi, 34.5kg of pure Sn, 100g of pure silver, 100g of pure Al, 50g of pure Ga and 25.75kg of pure In are added into a 200kg smelting furnace, the total is 100kg, 100g of ZnCl2 smelting covering agent is added, the temperature is heated to 650 ℃, and the temperature is kept for 30 min.

The metal wire prepared by the embodiment can ensure that the mechanical properties such as the strength, the toughness and the like of the wire are relatively good, and is beneficial to the printing operation of the wire. Meanwhile, the yield limit and tensile strength of the wire rod and the wettability of the wire rod can be improved by adding 0.1% of Ags, and the oxidation resistance of the wire rod can be effectively improved by adding 0.1% of Al and 0.05% of Ga in the proportion, so that the metal wire rod is beneficial to long-term storage.

Example 5

The embodiment relates to a low-melting-point metal wire for 3D printing, which is prepared from the following raw materials in percentage by mass: 38.5% of Bi, 36% of Sn, 0.5% of Zn, 0.2% of Al, 0.1% of P, 0.05% of Ga and the balance of In.

1) the weighed raw materials of 38.5kg of pure Bi, 36kg of pure Sn, 150g of pure Zn, 200g of pure Al, 100g of pure P, 50g of pure Ga and 23.65kg of pure In are added into a 200kg smelting furnace, the total is 100kg, 100g of ZnCl2 smelting covering agent is added, the temperature is heated to 650 ℃, and the temperature is kept for 30 min.

The metal wire prepared by the embodiment can ensure that the mechanical properties such as the strength, the toughness and the like of the wire are relatively good, and is beneficial to the printing operation of the wire. Meanwhile, 0.5% of Zn is added, and the wettability of the obtained wire rod is enhanced; when 0.2% of Al is added, 0.1% of P and 0.05% of Ga are matched, the oxidation resistance of the wire can be effectively improved in the proportion, and the long-term storage of the metal wire is facilitated.

Example 6

The embodiment relates to a low-melting-point metal wire for 3D printing, which is prepared from the following raw materials in percentage by mass: 38% of Bi, 35% of Sn, 0.1% of Ag, 0.1% of Cu, 0.1% of P and the balance of In.

1) adding weighed raw materials of 38kg of pure Bi, 35kg of pure Sn, 100g of pure Ag, 100g of pure Cu, 100g of pure P and 26.7kg of pure In into a 200kg smelting furnace, totaling 100kg, adding 100g of ZnCl2 smelting covering agent, heating to 650 ℃, and preserving heat for 30 min.

The metal wire prepared by the embodiment can ensure that the mechanical properties such as the strength, the toughness and the like of the wire are relatively good, and is beneficial to the printing operation of the wire. Meanwhile, the yield limit and tensile strength of the wire and the wettability of the wire can be improved by adding 0.1% of Ags and 0.1% of Cu, and the oxidation resistance of the wire can be effectively improved by adding 0.1% of P, so that the long-term storage of the metal wire is facilitated.

Comparative example 1

The difference from example 1 is that the composition of each raw material was Bi 45%, Sn 30%, Zn 0.2%, Al 0.15%, Cu 0.1%, P0.15%, and the balance was In.

The metal wire rod manufactured according to the proportion has insufficient oxidation resistance, can cause oxidation and blackening after being stored in the air for a long time, and increases the brittle failure of the metal wire rod along with the increase of Bi content, so that the metal wire rod cannot be normally used for printing operation due to the failure of the metal wire rod.

Experimental example 1

The experimental examples relate to the testing of the properties of the wire rods prepared in examples 1 to 5, and mainly the hardness, tensile strength, shear strength, wettability and melting point of the wire rods were tested, and the results are shown in table 1:

TABLE 1

Experimental example 2

The present experimental example relates to an example of 3D printing using the metal wire and plastic wire of the present invention in combination.

As shown in fig. 2, the device for performing 3D printing by combining metal wires and plastic wires in embodiment 3 adopts the FDM melt-jet printing principle to realize the whole printing process. The printing process is as follows: the metal wire spray head 3 and the plastic wire spray head 4 move along the X axis and the Y axis under the control of a computer; meanwhile, in the moving process, the metal wire 1 is extruded out from the metal wire spray head 3 under the control of a computer, the plastic wire 2 is extruded out from the plastic wire spray head 4 under the control of the computer, and the tray 5 moves up and down along the Z axis; along with the movement of the metal wire spray head 3 and the plastic wire spray head 4 and the extrusion of materials, a metal and plastic mixed structural part is formed on the tray 5 and comprises a plastic structure 6 and a metal structure 7, and finally, the metal wire and the plastic wire are combined to perform 3D printing.

Although the invention has been described in detail hereinabove by way of general description, specific embodiments and experiments, it will be apparent to those skilled in the art that many modifications and improvements can be made thereto based on the invention. Accordingly, such modifications and improvements are intended to be within the scope of the invention as claimed.

Claims

1. The low-melting-point metal wire for 3D printing is characterized by being prepared from the following raw materials in percentage by weight: 38-45% of Bi, 78-40% of Sn34, and the balance of In to 100%; the percentage content of Bi is 2-8% higher than that of Sn, and the percentage content of Sn is 6-12% higher than that of In;

or Bi 38%, Sn 35%, Ag 0.1%, Cu 0.1%, P0.1%, In to 100%.

2. The method for producing a metal wire rod according to claim 1, comprising the steps of:

1) adding the raw materials in parts by weight into a smelting furnace, and then addingSmelting covering agent ZnCl₂Heating to 600-680 ℃ to melt all the raw materials, and keeping the temperature for 20-40 min;

3. The preparation method according to claim 2, wherein the raw materials are heated to 650 ℃ in the step 1) and are melted, and the temperature is kept for 30 min; and/or, the smelting covering agent ZnCl₂The addition amount of (B) is 0.08-0.12% of the total weight of the raw materials.