CN116988134B - Cleaning device and method for friction stir additive manufacturing forming tool - Google Patents

Abstract

The present invention relates to a friction stir additive manufacturing tool cleaning device and method, and belongs to the field of robot friction stir additive manufacturing technology. The purpose is to solve the problem that it takes a long time to clean the attached aluminum chips during the cleaning process of the friction stir additive manufacturing welding tool, and the welding tool is easily damaged due to the long cleaning time. It includes an electrochemical workstation, a computer, an electrolyte cell, a heating device and an inert metal. The electrochemical workstation is electrically connected to the computer, the positive electrode of the electrochemical workstation is connected to the friction stir additive manufacturing tool, the negative electrode of the electrochemical workstation is electrically connected to the inert metal, the electrolyte cell contains electrolyte, the inert metal is placed in the electrolyte, and the heating device is placed in the electrolyte. The voltage monitoring of the cleaning process of the present invention can accurately control the cleaning time and will not cause corrosion damage to the friction stir forming tool.

Description

A friction stir additive manufacturing forming tool cleaning device and method

Technical Field

The invention relates to a tool cleaning device and a method, belonging to the technical field of robot friction stir additive manufacturing.

Background technique

Friction stir additive manufacturing technology is a full solid-phase additive manufacturing technology derived from friction stir welding technology. It uses a special welding tool to generate heat by friction with the material under high-speed rotation and the stirring action of the stirring head to plasticize the material to be added. Under the upsetting action of the shoulder, the material to be added is connected with the substrate or the additive layer, and then the material is plasticized and stacked layer by layer to manufacture high-strength and tough additive parts with uniform and refined structure.

Friction stir additive manufacturing technology mainly refers to the friction stir additive manufacturing method using rods, plates and wires as raw materials. The most promising application is the robot friction stir additive manufacturing method based on wire raw materials. This method can not only achieve continuous additive manufacturing but also realize complex additive manufacturing structures. This method mainly involves the extrusion and crushing of the wire raw material through the feeding hole of the friction stir welding tool under the push of the wire feeding device, and then the plastic flow of the material under the large plastic deformation of the stirring needle to prepare the additive manufacturing parts as planned. However, there are still some problems to be solved in this method. After the additive manufacturing is completed, part of the plasticized metal adheres to the surface of the feeding screw during the lifting process of the welding tool. When the friction stir additive manufacturing is performed again, the welding tool needs to be switched and cleaned. At present, the cleaning method for aluminum chips mainly focuses on soaking and cleaning with a strong alkaline solution. This process takes a long time and the bubbles generated cause air pollution; and soaking the welding tool in a strong alkaline solution is prone to stress corrosion in the solution, causing serious damage to the welding tool, reducing service time and increasing production costs.

Therefore, there is an urgent need to propose a friction stir additive manufacturing forming tool cleaning device and method to solve the above technical problems.

Summary of the invention

The purpose of the present invention is to solve the problem that it takes a long time to clean the attached aluminum chips during the cleaning process of the friction stir additive manufacturing welding tool, and the long cleaning time is easy to damage the welding tool, and provide a friction stir additive manufacturing tool cleaning device and method. A brief overview of the present invention is given below to provide a basic understanding of certain aspects of the present invention. It should be understood that this overview is not an exhaustive overview of the present invention. It is not intended to determine the key or important parts of the present invention, nor is it intended to limit the scope of the present invention.

The technical solution of the present invention:

A friction stir additive manufacturing forming tool cleaning device comprises an electrochemical workstation, a computer, an electrolyte cell, a heating device and an inert metal, wherein the electrochemical workstation is electrically connected to the computer, the positive electrode of the electrochemical workstation is connected to the friction stir additive manufacturing forming tool, the negative electrode of the electrochemical workstation is electrically connected to the inert metal, the electrolyte cell contains electrolyte, the inert metal is placed in the electrolyte, and the heating device is placed in the electrolyte.

Preferably: it also includes a robot and an electric spindle, the end of the robot is connected to the stator of the electric spindle, the friction stir additive manufacturing forming tool includes a rotating module and a non-rotating module, the non-rotating module is bolted to the stator of the electric spindle or the end of the robot, the rotating module is connected to the rotor of the electric spindle, a thread is provided on the rotating module, and the rotating module is located inside the non-rotating module.

Preferably: the electrolyte contained in the electrolyte cell is prepared from the following raw materials: sodium hydroxide, sodium chloride, sodium nitrate, aluminum chloride, 1-methyl-3-ethylimidazoline bromide, citrate, EDTA-2Na, sodium gluconate, and hard insoluble particles;

or hydrochloric acid, sodium chloride, sodium nitrate, aluminum tribromide, toluene, ethylbenzene, citrate, EDTA-2Na, sodium gluconate, hard insoluble particles;

Or aluminum chloride, lithium aluminum hydroxide, tetrahydrofuran, citrate, EDTA-2Na, sodium gluconate, hard insoluble particles.

A method for cleaning a friction stir additive manufacturing forming tool comprises the following steps:

Step 1: Place the welding tool in the electrolyte tank and immerse the welding tool in the electrolyte;

Step 2: Power on the electrochemical workstation and monitor the voltage change over time;

Step 3: When the voltage fluctuates significantly, the attached debris is removed and the electrochemical workstation is powered off.

Preferably: the electrochemical workstation applies a pulse current density of 0.1-100 A/dm2, a pulse frequency of 1-10000 Hz, a duty cycle of 0.01-0.9, and an electrolyte temperature of above 80°C.

The present invention has the following beneficial effects:

1. The present invention can realize the rapid removal of aluminum chips attached to the inside of the forming tool, ensuring the high efficiency of stir friction additive manufacturing;

2. The voltage monitoring of the cleaning process in the present invention can accurately control the cleaning time compared with the traditional direct immersion removal, and will not cause corrosion damage to the friction stir forming tool;

3. The present invention is green and environmentally friendly, will not release harmful gases to pollute the environment, and the electrolyte can be used for a long time without causing waste;

4. The present invention has low cost, simple device, easy construction and good application prospect;

5. The present invention is not only applicable to the removal of aluminum chips attached inside the friction stir additive manufacturing forming tool, but can also be applied to magnesium alloys, etc.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic structural diagram of a friction stir additive manufacturing forming tool cleaning device;

FIG2 is a schematic diagram of the structure of a friction stir additive manufacturing forming tool;

Fig. 3 is an enlarged view of point A in Fig. 2;

FIG. 4 is a flow chart of a method for cleaning a friction stir additive manufacturing forming tool.

In the figure, 1-robot, 2-electric spindle, 3-friction stir additive manufacturing forming tool, 4-electrochemical cleaning system, 301-rotating module, 302-non-rotating module, 401-electrochemical workstation, 402-computer, 403-electrolyte cell, 404-heating device, 405-inert metal.

Detailed ways

In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is described below by the specific embodiments shown in the accompanying drawings. However, it should be understood that these descriptions are only exemplary and are not intended to limit the scope of the present invention. In addition, in the following description, the description of well-known structures and technologies is omitted to avoid unnecessary confusion of the concept of the present invention.

Specific implementation method 1: Combined with Figures 1-3, this implementation method is a friction stir additive manufacturing forming tool cleaning device in this implementation method. The electrochemical cleaning system 4 includes an electrochemical workstation 401, a computer 402, an electrolyte cell 403, a heating device 404 and an inert metal 405. The electrochemical workstation 401 is electrically connected to the computer 402, the positive electrode of the electrochemical workstation 401 is connected to the friction stir additive manufacturing forming tool, the negative electrode of the electrochemical workstation 401 is electrically connected to one end of the inert metal 405, and the electrolyte cell 403 is electrically connected to the inert metal 405. The electrolyte is contained, and the other end of the inert metal 405 is placed in the electrolyte, the heating device 404 is placed in the electrolyte, and the electrochemical workstation 401 is a chi electrochemical workstation, and the chronopopotentiometry of the chi electrochemical workstation realizes voltage monitoring; the present invention has low cost, simple device, easy construction, and good application prospect. It is not only suitable for removing aluminum chips attached to the inside of stir friction additive manufacturing forming tools, but also can be applied to magnesium alloys, etc., and also provides a reference for removing alloy chips attached to the inside of welding tools.

Specific implementation method two: This implementation method is explained in conjunction with Figures 1-3. A stir friction additive manufacturing forming tool cleaning device in this implementation method also includes a robot 1 and an electric spindle 2. The end of the six-axis robot 1 is connected to the stator of the electric spindle 2 by bolts. The stir friction additive manufacturing forming tool 3 includes a rotating module 301 and a non-rotating module 302. The non-rotating module 302 is bolted to the stator of the electric spindle 2 or the end of the robot. The rotating module 301 is connected to the rotor of the electric spindle 2. The rotating module 301 is provided with a thread. The rotating module 301 is located inside the non-rotating module 302. The rotating module 301 is electrically connected to the electrochemical workstation 401 through a conductive slip ring, and the computer 402 is electrically connected to the electric spindle 2.

Specific implementation method three: This implementation method is described in conjunction with Figures 1-3. This implementation method is a friction stir additive manufacturing forming tool cleaning device. The electrolyte contained in the electrolyte pool 403 is an electrolyte for removing plasticized metal adhered to the inside of the friction stir additive manufacturing forming tool, and is prepared from the following raw materials: sodium hydroxide, sodium chloride, sodium nitrate, aluminum chloride, 1-methyl-3-ethylimidazoline bromide, citrate, EDTA-2Na, sodium gluconate, and hard insoluble particles;

or hydrochloric acid, sodium chloride, sodium nitrate, aluminum tribromide, toluene, ethylbenzene, citrate, EDTA-2Na, sodium gluconate, hard insoluble particles;

Or aluminum trichloride, lithium aluminum tetrahydride, tetrahydrofuran, citrate, EDTA-2Na, sodium gluconate, hard insoluble particles; the hard insoluble particles play the role of peeling off aluminum chips or hydrated aluminum compounds under the high-speed flow of electrolyte.

Specific implementation method four: Combined with Figures 1-4, this implementation method is a friction stir additive manufacturing forming tool cleaning method of this implementation method. Using the friction stir additive manufacturing forming tool cleaning device, the wire raw material is transported to the gap between the rotating module 301 and the non-rotating module 302 under the action of the wire feeding device, and the electric spindle drives the rotating module 301 and the non-rotating module 302 to move relative to each other at high speed, and the wire raw material is broken and thermoplasticized through strong plastic deformation, and then the additive material is accumulated layer by layer; after the additive manufacturing is completed, aluminum chips will be attached to the surface of the feeding screw in the process of lifting the tool, and the aluminum chips attached to the inside of the forming tool need to be cleaned for the additive manufacturing again;

The following steps are involved:

Step 1: First, configure the electrochemical cleaning aluminum alloy electrolyte 403, connect the rotating module 301 to the positive electrode of the DC pulse power supply, connect the inert metal 405 to the negative electrode of the DC pulse power supply, and the robot 1 places the welding tool (friction stir additive manufacturing forming tool) in the electrolyte tank 403, and immerses the welding tool in the electrolyte; during cleaning, the friction stir additive manufacturing forming tool itself does not need to be disassembled, and the friction stir additive manufacturing forming tool does not need to be disassembled from the robot, and can also be moved to the cleaning position by the robot itself. After cleaning, the additive manufacturing work can be directly carried out, which is efficient and easy to operate;

Step 2: When the electrolyte is lower than the set temperature of the electrolyte, the heating device 404 is started to heat the electrolyte. The electrochemical workstation 401 can be used as a DC power supply. The electrochemical workstation 401 is powered on, and the electric spindle 2 is started to rotate the stirring head at a high speed to drive the solution to flow. The non-rotating module does not move. The rotating module 301 is rotated forward or reversely, and the pressurization is achieved through the thread, which not only accelerates the flow rate in the stir friction additive manufacturing forming tool 3, but also makes the water flow flush its inner wall with greater pressure. At the same time, the hard insoluble particles peel off and take away the aluminum chips or hydrated aluminides under the high-speed flow of the electrolyte, which accelerates the reaction rate of the electrolyte and the aluminum chips. The physical and chemical aspects work together to remove the attached aluminum chips and other attachments, and improve the removal efficiency. In the process of electrochemical accelerated corrosion, the electrochemical workstation 401 is connected to the computer 402 to monitor the voltage change curve over time during the process of removing the attached aluminum chips on the forming tool;

Step 3: When an obvious wave suddenly appears on the curve, that is, the voltage fluctuates significantly, it means that the anode material changes, the welding tool begins to be sacrificed, the debris attached between the rotating module 301 and the non-rotating module 302 is removed, and the relevant signal is transmitted to the computer 402, the electrochemical workstation 401 stops and cuts off the power, and the electrochemical cleaning work stops; there is no need to disassemble the robot to stir the friction additive manufacturing forming tool, the reaction during the electrolyte cleaning does not pollute the atmosphere, and the voltage monitoring will not cause damage to the welding tool service; the robot 1 returns to the original additive track to continue additive, the whole process takes a short time, there is no need to disassemble the welding tool, the cleaning time is precisely controlled, and there is no damage to the forming tool.

Specific implementation method five: This implementation method is explained in conjunction with Figures 1-4. This implementation method is a method for cleaning a stir friction additive manufacturing forming tool. The electrochemical workstation 401 applies a pulse current density of 0.1-100A/dm2, a pulse frequency of 1-10000Hz, a duty cycle of 0.01-0.9, and an electrolyte setting temperature of above 80°C to increase the rate of removing aluminum chips. Cleaning can be completed in 10-15 minutes.

Embodiment 1:

This embodiment uses a friction stir additive manufacturing forming tool cleaning method, which is mainly based on the fact that the corrosion voltage of aluminum alloy or magnesium alloy is inconsistent with that of the additive device. The friction stir additive manufacturing forming tool is made of H13 steel, and the corrosion voltage is greater than that of aluminum alloy, magnesium alloy, etc., and it is more corrosion-resistant. During the cleaning process, aluminum chips are first corroded as anodes. When the alloy chips attached to the additive device are cleaned, corrosion will further occur on the additive device. At this time, the monitored voltage will change, thereby judging that the cleaning of the alloy chips is completed. The specific steps are as follows:

The 4043 aluminum alloy wire material is transported to the gap between the rotating module 301 and the non-rotating module 302 by the wire feeding device. The electric spindle drives the rotating module 301 and the non-rotating module 302 to move relative to each other at high speed. The wire material is broken and thermoplasticized by strong plastic deformation, and then additive manufacturing begins layer by layer. After additive manufacturing is completed, aluminum chips will adhere to the surface of the feeding screw in the forming tool during the tool lifting process. The aluminum chips inside the forming tool need to be cleaned for additive manufacturing again. At this time, the stirring is removed. Aluminum chips attached to the inside of the friction additive manufacturing forming tool; first, electrochemical cleaning aluminum alloy electrolyte 403 is prepared. The electrolyte 403 formula consists of sodium hydroxide (20g/L), sodium chloride (10g/L), sodium nitrate (5g/L), aluminum chloride (10g/L), 1-methyl-3-ethylimidazoline bromide (10g/L), citrate (0.5g/L), EDTA-2Na (0.1g/L), sodium gluconate (1g/L), zirconium oxide particles, etc., and then heated. The electrolyte 403 is heated to 80±5°C by the device 404, the rotating module 301 is connected to the positive electrode of the power supply, the titanium inert metal 405 is connected to the negative electrode of the DC pulse power supply, and the two are immersed in the electrolyte at the same time, then the electrochemical workstation 401 is turned on, the power supply is set to apply a pulse current density of 20A/dm2, a pulse frequency of 2000Hz, and a duty cycle of 0.3, and the work of removing the aluminum chips inside the forming tool is started, and at the same time, the electric spindle 2 is started to make the stirring head rotate at a high speed of 5000 rpm to drive the solution to flow; the zirconium oxide particles in the electrolyte 403 can peel off and take away the aluminum chips or hydrated aluminum compounds under the high-speed flow of the electrolyte; during the electrochemical accelerated corrosion process, the electrochemical workstation 401 is connected to the computer 402 to monitor the voltage change curve over time during the process of removing the aluminum chips attached to the forming tool. When the voltage fluctuation ΔV＞2V, it means that the aluminum chips attached to the inside of the forming tool are cleaned up, and the relevant signal is transmitted to the computer 402, and then the electrochemical cleaning work is stopped, and the robot 1 returns to the original additive track according to the set program to continue additive.

Example 2

This embodiment uses a method for cleaning a forming tool by stir friction additive manufacturing, and the specific steps are as follows:

The AZ31B magnesium alloy wire raw material is transported to the gap between the rotating module 301 and the non-rotating module 302 by the wire feeding equipment. The electric spindle drives the rotating module 301 and the non-rotating module 302 to move relative to each other at high speed. The wire raw material is broken and thermoplasticized through strong plastic deformation, and then the additive manufacturing begins layer by layer. After the additive manufacturing is completed, magnesium chips will adhere to the surface of the feeding screw during the tool lifting process inside the forming tool, and the magnesium chips inside the forming tool need to be cleaned for additive manufacturing again. At this time, the magnesium chips attached to the inside of the stir friction additive manufacturing forming tool are removed. First, an electrochemical cleaning aluminum alloy electrolyte 403 is prepared. The electrolyte 403 formula consists of sodium hydroxide (20g/L), sodium chloride (10g/L), sodium nitrate (5g/L), aluminum chloride (10g/L), 1-methyl-3-ethylimidazoline bromide (10g/L), citrate (0.5g/L), EDTA-2Na (0.1g/L), sodium gluconate (1g/L), hard insoluble particles, etc. The electrolyte 403 is heated to 60±5°C by a heating device 404, the rotating module 301 is connected to the positive electrode of the power supply, and the titanium inert metal 405 is connected to the negative electrode of the DC pulse power supply. The two are immersed in the electrolyte at the same time, and then the electrochemical workstation 401 is turned on, and the power supply is set to apply a pulse The impulse current density is 10A/dm2, the pulse frequency is 1000Hz, the duty cycle is 0.25, and the work of removing the aluminum chips inside the forming tool is started. At the same time, the electric spindle 2 is started to make the stirring head rotate at a high speed of 5000 rpm to drive the solution to flow; the zirconium oxide particles in the electrolyte 403 can peel off the magnesium chips or magnesium precipitates under the high-speed flow of the electrolyte; in the electrochemical accelerated corrosion process, the electrochemical workstation 401 is connected to the computer 402 to monitor the voltage change curve over time during the process of removing the magnesium chips attached to the forming tool. When the voltage fluctuation ΔV＞1V, it means that the magnesium chips attached to the inside of the forming tool are cleaned up, and the relevant signal is transmitted to the computer 402, and then the electrochemical cleaning work is stopped, and the robot 1 returns to the original additive track according to the set program to continue additive, and this parameter is the optimal parameter.

It should be noted that in the above embodiments, as long as the technical solutions are not contradictory, they can be arranged and combined, and those skilled in the art can exhaust all possibilities based on the mathematical knowledge of arrangement and combination. Therefore, the present invention will no longer describe the technical solutions after arrangement and combination one by one, but it should be understood that the technical solutions after arrangement and combination have been disclosed by the present invention.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims (2)

1. A cleaning method for a friction stir additive manufacturing forming tool is characterized by comprising the following steps: the cleaning device comprises an electrochemical workstation (401), a computer (402), an electrolyte tank (403), a heating device (404) and inert metal (405), wherein the electrochemical workstation (401) is electrically connected with the computer (402), the positive electrode of the electrochemical workstation (401) is connected with the friction stir additive manufacturing forming tool, the negative electrode of the electrochemical workstation (401) is electrically connected with the inert metal (405), electrolyte is contained in the electrolyte tank (403), the inert metal (405) is arranged in the electrolyte, and the heating device (404) is arranged in the electrolyte;

The friction stir additive manufacturing forming tool (3) comprises a rotating module (301) and a non-rotating module (302), wherein the non-rotating module (302) is connected with the stator of the electric spindle (2) or the tail end of the robot through bolts, the rotating module (301) is connected with a rotor of the electric spindle (2), threads are arranged on the rotating module (301), and the rotating module (301) is located inside the non-rotating module (302);

A cleaning method of a friction stir additive manufacturing forming tool comprises the following steps:

step one: placing the welding tool in an electrolyte tank (403), wherein the welding tool is immersed in the electrolyte;

Step two: the non-rotating module (302) is fixed, the rotating module (301) rotates forward or reversely, and the energizing monitoring voltage of the electrochemical workstation (401) changes with time;

Step three: when a significant fluctuation in voltage occurs, removal of the attached debris is completed and the electrochemical workstation (401) is de-energized.

2. A friction stir additive manufacturing forming tool cleaning method according to claim 1, characterized in that: the electrochemical workstation (401) applies pulse current with the density of 0.1-100A/dm2, the pulse frequency of 1-10000Hz, the duty ratio of 0.01-0.9, and the temperature of electrolyte is above 80 ℃.