Contact prepressing type additive manufacturing device and application thereof

Abstract

The invention provides a contact prepressing type additive manufacturing device and application thereof. Metal powder of different thicknesses is flatly laid on an additive substrate and compacted, a contact type pressing head is used for conducting secondary pressurization on a metal powder layer, then pulse current treatment is conducted, and generated joule heat enables the metal powder between the contact type pressing head and the additive substrate to be rapidly sintered. And then the steps are repeated on the next area so that continuous additive forming can be achieved. In the additive forming process, the pressure head exerts pressure on the metal powder so that the powder can be automatically filled into the pore positions, formation of the pores is reduced to a great extent, and the compactness of the materials and the bonding strength between all layers of materials are improved. Due to the pressure action at high temperature, additive manufacturing and micro-zone forging are synchronously carried out, dynamic and static recrystallization of a forming layer is promoted, thick columnar crystals are eliminated, the grain size is effectively refined, and the comprehensive mechanical property of an additive forming material is improved.

Description

Technical Field

[0001] The present invention belongs to the field of additive manufacturing, and in particular relates to a contact pre-pressing additive manufacturing device and an application thereof. Background Art

[0002] Additive manufacturing, also known as 3D printing, is considered one of the most disruptive and representative emerging technologies in the manufacturing industry, representing the development direction of high-end manufacturing. The main methods of additive manufacturing of metal materials are: direct energy deposition and powder bed fusion, both of which use electron beams or lasers as heat sources to heat metal powders, melt the metal powders to form a micro-molten pool, and then coat them layer by layer on the substrate to form a three-dimensional component.

[0003] In the above-mentioned additive manufacturing technology, the main one is non-contact, that is, the heat source generating device needs to keep a certain distance from the metal powder, so the area where the electron beam or laser beam is focused and heated is limited, which is a micro-melting pool spot welding mode. The above-mentioned welding area is narrow and the welding efficiency is low. Therefore, relative movement between the heat source device and the powder to be processed is required to realize the powder processing on the entire substrate. During the movement process, some powders will cause splashing, no powder to melt, and powder leakage, which will eventually make it easy for more pores to appear inside the material after additive manufacturing. In addition to the above, coarse columnar crystals induced by multiple thermal cycles will also appear. These problems lead to the anisotropy of performance of each layer of material or the whole material, reduce the mechanical properties of the material, and cause safety hazards to the material during service. In order to improve efficiency, reduce costs and reduce the occurrence of the above-mentioned problems, the existing technology needs to adjust the process and a large number of process parameters, including: heat source power, scanning speed, scanning spacing, metal powder layer thickness, metal powder particle size, and dryness and humidity parameters, which will make the processing technology complicated and increase costs. Therefore, how to simplify the process, reduce costs, improve efficiency, reduce the surface and internal porosity of materials after additive manufacturing, reduce material anisotropy, and improve material mechanical properties are technical challenges that need to be solved urgently. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a contact pre-pressing additive manufacturing device, which includes: an inert gas bottle 1, an additive manufacturing body 2, a numerical control system 3, a pulse power system 4, a program control computer 5 and a support platform 6, wherein the pulse power system 4 is located above the support platform 6, the numerical control system 3 is located at the upper left of the pulse power system 4, the program control computer 5 is located at the upper right of the pulse power system 4, the additive manufacturing body 2 is located on the left side of the support platform 6, the inert gas bottle 1 is located on the left side of the additive manufacturing body 2, the inert gas bottle 1 provides inert gas to the additive manufacturing body 2, the inert gas in the inert gas bottle 1 is one of argon and helium, the additive manufacturing body 2 is used to stack and additively mold metal powders to be processed, the numerical control system 3 controls the operation of the additive manufacturing body 2, the pulse power system 4 provides pulse current to the additive manufacturing body 2, and the program control computer 5 provides process parameter signals to the numerical control system 3;

[0005] The additive manufacturing body 2 includes: a multi-degree-of-freedom pressure head control device 21, a pressure head body 22, a material cylinder and a powder spreading device 23, an additive substrate settling device 24, a chamber atmosphere and temperature and humidity monitoring system 25, and a main body sealing top cover 26. The additive substrate settling device 24 is located at the bottom of the additive manufacturing body 2, the material cylinder and the powder spreading device 23 are located above the additive substrate settling device 24, the pressure head body 22 is located above the material cylinder and the powder spreading device 23, the multi-degree-of-freedom pressure head control device 21 is located above the pressure head body 22, the chamber atmosphere and temperature and humidity monitoring system 25 is located on the right side of the pressure head body 22, and the main body sealing top cover 26 is located above the multi-degree-of-freedom pressure head control device 21, and the multi-degree-of-freedom pressure head control device 21 is used to control the movement of the pressure head body 22 relative to the additive substrate sinking device 24. The chamber atmosphere and temperature and humidity monitoring system 25 is used to monitor and regulate the gas concentration, temperature and humidity inside the additive manufacturing body 2; the material cylinder and powder spreading device 23 are hollow structures, and the pressure head body 22 and the additive substrate sinking device 24 can move up and down inside the material cylinder and the powder spreading device 23, so that the contact between the pressure head body 22 and the additive substrate sinking device 24 can be adjusted and controlled; the pressure head body 22 includes: a pressure sensor 221 , a pressure head temperature monitoring and cooler 222 and a contact pressure head 223, wherein the contact pressure head 223 is located at the bottom of the pressure head body 22, the pressure head temperature monitoring and cooler 222 is located above the contact pressure head 223, the pressure sensor 221 is located above the pressure head temperature monitoring and cooler 222, the pressure sensor 221 is used to monitor the pressure borne by the contact pressure head 223 in real time, the pressure head temperature monitoring and cooler 222 is used to monitor and control the temperature of the contact pressure head 223 in real time, the contact pressure head 223 directly contacts and pressurizes the metal powder to be processed, and the material cylinder and powder spreading device 23 include: The cylinder wall 231, the scraper 232, the roller 233 and the motion mechanism 234, the cylinder wall 231 is in a thin-walled square shape and surrounds the cylinder and the powder spreading device 23, the scraper 232 is located above the cylinder and the powder spreading device 23, the roller 233 is located behind the scraper 232, and the motion mechanism 234 is located in front of the scraper 232. The scraper 232 is used to control the thickness of the layer of metal powder to be processed. The roller 233 is equipped with a pressure sensor, which can simultaneously complete the pre-compacting treatment and pressure monitoring of the metal powder to be processed. The motion mechanism 234 is used to control the speed of the synchronous movement of the scraper 232 and the roller 233;The additive substrate sinking device 24 includes: an up-down moving mechanism 241, an additive substrate fixing platform 242 and an additive substrate 243. The up-down moving mechanism 241 is located at the bottom of the additive substrate sinking device 24, the additive substrate fixing platform 242 is located above the up-down moving mechanism 241, and the additive substrate 243 is located above the additive substrate fixing platform 242. The up-down moving mechanism 241 is used to control the up-down movement of the additive substrate fixing platform 242, the additive substrate fixing platform 242 is used to support the additive substrate 243, the additive substrate fixing platform 242 is closely matched with the cylinder wall 231 to prevent powder leakage, and the additive substrate 243 is used to place the metal powder to be processed and the additive substrate 243 The type of material is adjustable or replaceable, and the multi-degree-of-freedom pressure head control device 21 is used to control the up and down and left and right movements of the pressure head body 22 relative to the additive substrate 243, wherein the multi-degree-of-freedom pressure head control device 21 controls the left and right movements of the pressure head body 22 relative to the additive substrate 243 to adjust the shape of the additively formed metal powder to be processed, and the multi-degree-of-freedom pressure head control device 21 controls the up and down movement of the pressure head body 22 relative to the additive substrate 243 to achieve adjustable and controllable pressure of the contact pressure head 223 on the metal powder to be processed, and the pulse current generated by the pulse power supply system 4 is used to perform pulse current processing on the metal powder to be processed through the additive substrate 243 and the contact pressure head 223. ;

[0006] The present invention also provides an application of a contact pre-pressing additive manufacturing device in the field of additive manufacturing, which comprises: placing metal powder on an additive substrate 243, wherein the powder particle size is 10 to 200 μm, and the additive substrate 243 and the metal powder have the same components or a material with good wettability with the metal powder component is selected; starting a numerical control system 3 and a program control computer 5, and using an inert gas bottle 1 to fill the inside of an additive manufacturing body 2, the oxygen concentration inside the additive manufacturing body 2 is less than 80 ppm, and starting a motion mechanism 234 so that the scraper The scraper 232 and the roller 233 move synchronously, and the movement speed of the two relative to the additive substrate 243 is 0.02-0.1 m / s. The scraper 232 lays a metal powder with a thickness of 500-2000 μm on the additive substrate 243, and the roller 233 applies a pressure of 50-800 N to the laid metal powder for compaction; in order to adapt to different processes and the overlap rate between surfaces, the contact pressure head 223 is a circular, square or curved surface, and the effective contact area of ​​the contact pressure head 223 is 1-150 mm 2In order to adapt to different materials and process parameters, the contact pressure head 223 is one of red copper, chromium zirconium copper, aluminum oxide copper, beryllium copper, tungsten copper, tungsten or molybdenum; the distance between the contact pressure head 223 and the surface of the metal powder to be processed is 1 to 5 mm, and the multi-degree-of-freedom pressure head control device 21 controls the movement speed of the pressure head body 22 relative to the additive substrate 243 to be 0.05 to 1 m / s. The multi-degree-of-freedom pressure head control device 21 controls the movement speed of the pressure head body 22 relative to the additive substrate 243 to be 0.5 to 1.5 cm / s, and the multi-degree-of-freedom pressure head control device 21 controls the up and down movement of the pressure head body 22 relative to the substrate 243 to achieve adjustable and controllable pressure of the contact pressure head 223 on the metal powder to be processed. The pressure applied by the contact pressure head 223 to the metal powder is 50 to 3000 N, and the pressure application time is 10-2000 ms. After the above steps reach the set values, the pulse current system 4 automatically starts to contact the pressure head. The metal powder between 223 and the additive substrate 243 is transmitted with a pulse current, wherein the pulse current has a voltage of 3 to 20 V, a current of 50 to 9000 A, a frequency of 20 to 1500 Hz, and a time of 50 to 800 ms. During the additive manufacturing process, the contact press head 223 will generate heat due to the electrical action, so it is necessary to ensure that the temperature of the contact press head 223 is constant during the additive manufacturing process. When the contact press head 223 exceeds the set temperature, the press head temperature monitoring and cooler 222 will be started to restore the temperature to the set temperature. The pressure head temperature monitoring and cooler 222 detect a temperature range of 20 to 800 ° C, so that the processing process and parameters of each area to be processed are consistent, and then the press head body 22 moves to the next area of ​​the additive substrate 243 at a left and right moving speed, and performs a continuous additive molding process according to the above-mentioned pressurization and pulse current until the additive molding of the metal powder on the entire additive substrate 243 is completed, and finally a metal profile is formed.

[0007] Furthermore, the metal powder is one of TC4 titanium alloy powder, 6061 aluminum alloy powder, K213 high temperature alloy powder, In718 high temperature alloy powder, TA1 titanium alloy powder, pure magnesium powder, AZ91 magnesium alloy powder, WE43 magnesium alloy powder, duplex stainless steel powder, high entropy alloy powder or tungsten carbide powder.

[0008] Compared with the prior art, the present invention has the following beneficial effects:

[0009] The prior art additive manufacturing device adopts a micro-melt pool spot welding mode. Due to spot welding, the overlap between the micro-melt pools will have leakage or discontinuity during the molding process, thereby forming holes. In addition, this spot welding mode requires point-to-point processing, so the molding efficiency is low. During the additive process, the powder will also splash, there will be no powder to melt, and the powder will leak, which will eventually lead to more pores in the additively manufactured material. In addition to the above, coarse columnar crystals induced by multiple thermal cycles will also appear. These problems lead to anisotropy of properties of each layer of material or the entire material, which ultimately leads to differences in the overall and local mechanical properties of the material, resulting in a decrease in the mechanical properties of the material and difficulty in improving the strength and plasticity simultaneously.

[0010] Compared with the prior art, the present invention achieves the following excellent effects simultaneously through the coordinated regulation of powder, process and process parameters: first, surface contact is used instead of the original point-to-point contact in the forming process, which has a larger additive area and forming efficiency; second, in the forming process, the occurrence of powder splashing, no powder to melt and powder leakage is suppressed, and at the same time, the generation of more pores inside the additive manufacturing material (effectively reducing the porosity) and the discontinuity between regions, the anisotropy of each layer of material or the whole material, etc. are suppressed, and finally the density and mechanical properties of the material are improved simultaneously (including the simultaneous improvement of strength and plasticity); third, the pressure given to the powder by the pressure head during the forming process can make the powder be automatically filled into the pores position, which greatly reduces the formation of pores, thereby making the material densified, improving the bonding strength of the molding material between each layer, increasing the mechanical properties of the molding material, and simultaneously improving the strength and plasticity of the material; fourthly, micro-area forging is achieved by pressurizing under high temperature, which promotes the dynamic and static recrystallization of the molding layer and eliminates coarse columnar crystals; fifthly, the process parameters adopted by the present invention are different when processing different materials. Therefore, the excellent performance of the material of the present invention is not determined by a certain process parameter, but is achieved by the coordinated regulation of powder, substrate and process parameters, none of which is indispensable, and only within the scope of protection of the claims of the present invention can the above-mentioned excellent effects be achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 This is a schematic diagram of the overall device of a contact pre-pressing additive manufacturing device proposed by the present invention;

[0012] Figure 2 This is a schematic diagram of the device for additive manufacturing of the main body 2 of the device of the present invention;

[0013] Figure 3 It is a schematic diagram of the device of the pressure head main body 22 of the present invention;

[0014] Figure 4 It is a schematic diagram of the material cylinder and the powder spreading device 23 of the present invention;

[0015] Figure 5 It is a schematic diagram of the additive substrate settling device 24 of the present invention;

[0016] Figure 6 This is the corrosion metallographic structure diagram of the TC4 titanium alloy profile obtained in Example 5. DETAILED DESCRIPTION

[0017] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0018] Embodiment 1:

[0019] From the attached Figure 1-5 It can be seen that a contact pre-pressing additive manufacturing device comprises: an inert gas bottle 1, an additive manufacturing body 2, a numerical control system 3, a pulse power system 4, a program control computer 5 and a support platform 6, wherein the pulse power system 4 is located above the support platform 6, the numerical control system 3 is located at the upper left of the pulse power system 4, the program control computer 5 is located at the upper right of the pulse power system 4, the additive manufacturing body 2 is located on the left side of the support platform 6, the inert gas bottle 1 is located on the left side of the additive manufacturing body 2, the inert gas bottle 1 provides inert gas for the additive manufacturing body 2, the inert gas in the inert gas bottle 1 is one of argon and helium, the additive manufacturing body 2 is used to stack and additively mold the metal powder to be processed, the numerical control system 3 controls the operation of the additive manufacturing body 2, the pulse power system 4 provides pulse current processing for the additive manufacturing body 2, and the program control computer 5 provides signal processing of process parameters for the numerical control system 3;

[0020] The additive manufacturing body 2 includes: a multi-degree-of-freedom pressure head control device 21, a pressure head body 22, a material cylinder and a powder spreading device 23, an additive substrate settling device 24, a chamber atmosphere and temperature and humidity monitoring system 25, and a main body sealing top cover 26. The additive substrate settling device 24 is located at the bottom of the additive manufacturing body 2, the material cylinder and the powder spreading device 23 are located above the additive substrate settling device 24, the pressure head body 22 is located above the material cylinder and the powder spreading device 23, the multi-degree-of-freedom pressure head control device 21 is located above the pressure head body 22, the chamber atmosphere and temperature and humidity monitoring system 25 is located on the right side of the pressure head body 22, and the main body sealing top cover 26 is located above the multi-degree-of-freedom pressure head control device 21, and the multi-degree-of-freedom pressure head control device 21 is used to control the movement of the pressure head body 22 relative to the additive substrate sinking device 24. The chamber atmosphere and temperature and humidity monitoring system 25 is used to monitor and regulate the gas concentration, temperature and humidity inside the additive manufacturing body 2; the material cylinder and powder spreading device 23 are hollow structures, and the pressure head body 22 and the additive substrate sinking device 24 can move up and down inside the material cylinder and the powder spreading device 23, so that the contact between the pressure head body 22 and the additive substrate sinking device 24 can be adjusted and controlled; the pressure head body 22 includes: a pressure sensor 221 , a pressure head temperature monitoring and cooler 222 and a contact pressure head 223, wherein the contact pressure head 223 is located at the bottom of the pressure head body 22, the pressure head temperature monitoring and cooler 222 is located above the contact pressure head 223, the pressure sensor 221 is located above the pressure head temperature monitoring and cooler 222, the pressure sensor 221 is used to monitor the pressure borne by the contact pressure head 223 in real time, the pressure head temperature monitoring and cooler 222 is used to monitor and control the temperature of the contact pressure head 223 in real time, the contact pressure head 223 directly contacts and pressurizes the metal powder to be processed, and the material cylinder and powder spreading device 23 include: The cylinder wall 231, the scraper 232, the roller 233 and the motion mechanism 234, the cylinder wall 231 is in a thin-walled square shape and surrounds the cylinder and the powder spreading device 23, the scraper 232 is located above the cylinder and the powder spreading device 23, the roller 233 is located behind the scraper 232, and the motion mechanism 234 is located in front of the scraper 232. The scraper 232 is used to control the thickness of the layer of metal powder to be processed, and the roller 233 is used to pre-compact the metal powder to be processed, specifically to pressurize and detect the metal powder layer, and the motion mechanism 234 is used to control the speed of synchronous movement of the scraper 232 and the roller 233;The additive substrate sinking device 24 includes: an up-down moving mechanism 241, an additive substrate fixing platform 242 and an additive substrate 243. The up-down moving mechanism 241 is located at the bottom of the additive substrate sinking device 24, the additive substrate fixing platform 242 is located above the up-down moving mechanism 241, and the additive substrate 243 is located above the additive substrate fixing platform 242. The up-down moving mechanism 241 is used to control the up-down movement of the additive substrate fixing platform 242, the additive substrate fixing platform 242 is used to support the additive substrate 243, the additive substrate fixing platform 242 is closely matched with the cylinder wall 231 to prevent powder leakage, and the additive substrate 243 is used to place the metal powder to be processed and the additive substrate 243 The type of material is adjustable or replaceable, and the multi-degree-of-freedom pressure head control device 21 is used to control the up and down and left and right movements of the pressure head body 22 relative to the additive substrate 243, wherein the multi-degree-of-freedom pressure head control device 21 controls the left and right movements of the pressure head body 22 relative to the additive substrate 243 to adjust the shape of the additively formed metal powder to be processed, and the multi-degree-of-freedom pressure head control device 21 controls the up and down movement of the pressure head body 22 relative to the additive substrate 243 to achieve adjustable and controllable pressure of the contact pressure head 223 on the metal powder to be processed, and the pulse current generated by the pulse power supply system 4 is used to perform pulse current processing on the metal powder to be processed through the additive substrate 243 and the contact pressure head 223. ;

[0021] Example 2

[0022] TA1 titanium alloy powder is placed on the additive substrate 243, wherein the particle size of the TA1 titanium alloy powder is 15 to 30 μm, and the additive substrate 243 and the TA1 titanium alloy powder have the same composition; the numerical control system 3 and the program control computer 5 are turned on, and after the interior of the additive manufacturing body 2 is filled with argon gas bottle 1, the oxygen concentration inside the additive manufacturing body 2 is less than 50 ppm; the scraper 232 and the roller 233 move synchronously, and the movement rate of the two relative to the additive substrate 243 is 0.02 m / s. The scraper 232 achieves the laying of TA1 titanium alloy powder with a thickness of 500 μm on the additive substrate 243, and the roller 233 gives the laid TA1 titanium alloy powder a pressure of 200N for compaction; the contact pressure head 223 is square and its effective contact area is 10 mm 2, the contact press head 223 is chromium-zirconium-copper; the distance between the contact press head 223 and the surface of the TA1 titanium alloy powder is set to 1mm, the multi-degree-of-freedom press head control device 21 controls the pressing head body 22 to move left and right relative to the additive substrate 243 at a speed of 0.1m / s, the multi-degree-of-freedom press head control device 21 controls the pressing head body 22 to move up and down relative to the additive substrate 243 at a speed of 0.5cm / s, and the multi-degree-of-freedom press head control device 21 controls the pressing head body 22 to move up and down relative to the substrate 243 to adjust the pressure of the contact press head 223 on the TA1 titanium alloy powder to be processed. The pressure applied by the contact press head 223 to the TA1 titanium alloy powder is 500N. After applying the pressure for 20ms, after the aforementioned steps reach the set values, the pulse current system 4 automatically starts to press the TA1 titanium alloy between the contact press head 223 and the additive substrate 243. Powder conveying pulse current, the pulse current processing: voltage is 5V, current is 4000A, frequency is 50Hz, time is 50ms. In the above processing process, the contact press head 223 will generate heat due to the electrical action. In order to ensure that the processing process and parameters of each area to be processed are consistent, the press head temperature is constant. The press head temperature monitoring and cooler 222 detect the temperature of 40°C. If the contact press head 223 exceeds the set temperature, the press head temperature monitoring and cooler 222 will be started to control the temperature of the contact press head 223 within the set temperature, so as to realize the continuous additive molding process, and then the press head body 22 moves to the next area of ​​the additive substrate 243 at a left and right moving speed, so as to realize the TA1 titanium alloy powder pressurization and pulse current circulation processing on the additive substrate 243 Continuous additive molding, and finally obtain TA1 titanium alloy profiles.

[0023] Example 3

[0024] 6061 aluminum alloy powder is placed on the additive substrate 243, wherein the particle size of the 6061 aluminum alloy powder is 20-45 μm, and the additive substrate 243 and the 6061 aluminum alloy powder have the same composition; the numerical control system 3 and the program control computer 5 are turned on, and after the interior of the additive manufacturing body 2 is filled with argon gas bottle 1, the oxygen concentration inside the additive manufacturing body 2 is less than 40 ppm; the scraper 232 and the roller 233 move synchronously, and the movement rate of the two relative to the additive substrate 243 is 0.03 m / s. The scraper 232 achieves the laying of 600 μm thick 6061 aluminum alloy powder on the additive substrate 243, and the roller 233 gives the laid 6061 aluminum alloy powder a pressure of 100 N for compaction; the contact pressure head 223 is square and its effective contact area is 15 mm 2, the contact pressure head 223 is copper; the distance between the contact pressure head 223 and the surface of the 6061 aluminum alloy powder is set to 1.5mm, the multi-degree-of-freedom pressure head control device 21 controls the pressure head body 22 to move left and right relative to the additive substrate 243 at a speed of 0.2m / s, the multi-degree-of-freedom pressure head control device 21 controls the pressure head body 22 to move up and down relative to the additive substrate 243 at a speed of 0.6cm / s, and the multi-degree-of-freedom pressure head control device 21 controls the pressure head body 22 to move up and down relative to the substrate 243 to adjust the pressure of the contact pressure head 223 on the 6061 aluminum alloy powder to be processed. The pressure applied by the contact pressure head 223 to the 6061 aluminum alloy powder is 400N. After applying the pressure for 30ms, after the aforementioned steps reach the set values, the pulse current system 4 automatically starts to press the 6061 aluminum between the contact pressure head 223 and the additive substrate 243. The alloy powder is delivered with a pulse current, and the pulse current treatment includes: a voltage of 4V, a current of 2000A, a frequency of 50Hz, and a time of 60ms. During the additive manufacturing process, the contact press head 223 will generate heat due to the electrical action. To ensure that the processing technology and parameters of each area to be processed are consistent, the temperature of the press head is constant. The pressure head temperature monitoring and the cooler 222 detect a temperature of 50°C. If the contact press head 223 exceeds the set temperature, the pressure head temperature monitoring and the cooler 222 will be started to control the temperature of the contact press head 223 within the set temperature, thereby realizing a continuous additive molding process. Then the press head body 22 moves to the next area of ​​the additive substrate 243 at a left and right moving speed, thereby realizing continuous additive molding of the 6061 aluminum alloy powder on the additive substrate 243 by pressurizing and cyclic processing of the pulse current, and finally obtaining a 6061 aluminum alloy profile.

[0025] Example 4

[0026] K213 high-temperature alloy powder is placed on the additive substrate 243, wherein the particle size of the K213 high-temperature alloy powder is 20 to 50 μm, and the additive substrate 243 and the K213 high-temperature alloy powder have the same composition. The numerical control system 3 and the program control computer 5 are turned on, and after the interior of the additive manufacturing body 2 is filled with the argon gas bottle 1, the oxygen concentration inside the additive manufacturing body 2 is less than 30 ppm; the scraper 232 and the roller 233 move synchronously, and the movement rate of the two relative to the additive substrate 243 is 0.05 m / s. The scraper 232 achieves the laying of 600 μm thick K213 high-temperature alloy powder on the additive substrate 243, and the roller 233 gives the laid K213 high-temperature alloy powder a pressure of 300 N for compaction; the contact pressure head 223 is square and its effective contact area is 20 mm 2, the contact pressure head 223 is beryllium copper; the distance between the contact pressure head 223 and the surface of the K213 high-temperature alloy powder is set to 2mm, the multi-degree-of-freedom pressure head control device 21 controls the pressure head body 22 to move left and right relative to the additive substrate 243 at a speed of 0.3m / s, the multi-degree-of-freedom pressure head control device 21 controls the pressure head body 22 to move up and down relative to the additive substrate 243 at a speed of 0.7cm / s, and the multi-degree-of-freedom pressure head control device 21 controls the pressure head body 22 to move up and down relative to the substrate 243, adjusts the pressure of the contact pressure head 223 on the K213 high-temperature alloy powder to be processed, the pressure applied by the contact pressure head 223 to the K213 high-temperature alloy powder is 400N, after the pressure is applied for 40ms, after the above steps reach the set value, the pulse current system 4 automatically starts to contact the pressure head 223 and the additive substrate 243 The K213 high-temperature alloy powder between is transmitted with a pulse current. The pulse current processing includes: a voltage of 6V, a current of 5000A, a frequency of 50Hz, and a time of 100ms. During the additive manufacturing process, the contact press head 223 will generate heat due to the electrical action. In order to ensure that the processing process and parameters of each area to be processed are consistent, the temperature of the press head needs to be constant. The pressure head temperature monitoring and cooler 222 detect the temperature of 60°C. If the contact press head 223 exceeds the set temperature, the pressure head temperature monitoring and cooler 222 will control the contact press head 223 within the set temperature range after cooling. Then the press head body 22 moves to the next area of ​​the additive substrate 243 at a speed of left and right movement, thereby realizing the K213 high-temperature alloy powder pressurization and pulse current circulation processing on the additive substrate 243 for continuous additive molding, and finally obtaining the K213 high-temperature alloy profile.

[0027] Example 5

[0028] TC4 titanium alloy powder is placed on the additive substrate 243, wherein the particle size of the TC4 titanium alloy powder is 20 to 60 μm, and the additive substrate 243 and the TC4 titanium alloy powder have the same composition; the numerical control system 3 and the program control computer 5 are turned on, and after the interior of the additive manufacturing body 2 is filled with the argon gas bottle 1, the oxygen concentration inside the additive manufacturing body 2 is less than 35 ppm; the scraper 232 and the roller 233 move synchronously, and the movement rate of the two relative to the additive substrate 243 is 0.08 m / s. The scraper 232 achieves the laying of TC4 titanium alloy powder with a thickness of 300 μm on the additive substrate 243, and the roller 233 applies a pressure of 150 N to the laid TC4 titanium alloy powder for compaction; the contact pressure head 223 is square and its effective contact area is 25 mm 2, the contact press head 223 is alumina copper; the distance between the contact press head 223 and the surface of the TC4 titanium alloy powder is set to 2.5mm, the multi-degree-of-freedom press head control device 21 controls the pressing head body 22 to move left and right relative to the additive substrate 243 at a speed of 0.4m / s, the multi-degree-of-freedom press head control device 21 controls the pressing head body 22 to move up and down relative to the additive substrate 243 at a speed of 0.8cm / s, and the multi-degree-of-freedom press head control device 21 controls the pressing head body 22 to move up and down relative to the substrate 243, adjusts the pressure of the contact press head 223 on the TC4 titanium alloy powder to be processed, the pressure applied by the contact press head 223 to the TC4 titanium alloy powder is 400N, after the pressure is applied for 50ms, after the above steps reach the set value, the pulse current system 4 automatically starts to contact the press head 223 and the additive substrate 2 43, the pulse current is processed: the voltage is 5V, the current is 4000A, the frequency is 50Hz, and the time is 65ms. During the additive manufacturing process, the contact press head 223 will generate heat due to the electrical action. In order to ensure that the processing process and parameters of each area to be processed are consistent, the temperature of the press head needs to be constant. The pressure head temperature monitoring and cooler 222 detect the temperature of 40°C. If the contact press head 223 exceeds the set temperature, the pressure head temperature monitoring and cooler 222 will control the contact press head 223 within the set temperature range after cooling. Then the press head body 22 moves to the next area of ​​the additive substrate 243 at the speed of left and right movement, so as to realize the pressurization of the TC4 titanium alloy powder on the additive substrate 243 and the continuous additive molding of the pulse current circulation treatment, and finally obtain the TC4 titanium alloy profile.

[0029] No pores were generated inside the TC4 titanium alloy profile obtained in Example 5; Figure 6 This is the metallographic structure diagram of the alloy profile after corrosion. As indicated by the white arrow in the figure, it can be seen that the internal structure of the alloy profile is a fine martensitic structure without any pores. Combined with the direction of the grain boundaries marked by the white dotted box, it can be seen that the present invention forms an equiaxed crystalline structure without producing coarse columnar crystals.

[0030] Example 6

[0031] Place tungsten carbide powder on the additive substrate 243, wherein the particle size of the tungsten carbide powder is 30-60 μm, and the additive substrate 243 is made of 45 steel plate; turn on the numerical control system 3 and the program control computer 5, and use the argon gas bottle 1 to fill the interior of the additive manufacturing body 2, and the oxygen concentration inside the additive manufacturing body 2 is less than 60 ppm; the scraper 232 and the roller 233 move synchronously, and the movement rate of the two relative to the additive substrate 243 is 0.09 m / s. The scraper 232 achieves the laying of tungsten carbide powder with a thickness of 350 μm on the additive substrate 243, and the roller 233 applies a pressure of 600N to the laid tungsten carbide powder for compaction; the contact pressure head 223 is square and its effective contact area is 36 mm 2 The contact pressure head 223 is beryllium copper; the distance between the contact pressure head 223 and the surface layer where the tungsten carbide powder is laid is set to 3mm, the multi-degree-of-freedom pressure head control device 21 controls the pressure head body 22 to move left and right relative to the additive substrate 243 at a speed of 0.5m / s, the multi-degree-of-freedom pressure head control device 21 controls the pressure head body 22 to move up and down relative to the additive substrate 243 at a speed of 0.9cm / s, and the multi-degree-of-freedom pressure head control device 21 controls the pressure head body 22 to move up and down relative to the substrate 243, adjusts the pressure of the contact pressure head 223 on the tungsten carbide powder to be processed, the pressure applied by the contact pressure head 223 on the tungsten carbide powder is 800N, and after the pressure is applied for 60ms, after the above steps reach the set values, the pulse current system 4 automatically starts to press the tungsten carbide between the contact pressure head 223 and the additive substrate 243. Powder conveying pulse current, the pulse current processing: voltage is 10V, current is 8000A, frequency is 50Hz, time is 85ms, during the additive manufacturing process, the contact press head 223 will generate heat due to electrical action. In order to ensure that the processing process and parameters of each area to be processed are consistent, the temperature of the press head needs to be constant. The press head temperature monitoring and cooler 222 detect the temperature of 70°C. If the contact press head 223 exceeds the set temperature, the press head temperature monitoring and cooler 222 will control the contact press head 223 within the set temperature range after cooling, and then the press head body 22 moves to the next area of ​​the additive substrate 243 at a speed of left and right movement, so as to realize the pressurization of tungsten carbide powder on the additive substrate 243 and the continuous single-layer additive molding of pulse current circulation treatment, and finally obtain a No. 45 steel plate with a single-layer tungsten carbide coating.

[0032] In summary: Compared with the prior art, the contact pre-pressing additive manufacturing device obtained by the present invention realizes the additive manufacturing of alloys through the synergistic effect of various components and the coordinated regulation of components and related parameters. While simplifying the process and realizing short-process additive manufacturing, it can overcome the problems of material powder splashing, no powder to melt and powder leakage in the traditional additive manufacturing process. The manufactured metal profile effectively reduces the porosity and the incoherence between regions. Micro-area forging is achieved by pressurizing at high temperature, which solves the problem of coarse columnar crystals caused by reciprocating thermal cycles. For example, a fine martensitic structure is formed, and no Any pores, in addition, an equiaxed crystalline structure is formed without producing coarse columnar crystals; the anisotropy of the local or overall mechanical properties of the material is reduced, and the present invention replaces the traditional point-to-point additive manufacturing micro-melting pool mode with a surface contact additive manufacturing mode. During the additive process, the powder can be automatically filled into the pore position, which greatly reduces the formation of pores and enables the material to be densified. The anisotropy between each layer and the whole is significantly reduced, avoiding stratification and cracking, improving the overall mechanical properties of the material and simultaneously improving the strength and plasticity of the material and the efficiency of additive manufacturing, which is suitable for industrial production.

Claims

1. A contact pre-pressing additive manufacturing device, characterized in that: It includes: An inert gas bottle 1, an additive manufacturing body 2, a numerical control system 3, a pulse power supply system 4, a program control computer 5 and a support platform 6, wherein the pulse power supply system 4 is located above the support platform 6, the numerical control system 3 is located at the upper left of the pulse power supply system 4, the program control computer 5 is located at the upper right of the pulse power supply system 4, the additive manufacturing body 2 is located on the left side of the support platform 6, the inert gas bottle 1 is located on the left side of the additive manufacturing body 2, the inert gas bottle 1 provides inert gas for the additive manufacturing body 2, the inert gas in the inert gas bottle 1 is one of argon and helium, the additive manufacturing body 2 is used to stack and additively mold metal powders to be processed, the numerical control system 3 controls the operation of the additive manufacturing body 2, the pulse power supply system 4 provides pulse current for the additive manufacturing body 2, and the program control computer 5 provides a signal of process parameters for the numerical control system 3; The additive manufacturing body 2 includes: a multi-degree-of-freedom pressure head control device 21, a pressure head body 22, a material cylinder and a powder spreading device 23, an additive substrate settling device 24, an indoor atmosphere and a temperature and humidity monitoring system 25, and a main body sealing top cover 26. The additive substrate settling device 24 is located at the bottom of the additive manufacturing body 2, the material cylinder and the powder spreading device 23 are located above the additive substrate settling device 24, the pressure head body 22 is located above the material cylinder and the powder spreading device 23, the multi-degree-of-freedom pressure head control device 21 is located above the pressure head body 22, the indoor atmosphere and the temperature and humidity monitoring system 25 is located on the right side of the pressure head body 22, and the main body sealing top cover 26. The capping cover 26 is located above the multi-degree-of-freedom pressure head control device 21, and the multi-degree-of-freedom pressure head control device 21 is used to control the movement of the pressure head body 22 relative to the additive substrate sinking device 24. The chamber atmosphere and temperature and humidity monitoring system 25 is used to monitor and regulate the gas concentration, temperature and humidity inside the additive manufacturing body 2; the material cylinder and powder spreading device 23 are hollow structures, and the pressure head body 22 and the additive substrate sinking device 24 can move up and down inside the material cylinder and the powder spreading device 23, so that the contact between the pressure head body 22 and the additive substrate sinking device 24 can be adjusted and controlled; the pressure head body 22 includes: a pressure sensor 2 21. A pressure head temperature monitoring and cooler 222 and a contact pressure head 223. The contact pressure head 223 is located at the bottom of the pressure head body 22. The pressure head temperature monitoring and cooler 222 is located above the contact pressure head 223. The pressure sensor 221 is located above the pressure head temperature monitoring and cooler 222. The pressure sensor 221 is used to monitor the pressure of the contact pressure head 223 in real time. The pressure head temperature monitoring and cooler 222 is used to monitor and control the temperature of the contact pressure head 223 in real time. The contact pressure head 223 directly contacts and pressurizes the metal powder to be processed. The material cylinder and powder spreading device 23 include : Cylinder wall 231, scraper 232, roller 233 and motion mechanism 234, the cylinder wall 231 is in a thin-walled square shape surrounding the cylinder and the powder spreading device 23, the scraper 232 is located above the cylinder and the powder spreading device 23, the roller 233 is located behind the scraper 232, the motion mechanism 234 is located in front of the scraper 232, the scraper 232 is used to control the thickness of the layer of metal powder to be processed, the roller 233 is equipped with a pressure sensor, which can simultaneously complete the pre-compacting treatment and pressure monitoring of the metal powder to be processed, and the motion mechanism 234 is used to control the speed of the synchronous movement of the scraper 232 and the roller 233;The additive substrate sinking device 24 includes: an up-down moving mechanism 241, an additive substrate fixing platform 242 and an additive substrate 243. The up-down moving mechanism 241 is located at the bottom of the additive substrate sinking device 24, the additive substrate fixing platform 242 is located above the up-down moving mechanism 241, and the additive substrate 243 is located above the additive substrate fixing platform 242. The up-down moving mechanism 241 is used to control the up-down movement of the additive substrate fixing platform 242, the additive substrate fixing platform 242 is used to support the additive substrate 243, the additive substrate fixing platform 242 is closely matched with the cylinder wall 231 to prevent powder leakage, and the additive substrate 243 is used to place the metal powder to be processed and the additive substrate 243 The type of material is adjustable or replaceable, and the multi-degree-of-freedom pressure head control device 21 is used to control the up and down and left and right movements of the pressure head body 22 relative to the additive substrate 243, wherein the multi-degree-of-freedom pressure head control device 21 controls the left and right movements of the pressure head body 22 relative to the additive substrate 243 to adjust the shape of the additively formed metal powder to be processed, and the multi-degree-of-freedom pressure head control device 21 controls the up and down movement of the pressure head body 22 relative to the additive substrate 243 to achieve adjustable and controllable pressure of the contact pressure head 223 on the metal powder to be processed, and the pulse current generated by the pulse power supply system 4 is used to perform pulse current processing on the metal powder to be processed through the additive substrate 243 and the contact pressure head 223. ; 2. The application of the contact pre-pressing additive manufacturing device in the field of additive manufacturing is characterized by: It includes: Place metal powder on the additive substrate 243, the metal powder particle size is 10-200 μm, the additive substrate 243 and the metal powder components are the same or a material with good wettability with the metal powder components is selected; turn on the numerical control system 3 and the program control computer 5, use the inert gas bottle 1 to fill the inside of the additive manufacturing body 2, the oxygen concentration inside the additive manufacturing body 2 is less than 80 ppm, turn on the motion mechanism 234 to make the scraper 232 and the roller 233 move synchronously, and the movement rate of the two relative to the additive substrate 243 is 0.02-0.1 m / s, the scraper 232 achieves the laying of metal powder with a thickness of 500-2000 μm on the additive substrate 243, and the roller 233 gives the laid metal powder a pressure of 50-800N for compaction; in order to adapt to different processes and the overlap rate between surfaces, the contact pressure head 223 is a circular, square or curved surface, and the effective contact area of ​​the contact pressure head 223 is 1-150 mm 2 In order to adapt to different materials and process parameters, the contact pressure head 223 is one of red copper, chromium zirconium copper, aluminum oxide copper, beryllium copper, tungsten copper, tungsten or molybdenum; the distance between the contact pressure head 223 and the surface of the metal powder to be processed is 1 to 5 mm, and the multi-degree-of-freedom pressure head control device 21 controls the left and right movement speed of the pressure head body 22 relative to the additive substrate 243 to be 0.05 to 1 m / s, and the multi-degree-of-freedom pressure head control device 21 controls the up and down movement speed of the pressure head body 22 relative to the additive substrate 243 to be 0.5 to 1.5 cm / s, and the multi-degree-of-freedom pressure head control device 21 controls the up and down movement of the pressure head body 22 relative to the additive substrate 243 to achieve adjustable and controllable pressure of the contact pressure head 223 on the metal powder to be processed. The pressure applied by the contact pressure head 223 to the metal powder is 50 to 3000 N, and the pressure application time is 10-2000 ms. After the above steps reach the set values, the pulse current system 4 automatically starts to contact the pressure head 223. The metal powder between the head 223 and the additive substrate 243 is transmitted with a pulse current, wherein the pulse current has a voltage of 3 to 20 V, a current of 50 to 9000 A, a frequency of 20 to 1500 Hz, and a time of 50 to 800 ms. During the additive manufacturing process, the contact press head 223 will generate heat due to the electrical action, so it is necessary to ensure that the temperature of the contact press head 223 is constant during the additive manufacturing process. When the contact press head 223 exceeds the set temperature, the press head temperature monitoring and cooler 222 will be started to restore the temperature to the set temperature. The pressure head temperature monitoring and cooler 222 detect a temperature range of 20 to 800 ° C, so that the processing process and parameters of each area to be processed are consistent, and then the press head body 22 moves to the next area of ​​the additive substrate 243 at a left and right moving speed, and performs a continuous additive molding process according to the above-mentioned pressurization and pulse current until the additive molding of the metal powder on the entire additive substrate 243 is completed, and finally a metal profile is formed.

3. The use of the contact preloading additive manufacturing device according to claim 2 in the field of additive manufacturing, characterized in that: The metal powder is one of TC4 titanium alloy powder, 6061 aluminum alloy powder, K213 high temperature alloy powder, In718 high temperature alloy powder, TA1 titanium alloy powder, pure magnesium powder, AZ91 magnesium alloy powder, WE43 magnesium alloy powder, duplex stainless steel powder, high entropy alloy powder or tungsten carbide powder.

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