A gantry type integrated additive and subtractive composite manufacturing device

Abstract

A gantry integrated additive and subtractive composite manufacturing equipment, comprising a machine tool base, a forming platform connected above the machine tool base, a 3-axis gantry milling subtractive device arranged in a sealed forming chamber, a powder feeding mechanism, a powder laying mechanism and a tool magazine installed on the forming platform, a forming base plate arranged in the middle of the forming platform, the forming base plate being connected with a forming cylinder, the forming cylinder being located inside the machine tool base; an optical path system mounting plate is arranged on the upper part of the sealed forming chamber, and an optical path system of an SLM additive device composed of a laser, a beam expander collimator, an optical lens module and a laser galvanometer is arranged on the optical path system mounting plate, the laser galvanometer being opposite to the forming base plate; the 3-axis gantry milling subtractive device and the tool magazine cooperate to realize tool changing; the size of the sealed forming chamber is reduced, the function of adding metal powder during the machining process is realized; the quantitative powder feeding and powder laying functions are realized; good motion sealing performance is achieved, and the machining precision of complex part structures is improved.

Description

Technical Field

[0001] This invention belongs to the field of additive and subtractive composite manufacturing technology, specifically relating to a gantry-type integrated additive and subtractive composite manufacturing equipment. Background Technology

[0002] Additive-subtractive manufacturing (ALM) is a composite manufacturing technology that combines additive manufacturing and subtractive manufacturing. Its principle is to combine additive manufacturing and subtractive manufacturing modules within the same machine; during processing, additive manufacturing and subtractive manufacturing are performed alternately, meaning that after completing several layers of additive manufacturing, subtractive processing is performed on the already formed areas. ALM can form complex and precision parts, improving processing efficiency and accuracy.

[0003] For additive and subtractive manufacturing technologies, a university has developed a selective laser melting and milling composite processing equipment and method (application number: CN201410768535.3). This equipment integrates a 4-axis milling system and a four-station selective laser melting additive manufacturing system. The 4-axis milling system is located inside the sealed forming chamber and is used to cut the layered contours and internal holes of the parts. A forming cylinder and a powder cylinder are arranged below the forming chamber, and the powder spreading arm slides on an independent guide rail. The equipment uses a chain-type tool magazine for tool changing. The working principle of the equipment is as follows: after scanning several layers of metal powder, it switches to milling, which high-speed and precision cuts the layered contours and internal holes of the parts, and removes the protruding parts of the forming surface to improve the powder spreading quality of the next laser forming. However, this equipment has the following drawbacks: First, the forming cylinder and powder cylinder are located below the forming chamber, which increases the volume of the forming chamber, increases the inert gas deoxygenation time, and reduces production efficiency; Second, the powder cylinder is located below the forming chamber, which means that for some large and complex parts, there will be a problem of replenishing powder in the powder cylinder during processing, and this structure cannot replenish powder during the processing of the equipment; Third, the drive motor of the subtractive manufacturing module is exposed to the dust environment, which can easily reduce the service life of the motor, affect the motor's motion accuracy, and thus reduce the quality of the parts processing.

[0004] A company has developed a composite additive and subtractive manufacturing equipment combining laser powder bed melting and 3-axis milling (application number CN202022932075.7). The additive manufacturing and subtractive manufacturing devices are both located in a sealed chamber. The subtractive manufacturing device uses a moving column-type 3-axis milling unit, with the kinematic pairs separated from the additive manufacturing work area by a protective cover. The additive manufacturing device employs selective laser melting. The powder feeding mechanism uses an upward powder feeding method, and the upward powder feeding mechanism is separated from the forming cavity by a dustproof sheet metal partition. During operation, after the additive manufacturing device completes one or more layers of printing, the control system controls the subtractive manufacturing device to process the model outline, and then the additive manufacturing process continues, with the two alternating. However, this equipment has the following drawbacks: First, the forming sealed cavity is large, and the protective cover separates the milling mechanism's kinematic pairs from the additive manufacturing work area, affecting airflow and reducing the efficiency of inert gas deoxygenation, thus impacting processing efficiency. Second, the powder feeding mechanism may experience powder blockage, affecting the quantitative powder feeding efficiency. Summary of the Invention

[0005] To overcome the shortcomings of the prior art, the present invention aims to provide a gantry-type integrated additive and subtractive composite manufacturing equipment. The motion mechanism drive motor, powder hopper, and laser module are arranged outside the sealed forming chamber. The powder spreading mechanism and the 3-axis gantry milling and cutting device share a single guide rail, reducing the size of the sealed forming chamber, accelerating the inert gas deoxygenation speed, avoiding interference from metal dust to the drive motor, and enabling the addition of metal powder during processing. The use of a powder feeding and spreading mechanism with a spiral conveying structure avoids the problem of metal powder clogging the transmission mechanism and achieves quantitative powder feeding and spreading functions. The use of a bellows-type sealing mechanism isolates the sealed forming chamber from the drive motor, providing excellent motion sealing performance and ensuring the overall sealing effect of the equipment. This equipment can further improve the processing accuracy of complex parts.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A gantry-type integrated additive and subtractive manufacturing equipment includes a machine base 1, a forming platform 4 connected above the machine base 1, and a 3-axis gantry milling cutting device 6, a powder feeding mechanism 7, a powder spreading mechanism 8, and a tool magazine 14 mounted on the forming platform 4. The 3-axis gantry milling cutting device 6, the powder feeding mechanism 7, the powder spreading mechanism 8, and the tool magazine 14 are all arranged inside a sealed forming chamber 3. A forming substrate 5 is arranged in the middle of the forming platform 4 and is connected to a forming cylinder 2, which is located inside the machine base 1. An optical path system mounting plate 20 is provided on the upper part of the sealed forming chamber 3. An optical path system of an SLM additive manufacturing device, consisting of a laser 10, a beam expander collimator 11, an optical lens module 12, and a laser galvanometer 13, is arranged on the optical path system mounting plate 20. The laser galvanometer 13 faces the forming substrate 5. The 3-axis gantry milling cutting device 6 and the tool magazine 14 cooperate to achieve tool changing.

[0008] An oxygen sensor 21 is arranged on the top of the sealed forming chamber 3.

[0009] An operating door 22 is provided on the sealed forming chamber 3.

[0010] A bellows-type sealing mechanism 9 is arranged on the side of the sealed forming chamber 3. An air blowing port 18 and a smoke extraction port 19 are arranged on both sides of the forming substrate 5 to blow inert gas during the additive manufacturing process. An x-axis drive motor mounting base 15, a powder spreading mechanism drive motor mounting base 16, and a y-axis drive motor sliding support base 17 are arranged outside the sealed forming chamber 3 to support the corresponding drive motors.

[0011] The 3-axis gantry milling and cutting device 6 uses ball screw kinematic pairs, which have three degrees of freedom in the x, y, and z directions. The x-axis drive motor 601, the y-axis drive motor 606, and the z-axis drive motor 610 drive the x-axis ball screw 602, the y-axis ball screw 607, and the z-axis ball screw 611 to rotate, respectively, to realize the 3-axis milling and cutting function. The x-direction slide 605 of the x-direction guide rail 603 installed on both sides of the forming platform 4 is connected to the gantry frame 604. The y-direction guide rail 608 on the gantry frame 604 is connected to the y-direction motion slide 609 via the y-direction slide. The z-direction guide rail 612 on the y-direction motion slide 609 is connected to the z-direction motion slide 613 via the z-direction slide. An electric spindle 614 is installed on the z-direction motion slide 613.

[0012] The x-axis drive motor 601 and the y-axis drive motor 606 are arranged on the x-axis drive motor mounting base 15 and the y-axis drive motor sliding support base 17, respectively. The z-axis drive motor 610 is a dustproof motor. The x-axis ball screw 602 is provided with an x-axis ball screw sealing ring 615 at the contact part with the sealed forming chamber 3.

[0013] Dust covers 616 for milling mechanisms are installed on the guide rails and ball screws in all directions.

[0014] The powder feeding mechanism 7 adopts a spiral conveying form, including a powder hopper 701 arranged at the top, a sealing cover 702 installed on the top of the powder hopper 701, the powder hopper 701 is connected to the feeding port 706 through the conveying pipe 703, and the feeding port 706 is connected to the powder spreading mechanism 8.

[0015] The conveying pipe 703 is provided with conveying shaft mounting seats 705 at both ends. A spiral blade conveying shaft 704 is installed on the conveying shaft mounting seat 705. The spiral blade conveying shaft 704 can realize the quantitative conveying of metal powder. The speed of conveying metal powder is controlled by adjusting the rotation speed. A magnetic levitation drive motor 707 is installed on the outer side of the upper end of the conveying pipe 703. The magnetic levitation drive motor 707 drives the rotor coil 708 installed on the upper part of the spiral blade conveying shaft 704 to rotate, thereby driving the spiral blade conveying shaft 704 to rotate and realize the function of spiral conveying metal powder.

[0016] The powder spreading mechanism 8 includes a powder spreading mechanism slide 803 that cooperates with the x-direction guide rail 603. The powder spreading mechanism slide 803 is connected to the powder spreading mechanism ball screw 802, and the powder spreading mechanism ball screw 802 is connected to the powder spreading mechanism drive motor 801. A powder spreading box 804 is connected between the two powder spreading mechanism slides 803. The powder spreading box 804 is suspended between the x-direction guide rails 603. A feed inlet 806 is opened on one side of the powder spreading box 804. Two parallel powder spreading scrapers 805 are arranged below the powder spreading box 804. The powder spreading box 804 is divided into a powder dropping chamber 807, a motor mounting chamber 812, and a powder storage chamber 819. Two spiral conveyors rotating in opposite directions are arranged inside the powder dropping chamber 807. The conveying shafts consist of an upper screw conveyor shaft 808 and a lower screw conveyor shaft 810. A gear 815 is installed at the end of the screw conveyor shaft 808, and the gear 815 meshes with a gear 816 installed on the screw conveyor shaft 810. A powder-extracting plate 809 is installed between the screw conveyor shaft 808 and the screw conveyor shaft 810, and a powder-extracting plate 811 is installed between the screw conveyor shaft 810 and the powder storage bin 819. A screw conveyor shaft drive motor 813 is installed in the motor mounting bin 812, and the screw conveyor shaft drive motor 813 is connected to the screw conveyor shaft 810 through a screw conveyor shaft coupling 814. A powder discharge port 820 is opened at the bottom of the powder storage bin 819.

[0017] A ball screw sealing ring 821 is arranged at the contact point between the ball screw 802 of the powder spreading mechanism and the sealed forming chamber 3; the drive motor 801 of the powder spreading mechanism is arranged on the drive motor mounting base 16 of the powder spreading mechanism; the motor mounting chamber 812 and the powder dropping chamber 807 are separated by a partition 817, and a screw conveyor shaft sealing ring 818 is installed at the contact point between the partition 817 and the screw conveyor shaft 1 808 and the screw conveyor shaft 2 810; a dust cover 822 of the powder spreading mechanism is installed on the motion guide rail of the powder spreading mechanism 8.

[0018] The bellows-type sealing mechanism 9 is arranged on the mounting side of the y-axis drive motor 606. The bellows-type sealing mechanism 9 consists of two sliding sealing grooves 901 and two sealing side plates 902 forming a sealing cavity. A sliding sealing cavity 903 is installed in the sliding sealing groove 901. The sliding sealing cavity 903 is installed on the y-axis ball screw 607. Sliding sealing rings 904 are installed on both sides of the sliding sealing cavity 903 in contact with the y-axis ball screw 607. Bellows-type seals 905 are installed on both sides of the sliding sealing cavity 903. The upper and lower surfaces of the bellows-type seals 905 are in close contact with the inner surface of the sliding sealing groove 901. The cavity has vent holes and is filled with inert protective gas. Vent holes 906 are opened on the sealing side plates 902. Two air guide pipes 907 are led out from the vent holes 906 and connected to the gas storage tank 908. The gas storage tank 908 is installed on the gas storage tank bracket 909 and connected to the outer shell of the sealing forming chamber 3 through the gas storage tank bracket 909.

[0019] The tool magazine 14 includes an outer tool magazine cover 1401, on which a tool magazine door 1402 is provided; a tool disc holder 1404 is installed on the outer tool magazine cover 1401 inside the tool magazine door 1402, and a rotating tool disc 1403 is connected to the tool disc holder 1404, which can realize the automatic tool changing function.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0021] (1) Since the present invention arranges the x-axis drive motor, y-axis drive motor, powder spreading mechanism drive motor and powder hopper outside the sealed forming chamber, the size of the sealed forming chamber is reduced. It has the advantages of short inert gas deoxygenation time and the ability to add metal powder during processing, thus avoiding metal dust pollution of the drive motor and extending the service life of the drive motor.

[0022] (2) Since the powder feeding mechanism and the powder spreading mechanism of the present invention adopt the spiral conveying method, they have the advantages of smooth movement of metal powder, no blockage, quantitative conveying of metal powder, and precise control of the amount of powder falling, which improves the powder spreading efficiency and quality, reduces metal powder waste, and saves production costs.

[0023] (3) Since the 3-axis gantry milling cutting device and the powder spreading mechanism of the present invention share the x-direction guide rail, the internal space of the sealed forming chamber is saved, the structure is compact, and the deoxygenation efficiency of inert gas can be improved.

[0024] (4) The present invention uses a bellows-type sealing mechanism to isolate the y-axis drive motor outside the sealing forming chamber. This mechanism can follow the x-axis to move in the x direction and maintain a good sealing effect, ensuring the stability of the oxygen content inside the sealing forming chamber. It has the advantages of reducing the size of the forming sealing cavity, ensuring good sliding sealing performance of the forming sealing chamber, and avoiding metal dust interference with the y-axis drive motor. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the external structure of the present invention.

[0026] Figure 2 This is a schematic diagram of the internal structure of the present invention.

[0027] Figure 3 This is a top view of the internal structure of the present invention.

[0028] Figure 4 This is a schematic diagram of the 3-axis gantry milling device of the present invention.

[0029] Figure 5 This is a top view of the 3-axis gantry milling device of the present invention.

[0030] Figure 6 This is a cross-sectional view of the powder feeding mechanism of the present invention.

[0031] Figure 7 This is a schematic diagram of the powder spreading mechanism of the present invention.

[0032] Figure 8 This is a cross-sectional view of the powder spreading mechanism of the present invention.

[0033] Figure 9 This is a schematic diagram of the bellows-type sealing mechanism of the present invention.

[0034] Figure 10 This is a schematic diagram of the tool magazine structure of the present invention. Detailed Implementation

[0035] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.

[0036] like Figures 1-3As shown, a gantry-type integrated additive and subtractive composite manufacturing equipment includes a machine tool base 1, with a forming platform 4 connected above the machine tool base 1. A 3-axis gantry milling cutting device 6, a powder feeding mechanism 7, a powder spreading mechanism 8, and a tool magazine 14 are installed on the forming platform 4. The 3-axis gantry milling cutting device 6, powder feeding mechanism 7, powder spreading mechanism 8, and tool magazine 14 are all arranged inside a sealed forming chamber 3. A forming substrate 5 is arranged in the middle of the forming platform 4, and the forming substrate 5 is connected to a forming cylinder 2. The forming cylinder 2 is located inside the machine tool base 1. When the equipment is working, the forming cylinder 2 drives the forming substrate 5 downwards, always ensuring that the powder is always on the surface. The surface is flush with the forming platform 4; the upper part of the sealed forming chamber 3 is provided with an optical path system mounting plate 20, on which the optical path system mounting plate 20 is arranged, consisting of a laser 10, a beam expander collimator 11, an optical lens module 12 and a laser galvanometer 13 connected together. The laser galvanometer 13 faces the forming substrate 5, and the laser galvanometer 13 and the 3-axis gantry milling cutting device 6 do not interfere with each other; the powder feeding mechanism 7, the powder spreading mechanism 8, the forming substrate 5, the forming cylinder 2, and the optical path system of the SLM additive device constitute the SLM additive device; the 3-axis gantry milling cutting device 6 and the tool magazine 14 cooperate to realize tool changing.

[0037] An oxygen sensor 21 is arranged on the top of the sealing molding chamber 3 to monitor the changes in oxygen content inside the sealing molding chamber 3 in real time.

[0038] An operating door 22 is provided on the sealed forming chamber 3 to facilitate the removal of the part after processing.

[0039] like Figure 3 As shown, a bellows-type sealing mechanism 9 is arranged on the side of the sealed forming chamber 3, and an air blowing port 18 and a smoke extraction port 19 are arranged on both sides of the forming substrate 5 respectively. Inert gas is blown in during the additive manufacturing process to remove the black smoke generated by laser sintering and improve the quality of additive manufacturing. An x-axis drive motor mounting base 15, a powder spreading mechanism drive motor mounting base 16, and a y-axis drive motor sliding support base 17 are arranged outside the sealed forming chamber 3 to support the corresponding drive motors and ensure the rigidity of the motion system.

[0040] like Figure 4 and Figure 5As shown, the 3-axis gantry milling and cutting device 6 uses ball screw kinematic pairs, which have degrees of freedom in the x, y, and z directions. The x-axis drive motor 601, the y-axis drive motor 606, and the z-axis drive motor 610 drive the x-axis ball screw 602, the y-axis ball screw 607, and the z-axis ball screw 611 to rotate, respectively, to realize the 3-axis milling and cutting function. The x-direction guide rail 603 installed on both sides of the forming platform 4 has an x-direction slide 605 connected to the gantry frame 604. The y-direction guide rail 608 on the gantry frame 604 is connected to the y-direction motion slide 609 via the y-direction slide. The z-direction guide rail 612 on the y-direction motion slide 609 is connected to the z-direction motion slide 613 via the z-direction slide. An electric spindle 614 is installed on the z-direction motion slide 613.

[0041] The x-axis drive motor 601 and the y-axis drive motor 606 are mounted on the x-axis drive motor mounting base 15 and the y-axis drive motor sliding support base 17 on the outside of the sealed forming chamber 3. The z-axis drive motor 610 is a dustproof motor to ensure its working reliability in dusty environments. The x-axis ball screw 602 is provided with an x-axis ball screw sealing ring 615 at the contact part with the sealed forming chamber 3 to ensure sealing performance.

[0042] Dust covers 616 for the milling mechanism are installed on the guide rails and ball screws in all directions to prevent metal dust from entering the moving guide rails and ball screws and affecting the motion accuracy of the 3-axis gantry milling cutting device 6.

[0043] like Figure 6 As shown, the powder feeding mechanism 7 adopts a spiral conveying form, including a powder hopper 701 arranged at the top for storing metal powder. A sealing cover 702 is installed on the top of the powder hopper 701 to ensure the sealing performance of the powder hopper 701. The powder hopper 701 is connected to the feeding port 706 through the conveying pipe 703. The feeding port 706 is connected to the powder spreading mechanism 8.

[0044] The conveying pipe 703 has conveying shaft mounting seats 705 arranged at both ends. A spiral blade conveying shaft 704 is installed on the conveying shaft mounting seat 705. The spiral blade conveying shaft 704 can realize the quantitative conveying of metal powder. The speed of conveying metal powder can be controlled by adjusting the rotation speed. A magnetic levitation drive motor 707 is installed on the outer side of the upper end of the conveying pipe 703. The magnetic levitation drive motor 707 drives the rotor coil 708 installed on the upper part of the spiral blade conveying shaft 704 to rotate through the principle of electromagnetic induction, thereby driving the spiral blade conveying shaft 704 to rotate and realize the spiral conveying of metal powder. The magnetic levitation drive motor 707 can save internal space of the equipment and reduce the interference of metal dust on motor components.

[0045] When the powder feeding mechanism 7 is working, the metal powder falls into the conveying pipe 703 under the action of gravity; the magnetic levitation drive motor 707 drives the spiral blade conveying shaft 704 to rotate, pushing the metal powder downward; the spiral blade conveying shaft can quantitatively convey materials, and its conveying capacity Q is:

[0046]

[0047] In the formula, Q is the conveying capacity of the helical blade conveyor shaft, t / h; D is the diameter of the helical blade conveyor shaft, m; d is the diameter of the helical blade conveyor shaft, m; S is the pitch of the helical blade conveyor shaft, m; n is the rotational speed of the helical blade conveyor shaft, r / min; and ρ is the material density. is the material filling coefficient; C is the inclination angle of the spiral blade conveyor shaft.

[0048] Therefore, the amount of metal powder conveyed by the spiral blade conveying shaft 704 per revolution is constant. By controlling the rotation speed of the spiral blade conveying shaft 704 to make it rotate a certain number of times, the amount of metal powder conveyed can be controlled, thus achieving quantitative conveying of metal powder. Driven by the spiral blade conveying shaft 704, the metal powder is fed into the powder spreading mechanism 8 through the feeding port 706.

[0049] like Figure 7 and Figure 8 As shown, the powder spreading mechanism 8 includes a powder spreading mechanism slide 803 that cooperates with the x-direction guide rail 603. The powder spreading mechanism slide 803 is connected to the powder spreading mechanism ball screw 802. The powder spreading mechanism ball screw 802 is connected to the powder spreading mechanism drive motor 801. The powder spreading mechanism drive motor 801 drives the powder spreading mechanism ball screw 802 to rotate, realizing the reciprocating motion of the powder spreading mechanism on the x-direction guide rail 603, thus achieving the powder spreading function. A powder spreading mechanism ball screw sealing ring 821 is arranged at the contact part between the powder spreading mechanism ball screw 802 and the sealing forming chamber 3 to achieve a good sealing effect. The powder spreading mechanism drive motor 801 is arranged on the powder spreading mechanism drive motor mounting seat 16 outside the sealing forming chamber 3, which isolates the dust environment and improves the working stability.

[0050] A powder spreading box 804 is connected between the two powder spreading mechanism slides 803. The powder spreading box 804 is suspended between the x-direction guide rails 603. A feed port 806 is opened on the left side of the powder spreading box 804 to receive the metal powder conveyed by the powder feeding mechanism 7. Two parallel powder spreading scrapers 805 are arranged below the powder spreading box 804 to spread the metal powder evenly on the forming substrate 5 and improve the powder spreading quality. The powder spreading box 804 is divided into a powder dropping chamber 807, a motor mounting chamber 812, and a powder storage chamber 819. Two spiral conveying shafts rotating in opposite directions are arranged inside the powder dropping chamber 807, namely the upper spiral conveying shaft 1 808 and the lower spiral conveying shaft 2 810. A gear 1 815 is installed on the shaft end of the spiral conveying shaft 1 808, and the gear 1 815 meshes with the gear 2 816 installed on the spiral conveying shaft 2 810. A powder-straining plate 809 is installed between the screw conveyor shaft 8 and the second screw conveyor shaft 810, and a powder-straining plate 811 is installed between the screw conveyor shaft 810 and the powder storage bin 819. A screw conveyor shaft drive motor 813 is installed in the motor mounting bin 812, and the screw conveyor shaft drive motor 813 is connected to the second screw conveyor shaft 810 through a screw conveyor shaft coupling 814. The motor mounting bin 812 is separated from the powder drop bin 807 by a partition 817, creating a dust-free working environment for the drive motor 813. A screw conveyor shaft sealing ring 818 is installed at the contact point between the partition 817 and the screw conveyor shaft 808 and the second screw conveyor shaft 810. A powder drop port 820 is opened at the bottom of the powder storage bin 819, which can drop metal powder onto the forming substrate 5. A dust cover 822 of the powder spreading mechanism is installed on the motion guide rail of the powder spreading mechanism 8 to prevent metal dust from entering the moving parts.

[0051] When the powder spreading mechanism 8 is working, firstly, driven by the powder spreading mechanism drive motor 801, the feed inlet 806 is aligned with the feed inlet 706 of the powder feeding mechanism 7. The powder feeding mechanism 7 then conveys the metal powder through the feed inlet 806 into the powder dropping bin 807. Due to the size limitation of the feed inlet 806, the metal powder accumulates on one side of the powder storage bin 806. At this time, the screw conveyor shaft drive motor 813 drives the screw conveyor shaft 810 to rotate, conveying the metal powder from the left end to the right end of the powder dropping bin 807. Some of the metal powder falls into the powder storage bin 819 through the powder leakage plate 811. Under the push of the screw conveyor shaft 810, another part of the metal powder will accumulate on the right side of the powder dropping bin 807. The rotation direction of the screw conveyor shaft 808 is as follows: Contrary to the second screw conveyor shaft 810, it pushes the metal powder accumulated on the right side of the powder drop hopper 807 to the left. Some of the metal powder falls into the second screw conveyor shaft 810 through the first powder discharge plate 809, while the other part is sent to the feed inlet 806. Therefore, the metal powder circulates in the powder drop hopper 807, avoiding powder accumulation. After the powder storage hopper 819 is full of metal powder, the metal powder conveying stops and the powder spreading work begins. Under the action of gravity, the metal powder falls onto the forming substrate 5 through the powder drop inlet 820, and the powder spreading scraper 805 spreads the metal powder evenly. After completing one powder spreading action, the powder spreading mechanism returns to its original position, and the powder spreading scraper 805 compacts and spreads the spread metal powder again to improve the powder spreading quality.

[0052] like Figure 9 As shown, the bellows-type sealing mechanism 9 is arranged on the mounting side of the y-axis drive motor 606. The bellows-type sealing mechanism 9 consists of two sliding sealing grooves 901 and two sealing side plates 902 forming a sealing cavity. A sliding sealing cavity 903 is installed in the sliding sealing groove 901. The sliding sealing cavity 903 is installed on the y-axis ball screw 607. Sliding sealing rings 904 are installed on both sides of the sliding sealing cavity 903 in contact with the y-axis ball screw 607, which creates a good sealing effect for the sliding sealing cavity. Bellows-type seals 905 are installed on both sides of the sliding sealing cavity 903. The upper and lower surfaces of the bellows-type seals 905 are in close contact with the inner surface of the sliding sealing groove 901. It has air holes inside and is filled with inert protective gas. A vent hole 906 is opened on the sealing side plate 902. Two air guide pipes 907 are led out from the vent hole 906 and connected to the gas storage tank 908. The gas storage tank 908 is installed on the gas storage tank bracket 909 and connected to the outer shell of the sealing forming chamber 3 through the gas storage tank bracket 909.

[0053] The bellows-type sealing mechanism 9 is filled with an inert protective gas at a certain pressure. When the x-axis moves, the sliding sealing cavity 903 moves with the x-axis, and the bellows-type seal 905 extends and contracts with the sliding sealing cavity 903. The gas inside the compressed bellows-type seal 905 is discharged and input into the gas storage tank 908 through the gas guide pipe 907. When the bellows-type seal 905 is stretched, the gas pressure inside the stretched bellows-type seal 905 decreases, and the gas in the gas storage tank 908 is filled into the stretched bellows-type seal 905 through the gas guide pipe 907, so that the gas pressure on both sides is balanced, ensuring the stability of the movement. At the same time, the sliding sealing cavity 903, the bellows-type seal 905 and the inner surface of the sliding sealing groove 901 are tightly fitted, which not only isolates the y-axis drive motor outside the sealing forming chamber, but also ensures a good sliding sealing effect and maintains the stability of the oxygen content in the sealing forming chamber.

[0054] like Figure 10 As shown, the tool magazine 14 includes an outer tool magazine cover 1401, and a tool magazine door 1402 is provided on the outer tool magazine cover 1401; a tool disc holder 1404 is installed on the outer tool magazine cover 1401 inside the tool magazine door 1402, and a rotating tool disc 1403 is connected to the tool disc holder 1404, which can realize the automatic tool changing function.

[0055] The working principle of this invention is as follows:

[0056] The additive and subtractive manufacturing method of this invention is to add and subtract materials simultaneously. Since this invention integrates the SLM additive manufacturing device and the 3-axis gantry milling subtractive device into one device, all motor control and laser galvanometer can be planned through G-code programming, realizing the alternation of additive manufacturing and subtractive manufacturing to produce high-quality complex components.

[0057] Before starting work, in the initial state, the electric spindle 614 and powder spreading mechanism 8 of the 3-axis gantry milling cutting device 6 move to the standby positions on both sides respectively by means of their respective drive motors through ball screws and guide rails. The electric spindle 614 is close to the tool magazine 14, and the powder spreading mechanism 8 moves to the bottom of the powder feeding mechanism 7, connecting the feed port 806 with the feed port 706 of the powder feeding mechanism 7. The forming substrate 5 is returned to the position flush with the upper surface of the forming worktable 4, and the powder hopper 701 is filled with the specified metal powder.

[0058] First, the space inside the sealed forming chamber 3 needs to be protected by an atmosphere. Using various gas pipelines and circulating fans, the oxygen in the working area is exhausted and filled with inert gases such as argon. The oxygen content is monitored in real time by the oxygen content sensor 21 to ensure that the oxygen content is below the critical value during the processing, especially during SLM additive manufacturing. Once these indicators meet the requirements, it enters the standby state.

[0059] Users import the pre-processed data package (including the part's 3D model, material addition / subtraction processing paths, tool selection, electric spindle speed, and laser power) into the control software. After confirming that everything is correct, the user can autonomously perform the complete processing flow. First, pre-processing preparations are performed. The spiral blade conveyor shaft 704 of the powder feeding mechanism 7 begins to rotate, conveying metal powder from the feed inlet 806 of the powder spreading mechanism 8 to the powder dropper 807. To prevent powder accumulation in the powder dropper 807, the first spiral conveyor shaft 808 and the second spiral conveyor shaft 810 rotate in opposite directions, propelling the metal powder in a circulating motion within the powder dropper 807. The metal powder falls into the powder storage hopper 819 through the first powder discharge plate 809 and the second powder discharge plate 811. Once the powder storage hopper 819 is full of metal powder, the conveying of metal powder stops.

[0060] The SLM additive manufacturing process begins with the following steps: the forming substrate 5 descends under the drive of the forming cylinder 2, dropping by the height of one powder layer to be laid; then, the powder spreading mechanism 8 performs powder spreading under the drive of the powder spreading mechanism drive motor 801. Metal powder falls onto the forming substrate 5 through the powder drop port 820, and the powder spreading scrapers 805 on both sides of the powder spreading mechanism spread the metal powder evenly and then return to the initial standby position; subsequently, the laser emitted by the laser galvanometer 13 scans the powder layer surface along the printing path of the part layer, completing the accumulation of one layer of material for the part; the subsequent SLM additive manufacturing process begins with the re-descent of the forming substrate 5 and the re-powder spreading movement of the powder spreading mechanism 8, repeating the cycle to accumulate material layer by layer and generate the part entity.

[0061] After the SLM additive manufacturing process prints a specific number of layers (the number of cycles is set according to the process data package), the laser galvanometer 13 stops working and the subtractive manufacturing process begins: the tool magazine door 1402 of the tool magazine 14 opens, the electric spindle 614 of the 3-axis gantry milling subtractive device 6 selects a suitable tool on the rotating tool head 1403, and then closes the tool magazine door 1402. The electric spindle 614 uses the x, y, and z degrees of freedom of movement to perform subtractive machining on important positions such as the internal structure of the part in order to improve the surface quality and accuracy of the part.

[0062] After the subtractive manufacturing process is completed, the electric spindle 614 of the 3-axis gantry milling subtractive device 6 moves back to its standby position, the laser galvanometer 13 starts working again, and the SLM additive manufacturing process is repeated several times. Then comes the subtractive manufacturing process, and so on, until the high-quality manufacturing of complex parts is finally completed.

[0063] After the part is machined, the electric spindle 614 of the 3-axis gantry milling cutting device 6 moves back to its standby position, the powder spreading mechanism 8 moves to the side close to the tool magazine 14, and the operating door 22 is opened to take out the part.

[0064] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A gantry-type integrated additive and subtractive manufacturing equipment, comprising a machine tool base (1), characterized in that: A forming platform (4) is connected above the machine tool base (1). A 3-axis gantry milling cutting device (6), a powder feeding mechanism (7), a powder spreading mechanism (8), and a tool magazine (14) are installed on the forming platform (4). The 3-axis gantry milling cutting device (6), the powder feeding mechanism (7), the powder spreading mechanism (8), and the tool magazine (14) are all arranged inside the sealed forming chamber (3). A forming substrate (5) is arranged in the middle of the forming platform (4). The forming substrate (5) is connected to the forming cylinder (2). The forming cylinder (2) is located inside the machine tool base (1). An optical path system mounting plate (20) is provided on the upper part of the sealed forming chamber (3). An optical path system of an SLM additive manufacturing device is arranged on the optical path system mounting plate (20), which is composed of a laser (10), a beam expander collimator (11), an optical lens module (12), and a laser galvanometer (13). The laser galvanometer (13) faces the forming substrate (5). The 3-axis gantry milling cutting device (6) and the tool magazine (14) cooperate to change tools. A bellows-type sealing mechanism (9) is arranged on the side of the sealed forming chamber (3), and an air blowing port (18) and a smoke extraction port (19) are arranged on both sides of the forming substrate (5) respectively, so that inert gas is blown in during the additive manufacturing process; an x-axis drive motor mounting base (15), a powder spreading mechanism drive motor mounting base (16) and a y-axis drive motor sliding support base (17) are arranged outside the sealed forming chamber (3). The 3-axis gantry milling cutting device (6) uses a ball screw kinematic pair, which has three degrees of freedom in the x, y, and z directions. The x-axis drive motor (601), y-axis drive motor (606), and z-axis drive motor (610) drive the x-axis ball screw (602), y-axis ball screw (607), and z-axis ball screw (611) to rotate, respectively, to realize the 3-axis milling cutting function. The x-direction slide (605) of the x-direction guide rail (603) installed on both sides of the forming platform (4) is connected to the gantry (604). The y-direction guide rail (608) on the gantry (604) is connected to the y-direction motion slide (609) via the y-direction slide. The z-direction guide rail (612) on the y-direction motion slide (609) is connected to the z-direction motion slide (613) via the z-direction slide. An electric spindle (614) is mounted on the z-axis motion slide (613); the x-axis drive motor (601) and the y-axis drive motor (606) are arranged on the x-axis drive motor mounting base (15) and the y-axis drive motor sliding support base (17); the z-axis drive motor (610) is a dustproof motor; an x-axis ball screw sealing ring (615) is provided at the contact part between the x-axis ball screw (602) and the sealed forming chamber (3); a milling mechanism dust cover (616) is installed on the guide rails and ball screws in each direction. The powder feeding mechanism (7) adopts a spiral conveying form, including a powder hopper (701) arranged at the top, a sealing cover (702) installed on the top of the powder hopper (701), the powder hopper (701) is connected to the feeding port (706) through the conveying pipe (703), and the feeding port (706) is connected to the powder spreading mechanism (8); conveying shaft mounting seats (705) are arranged at both ends of the conveying pipe (703), and a spiral blade conveying shaft (704) is installed on the conveying shaft mounting seat (705). The spiral blade conveying shaft (704) can realize the quantitative conveying of metal powder, and the speed of conveying metal powder is controlled by adjusting the rotation speed; a magnetic levitation drive motor (707) is installed on the outer side of the upper end of the conveying pipe (703), and the magnetic levitation drive motor (707) drives the rotor coil (708) installed on the upper part of the spiral blade conveying shaft (704) to rotate, thereby driving the spiral blade conveying shaft (704) to rotate and realize the function of spiral conveying metal powder; The powder spreading mechanism (8) includes a powder spreading mechanism slide (803) that cooperates with the x-direction guide rail (603). The powder spreading mechanism slide (803) is connected to the powder spreading mechanism ball screw (802), and the powder spreading mechanism ball screw (802) is connected to the powder spreading mechanism drive motor (801). A powder spreading box (804) is connected between the two powder spreading mechanism slides (803). The powder spreading box (804) is suspended between the x-direction guide rails (603). A feed port (806) is opened on one side of the powder spreading box (804). 4) Two parallel powder spreading scrapers (805) are arranged below. The powder spreading box (804) is divided into a powder dropping chamber (807), a motor mounting chamber (812), and a powder storage chamber (819). The powder dropping chamber (807) is equipped with two spiral conveyor shafts rotating in opposite directions, namely the upper spiral conveyor shaft one (808) and the lower spiral conveyor shaft two (810). The shaft end of the spiral conveyor shaft one (808) is equipped with a gear one (815). The gear one (815) and the gear installed on the spiral conveyor shaft two (810) Two (816) meshing; a powder-straining plate one (809) is installed between screw conveyor shaft one (808) and screw conveyor shaft two (810), and a powder-straining plate two (811) is installed between screw conveyor shaft two (810) and powder storage bin (819); a screw conveyor shaft drive motor (813) is installed in the motor mounting bin (812), and the screw conveyor shaft drive motor (813) is connected to screw conveyor shaft two (810); a powder drop outlet (820) is opened at the bottom of the powder storage bin (819); the ball screw (802) of the powder spreading mechanism is connected to the dense The contact area of ​​the sealing chamber (3) is provided with a ball screw sealing ring (821) for the powder spreading mechanism; the powder spreading mechanism drive motor (801) is arranged on the powder spreading mechanism drive motor mounting base (16); the motor mounting chamber (812) and the powder dropping chamber (807) are separated by a partition (817), and a screw conveyor shaft sealing ring (818) is installed at the contact area between the partition (817) and the screw conveyor shaft one (808) and the screw conveyor shaft two (810); a dust cover (822) for the powder spreading mechanism is installed on the motion guide rail of the powder spreading mechanism (8). The bellows-type sealing mechanism (9) is arranged on the mounting side of the y-axis drive motor (606). The bellows-type sealing mechanism (9) consists of two sliding sealing grooves (901) and two sealing side plates (902) forming a sealing cavity. A sliding sealing cavity (903) is installed in the sliding sealing groove (901). The sliding sealing cavity (903) is installed on the y-axis ball screw (607), and sliding sealing cavity sealing rings (904) are installed on both sides that contact the y-axis ball screw (607). Both sides of the sliding sealing cavity (903) have Install the bellows-type seal (905), the upper and lower surfaces of the bellows-type seal (905) are in close contact with the inner surface of the sliding sealing groove (901); it has an air hole inside, filled with inert protective gas; the sealing side plate (902) has a vent hole (906), and two air guide pipes (907) are led out from the vent hole (906) to connect to the gas storage tank (908). The gas storage tank (908) is installed on the gas storage tank bracket (909) and connected to the outer shell of the sealing forming chamber (3) through the gas storage tank bracket (909).

2. The device according to claim 1, characterized in that: An oxygen sensor (21) is arranged on the top of the sealed forming chamber (3); an operating door (22) is opened on the sealed forming chamber (3).

3. The device according to claim 1, characterized in that: The tool magazine (14) includes an outer tool magazine cover (1401), and a tool magazine door (1402) is provided on the outer tool magazine cover (1401). A tool disc holder (1404) is installed on the outer tool magazine cover (1401) inside the tool magazine door (1402). A rotating tool disc (1403) is connected to the tool disc holder (1404). The rotating tool disc (1403) can realize the automatic tool changing function.

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