Automatic tool changer of 3D printer and printing tool changing control method

Abstract

The application relates to an automatic tool changing device of a 3D printer and a printing tool changing control method. The automatic tool changing device comprises a tool base block, a rotating mechanism, a lifting mechanism and a control system. The tool base block is connected with the rotating mechanism and is driven to rotate by the rotating mechanism. A plurality of mounting structures for mounting scrapers are arranged on the tool base block and are arranged on the same circle around the rotation axis of the tool base block. The lifting mechanism can drive the tool base block and the rotating mechanism to move linearly along the Z direction to be close to or away from the working groove of the scraper frame. The lifting mechanism can lock the tool base block in a working position and a switching position. When the tool base block is in the working position, the scraper mounted thereon can normally work in the working groove. When the tool base block is in the switching position, the scraper leaves the working groove. The control system is connected with the rotating mechanism and the lifting mechanism.

Description

Technical Field

[0001] This invention relates to the field of 3D printing technology, specifically to an automatic tool changer for a 3D printer and a tool changer control method. Background Technology

[0002] In existing selective laser melting metal 3D printing equipment, each machine is always equipped with one or more types of squeegees during the printing process. However, during printing, it's possible to encounter situations where the same part has both lattice and solid structures (rubber squeegees are better suited for lattice structures, while hard squeegees are better suited for solid structures). Therefore, neither hard nor rubber squeegees can achieve optimal printing results. Furthermore, since the powder spreading process is a repetitive cycle, the powder spreading squeegee often fails due to frequent use. Once a squeegee fails, the printing process may be interrupted, requiring machine shutdown for squeegee repair and blade replacement. Moreover, the parts are generally protected with inert gas during printing, and the shutdown and restart process wastes gas. Therefore, stopping to change squeegees increases printing time and costs, affects print quality, and increases the scrap rate. Market research has not found any mature equipment or publicly available patents that offer a good solution to this problem. Summary of the Invention

[0003] In view of the shortcomings of the prior art described above, the technical problem to be solved by the present invention is to provide an automatic tool changing device for a 3D printer and a printing tool changing control method, which can realize automatic tool changing without stopping the machine, thereby improving printing efficiency and quality and reducing printing costs.

[0004] To achieve the above objectives, the present invention provides an automatic tool changer for a 3D printer, which is installed in the working slot of the scraper holder of the 3D printer. The automatic tool changer includes a tool base, a rotating mechanism, a lifting mechanism, and a control system. The tool base is connected to and driven to rotate by the rotating mechanism. The tool base has multiple mounting structures for mounting scrapers, and the multiple mounting structures are arranged circumferentially on the same circle around the rotation axis of the tool base. The lifting mechanism can drive the tool base and the rotating mechanism to move synchronously along the Z-axis to the working slot near or away from the scraper holder. The lifting mechanism can lock the tool base in the working position and the switching position. When the tool base is in the working position, the scraper mounted on it can work normally in the working slot. When it is in the switching position, the scraper leaves the working slot. The control system is connected to both the rotating mechanism and the lifting mechanism.

[0005] Furthermore, the mounting structure on the tool base block is a tool slot.

[0006] Furthermore, multiple mounting structures on the tool base are evenly arranged circumferentially around its axis of rotation.

[0007] Furthermore, it also includes a guiding mechanism, which includes a guiding structure disposed on the scraper holder and a guiding block installed on the guiding structure. The guiding block is fixed to the tool base block and can move linearly in the Z direction in coordination with the guiding structure.

[0008] Furthermore, the rotating mechanism includes a rotating motor, which is mounted on a guide block, and the conveying shaft of the rotating motor is connected to the tool base block.

[0009] Furthermore, it also includes a locking structure provided on the guide block. The locking structure includes a mounting hole on the guide block, a spring provided at the bottom of the mounting hole, and a pin provided in the mounting hole and abutting against the end of the spring. The outer end of the pin is spherical and extends out of the mounting hole. The scraper holder is also provided with a limiting groove extending along the Z direction. The side of the limiting groove is provided with a first limiting hole and a second limiting hole. When the guide block is located in the limiting groove and the tool base block is in the working position, the pin is aligned with the first limiting hole, and when it is in the switching position, it is aligned with the second limiting hole.

[0010] Furthermore, it also includes an automatic unlocking mechanism, which includes a plug rod and a driving component. The driving component can drive the plug rod to be inserted into the first limiting hole and the second limiting hole. The control system is connected to the driving component.

[0011] Furthermore, the lifting mechanism includes a rack, a gear meshing with the rack, and a drive motor connected to the gear. The drive motor is fixed on the scraper holder. The rack is along the Z-direction in its length direction. The rack is fixed to the tool base block in the Z-direction and can rotate relative to the rotation axis of the tool base block.

[0012] Further, the lifting mechanism includes a first connecting block, a first support arm, a second support arm, a third support arm, a fourth support arm, a second connecting block, a lead screw, a first nut, a second nut, and a drive motor. The drive motor is mounted on the scraper holder and can move linearly along the Z-direction on the scraper holder. The lead screw is connected to the drive motor. The first nut is screwed onto the lead screw. The second nut is screwed onto the lead screw with its thread direction opposite to that of the first nut, or the second nut is automatically movable and mounted on the lead screw. The first connecting block is fixed on the scraper holder. One end of the first support arm is hinged to the first connecting block and the other end is hinged to the first nut. One end of the second support arm is hinged to the first connecting block and the other end is hinged to the second nut. One end of the third support arm is hinged to the second connecting block and the other end is hinged to the first nut. One end of the fourth support arm is hinged to the second connecting block and the other end is hinged to the second nut. The second connecting block is fixedly connected to the tool base block.

[0013] The present invention also provides a printing tool changing control method for a 3D printer, wherein the 3D printer has the above-mentioned automatic tool changing device, and the printing tool changing control method includes the following steps:

[0014] S1. Based on the proportion of the crystal structure in the part to be printed, different printing types are classified, and the required squeegees are determined. The squeegees correspond to the printing types. Various squeegees are installed on the tool base of the automatic tool changer, and the angular position of each squeegee on the tool base is recorded.

[0015] S2. Import the 3D model of the part to be printed into the computer, generate a printing program according to the printing task, and generate a tool change control program according to the printing type in the printing task and the angle and position of the scraper on the tool base. The tool change control program includes several tool change instructions, and the tool change instructions correspond to the printing type of the printing task. The tool change instructions include the tool change time and the rotation angle of the tool base.

[0016] S3. Start the printing program and begin printing. If the print type changes during the printing process, the tool change control program executes the corresponding tool change command, controlling the automatic tool changer to start changing the tool, so that the required doctor blade is in the doctor blade working position.

[0017] As described above, the automatic tool changer and printing tool changer control method of the present invention have the following beneficial effects:

[0018] By configuring a tool base block, a rotating mechanism, a lifting mechanism, and a control system, different scrapers are mounted on different mounting structures of the tool base block. When a tool change is required, the control system controls the lifting mechanism to move the tool base block and the rotating mechanism synchronously along the Z-axis to the switching position, at which point the tool base block is at an appropriate distance from the working slot. Then, at the switching position, the rotating mechanism drives the tool base block to rotate to the working slot corresponding to its scraper. The lifting mechanism then drives the tool base block back to the working position, where the scraper reaches its working position, completing the tool change. The entire tool change process can be performed without manual operation. This automatic tool changer can automatically change tools without stopping the printer, offering high tool change efficiency, improving printing efficiency and quality, and reducing printing costs. It can automatically change tools according to the printing situation, ensuring high efficiency and precision, effectively reducing printing time and costs, improving print quality, and lowering the scrap rate. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the automatic blade changing device of the present invention in the scraper holder.

[0020] Figure 2 for Figure 1 A magnified view of circle C.

[0021] Figure 3This is a schematic diagram of the structure of an embodiment of the automatic tool changer of the present invention.

[0022] Figure 4 for Figure 1 Side view.

[0023] Figure 5 for Figure 4 Sectional view along direction AA.

[0024] Figure 6 for Figure 4 BB-direction sectional view.

[0025] Figure 7 A schematic diagram of the arrangement of tool slots on the tool base block in this invention.

[0026] Figure 8 A schematic diagram showing the interaction between the tool base block and the baffle in the working position of this invention.

[0027] Figure 9 A schematic diagram of the structure of Embodiment 2 of the automatic tool changer of the present invention.

[0028] Figure 10 A schematic diagram of the lifting mechanism in Example 2.

[0029] Component designation explanation

[0030] 1. Scraper holder

[0031] 11 Working slots

[0032] 12 Powder Dropper

[0033] 13 Limiting grooves

[0034] 14 First limiting hole

[0035] 15 Second limiting hole

[0036] 2. Tool base block

[0037] 21 Tool slot

[0038] 3 baffles

[0039] 31 Through-hole groove

[0040] 4. Rotating mechanism

[0041] 41 Rotating motor

[0042] 42 Connecting shaft

[0043] 5. Lifting mechanism

[0044] 501 rack

[0045] 502 Gear

[0046] 503 drive motor

[0047] 504 First Connector Block

[0048] 505 First Support Arm

[0049] 506 Second Support Arm

[0050] 507 Third Support Arm

[0051] 508 Fourth Support Arm

[0052] 509 Second Connecting Block

[0053] 510 lead screw

[0054] 6. Guiding mechanism

[0055] 61 Guide rail

[0056] 62 guide blocks

[0057] 7 Pins Detailed Implementation

[0058] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification.

[0059] It should be understood that the structures, proportions, sizes, etc., depicted in the accompanying drawings of this specification are merely for illustrative purposes to aid those skilled in the art in understanding and reading the content disclosed herein, and are not intended to limit the conditions under which the invention can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to the size, without affecting the effects and objectives achieved by the invention, should still fall within the scope of the technical content disclosed herein. Furthermore, the terms such as "upper," "lower," "left," "right," and "middle" used in this specification are merely for clarity and are not intended to limit the scope of the invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the invention's implementation.

[0060] See Figures 1 to 10 The present invention provides an automatic blade changer for a 3D printer, which is installed in the working slot 11 of the blade holder 1 of the 3D printer. During normal operation, the blade is located in the working slot 11 and in an appropriate position. The working slot 11 has powder drop troughs 12 on both sides.

[0061] The automatic tool changer of the present invention includes a tool base block 2, a rotating mechanism 4, a lifting mechanism 5, and a control system. The tool base block 2 is connected to the rotating mechanism 4 and is driven to rotate by the rotating mechanism 4. The tool base block 2 is provided with multiple mounting structures for mounting the scraper blades, and the multiple mounting structures are arranged circumferentially on the same circle around the rotation axis of the tool base block 2. The lifting mechanism 5 can drive the tool base block 2 and the rotating mechanism 4 to move synchronously along the Z-axis to approach or move away from the working slot 11 of the scraper holder 1. During operation, the working slot 11 of the scraper holder 1 faces downward, the Z-axis is the up and down direction, and the lifting mechanism 5 can lock the tool base block 2 in the working position and the switching position. When the tool base block 2 is in the working position, the scraper blade mounted on it works normally in the working slot 11. When it is in the switching position, the scraper blade leaves the working slot 11. The control system is connected to both the rotating mechanism 4 and the lifting mechanism 5. In the present invention, the control system of the automatic tool changer can be set independently or can be borrowed from the printer's own control system.

[0062] The automatic tool changing device of the present invention can install different scrapers on different mounting structures of the tool base block 2. During normal operation, the tool base block 2 is located in the working position, and one of the scrapers on it is located in the working groove 11. When a tool change is required, the control system controls the lifting mechanism 5 to move synchronously along the Z-direction, moving the tool base block 2 and the rotating mechanism 4 away from the working groove 11 of the scraper holder 1 and reaching the switching position. At this time, the tool base block 2 and the working groove 11 have an appropriate distance, and the tool on it will not interfere with or collide with the scraper holder 1 during rotation. Then, at the switching position, the rotating mechanism 4 drives the tool base block 2 to rotate until the corresponding scraper on it faces the working groove 11. Then, the lifting mechanism 5 drives the tool base block 2 back to the working position, and the scraper reaches the working position, completing the tool change. The entire tool change process can be performed without manual operation and can be carried out at all non-powder spreading times, including laser sintering, scraper lifting, etc. The tool change time lasts about 0.1-5 seconds. The automatic tool changer of the present invention can automatically change the tool without stopping the machine, with high tool changing efficiency, which can improve printing efficiency and quality and reduce printing costs.

[0063] The automatic tool changer of the present invention will be further described in the following one or two specific embodiments.

[0064] Example 1:

[0065] See Figures 1 to 8 This is a structural schematic diagram of Embodiment 1. In this embodiment, see... Figure 1 and Figure 3 Both the scraper holder 1 and the tool base 2 are elongated, with their length direction defined as the X-axis and their width direction as the Y-axis. As a preferred design, the mounting structure on the tool base 2 is a tool slot 21, see [reference]. Figure 7The tool slot 21 extends along the X direction and has a T-shaped cross-section. The slot is wide inside and narrow at the opening, making installation simple; the scraper is simply inserted into the slot. The number of tool slots 21 on the tool base block 2 can be set according to actual needs, preferably 2 to 4. See [reference needed]. Figure 7 Furthermore, the multiple mounting structures on the tool base block 2 are evenly arranged around its rotation axis, making it easy to control the rotation angle of the tool base block 2 when changing tools.

[0066] In this embodiment, see Figure 2 , Figure 3 and Figure 5 As a preferred design, the automatic tool changer also includes a guide mechanism 6. The guide mechanism 6 includes a guide structure mounted on the scraper holder 1 and a guide block 62 mounted on the guide structure. The guide structure uses a guide rail 61, fixedly mounted on the scraper holder 1; alternatively, it can be a guide rod or a guide groove. The guide block 62 is fixed to the tool base block 2. Specifically, the guide block 62 is fixedly connected to the tool base block 2 via a connecting shaft 42. The guide block 62 can move linearly along the Z-direction on the guide rail 61, thereby guiding the movement of the tool base block 2 stably and reliably. Preferably, a guide mechanism 6 is provided at both ends of the tool base block 2 along the X-direction. Alternatively, the guide block 62 can also be fixedly connected to the rotating mechanism 4, i.e., indirectly fixed to the tool base block 2.

[0067] In this embodiment, see Figure 2 , Figure 3 and Figure 5 The rotating mechanism 4 includes a rotating motor 41, which is mounted on a guide block 62 on one side of the tool base block 2. The conveying shaft of the rotating motor 41 is fixedly connected to the tool base block 2 through a connecting shaft 42. The rotating motor 41 drives the tool base block 2 to rotate. The structure is simple and the control of the rotation angle is precise and efficient. When the rotating motor 41 stops, it has a certain locking function, and the tool base block 2 no longer rotates.

[0068] In this embodiment, further, see... Figure 3 and Figure 5The automatic tool changer also includes a locking structure on the guide block 62. The locking structure includes a mounting hole (not shown in the figure) on the guide block 62, a spring (not shown in the figure) at the bottom of the mounting hole, and a pin 7 in the mounting hole that abuts against the end of the spring. The outer end of the pin 7 is spherical and extends out of the mounting hole. Preferably, the guide block 62 has a locking structure on both sides in the Y direction. The scraper holder 1 also has a limiting groove 13 extending in the Z direction. The limiting groove 13 has a first limiting hole 14 and a second limiting hole 15 on both sides. When the guide block 62 is in the limiting groove 13, the pin 7 is aligned with the first limiting hole 14 when the tool base block 2 is in the working position. Under the action of the spring, the pin 7 is inserted into the first limiting hole 14, thereby stably limiting the tool base block 2 in the working position. When the tool base block 2 is in the switching position, it is aligned with the second limiting hole 15. Under the action of the spring, the pin 7 is inserted into the second limiting hole 15, thereby stably limiting the tool base block 2 in the switching position.

[0069] In this embodiment, an automatic unlocking mechanism is further included. Each first limiting hole 14 and second limiting hole 15 is equipped with an automatic unlocking mechanism. The automatic unlocking mechanism includes a rod and a driving component. The driving component can be an electric cylinder. The control system is connected to the driving component. The driving component can drive the rod to insert into the first limiting hole 14 and the second limiting hole 15. When switching is required, the automatic unlocking mechanism at the first limiting hole 14 activates, inserting the rod into the first limiting hole 14 to push out the pin 7, thus locking the guide block 62. This allows the lifting mechanism 5 to smoothly move the tool base block 2. After the tool base block 2 leaves the working position, the driving component drives the rod to leave the first limiting hole 14. Similarly, after the tool base block 2 has rotated to the switching position, the automatic unlocking mechanism at the second limiting hole 15 activates, inserting the rod into the second limiting hole 15 to push out the pin 7. This allows the lifting mechanism 5 to smoothly move the tool base block 2 back to the working position. After the tool base block 2 leaves the switching position, the driving component drives the rod to leave the second limiting hole 15. Of course, in other embodiments, the automatic unlocking mechanism may also adopt other suitable structures.

[0070] In this embodiment, as a preferred design, see [reference needed]. Figure 3 and Figure 6Furthermore, the lifting mechanism 5 includes a rack 501, a gear 502 meshing with the rack 501, and a drive motor 503 connected to the gear 502. The drive motor 503 is fixed on the scraper holder 1. The rack 501 is along the Z-direction in its length direction. The rack 501 is fixed to the tool base 2 in the Z-direction and can rotate relative to the rotation axis of the tool base 2. Specifically, the rack 501 is fitted onto the connecting shaft 42 and can rotate relative to it. The drive motor 503 drives the gear 502 to rotate, which in turn drives the rack 501 to move linearly along the Z-direction through meshing transmission, thereby driving the tool base 2 to move linearly up and down. The rotation of the tool base 2 does not affect the movement of the rack 501. The rack 501 can be restricted from rotation by the scraper holder 1 and can only move in the Z-direction. The drive motor 503 also has a certain self-locking capability, which can limit the vertical position of the tool base 2 when it stops rotating.

[0071] In this embodiment, see Figure 1 The scraper holder 1 has an internal cavity for mounting the automatic blade changer. The working slot 11 is located on the lower side, while the other sides can be enclosed. For a preferred design, see [reference needed]. Figure 10 The automatic tool changer also includes a baffle 3, which is installed on the scraper holder 1 and close to the upper side of the working groove 11, located between the working groove 11 and the tool base block 2. The baffle 3 has a through hole groove 31. When the tool base block 2 is in the working position, the tool slot 21 aligned with the working groove 11 passes through the through hole groove 31 and is located on the lower side of the baffle 3. The remaining tool slots 21 are located on the lower side of the baffle 3, and the tool base block 2 is close to the side of the through hole groove 31. The baffle 3 has a certain blocking effect, which can effectively prevent metal powder from seeping in from the lower side and affecting the motors in the rotating mechanism 4 and the lifting mechanism 5. During continuous operation, the dust is blocked by the baffle 3 and it is difficult for it to enter the interior of the scraper holder 1 and cause harm, thus playing a certain protective role.

[0072] Example 2:

[0073] See Figures 9 to 10The diagram below shows the structure of Embodiment 2. In this embodiment, a different lifting mechanism 5 is used. Specifically, the lifting mechanism 5 includes a first connecting block 504, a first support arm 505, a second support arm 506, a third support arm 507, a fourth support arm 508, a second connecting block 509, a lead screw 510, a first nut (not shown in the diagram), a second nut (not shown in the diagram), and a drive motor 503. The drive motor 503 is mounted on the scraper holder 1 and can move linearly along the Z direction on the scraper holder 1. The lead screw 510 is connected to the drive motor 503 along the Y direction. The first nut and the second nut are both screwed onto the lead screw 510. The threads are opposite in direction. Of course, the second nut can also be installed on the lead screw in a freely movable manner. The first connecting block 504 is fixed on the scraper holder 1 and located directly above the lead screw 510. One end of the first support arm 505 is hinged to the first connecting block 504 and the other end is hinged to the first nut. One end of the second support arm 506 is hinged to the first connecting block 504 and the other end is hinged to the second nut. One end of the third support arm 507 is hinged to the second connecting block 509 and the other end is hinged to the first nut. One end of the fourth support arm 508 is hinged to the second connecting block 509 and the other end is hinged to the second nut. The second connecting block 509 is fixedly connected to the tool base block 2. During operation, the drive motor 503 rotates, causing the lead screw 510 to rotate. The first nut and the second nut move on the lead screw 510 in opposite directions. When the first nut and the second nut come together, the first support arm 505, the second support arm 506, the third support arm 507, and the fourth support arm 508 all rotate and push downwards. The second connecting block 509 moves downwards, thereby causing the tool base block 2 to move downwards. Conversely, when the first nut and the second nut separate, the first support arm 505, the second support arm 506, the third support arm 507, and the fourth support arm 508 all retract upwards, and the second connecting block 509 moves upwards, thereby causing the tool base block 2 to move upwards. Furthermore, the lifting mechanism 5 in this embodiment has a good self-locking function, ensuring that the position of the tool base block 2 remains stable in the working position and the switching position. In this embodiment, a lifting mechanism 5 is provided at both ends of the tool base block 2 in the X direction, and the two lifting mechanisms 5 operate synchronously.

[0074] The lifting mechanism 5 in this embodiment has a good locking function when the drive motor 503 stops, so the locking structure in Embodiment 1 is not required, although a locking structure can be provided. In this embodiment, an upper partition and a lower partition can be provided above and below the guide block 62 respectively to limit the guide block 62. When the tool base block 2 moves to the working position, the guide block 62 abuts against the lower partition; when the tool base block 2 moves to the switching position, the guide block 62 abuts against the upper partition, thereby achieving the limiting function.

[0075] Except for the structure described above, the other structures in this embodiment are basically the same as those in Embodiment 1, so they will not be described in detail here.

[0076] Of course, the lifting mechanism and rotating mechanism in the automatic tool changer of the present invention are not limited to the specific embodiments described above. Some existing suitable mechanisms can also be used to achieve the above functions.

[0077] The present invention also provides a printing tool changing control method for a 3D printer. The 3D printer has the above-mentioned automatic tool changing device, and the printing tool changing control method includes the following steps:

[0078] S1. Based on the proportion of the lattice structure in the part to be printed, different printing types are divided, and the required squeegee is determined. The squeegee corresponds to the printing type. Various squeegees are installed on the tool base block 2 of the automatic tool changer, and the angular position of each squeegee on the tool base block 2 is recorded.

[0079] In this step, specifically, when the proportion of the crystal structure is 0% to 30%, it can be recorded as printing type A, corresponding to the use of the hardest squeegee (Mohs hardness range: 6-7.5); when it is 30% to 60%, it can be recorded as printing type B, using a medium-hardness squeegee (Mohs hardness range: 4.5-6); and when it is 60% to 100%, it can be recorded as printing type C, using the softest squeegee (Mohs hardness range: less than 4.5). Taking the printed part as a nickel-based alloy structure as an example, it is necessary to select one of a stainless steel squeegee, a ceramic squeegee, or a rubber squeegee, and install one stainless steel squeegee, one rubber squeegee, and one ceramic squeegee respectively in the three tool slots 21 of the tool base block 2.

[0080] S2. The 3D model of the part to be printed is imported into the computer. A printing program is generated according to the printing task. Based on the printing type in the printing task and the angle and position of the scraper on the tool base 2, a tool changing control program is generated. The tool changing control program includes several tool changing instructions, and the tool changing instructions correspond to the printing type of the printing task. The tool changing instructions include the tool changing time and the rotation angle of the tool base 2. The printing program and the tool changing control program can be imported into the printer's control system. In this embodiment, the automatic tool changing device adopts the printer's control system, using the MCP (Materialize Control Platform). The printing program and the tool changing control program are imported into the MCP (Materialize Control Platform).

[0081] Specifically, parts are generally printed in layers, from bottom to top. Each layer can be considered a printing task. The proportion of the crystal structure varies in each layer, which may belong to the same printing type or different printing types. If the crystal structure changes when printing the next layer, it belongs to a different printing type, for example, from 0% to 30% to 30% to 60%. At this time, a tool change is required. Therefore, based on the printing type in the overall printing task, the time when a tool change is required and the required scraper are determined to generate a tool change instruction. If multiple tool changes are required, multiple tool change instructions are set accordingly.

[0082] S3. Start the printing program and begin printing. When the printing type changes during the printing process (usually when printing the next layer), the tool change control program executes the corresponding tool change command, controls the automatic tool changer to start changing the tool, and places the required scraper in the scraper working position.

[0083] Specifically, the tool change process is as follows: The MCP sends a tool change command to the lifting mechanism 5 and the rotating mechanism 4. First, it controls the lifting mechanism 5 to move the tool base block 2 from the working position to the switching position. The lifting mechanism 5 then stops. Next, it controls the rotating mechanism 4 to drive the tool base block 2 to rotate by a specified angle so that the required scraper faces the working slot 11. Then, the lifting mechanism 5 moves the tool base block 2 from the switching position to the working position. The lifting mechanism 5 stops, and the tool base block 2 stabilizes in the working position, completing the tool change process. Tool changes can occur during non-powder-spreading moments, including laser sintering and scraper lifting. The tool change time is approximately 0.1 to 5 seconds, making it highly efficient. When printing parts with nickel-based alloy structures, a rubber scraper is selected when the lattice structure ratio of the printed layer is less than 30%, a stainless steel scraper is selected when the lattice structure ratio of the printed layer is 30%-60%, and a ceramic scraper is selected when the lattice structure ratio of the printed layer is greater than 60%.

[0084] As can be seen from the above, the automatic tool changing device and printing tool changing control method of the present invention can automatically change the tool according to the printing situation without stopping the machine. It is efficient and accurate, and can effectively reduce printing time and printing costs, improve printing quality, and reduce scrap rate.

[0085] In summary, this invention effectively overcomes the various shortcomings of the prior art and has high industrial application value.

[0086] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. An automatic tool changer for a 3D printer, for installation in the working slot (11) of the scraper holder (1) of the 3D printer, characterized in that: The automatic tool changer includes a tool base (2), a rotating mechanism (4), a lifting mechanism (5), and a control system. The tool base (2) is connected to the rotating mechanism (4) and is driven to rotate by the rotating mechanism (4). The tool base (2) is provided with multiple mounting structures for mounting scrapers, and the multiple mounting structures are arranged circumferentially on the same circle around the rotation axis of the tool base (2). The lifting mechanism (5) can drive the tool base (2) and the rotating mechanism (4) to move synchronously along the Z-direction to the working slot (11) near or away from the scraper holder (1). The lifting mechanism (5) can lock the tool base (2) in the working position and the switching position. The tool base (2) is located in the working position. The scraper installed on it can work normally in the working groove (11) when it is in the switching position, and the scraper leaves the working groove (11); the control system is connected to the rotating mechanism (4) and the lifting mechanism (5); it also includes a guide mechanism (6), which includes a guide structure set on the scraper holder (1) and a guide block (62) installed on the guide structure. The guide block (62) is fixed to the tool base block (2), and the guide block (62) can move linearly in the Z direction in coordination with the guide structure; it also includes a locking structure set on the guide block (62), which includes a mounting hole opened on the guide block (62), a spring set at the bottom of the mounting hole, and a locking mechanism. A pin (7) is placed in the mounting hole and abuts against the end of the spring. The outer end of the pin (7) is spherical and extends out of the mounting hole. The scraper holder (1) is also provided with a limiting groove (13) extending along the Z direction. The side of the limiting groove (13) is provided with a first limiting hole (14) and a second limiting hole (15). The guide block (62) is located in the limiting groove (13). When the tool base block (2) is in the working position, the pin (7) is aligned with the first limiting hole (14) and when it is in the switching position, it is aligned with the second limiting hole (15). It also includes an automatic unlocking mechanism. The automatic unlocking mechanism includes a plug rod and a driving member. The driving member can drive the plug rod to be inserted into the first limiting hole (14) and the second limiting hole (15). In 5), the control system is connected to the drive unit; the mounting structure on the tool base block (2) is a tool slot (21); the scraper holder (1) has an internal mounting cavity for an automatic tool changer, the working slot (11) is located on the lower side of the mounting cavity, and the other sides of the mounting cavity are closed, and also includes a baffle (3), the baffle (3) is installed on the scraper holder (1), near the upper side of the working slot (11) and located between the working slot (11) and the tool base block (2), the baffle (3) has a through hole slot (31), the tool slot (21) aligned with the working slot (11) when the tool base block (2) is in the working position passes through the through hole slot (31) and is located on the lower side of the baffle (3).

2. The automatic tool changer according to claim 1, characterized in that: Multiple mounting structures on the tool base block (2) are evenly arranged circumferentially around its rotation axis.

3. The automatic tool changer according to claim 1, characterized in that: The rotating mechanism (4) includes a rotating motor (41), which is mounted on a guide block (62). The conveying shaft of the rotating motor (41) is connected to the tool base block (2).

4. The automatic tool changer according to claim 1, characterized in that: The lifting mechanism (5) includes a rack (501), a gear (502) meshing with the rack (501), and a drive motor (503) connected to the gear (502). The drive motor (503) is fixed on the scraper holder (1). The rack (501) is along the Z direction in the length direction. The rack (501) is fixed to the tool base block (2) in the Z direction and can rotate relative to the rotation axis of the tool base block (2).

5. The automatic tool changer according to claim 1, characterized in that: The lifting mechanism (5) includes a first connecting block (504), a first support arm (505), a second support arm (506), a third support arm (507), a fourth support arm (508), a second connecting block (509), a lead screw (510), a first nut, a second nut, and a drive motor (503). The drive motor (503) is mounted on the scraper holder (1) and can move linearly along the Z direction on the scraper holder (1). The lead screw (510) is connected to the drive motor (503). The first nut is screwed onto the lead screw (510), and the second nut is screwed onto the lead screw (510) with its thread direction opposite to that of the first nut, or the second nut can move automatically. The first connecting block (504) is fixed on the scraper holder (1), and one end of the first support arm (505) is hinged to the first connecting block (504) and the other end is hinged to the first nut. One end of the second support arm (506) is hinged to the first connecting block (504) and the other end is hinged to the second nut. One end of the third support arm (507) is hinged to the second connecting block (509) and the other end is hinged to the first nut. One end of the fourth support arm (508) is hinged to the second connecting block (509) and the other end is hinged to the second nut. The second connecting block (509) is fixedly connected to the tool base block (2).

6. A print tool change control method of a 3D printer, characterized by: The 3D printer has an automatic tool changer as described in any one of claims 1 to 5, and the printing tool changer control method includes the following steps: S1. Based on the proportion of the lattice structure in the part to be printed, different printing types are divided, and the required scrapers are determined. The scrapers correspond to the printing types. Various scrapers are installed on the tool base block (2) of the automatic tool changer, and the angular position of each scraper on the tool base block (2) is recorded. S2. Import the 3D model of the part to be printed into the computer, generate a printing program according to the printing task, and generate a tool change control program according to the printing type in the printing task and the angle and position of the scraper on the tool base block (2). The tool change control program includes several tool change instructions, and the tool change instructions correspond to the printing type of the printing task. The tool change instructions include the tool change time and the rotation angle of the tool base block (2). S3, starting the printing program, starting printing, when the printing type changes in the printing process, the tool changing control program executes the corresponding tool changing instruction, controls the automatic tool changing device to start tool changing, and makes the required doctor blade in the doctor blade working position.

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