3D printing equipment and column-dividing, sequential displacement, static and compensation scanning method

Abstract

The invention discloses 3D printing equipment and a column dividing, sequential displacement, static and compensation scanning method. A scanning field is divided into a plurality of Y-axis columns, each column of the scanning field is divided into a plurality of scanning subareas arranged in the Y direction, a moving frame translating along the X axis is arranged above the scanning field, the moving frame stops for set time after moving by the distance of one column, and the scanning subareas are arranged in the Y direction; a laser scanning module corresponding to a column of scanning subareas on the movable frame scans one scanning subarea in a column of scanning fields, and a precision grating closed-loop system outputs a difference value between a theoretical value and an actual value of the repeated stop precision of the movable frame in real time and sends the difference value into an STL hierarchical file of a formed part in real time. According to the method, the laser scanning modules are divided into multiple groups, coordinate values of scanning points of the laser scanning modules are modified in real time, modified STL hierarchical files are formed, the laser scanning modules conduct path optimization according to the modified STL hierarchical files to scan the scanning partitions, and the overlapping precision of the scanned graph position and the front layer is guaranteed.

Description

Technical Field

[0001] The present invention relates to the technical field of 3D laser printing, and in particular to a 3D printing device and a column, sequential displacement, static, and compensation scanning method. Background Art

[0002] 3D printing 3C (Computer Communication Consumer Electronics) equipment is a fast-growing, large-scale and wide-ranging advanced equipment in the field of contemporary additive manufacturing, which runs the SLM process. Its output and market value have increased year by year, and it can be compared with military 3D printing equipment. The obvious characteristics of 3D printing 3C equipment are that the scan area of ​​the formed part is small, the height is small, the number of layers is small, and the formed part does not need to be spliced.

[0003] 3C equipment is small or medium-sized equipment with only 1 to 2 laser beams (only recently have models with 6 laser beams appeared). 3C parts are mass-produced products, with a particular emphasis on the output of the equipment. In addition, 3C equipment is a high-scanning precision device. In order to improve scanning accuracy, the positional relationship between the galvanometer and the scanning field is fixed. The above reasons cause 3C equipment to have a small proportion of laser scanning time to auxiliary time (changing layers and spreading powder. Cleaning powder, opening doors, taking parts, installing boards, closing doors, inflating, spreading powder) - "scanning time proportion", and a large amount of time is auxiliary time, which seriously affects production efficiency. How to improve the production efficiency of 3D printing 3C equipment is an important issue that the industry is concerned about but has not yet solved. Summary of the invention

[0004] In order to make up for the above shortcomings, the present invention provides a 3D printing device and a column-by-column, sequential displacement, static, and compensated scanning method. The 3D printing device uses a column-by-column, sequential displacement, static, and compensated scanning method for laser scanning and forming, which can effectively improve product forming accuracy and production efficiency and ensure the stability of product forming quality.

[0005] The technical solution adopted by the present invention to solve the technical problem is: a column-by-column, sequential displacement, static, and compensation scanning method, assuming that the X-axis and the Y-axis extend in two directions perpendicular to each other on a horizontal plane, comprising the following steps:

[0006] Step 1: Divide the scanning field: divide the scanning field into a number of columns parallel to the Y axis, and divide each column of the scanning field into a number of scanning partitions arranged along the Y direction;

[0007] Step 2: A mobile frame that moves along the X-axis is set above the scanning field. The length and width of the mobile frame correspond to a column of scanning fields. Several groups of laser scanning modules are installed on the mobile frame. Each group of laser scanning modules can scan a scanning partition in a column of scanning fields.

[0008] Step 3: The mobile frame moves intermittently in the positive order along the X axis above the scanning field. After the mobile frame moves from one end of the scanning field to the other end in the X direction, the mobile frame moves intermittently in the reverse order along the X axis above the scanning field. After the mobile frame moves from one column of scanning fields to the next column of adjacent scanning fields, it remains stationary for a set time.

[0009] Step 4: During the movement of the mobile frame, the precision grating closed-loop system outputs the difference (ΔX, ΔY) between the theoretical value and the actual value of the repeated stop accuracy of the mobile frame in real time, and sends the difference to the STL layered file of the formed part in real time, and then modifies the coordinate values ​​of the scanning points of each group of laser scanning modules in real time, and forms a modified STL layered file;

[0010] Step 5: The laser scanning module scans the corresponding scanning partition according to the optimized path of the modified STL layered file. After the scanning process is completed, the mobile frame moves to the next column position in the scanning field.

[0011] As a further improvement of the invention, in step 1, the scanning field is divided into 4 to 6 columns, each column of the scanning field is 250 to 400 mm wide, each column of the scanning field is divided into 6 to 10 independent scanning partitions, and each group of laser scanning modules emits two laser beams.

[0012] As a further improvement of the invention, the mobile frame is installed in the laser optical layer room of the 3D printing equipment, the mobile frame is guided by a precision linear guide extending along the X-axis, the motor drives the mobile frame through a precision screw nut system, and the precision gratings located on both sides of the mobile frame in the Y direction measure the X displacement of the mobile frame to the two side walls. The precision grating closed-loop system performs closed-loop calculation based on the measurement data of the two precision gratings to obtain the difference (ΔX, ΔY) between the theoretical value and the actual value of the repeatable stopping accuracy of the mobile frame.

[0013] As a further improvement of the invention, the mobile frame adopts a high-rigidity simply supported beam system, the load-bearing capacity of the mobile frame is 300 to 800 kg, the deflection of the mobile frame is 0.1 mm / m, and the displacement speed of the mobile frame is 125 to 200 mm / s.

[0014] A 3D printing device comprises a laser optical chamber, a molding chamber, a molding cylinder, a molding cylinder driving system, a laser scanning module, a mobile frame, a mobile frame driving system, a precision grating closed-loop system, a powder spreading system and a control system, wherein the laser optical chamber is fixedly arranged directly above the molding chamber, a precision linear guide extending in the X direction is fixedly installed on the bottom plate of the laser optical chamber, the mobile frame can be installed on the precision linear guide in a sliding manner in the X direction, a plurality of groups of laser scanning modules are fixedly installed on the mobile frame, the mobile frame driving system drives the mobile frame to intermittently move in the X direction in the laser optical chamber, the grating of the precision grating closed-loop system respectively measures the displacement of the mobile frame in the X direction and the Y direction in real time, the precision grating closed-loop system can calculate the difference (ΔX, ΔY) between the theoretical value and the actual value of the repeated stopping accuracy of the mobile frame in real time, and the precision grating closed-loop system and The control system communicates, the precision grating closed-loop system can send the difference to the STL layered file of the formed part in the control system in real time, and modify the coordinate values ​​of the scanning points of each group of laser scanning modules in the STL layered file in real time. The control system controls each group of laser scanning modules to adjust the scanning point positions according to the modified STL layered file. The upper end of the forming cylinder is fixedly and sealedly installed on the forming bottom surface of the forming chamber. The forming cylinder drive system drives the piston of the forming cylinder to intermittently descend, and a scanning field is formed on the piston of the forming cylinder. The powder spreading system can spread powder quantitatively on the scanning field. The laser beam emitted by each group of laser scanning modules can pass through the light-transmitting plate cover on the upper side of the forming chamber to scan and form a column of scanning fields directly opposite to it. The control system controls the forming cylinder drive system, the laser scanning module, the mobile frame drive system and the powder spreading system to start and stop intermittently according to the design conditions.

[0015] As a further improvement of the invention, the mobile frame includes a high-rigidity simply supported beam frame, a bearing base and a supporting cover plate. The supporting cover and the bearing base are respectively fixedly installed at the upper and lower ends of the simply supported beam frame. The laser scanning module includes a laser, a galvanometer, a collimator and an optical fiber. Several groups of galvanometers are fixedly installed on the bearing base at intervals along the Y direction. Several groups of lasers are fixedly installed on the supporting cover at intervals along the Y direction. Each laser is connected to each galvanometer through an optical fiber to realize the transmission of the laser beam.

[0016] As a further improvement of the invention, the mobile frame driving system includes a motor, a screw, a screw mounting seat and a nut fixing block. The motor and the screw mounting seat are respectively fixedly installed in the laser optical chamber, and both ends of the screw are respectively connected to a screw mounting seat for axial stop and circumferential rotation. The screw extends along the X direction, and one end of the screw is connected to the motor power output shaft. The nut fixing block is fixedly installed at the middle position of the mobile frame along the Y direction, and the nut fixing block is movably screwed to the screw.

[0017] As a further improvement of the invention, a high-strength horizontal substrate is provided on the bottom surface of the laser optical chamber, and a plurality of groups of air-avoiding holes corresponding to each scanning partition of the scanning field are provided on the horizontal substrate. The laser beam emitted by the laser scanning module can pass through the air-avoiding holes and shoot to each scanning partition in the molding chamber. Two precision linear guide rails extending along the X direction are provided on the high-strength horizontal substrate, and the two precision linear guide rails are arranged at intervals along the Y direction. The sliders of the two precision linear guide rails are respectively fixedly connected to the lower side of the bearing base of the movable frame.

[0018] As a further improvement of the invention, two gratings of the precision grating closed-loop system are fixedly installed on both sides of the laser optical chamber along the Y direction, and the two gratings read the position data of both sides of the moving frame along the Y direction in real time.

[0019] As a further improvement of the invention, an air inlet system is provided on one side wall of the molding chamber along the X direction, and an air outlet system is provided on the other side wall of the molding chamber along the X direction.

[0020] The beneficial technical effect of the present invention is as follows: the present invention divides the scanning field into multiple columns, installs the laser scanning module on the mobile frame, and translates the mobile frame so that the laser scanning module sequentially scans the scanning partitions in each column of the scanning field, and scans column by column in sequence without allowing column skipping, thereby avoiding empty travel. During scanning, the mobile frame remains stationary, thereby eliminating dynamic errors in the frame movement. At the same time, the stopping accuracy of the mobile frame is detected and compensated in real time through a precise grating closed-loop system, thereby effectively controlling the stopping accuracy of the frame, ensuring that the scanned graphic position has an extremely high overlap accuracy with the previous layer, and fully ensuring the molding accuracy of 3C precision small parts. The present invention realizes the one-time molding of a large number of 3C precision small parts through a column of laser scanning modules in conjunction with a mobile frame, with high molding efficiency and a large proportion of scanning time, saving equipment cost and time cost, and avoiding the interference problem of assembling too many laser scanning modules. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A schematic diagram of the setting state of a scanning field according to an embodiment of the present invention;

[0022] Figure 2 This is a schematic diagram of the scanning state of the first column scanning field of the present invention;

[0023] Figure 3 This is a schematic diagram of the scanning state of the fifth scanning field of the present invention;

[0024] Figure 4 This is a schematic diagram showing the principle of compensating the repeatable stopping accuracy of the moving frame by the precision grating closed-loop system of the present invention;

[0025] Figure 5 It is a three-dimensional diagram of the 3D scanning device of the present invention. DETAILED DESCRIPTION

[0026] Embodiment: A column-by-column, sequential displacement, static, and compensation scanning method, assuming that the X-axis and the Y-axis extend in two directions perpendicular to each other on a horizontal plane, comprises the following steps:

[0027] Step 1: Divide the scanning field 10: divide the scanning field 10 into a number of columns parallel to the Y axis, and divide each column of the scanning field 10 into a number of scanning partitions arranged along the Y direction;

[0028] Step 2: A mobile frame 20 is arranged above the scanning field 10 to translate along the X-axis. The length and width of the mobile frame 20 correspond to a column of scanning fields 10. A plurality of groups of laser scanning modules 30 are installed on the mobile frame 20. Each group of laser scanning modules 30 can scan a scanning partition in a column of scanning fields 10.

[0029] Step 3: The mobile frame 20 intermittently moves in a positive order along the X axis above the scanning field 10. After the mobile frame 20 moves from one end of the scanning field 10 to the other end in the X direction, the mobile frame 20 intermittently moves in a reverse order along the X axis above the scanning field 10. After the mobile frame 20 moves from one column of scanning fields 10 to the next column of adjacent scanning fields 10, it remains stationary for a set time.

[0030] Step 4: During the movement of the mobile frame 20, the precision grating closed-loop system outputs the difference (ΔX, ΔY) between the theoretical value and the actual value of the repeat stop accuracy of the mobile frame 20 in real time, and sends the difference to the STL layered file of the formed part in real time, and then modifies the coordinate values ​​of the scanning points of each group of laser scanning modules 30 in real time, and forms a modified STL layered file;

[0031] Step 5: The laser scanning module scans the corresponding scanning partition according to the optimized path of the modified STL layered file. After the scanning process is completed, the mobile frame 20 moves to the next column position of the scanning field 10.

[0032] The present invention divides the scanning field 10 into several columns parallel to the Y axis, and then divides each column of the scanning field 10 into several independent scanning partitions along the Y direction, and installs several groups of laser scanning modules 30 on the mobile frame 20. The mobile frame 20 carries the laser scanning module to move intermittently in sequence along the X direction. Each time it moves to the top of a column of the scanning field 10, a group of laser scanning modules 30 scans the scanning partitions one by one. During laser scanning, the mobile frame 20 remains stationary. When the mobile frame 20 moves, the laser scanning module stops scanning. In this way, each column of the scanning field 10 is scanned column by column along the X axis in sequence. After scanning a layer of the scanning field 10, the mobile frame 20 moves in the reverse direction, and then the scanning field 10 is reversely scanned column by column. During scanning, the present invention stops the mobile frame 20 completely. The stationary state can eliminate dynamic errors in the movement of the mobile frame 20: micro-vibration, micro-sway, micro-bumping, etc. This kind of stop is repeated, so there is a problem of repeated stop accuracy of each layer in the same column. The accuracy of the frame stop is guaranteed by the closed-loop control of the precision grating 90. When the mobile frame 20 is moved, the grating 90 of the precision grating closed-loop system measures the position of the mobile frame 20 in real time, and then the precision grating closed-loop system calculates and outputs the difference (ΔX, ΔY) between the theoretical value and the actual value of the repeated stop accuracy of the mobile frame 20 in real time, and sends the difference to the STL layered file of the formed part in real time, and then modifies the coordinate values ​​of the scanning points of each group of laser scanning modules 30 in real time, and forms a modified STL layered file, so that each group of laser scanning modules 30 The scanning points are automatically adjusted during scanning to ensure that the overlap accuracy of the scanned graphic position with the previous layer is ≤0.5-1μm, thus fully ensuring the molding accuracy of 3C precision small parts. This method of automatic calculation and compensation through a precision grating closed-loop system avoids the practice of improving the repeated stopping accuracy of the frame through hardware, thereby greatly reducing the cost of the positioning system of the mobile frame 20 and the requirements for the rigidity of the related mechanical structure; the mobile frame 20 of the present invention moves along the positive X direction in the order of the 1st, 2nd, 3rd, 4th, 5th...columns, or moves in the negative X direction in the order of...5th, 4th, 3rd, 2nd, 1st columns, and skipping of columns is not allowed. The purpose of sequential movement is to avoid empty travel.

[0033] In the step 1, the scanning field 10 is divided into 4 to 6 columns, each column of the scanning field 10 is 250 to 400 mm wide, each column of the scanning field 10 is divided into 6 to 10 independent scanning partitions, and each group of laser scanning modules 30 emits two laser beams.

[0034] An embodiment is as follows: the scanning field 10 is divided into 5 columns (respectively, the 1st column, the 2nd column, the 3rd column, the 4th column and the 5th column), each column is divided into 8 independent scanning partitions (the 1st column is divided into 1-1 scanning partition, 1-2 scanning partition, 1-3 scanning partition ... 1-8 scanning partition, the 2nd column is divided into 2-1 scanning partition, 2-2 scanning partition, 2-3 scanning partition ... 2-8 scanning partition, the 3rd column is divided into 3-1 scanning partition, 3-2 scanning partition, 3-3 scanning partition ... 3-8 scanning partition, the 4th column is divided into 4-1 scanning partition, 4-2 scanning partition, 4-3 scanning partition ... 4-8 scanning partition, the 5th column is divided into 5-1 scanning partition, 5-2 scanning partition, 5-3 scanning partition ... 5-8 scanning partition, the width of each column in the X direction is 300 mm, the length of each scanning partition in the Y direction is 200 mm, and the size of the entire scanning field 10 is 1500 mm×1600 mm.

[0035] Each scanning partition corresponds to two laser beams for scanning. During scanning, after scanning the first column of a layer, the moving frame 20 moves to the right to the position of the second column, and after stopping (only 2 seconds), the adjacent second column scanning work begins. By analogy, the scanning work of one layer of all 5 columns is completed. Then the layer is changed and the powder is spread, and then the sequence of the 5th, 4th, 3rd, 2nd, and 1st columns is scanned. The product of the present invention needs to be scanned back and forth thousands of times. After completing all the scanning work of this batch of parts, auxiliary work (powder cleaning, pushing plate-picking, loading plate, lifting cylinder, inflating-powder spreading) is required. Obviously, the time consumption of its auxiliary work corresponds to the scanning work of 16×5=80 laser beams; and general 3C products are mostly scanned by small and medium-sized equipment due to their small size. One auxiliary work of small and medium-sized equipment (similar to the steps of large equipment such as the present invention, and the time consumption is almost the same) corresponds to the work of scanning the same number of layers of 2 to 6 laser beams. It can be seen that the "scanning time ratio" value of the present invention is greatly improved, thereby greatly improving production efficiency.

[0036] Preliminary estimates show that the production efficiency of 10 16-beam laser Super SLM-3C devices (scanning volume L×W×H 1600×1500×250mm3) is the same as that of 150 2-beam lasers with a scanning volume of L×W×H 220×140×200mm 3 )’s production efficiency is comparable to that of the former. Obviously, the costs of factory construction, production operation, logistics management, automation and energy consumption of the latter far exceed those of the former.

[0037] The present invention adopts a mobile frame 20 to install a group of laser scanning modules 30 (laser 301, galvanometer 302, collimator 303 and optical fiber 304) corresponding to a column of scanning fields 10. On the one hand, it can avoid the problem of interference and installation failure caused by fixed installation of laser scanning modules in each scanning partition, and it can also greatly reduce equipment costs and maintenance costs, and reduce installation difficulty.

[0038] The mobile frame 20 is installed in the laser optical layer room of the 3D printing equipment. The mobile frame 20 is guided by a precision linear guide rail 80 extending along the X-axis. The motor drives the mobile frame 20 through a precision screw 204 nut system. The precision gratings 90 located on both sides of the mobile frame 20 in the Y direction measure the X displacement of the mobile frame 20 toward the two side walls. The precision grating closed-loop system performs closed-loop calculation based on the measurement data of the two precision gratings 90 to obtain the difference (ΔX, ΔY) between the theoretical value and the actual value of the repeatability stop accuracy of the mobile frame 20.

[0039] The displacements on both sides of the movable frame 20 are measured respectively by two gratings 90 extending along the X direction, and then the scanning point data of each laser beam in the X direction and the Y direction can be obtained by calculation. The difference between the theoretical value and the actual value of the repeatable stopping accuracy of the movable frame 20 can be obtained by subtracting it from the theoretical position (ΔX, ΔY). Then, by compensating for this difference, the position of each layer during laser scanning molding can be guaranteed to be consistent, avoiding the misalignment between layers, and ensuring the stability of molding accuracy and product quality.

[0040] The mobile frame 20 adopts a high-rigidity simply supported beam system, the carrying capacity of the mobile frame 20 is 300-800 kg, the deflection of the mobile frame 20 is 0.1 mm / m, and the displacement speed of the mobile frame 20 is 125-200 mm / s.

[0041] A 3D printing device includes a laser optical chamber 40, a molding chamber 50, a molding cylinder 60, a molding cylinder driving system 70, a laser scanning module, a mobile frame 20, a mobile frame 20 driving system, a precision grating closed-loop system, a powder spreading system and a control system. The laser optical chamber 40 is fixedly arranged directly above the molding chamber 50. A precision linear guide 80 extending along the X direction is fixedly installed on the bottom plate of the laser optical chamber 40. The mobile frame 20 can be installed on the precision linear guide 80 so as to slide along the X direction. Several groups of laser scanning modules are fixedly installed on the mobile frame. The mobile frame 20 driving system drives the mobile frame 20 to intermittently move along the X direction in the laser optical chamber 40. The grating 90 of the precision grating closed-loop system respectively measures the displacement of the mobile frame 20 in the X direction and the Y direction in real time. The precision grating closed-loop system can calculate the difference (ΔX, ΔY) between the theoretical value and the actual value of the repeat stop accuracy of the mobile frame 20 in real time. The system communicates with the control system, and the precision grating closed-loop system can send the difference to the STL layered file of the formed part in the control system in real time, and modify the coordinate values ​​of the scanning points of each group of laser scanning modules 30 in the STL layered file in real time. The control system controls each group of laser scanning modules 30 to adjust the scanning point positions according to the modified STL layered file. The upper end of the forming cylinder 60 is fixedly and sealedly installed on the forming bottom surface of the forming chamber 50. The forming cylinder drive system 70 drives the piston of the forming cylinder 60 to intermittently descend, and a scanning field 10 is formed on the piston of the forming cylinder 60. The powder spreading system can spread powder on the scanning field 10 in a quantitative manner. The laser beam emitted by each group of laser scanning modules 30 can pass through the upper light-transmitting plate cover of the forming chamber 50 to scan and form a column of scanning fields 10 opposite to it. The control system controls the forming cylinder drive system 70, the laser scanning module, the mobile frame 20 drive system and the powder spreading system to start and stop intermittently according to the design conditions.

[0042] The scanning field is composed of several columns parallel to the Y axis, and each column of the scanning field is composed of several scanning partitions arranged along the Y direction. Each group of laser scanning modules on the mobile frame can scan a scanning partition in a column of scanning fields opposite to the mobile frame, and each group of laser scanning modules on the mobile frame is arranged one by one corresponding to each scanning partition in a column of scanning fields.

[0043] The mobile frame 20 includes a high-rigidity simply supported beam frame 201, a bearing base 202 and a supporting cover plate 203. The supporting cover plate and the bearing base 202 are respectively fixedly installed at the upper and lower ends of the simply supported beam frame 201. The laser scanning module includes a laser 301, a galvanometer 302, a collimator 303 and an optical fiber 304. Several groups of galvanometers 302 are fixedly installed on the bearing base 202 at intervals along the Y direction. Several groups of lasers 301 are fixedly installed on the supporting cover plate at intervals along the Y direction. Each laser 301 is connected to each galvanometer 302 through an optical fiber 304 to realize the transmission of the laser beam.

[0044] The driving system of the mobile frame 20 includes a motor, a screw 204, a screw mounting seat 205 and a nut fixing block 206. The motor and the screw mounting seat 205 are respectively fixedly mounted in the laser optical chamber 40. The two ends of the screw 204 are respectively connected to a screw mounting seat 205 for axial stop and circumferential rotation. The screw 204 extends along the X direction, and one end of the screw 204 is connected to the motor power output shaft. The nut fixing block 206 is fixedly mounted at the middle position of the mobile frame 20 along the Y direction, and the nut fixing block 206 is movably screwed with the screw 204. The nut fixing block 206 is set in the middle position of the mobile frame 20. The nut fixing block 206 can be set at the front and rear sides of the simply supported beam frame 201 of the mobile frame 20 along the X-axis direction to improve the transmission stability.

[0045] A high-strength horizontal substrate 401 is provided on the bottom surface of the laser optical chamber 40. The horizontal substrate is provided with a plurality of groups of air-avoiding holes 4011 corresponding to each scanning partition of the scanning field 10. The laser beam emitted by the laser scanning module can pass through the air-avoiding holes 4011 and be directed to each scanning partition in the molding chamber 50. Two precision linear guides 80 extending along the X direction are provided on the high-strength horizontal substrate 401. The two precision linear guides 80 are arranged at intervals along the Y direction. The sliders of the two precision linear guides 80 are respectively fixedly connected to the lower side of the bearing base 202 of the moving frame 20. The two precision linear guides 80 located on both sides of the moving frame 20 in the Y direction cooperate with the screw 204 nut driving mechanism located in the middle of the moving frame 20 to form a stable linear drive system, which can prevent the moving frame 20 from swaying during movement.

[0046] The two gratings 90 of the precision grating closed-loop system are respectively fixedly installed on both sides of the laser optical chamber 40 along the Y direction, and the two gratings 90 read the position data of both sides of the moving frame 20 along the Y direction in real time.

[0047] An air inlet system 501 is provided on one side wall along the X direction in the molding chamber 50, and an air outlet system 502 is provided on the other side wall along the X direction in the molding chamber 50. The air inlet system 501 sends nitrogen gas into the molding chamber 50, so that the product is molded under the protection of the inert gas. At the same time, a wind field is formed in the molding chamber 50, and the wind field is discharged from the air outlet system 502 with dust to ensure the molding quality of the product.

Claims

1. A column-by-column, sequential displacement, static, and compensation scanning method, characterized in that: Assuming that the X-axis and the Y-axis extend in two directions perpendicular to each other on a horizontal plane, the following steps are included: Step 1: Divide the scanning field: divide the scanning field (10) into a number of columns parallel to the Y axis, and divide each column of the scanning field into a number of scanning partitions arranged along the Y direction; Step 2: a movable frame (20) is arranged above the scanning field and is movable along the X-axis, the length and width of the movable frame correspond to a column of scanning fields, and a plurality of groups of laser scanning modules (30) are installed on the movable frame, each group of laser scanning modules can scan a scanning partition in a column of scanning fields; Step 3: The mobile frame moves intermittently in the positive order along the X axis above the scanning field. After the mobile frame moves from one end of the scanning field to the other end in the X direction, the mobile frame moves intermittently in the reverse order along the X axis above the scanning field. After the mobile frame moves from one column of scanning fields to the next column of adjacent scanning fields, it remains stationary for a set time. Step 4: During the movement of the mobile frame, the precision grating closed-loop system outputs the difference between the theoretical value and the actual value of the repeated stop accuracy of the mobile frame in real time, and sends the difference to the STL layered file of the formed part in real time, and then modifies the coordinate values ​​of the scanning points of each group of laser scanning modules in real time, and forms a modified STL layered file; Step 5: The laser scanning module scans the corresponding scanning partition according to the optimized path of the modified STL layered file. After the scanning process is completed, the mobile frame moves to the next column position in the scanning field.

2. The column-by-column, sequential shift, static, and compensation scanning method according to claim 1, characterized in that: In the step 1, the scanning field is divided into 4 to 6 columns, each column of the scanning field is 250 to 400 mm wide, each column of the scanning field is divided into 6 to 10 independent scanning partitions, and each group of laser scanning modules emits two laser beams.

3. The column-by-column, sequential shift, static, and compensation scanning method according to claim 2, characterized in that: The mobile frame is installed in the laser optical layer room of the 3D printing equipment. The mobile frame is guided by a precision linear guide extending along the X-axis. The motor drives the mobile frame through a precision screw nut system. The precision gratings located on both sides of the mobile frame in the Y direction measure the X displacement of the mobile frame to the two side walls. The precision grating closed-loop system performs closed-loop calculation based on the measurement data of the two precision gratings to obtain the difference between the theoretical value and the actual value of the repeated stopping accuracy of the mobile frame.

4. The column-by-column, sequential shift, static, and compensation scanning method according to claim 2, characterized in that: The mobile frame adopts a high-rigidity simply supported beam system, the carrying capacity of the mobile frame is 300-800 kg, the deflection of the mobile frame is 0.1 mm / m, and the displacement speed of the mobile frame is 125-200 mm / s.

5. A 3D printing device for implementing the column, sequential displacement, static, and compensation scanning methods described in claims 1-4, characterized in that: The invention comprises a laser optical chamber (40), a molding chamber (50), a molding cylinder (60), a molding cylinder driving system (70), a laser scanning module, a mobile frame, a mobile frame driving system, a precision grating closed-loop system, a powder spreading system and a control system. The laser optical chamber is fixedly arranged directly above the molding chamber. A precision linear guide rail (80) extending in the X direction is fixedly installed on the bottom plate of the laser optical chamber. The mobile frame is mounted on the precision linear guide rail so as to be able to slide in the X direction. A plurality of groups of laser scanning modules are fixedly installed on the mobile frame. The mobile frame driving system drives the mobile frame to intermittently move in the X direction in the laser optical chamber. The grating (90) of the precision grating closed-loop system respectively measures the displacement of the mobile frame in the X direction and the Y direction in real time. The precision grating closed-loop system can calculate in real time the difference between the theoretical value and the actual value of the repeated stopping accuracy of the mobile frame. The loop system communicates with the control system, the precision grating closed-loop system can send the difference to the STL layered file of the formed part in the control system in real time, and modify the coordinate values ​​of the scanning points of each group of laser scanning modules in the STL layered file in real time. The control system controls each group of laser scanning modules to adjust the scanning point positions according to the modified STL layered file. The upper end of the forming cylinder is fixedly and sealedly installed on the forming bottom surface of the forming chamber. The forming cylinder drive system drives the piston of the forming cylinder to intermittently descend, and a scanning field is formed on the piston of the forming cylinder. The powder spreading system can spread powder quantitatively on the scanning field. The laser beam emitted by each group of laser scanning modules can pass through the light-transmitting plate cover on the upper side of the forming chamber to scan and form a column of scanning fields directly opposite to it. The control system controls the forming cylinder drive system, the laser scanning module, the mobile frame drive system and the powder spreading system to start and stop intermittently according to the design conditions.

6. The 3D printing device according to claim 5, characterized in that: The mobile frame comprises a high-rigidity simply supported beam frame (201), a bearing base (202) and a supporting cover plate (203); the supporting cover plate and the bearing base are respectively fixedly mounted on the upper and lower ends of the simply supported beam frame; the laser scanning module comprises a laser (301), a galvanometer (302), a collimator (303) and an optical fiber (304); a plurality of groups of galvanometers are fixedly mounted on the bearing base at intervals arranged along the Y direction; a plurality of groups of lasers are fixedly mounted on the supporting cover plate at intervals arranged along the Y direction; and each laser is connected to each galvanometer via an optical fiber to realize the transmission of a laser beam.

7. The 3D printing device according to claim 6, characterized in that: The mobile frame driving system comprises a motor, a screw (204), a screw mounting seat (205) and a nut fixing block (206); the motor and the screw mounting seat are respectively fixedly mounted in the laser optical chamber; both ends of the screw are respectively connected to a screw mounting seat in an axially fixed manner and rotatable in a circumferential direction; the screw extends along the X direction; one end of the screw is connected to the motor power output shaft; the nut fixing block is fixedly mounted at a middle position of the mobile frame along the Y direction; and the nut fixing block is movably threadedly connected to the screw.

8. The 3D printing device according to claim 6, characterized in that: A high-strength horizontal substrate (401) is provided on the bottom surface of the laser optical chamber, and a plurality of groups of air-avoiding holes (4011) corresponding to the scanning subareas of the scanning field are provided on the horizontal substrate, and the laser beam emitted by the laser scanning module can pass through the air-avoiding holes and be emitted to the scanning subareas in the molding chamber, and two precision linear guide rails extending along the X direction are provided on the high-strength horizontal substrate, and the two precision linear guide rails are arranged at intervals along the Y direction, and the sliders of the two precision linear guide rails are respectively fixedly connected to the lower side of the bearing base of the movable frame.

9. The 3D printing device according to claim 5, characterized in that: The two gratings of the precision grating closed-loop system are respectively fixedly installed on both sides of the laser optical chamber along the Y direction, and the two gratings read the position data of both sides of the moving frame along the Y direction in real time.

10. The 3D printing device according to claim 5, characterized in that: An air inlet system (501) is provided on one side wall of the molding chamber along the X direction, and an air outlet system (502) is provided on the other side wall of the molding chamber along the X direction.

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