A 3D printing system with linear reciprocating cyclic feeding and its control method

Abstract

A 3D printing system with a linear reciprocating cyclic feeding mechanism, comprising a mounting plate, a doctor blade module, a doctor blade movement module, a forming module, a feeding module, and a lifting module; a printing groove is provided on the mounting plate, and the forming module and the feeding module are respectively connected to the printing groove; the doctor blade movement module is connected to the doctor blade module and drives the doctor blade module to move back and forth. The doctor blade module includes a synchronous plate and a doctor blade, and the doctor blade is rotatably connected to the synchronous plate; the doctor blade has a coating state and a lifted state, and the doctor blade switches between the coating state and the lifted state by rotation. A control method for a 3D printing system with a linear reciprocating cyclic feeding mechanism uses the above-mentioned 3D printing system with a linear reciprocating cyclic feeding mechanism. The present invention can re-coat the excess material generated during the laying of this layer into the forming module or scrape it back into the feeding module again when the doctor blade is reset each time, so as to improve the utilization rate of the printing material and reduce the starting amount of the material required for printing, belonging to the technical field of additive manufacturing.

Description

Technical Field

[0001] The present invention relates to the technical field of additive manufacturing, and particularly relates to a 3D printing system with a linear reciprocating cyclic feeding and a control method thereof. Background Art

[0002] As a rapid prototyping technology, 3D printing technology has unique advantages such as being able to form complex parts, integrated manufacturing, and a relatively short production cycle. In recent years, it has received extensive attention from experts and scholars at home and abroad and has been widely used in fields such as biomedical, aerospace manufacturing, and automotive manufacturing.

[0003] Currently, the common 3D printing technologies mainly include Fused Deposition Modeling (FDM), Selective Laser Sintering (SLS), and StereoLithography Apparatus (SLA / Digital Light Projection, DLP). Among them, the FDM technology has the problem of relatively low forming accuracy. The laser selective melting technology and stereolithography technology with relatively high forming accuracy are all related to the laying of printing materials such as metal powders and ceramic slurries. For additive manufacturing equipment using a combination of a cylinder and a piston, a circular cylinder and a circular piston are often used based on the sealing performance of the piston. However, when laying printing materials, especially high-viscosity slurries, the circular cylinder needs to provide 1 to 3 times the amount required for the printing layer thickness to ensure the full and uniform laying of the materials. However, the common linear reciprocating scraper cannot scrape the materials back for reuse when retracting. Most of the materials are scraped into another storage cylinder for storage. However, the materials will be further lost and wasted during this process. Especially for materials such as ceramic slurries, due to their high viscosity, they will adhere to the surface of the equipment wall more. This results in the amount of materials consumed for a complete formed part being often several times more than the amount of materials occupied by the part itself. The utilization rate of the printing materials stored at one time is relatively low. Therefore, the amount of materials required to start printing is also relatively large. This disadvantage is particularly prominent when the cost of printing materials is relatively high. Summary of the Invention

[0004] Aiming at the technical problems existing in the prior art, the object of the present invention is to provide a 3D printing system with a linear reciprocating cyclic feeding that has high printing efficiency and can save materials and a control method thereof.

[0005] To achieve the above object, the present invention adopts the following technical solution: a 3D printing system with linear reciprocating cyclic feeding, comprising a mounting plate, a doctor blade module, a doctor blade movement module, a forming module, a feeding module, and a lifting module; a printing groove is provided on the mounting plate, and the forming module and the feeding module are respectively connected to the printing groove; the doctor blade movement module is connected to the doctor blade module and drives the doctor blade module to move back and forth, the doctor blade module includes a synchronous plate and a doctor blade, and the doctor blade is rotatably connected to the synchronous plate; the doctor blade has a coating state and a lifted state, in the coating state, the blade edge of the doctor blade contacts the bottom surface of the printing groove, in the lifted state, the blade edge of the doctor blade leaves the bottom surface of the printing groove, and the doctor blade switches between the coating state and the lifted state by rotation; the lifting module includes a lifting plate, the lifting plate is movably connected to the mounting plate, and the lifting plate is located on the moving path of the doctor blade module; when the doctor blade module moves forward past the lifting plate, the doctor blade is lifted by the lifting plate to the lifted state, and when the doctor blade module moves backward past the lifting plate, the doctor blade maintains the coating state. After adopting this structure, after the doctor blade completes one coating, when it continues to move forward and contacts the lifting plate, the doctor blade is lifted by the lifting plate, so that the remaining printing material on the doctor blade stays in place. When the doctor blade passes by the lifting plate, the doctor blade drops and resets to the coating state, so that when moving backward, it can scrape the printing material left in place back.

[0006] As a preference, the lifting plate is rotatably connected to the mounting plate, and a first spring for restricting the rotation of the lifting plate is connected between the lifting plate and the mounting plate; the lifting plate has an extended state and a contracted state, the lifting plate in the extended state extends into the area where the doctor blade module moves back and forth, and the lifting plate in the contracted state is located outside the area where the doctor blade module moves back and forth; when the doctor blade module moves forward past the lifting plate, the lifting plate maintains the extended state, and when the doctor blade module moves backward past the lifting plate, the lifting plate rotates to the contracted state under the extrusion of the doctor blade module. After adopting this structure, when the doctor blade moves backward, since the lifting plate is pushed to the contracted state by the doctor blade module, the lifting plate does not affect the state of the doctor blade, and the doctor blade maintains the coating state, so as to scrape the printing material back.

[0007] As a preference, the doctor blade module further includes a doctor blade connecting frame and an adjustment block with adjustable front and rear positions, the doctor blade connecting frame is rotatably connected to the synchronous plate, and the doctor blade is installed on the doctor blade connecting frame; a second spring is connected between the doctor blade connecting frame and the synchronous plate, the second spring is a torsion spring, the adjustment block is located in front of the doctor blade, and the elastic force direction of the second spring on the doctor blade faces the adjustment block. After adopting this structure, when the doctor blade module is not affected by external forces, the doctor blade maintains the coating state under the action of the second spring and the adjustment block. Therefore, after the doctor blade module moves forward past the lifting plate, the doctor blade can be restored to the coating state under the action of the second spring.

[0008] As a preference, the scraper module further includes a motion adapter plate, bolts, and nuts. The motion adapter plate is fixedly connected to the synchronization plate. A strip-shaped through hole is formed in the motion adapter plate, and a mounting hole for installing the bolts is formed in the adjustment block. The rod portion of the bolt passes through the strip-shaped through hole and the mounting hole, and the nut cooperates with the bolt to lock the adjustment block on the motion adapter plate. After adopting this structure, if the laying angle of the scraper needs to be adjusted before starting printing, the nut can be loosened to enable the bolt to slide along the strip-shaped through hole. After the adjustment block moves back and forth with the bolt to a suitable position, the nut is tightened. The scraper connecting frame always abuts against the adjustment block under the action of the second spring, thereby realizing the angle adjustment of the scraper. Then, the height of the scraper can be adaptively adjusted.

[0009] As a preference, the scraper module further includes a damping rotating shaft and a bearing seat. The bearing seat is installed on the motion adapter plate. A bearing is provided in the bearing seat. The scraper connecting frame is connected to the bearing through the damping rotating shaft.

[0010] As a preference, a storage groove is formed in the mounting plate. A side opening is provided on the side of the storage groove. The lifting plate is located in the storage groove in the contracted state and extends out of the storage groove from the side opening in the extended state. The lifting plate is a sector plate, and a rotating shaft is connected to the center of the sector plate. The lifting plate is connected to the mounting plate through the rotating shaft.

[0011] As a preference, the scraper motion module includes a linear module and a slide rail. Both the linear module and the slide rail are installed on the mounting plate. The linear module is connected to the synchronization plate and drives the synchronization plate to move back and forth. The synchronization plate is slidably connected to the slide rail.

[0012] As a preference, the forming module includes a forming cylinder and a forming piston. A printing platform is fixedly installed on the forming piston. The feeding module includes a feeding cylinder and a feeding piston. Both the forming cylinder and the feeding cylinder are fixedly installed below the printing tank. A forming cavity and a feeding cavity are respectively formed in the forming cylinder and the feeding cylinder. The forming cavity and the feeding cavity are both communicated with the inside of the printing tank. The forming piston is slidably embedded in the forming cavity, and the feeding piston is slidably embedded in the feeding cavity. The forming cavity is located in front of the feeding cavity.

[0013] As a preference, a 3D printing system with linear reciprocating cyclic feeding further includes a photocuring module, and the photocuring module includes a light source. The forming module further includes a first lifting platform, which is connected to the forming piston and drives the forming piston to lift. The feeding module further includes a second lifting platform, which is connected to the feeding piston and drives the feeding piston to lift.

[0014] An initial station, a feeding station, a laying station, and a lifting-off station are provided on the moving path of the doctor blade. The feeding station is above the feeding chamber, the laying station is above the forming chamber, the initial station is behind the feeding station, the lifting-off station is in front of the laying station, and the doctor blade contacts the lifting-off plate at the lifting-off station. A control method for a 3D printing system with linear reciprocating cyclic feeding includes the following steps:

[0015] S1, controlling the first lifting platform to drive the forming piston to move downward by a printing layer thickness;

[0016] S2, controlling the second lifting platform to drive the feeding piston to move upward to push the printing material into the printing groove;

[0017] S3, controlling the doctor blade to move forward from the initial station to between the forming station and the lifting-off station, so as to lay the printing material on the printing platform;

[0018] S4, controlling the light source to selectively cure the laid printing material;

[0019] S5, controlling the doctor blade to continue moving forward through the lifting-off station. After the doctor blade passes through the lifting-off station, controlling the doctor blade to move backward to between the lifting-off station and the forming station;

[0020] S6, controlling the printing platform to move downward by a printing layer thickness;

[0021] S7, controlling the feeding piston to move downward;

[0022] S8, if the current laying angle of the doctor blade is zero, controlling the doctor blade to continue moving backward to lay the printing material on the printing platform and return to the initial station, then controlling the light source to selectively cure the laid printing material, and controlling the printing platform to move downward by a printing layer thickness;

[0023] If the current laying angle of the doctor blade is not zero, controlling the doctor blade to continue moving backward to the initial station;

[0024] S9, repeating steps S2 to S8 until the entire model printing is completed.

[0025] The laying angle of the doctor blade being zero means that the doctor blade is perpendicular to the bottom surface of the printing groove.

[0026] S1 and S2 can be carried out simultaneously, and S6 and S7 can be carried out simultaneously.

[0027] Generally speaking, the present invention has the following advantages: In the present invention, after the scraping blade finishes paving, it passes through the lifting plate. The lifting plate lifts it off the printing material and continues to move. After the scraping blade leaves the lifting plate, it falls, and then drives the excess printing material to move back. When the scraping blade resets, the excess printing material is scraped back into the feeding cylinder for reuse, thereby improving the utilization rate of the stored printing material and reducing the amount of material required to print the same part.

[0028] The present invention realizes the cyclic supply of materials in a purely mechanical manner, without the need for additional collection devices or drive modules, which can make the equipment more compact and further reduce costs. With the control method in the present invention, it is possible to reduce the time occupied by material paving while improving the material utilization rate during each material paving. Description of the Drawings

[0029] Figure 1 It is a three-dimensional structure diagram of a 3D printing system with linear reciprocating cyclic feeding.

[0030] Figure 2 It is a partial structure diagram of a 3D printing system with linear reciprocating cyclic feeding.

[0031] Figure 3 It is Figure 2 an enlarged view of area A in

[0032] Figure 4 It is a three-dimensional structure diagram of the scraping blade module.

[0033] Figure 5 It is a three-dimensional structure diagram of the connection between the scraping blade connecting frame and the scraping blade.

[0034] Figure 6 It is a structure diagram of the adjusting block.

[0035] Figure 7 It is a three-dimensional structure diagram of the feeding module and the forming module.

[0036] Figure 8 It is a flowchart of the control method of a 3D printing system with linear reciprocating cyclic feeding.

[0037] Among them, 1 is the mounting plate, 2 is the scraping blade movement module, 3 is the scraping blade module, 4 is the lifting module, 5 is the forming cylinder, 6 is the feeding cylinder, 7 is the first lifting platform, 8 is the second lifting platform, and 9 is the printing platform

[0038] 11 is the printing groove, and 12 is the storage groove.

[0039] 21 is the linear module, and 22 is the slide rail.

[0040] 31 is a squeegee, 32 is a synchronous plate, 33 is a squeegee connecting frame, 34 is a motion adapter plate, 35 is an adjustment block, 36 is a damping rotating shaft, 37 is a second spring, and 38 is a bearing seat.

[0041] 41 is a lifting plate, and 42 is a first spring. Specific embodiments

[0042] The present invention will be further described in detail below in conjunction with specific embodiments.

[0043] Embodiment 1

[0044] A 3D printing system with linear reciprocating cyclic feeding includes a mounting plate, a squeegee module, a squeegee motion module, a forming module, a feeding module, and a lifting module; a printing groove is provided on the mounting plate, and the forming module and the feeding module are respectively connected to the printing groove; the squeegee motion module is connected to the squeegee module and drives the squeegee module to move forward and backward. The squeegee module includes a synchronous plate and a squeegee, and the squeegee is rotatably connected to the synchronous plate; the squeegee has a scraping state and a lifted state. In the scraping state, the blade of the squeegee contacts the bottom surface of the printing groove, and in the lifted state, the blade of the squeegee leaves the bottom surface of the printing groove. The squeegee switches between the scraping state and the lifted state by rotation; the lifting module includes a lifting plate, and the lifting plate is movably connected to the mounting plate. The lifting plate is located on the moving path of the squeegee module; when the squeegee module moves forward past the lifting plate, the squeegee is lifted by the lifting plate to the lifted state, and when the squeegee module moves backward past the lifting plate, the squeegee remains in the scraping state.

[0045] The lifting plate is rotatably connected to the mounting plate, and a first spring for restricting the rotation of the lifting plate is connected between the lifting plate and the mounting plate; the lifting plate has an extended state and a contracted state. The lifting plate in the extended state extends into the area where the squeegee module moves forward and backward, and the lifting plate in the contracted state is located outside the area where the squeegee module moves forward and backward; when the squeegee module moves forward past the lifting plate, the lifting plate remains in the extended state, and when the squeegee module moves backward past the lifting plate, the lifting plate rotates to the contracted state under the extrusion of the squeegee module.

[0046] The squeegee module further includes a squeegee connecting frame and an adjustment block with adjustable front and rear positions. The squeegee connecting frame is rotatably connected to the synchronous plate, and the squeegee is installed on the squeegee connecting frame; a second spring is connected between the squeegee connecting frame and the synchronous plate. The second spring is a torsion spring, and the adjustment block is located in front of the squeegee. The elastic force direction of the second spring on the squeegee is towards the adjustment block.

[0047] The squeegee module further includes a motion adapter plate, a bolt, and a nut. The motion adapter plate and the synchronous plate are fixedly connected. A strip-shaped through hole is provided on the motion adapter plate, and a mounting hole for installing the bolt is provided on the adjustment block. The rod portion of the bolt passes through the strip-shaped through hole and the mounting hole, and the nut cooperates with the bolt to lock the adjustment block on the motion adapter plate.

[0048] The scraper module further includes a damping rotating shaft and a bearing seat. The bearing seat is installed on the moving adapter plate. A bearing is provided inside the bearing seat. The scraper connecting frame is connected to the bearing through the damping rotating shaft.

[0049] A storage groove is formed on the mounting plate. A side opening is provided on the side of the storage groove. The lifting plate is located inside the storage groove in the retracted state and extends out of the storage groove through the side opening in the extended state. The lifting plate is a sector plate. A rotating shaft is connected to the center of the sector plate. The lifting plate is connected to the mounting plate through the rotating shaft.

[0050] The scraper movement module includes a linear module and a slide rail. Both the linear module and the slide rail are installed on the mounting plate. The linear module is connected to the synchronization plate and drives the synchronization plate to move back and forth. The synchronization plate is slidably connected to the slide rail.

[0051] The forming module includes a forming cylinder and a forming piston. A printing platform is fixedly installed on the forming piston. The feeding module includes a feeding cylinder and a feeding piston. Both the forming cylinder and the feeding cylinder are fixedly installed below the printing tank. A forming cavity and a feeding cavity are respectively formed inside the forming cylinder and the feeding cylinder. The forming cavity and the feeding cavity are both communicated with the inside of the printing tank. The forming piston is slidably embedded in the forming cavity, and the feeding piston is slidably embedded in the feeding cavity. The forming cavity is located in front of the feeding cavity.

[0052] A 3D printing system with linear reciprocating cyclic feeding further includes a light curing module. The light curing module includes a light source. The forming module further includes a first lifting platform, which is connected to the forming piston and drives the forming piston to lift and lower. The feeding module further includes a second lifting platform, which is connected to the feeding piston and drives the feeding piston to lift and lower.

[0053] The adjusting block has an arc-shaped surface and abuts against the scraper connecting frame through the arc-shaped surface.

[0054] The number of strip-shaped through holes is two, which are respectively located on both sides of the moving adapter plate.

[0055] The scraper module further includes a spring fixing block, which is fixedly connected to the synchronization plate. Straight grooves are respectively formed on the spring fixing block and the scraper connecting frame. One end of the second spring is embedded in the straight groove on the fixing block, and the other end of the second spring is embedded in the straight groove on the scraper connecting frame.

[0056] The forming cylinder and the feeding cylinder are respectively threadedly connected to the mounting plate.

[0057] Lifting adapter plates are respectively provided on the first lifting platform and the second lifting platform. The first lifting platform and the second lifting platform are respectively connected to the forming cylinder and the feeding cylinder through the lifting adapter plates. Both the first lifting platform and the second lifting platform adopt electric cylinders and are driven by servo motors.

[0058] A 3D printing system with linear reciprocating cyclic feeding further includes a frame, and the mounting plate is fixed inside the frame.

[0059] An initial station, a feeding station, a paving station, and a lifting-off station are provided on the moving path of the scraper. The feeding station is above the feeding chamber, the paving station is above the forming chamber, the initial station is behind the feeding station, the lifting-off station is in front of the paving station, and the scraper contacts the lifting-off plate at the lifting-off station.

[0060] A control method for a 3D printing system with linear reciprocating cyclic feeding includes the following steps:

[0061] S1, controlling the first lifting platform to drive the forming piston to move downward by a printing layer thickness;

[0062] S2, controlling the second lifting platform to drive the feeding piston to move upward to push the printing material into the printing groove;

[0063] S3, controlling the scraper to move forward from the initial station to between the forming station and the lifting-off station, so as to pave the printing material on the printing platform;

[0064] S4, controlling the light source to selectively cure the paved printing material;

[0065] S5, controlling the scraper to continue moving forward through the lifting-off station. After the scraper passes through the lifting-off station, controlling the scraper to move backward to between the lifting-off station and the forming station;

[0066] S6, controlling the printing platform to move downward by a printing layer thickness;

[0067] S7, controlling the feeding piston to move downward;

[0068] S8, if the current paving angle of the scraper is zero, controlling the scraper to continue moving backward to pave the printing material on the printing platform and return to the initial station, then controlling the light source to selectively cure the paved printing material, and controlling the printing platform to move downward by a printing layer thickness;

[0069] If the current paving angle of the scraper is not zero, controlling the scraper to continue moving backward to the initial station;

[0070] S9, repeating steps S2 to S8 until the entire model printing is completed.

[0071] The scraper paving angle being zero means that the scraper is perpendicular to the bottom surface of the printing groove.

[0072] During operation, operate in the order of S1 to S9. Among them, S1 and S2 can be carried out simultaneously or in an interchangeable order, and S6 and S7 are carried out simultaneously or in an interchangeable order.

[0073] In step S3, the squeegee first moves forward rapidly to between the feeding station and the forming station, and then moves slowly past the forming station to spread the printing material on the printing platform. In step S8, if the current spreading angle is zero, control the squeegee to move backward slowly to spread the printing material, and then reset rapidly; if the current spreading angle is not zero, control the squeegee to move backward rapidly to reset to the initial station.

[0074] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present invention shall be equivalent replacement methods and are all included in the protection scope of the present invention.

Claims

1. A 3D printing system with a linear reciprocating cyclic feeding, characterized in that: It includes a mounting plate, a scraper module, a scraper movement module, a forming module, a feeding module, and a lifting module; A printing groove is provided on the mounting plate, and the forming module and the feeding module are respectively connected to the printing groove; The scraper movement module is connected to the scraper module and drives the scraper module to move back and forth. The scraper module includes a synchronous plate and a scraper, and the scraper is rotatably connected to the synchronous plate; The scraper has a scraping state and a lifted state. In the scraping state, the blade of the scraper contacts the bottom surface of the printing groove. In the lifted state, the blade of the scraper leaves the bottom surface of the printing groove. The scraper switches between the scraping state and the lifted state by rotating; The lifting module includes a lifting plate, and the lifting plate is movably connected to the mounting plate. The lifting plate is located on the moving path of the scraper module; when the scraper module moves forward past the lifting plate, the scraper is lifted by the lifting plate to the lifted state. When the scraper module moves backward past the lifting plate, the scraper maintains the scraping state; The lifting plate is rotatably connected to the mounting plate, and a first spring for restricting the rotation of the lifting plate is connected between the lifting plate and the mounting plate; The lifting plate has an extended state and a contracted state. The lifting plate in the extended state extends into the area where the scraper module moves back and forth, and the lifting plate in the contracted state is located outside the area where the scraper module moves back and forth; When the scraper module moves forward past the lifting plate, the lifting plate maintains the extended state. When the scraper module moves backward past the lifting plate, the lifting plate rotates to the contracted state under the extrusion of the scraper module; 2. The 3D printing system for linear reciprocating cyclic feeding according to claim 1, wherein: The scraper module further includes a scraper connecting frame and an adjustment block with adjustable front and rear positions. The scraper connecting frame is rotatably connected to the synchronous plate, and the scraper is installed on the scraper connecting frame; A second spring is connected between the scraper connecting frame and the synchronous plate. The second spring is a torsion spring. The adjustment block is located in front of the scraper, and the elastic force direction of the second spring on the scraper faces the adjustment block; 3. The 3D printing system with linear reciprocating cyclic feeding according to claim 2, characterized in that: The scraper module further includes a movement adapter plate, a bolt, and a nut. The movement adapter plate and the synchronous plate are fixedly connected. A strip-shaped through hole is formed on the movement adapter plate, and a mounting hole for installing the bolt is formed on the adjustment block. The rod portion of the bolt passes through the strip-shaped through hole and the mounting hole, and the nut cooperates with the bolt to lock the adjustment block on the movement adapter plate; 4. A 3D printing system with a linear reciprocating cyclic feeding according to claim 2, characterized in that: The scraper module further includes a damping rotating shaft and a bearing seat. The bearing seat is installed on the movement adapter plate, a bearing is provided in the bearing seat, and the scraper connecting frame is connected to the bearing through the damping rotating shaft; 5. A 3D printing system with linear reciprocating cyclic feeding according to claim 1, characterized in that: A storage groove is formed on the mounting plate, and a side opening is provided on the side of the storage groove. The lifting plate is located in the storage groove in the contracted state, and the lifting plate extends out of the storage groove from the side opening in the extended state; The lifting plate is a sector plate, and a rotating shaft is connected to the center of the sector plate. The lifting plate is connected to the mounting plate through the rotating shaft; 6. A 3D printing system with linear reciprocating cyclic feeding according to claim 1, characterized in that: The scraper movement module includes a linear module and a slide rail. Both the linear module and the slide rail are installed on the mounting plate. The linear module is connected to the synchronous plate and drives the synchronous plate to move back and forth. The synchronous plate is slidably connected to the slide rail.

7. A 3D printing system with linear reciprocating cyclic feeding according to claim 1, characterized in that: The forming module includes a forming cylinder and a forming piston. A printing platform is fixedly installed on the forming piston. The feeding module includes a feeding cylinder and a feeding piston. The forming cylinder and the feeding cylinder are both fixedly installed below the printing tank. A forming cavity and a feeding cavity are respectively formed in the forming cylinder and the feeding cylinder. The forming cavity and the feeding cavity are both communicated with the inside of the printing tank. The forming piston is slidably inserted into the forming cavity, and the feeding piston is slidably inserted into the feeding cavity. The forming cavity is located in front of the feeding cavity.

8. A 3D printing system with linear reciprocating cyclic feeding according to claim 7, characterized in that: It further includes a light curing module, and the light curing module includes a light source; The forming module further includes a first lifting platform, which is connected to the forming piston and drives the forming piston to lift. The feeding module further includes a second lifting platform, which is connected to the feeding piston and drives the feeding piston to lift.

9. A control method for a 3D printing system with linear reciprocating cyclic feeding, using a 3D printing system with linear reciprocating cyclic feeding as described in claim 8, characterized in that: An initial station, a feeding station, a spreading station and a lifting-off station are arranged on the moving path of the squeegee. The feeding station is located above the feeding cavity, the spreading station is located above the forming cavity, the initial station is located behind the feeding station, the lifting-off station is located in front of the spreading station, and the squeegee contacts the lifting-off plate at the lifting-off station; A control method for a 3D printing system with linear reciprocating cyclic feeding includes the following steps: S1, controlling the first lifting platform to drive the forming piston to move downward by a printing layer thickness; S2, controlling the second lifting platform to drive the feeding piston to move upward to push the printing material into the printing tank; S3, controlling the squeegee to move forward from the initial station to between the forming station and the lifting-off station, so as to spread the printing material on the printing platform; S4, controlling the light source to selectively cure the spread printing material; S5, controlling the squeegee to continue moving forward through the lifting-off station. After the squeegee passes through the lifting-off station, controlling the squeegee to move backward to between the lifting-off station and the forming station; S6, controlling the printing platform to move downward by a printing layer thickness; S7, controlling the feeding piston to move downward; S8, if the current spreading angle of the squeegee is zero, controlling the squeegee to continue moving backward to spread the printing material on the printing platform and return to the initial station, then controlling the light source to selectively cure the spread printing material, and controlling the printing platform to move downward by a printing layer thickness; if the current spreading angle of the squeegee is not zero, controlling the squeegee to continue moving backward to the initial station; S9, repeating steps S2 to S8 until the entire model printing is completed.

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