CN113665101A

CN113665101A - FDM printing method and FDM printer

Info

Publication number: CN113665101A
Application number: CN202111224064.6A
Authority: CN
Inventors: 成伟华
Original assignee: Guangdong Vocational and Technical College
Current assignee: Guangdong Vocational and Technical College
Priority date: 2021-10-21
Filing date: 2021-10-21
Publication date: 2021-11-19

Abstract

The invention provides an FDM printing method and an FDM printer, and particularly relates to the field of additional manufacturing, wherein the FDM printing method comprises the following steps of: analyzing the model to obtain a basic printing code, and controlling a hot-melting extrusion head in the FDM printer to print the model on a working platform layer by layer on the basis of the basic printing code; when the vertical coordinate of the hot-melting extrusion head changes and the number of printing layers i printed by the hot-melting extrusion head is greater than a preset number n, triggering to execute a repairing operation; the repair operation comprises the following steps: acquiring known data; acquiring unknown data; repairing and judging; generating a patching file; and (5) driving a repairing device. The FDM printing method supplements real-time step gap repairing operation on the basis of the original FDM printing method so as to repair the printing entity of the model, so that the surface of the printing entity of the model can be smoother, the speed of the post-processing technology of the surface of the model is increased, and the production efficiency is improved.

Description

FDM printing method and FDM printer

Technical Field

The invention relates to the field of additional manufacturing, in particular to an FDM printing method and an FDM printer.

Background

Fused Deposition Modeling (FDM) was invented by Stratasys corporation of the united states by Scott krenpu (Scott column) in the end of the last eighties, another widely used 3D printing technique following photocuring rapid prototyping (SLA) and laminated solid rapid prototyping (LOM).

The FDM has the working principle that filamentous thermoplastic materials are heated and melted through a spray head, a fine spray nozzle is arranged at the bottom of the spray head, the spray head moves to a specified position according to data of a 3D model under the control of a program, and liquid materials in a molten state are extruded and sprayed out and finally solidified; the material is sprayed out and deposited on the previous layer of solidified material, and the final finished product is formed by the layer-by-layer accumulation of the material.

Fig. 1 of the accompanying drawings shows a partially enlarged cross-sectional view of an edge of a conventional FDM printed model, and due to a mechanism limitation of molding, a step gap 200 generated due to layered deposition is easy to appear on the edge of a printed entity 100 printed by FDM, so that the surface of the model is not smooth, and therefore, the printed entity 100 printed by FDM generally needs to obtain a required model through a complicated surface post-processing process.

Specifically, according to practical experience statistics, it is found that the smaller the step gap recession degree of a model obtained through FDM printing is, the faster the model surface post-processing process operation is, and therefore, it is necessary to improve the existing FDM printing method to improve the production efficiency.

Disclosure of Invention

The invention provides an FDM printing method and an FDM printer, wherein the FDM printing method supplements real-time step gap repairing operation on the basis of the original FDM printing method so as to repair the step gap of a printing entity of a model, so that the printing entity surface of the model can be smoother, the speed of a model surface post-treatment process is increased, and the production efficiency is improved.

Correspondingly, the invention provides an FDM printing method, which comprises the following steps:

analyzing a model to obtain a basic printing code, wherein the basic printing code comprises a main code and a supplementary code which are sequentially arranged, the main code is generated based on a printing driver of an FDM printer, the supplementary code is a code for driving a hot-melt extrusion head to displace n-1 layers layer by layer, the total number of displacement layers of the hot-melt extrusion head in the basic printing code is K, K is an integer larger than n, and n is an integer larger than or equal to 2;

controlling a hot-melt extrusion head in an FDM printer to process the model on a processing platform based on the basic printing code;

when the vertical coordinate of the hot-melt extrusion head changes and the number of printing layers i printed by the hot-melt extrusion head is greater than a preset number of layers n, triggering to execute a repairing operation, wherein i =1, 2, … …, K;

the repair operation comprises the following steps:

acquiring known data: acquiring a vertical coordinate z1 of the i-n layer printing entity from the basic printing code, acquiring a model outline of the model at a vertical coordinate z1, and acquiring a transverse dimension a1 of the model outline at a preset lateral viewing angle;

acquiring unknown data: capturing, by an external detection device, a transverse dimension a2 of the printed entity at a vertical coordinate z1 at the preset lateral perspective;

and (4) repairing and judging: if a1= a2, stopping the repairing operation, and if a1 ≠ a2, continuing to execute the repairing operation;

and (3) patch file generation: scaling the model contour based on the difference value of a1 and a2 to obtain a patching track, and generating a patching file comprising a vertical coordinate z1 and the patching track through a driver adapted to a patching device;

driving a repairing device: and driving the patching equipment to act through the patching file, so that the patching equipment performs FDM patching operation on the outer surface of the printing entity on a vertical coordinate z 1.

In an alternative embodiment, the external detection device comprises a measuring light curtain driven in motion by the detection drive assembly.

In an alternative embodiment, the repair apparatus includes a repair hot melt extrusion head based on a repair drive assembly drive motion.

Correspondingly, the invention provides an FDM printer which comprises a printer main body, wherein the printer main body is a DELTA FDM printer and comprises a cylindrical processing platform, a hot-melt extrusion head and a movement driving assembly for driving the hot-melt extrusion head to move;

the motion driving assembly comprises three groups of driving units which are uniformly distributed around the circumference of the processing platform; each group of driving units comprises an upright post, a sliding block and a connecting rod group, wherein the sliding block is in sliding fit with the corresponding upright post, and two ends of the connecting rod group are respectively connected with the hot melting extrusion head and the sliding block;

a preset circumferential area on the top surface of the processing platform is a working area;

the FDM printing method is realized, and the FDM printer further comprises a rotary driving device, an external detection device and a repairing device;

the rotary driving device is used for driving the machining platform to rotate around the axis of the machining platform;

the external detection equipment comprises a detection driving assembly and a measurement light curtain, the measurement width of the measurement light curtain is greater than or equal to the diameter of the working area, the measurement detection driving assembly drives the measurement light curtain to move up and down, and the measurement end of the measurement light curtain faces one side of the processing platform;

the repairing device comprises a repairing driving assembly and a repairing hot-melt extrusion head, the repairing driving assembly drives the repairing hot-melt extrusion head to move, and the extrusion tail end of the repairing hot-melt extrusion head faces one side of the processing platform.

In an alternative embodiment, the external detection device and the repair device are integrated in a single module.

In an optional embodiment, the integrated module comprises a lifting driving assembly, a lifting platform, the measuring light curtain, a telescopic driving unit and the repairing hot-melting extrusion head;

the lifting platform is in sliding fit with the upright post, and the lifting driving assembly drives the lifting platform to move along the upright post;

the measuring light curtain is fixedly arranged on the lifting platform;

the flexible drive unit comprises a flexible guide block and a flexible drive assembly, the flexible guide block is fixedly arranged on the lifting platform, the repairing hot-melt extrusion head is in sliding fit on the flexible guide block, and the flexible drive assembly drives the repairing hot-melt extrusion head to move towards or away from the working area in a translation mode.

In an optional embodiment, the measuring light curtain is fixedly arranged on the bottom surface of the lifting platform;

the telescopic guide block is fixedly arranged on the bottom surface of the lifting platform.

In an alternative embodiment, the height of the measuring end of the measuring light curtain is higher than the height of the extrusion end of the repair hot-melt extrusion head.

In an alternative embodiment, the lifting platform is slidably fitted on the upright of each of the three sets of drive units;

the middle part of the lifting platform is provided with a through groove matched with the outer wall of the processing platform, and the lifting platform surrounds the outer wall of the processing platform.

In conclusion, the FDM printing method and the FDM printer provided by the invention have the advantages that the FDM printing method supplements real-time repairing operation on the basis of the original FDM printing method so as to repair the printing entity of the model, so that the printing entity surface of the model can be smoother, the speed of the model surface post-processing process is increased, and the production efficiency is improved; the shrinkage change condition of the step gap profile is estimated by combining the FDM printing characteristics and utilizing the mode of measuring the transverse dimension by using the measuring light curtain, so that the implementation is more convenient; this FDM printer fully combines the structural feature of DELTA 3D printer, and the structural correlation structure that incorporates into rotary driving equipment, outside check out test set and repair equipment in DELTA 3D printer for this FDM printer structure is comparatively compact, has good convenience of use.

Drawings

FIG. 1 is a schematic partial enlarged cross-sectional view of a prior art FDM printed model edge;

FIG. 2 is a flow chart of an FDM printing method according to an embodiment of the invention;

FIG. 3 is a flow chart of a repair operation according to an embodiment of the present invention;

FIG. 4 is a schematic three-dimensional structure diagram of an FDM printer according to an embodiment of the invention;

FIG. 5 is a schematic front view of an FDM printer according to an embodiment of the invention;

fig. 6 is a schematic diagram of an integrated module according to an embodiment of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Fig. 2 is a flowchart of an FDM printing method of the embodiment of the present invention.

The invention provides an FDM printing method, which comprises the following steps:

s101: analyzing the model to obtain a basic printing code;

basically, for the FDM printer, there are corresponding drivers according to the difference of the driver hardware (firmware) of the FDM printer, and a terminal such as a computer analyzes the model into the basic printing code corresponding to the FDM printer through the corresponding drivers, so as to be executed by the FDM printer.

Specifically, in the open source field, the commonly used basic printing codes generally conform to the RepRap G-M instruction set, that is, the essence of analyzing the model to obtain the basic printing codes is to convert the model into a data file described by the instructions in the RepRap G-M instruction set, and the data file can be used by the hot melt extrusion head 11 of the FDM printer to complete the printing operation corresponding to the model.

Specifically, since the trigger action of the repair job is started from the i = n +1 layer, if the trigger action is performed according to the original code of the model, the printed printing entity has n-1 step gaps that are not subjected to the repair job, and in order to ensure that the repair job is performed on each step gap in the whole printing entity, in an embodiment of the present invention, the obtaining of the basic print code by the analysis model includes:

generating a subject code based on a print driver of the FDM printer; the main body code is a driving code for printing the model;

supplementing a supplementary code which drives the hot-melt extrusion head 11 to displace layer by layer and has n-1 layers of displacement layers behind the main code;

the body code and the supplemental code are combined to form the base print code.

Specifically, for the operation of the FDM printer, after the main code is executed, the hot-melt extrusion head 11 stops heating and moves to the preset regression position, in the embodiment of the present invention, a supplement code (not including the heating instruction of the hot-melt extrusion head 11) that is only shifted by n-1 layers with respect to the hot-melt extrusion head 11 is supplemented at the end of the main code, and the repair operation can be triggered by the shift instruction in the supplement code, so that the repair operation can be covered in each step gap 200 of the printing entity 100, and the repair effect can be ensured.

Specifically, for a step gap, when i = n +1, a repairing action for the i-n (i.e. the first) step gap is triggered; when i = a, triggering the repairing action of the gap of the a-n steps;

theoretically, the total number of step gaps of the printing entity is a-1, and after the repairing action of the step gaps of the (a) -n th step is finished, the number of the step gaps needing to be repaired is (a-1) - (a-n) = n-1; correspondingly, in order to finish the repair of the gap of the n-1 steps, the number of printing layers is increased by n-1 layers so as to trigger the repair action for n-1 times.

Therefore, in the supplement codes for supplementarily driving the hot melt extrusion heads to displace n-1 layers layer by layer, the total number of the displaced layers of the hot melt extrusion heads in the basic printing codes is K layers.

S102: controlling a hot-melt extrusion head 11 in the FDM printer to process the model on the processing platform 1 based on the basic printing code;

and processing the model on the processing platform 1 through the hot-melt extrusion head 11, wherein the processing process of the model comprises actual processing of the hot-melt extrusion head 11 corresponding to the main body code and layer-by-layer displacement of the hot-melt extrusion head 11 corresponding to the supplementary code.

S103: when the vertical coordinate of the hot-melt extrusion head 11 changes and the number of printing layers i printed by the hot-melt extrusion head 11 is greater than a preset number of layers n, triggering to execute a repairing operation once, wherein n is an integer greater than or equal to 2, and i =1, 2, … …, K;

specifically, the reason why the repair operation needs to be triggered to be executed when the number of printing layers i is greater than the preset number of layers n is that, on one hand, in terms of the forming of the solid model, because the temperature of the formed material just extruded is high, the shape and structure of the formed material can generate relatively large deformation during curing or semi-curing, and therefore, the repair operation needs to be performed after a certain number of printing layers is completed to ensure the repair effect, and meanwhile, when the formed material is repaired after being completely cured, the situation that the material is not tightly bonded occurs, and therefore, the repair time needs to be reasonably arranged; on the other hand, the hot-melt extrusion head 11 in the FDM printer generally moves upward layer by layer, the hot-melt extrusion head 11 and the related driving structure are located above the printing entity 100, and in consideration of the position interference between the devices, the repair operation needs to be executed after the hot-melt extrusion head 11 moves to a certain number of layers, so as to avoid the interruption of printing caused by the position interference between the devices related to the repair operation and the related structures in the FDM printer.

Specifically, fig. 3 is a flowchart of a repairing operation according to an embodiment of the present invention.

Specifically, the repairing operation of the embodiment of the present invention includes:

s201: acquiring known data;

acquiring a vertical coordinate z1 of the i-n layer printing entity from the basic printing code, acquiring a model outline of the model at a vertical coordinate z1, and acquiring a transverse dimension a1 of the model outline at a preset lateral viewing angle;

specifically, in the conventional FDM printing process, the printing entity is formed by printing the modeling material layer by layer; when a layer of printing entity is processed, the lower end tail (discharge port) of a hot-melting extrusion head in an FDM printer is positioned above the highest point of the layer of printing entity, and a molten printing material is extruded from the lower end tail of the hot-melting extrusion head and is printed according to a preset pattern under the driving of the movement of the hot-melting extrusion head. Generally, the cross section of the molding material extruded by the hot-melt extrusion head is circular, and under the action of surface tension, the edge of the molding material is of a convex structure, and correspondingly, the outline edge of each layer of printing entity is also of a convex structure; the overlapping of the convex structures of the two adjacent layers of printing entities generates a step gap; in the two adjacent layers of printing entities, because the molding materials of the upper layer printing entity and the lower layer printing entity at the contact position are fused and combined, the deepest part of the step gap is generally close to the top surface of the lower layer printing entity, and in order to facilitate the acquisition of data, the top surface height of the lower layer printing entity is generally selected as the height of the corresponding step gap.

Referring to fig. 1 of the drawings, assuming that the height of the top surface of the lower printing entity is the height of the corresponding step gap, and correspondingly, the height of the top surface of each layer of printing entity is generally the height of the lower end of the hot-melt extrusion head when the layer of printing entity is printed, the height data can be obtained from the basic printing code, in the embodiment of the present invention, for the i-n layers of printing entities, the vertical coordinate z1 of the top surface is identified as the height of the i-n layers of printing entities, and correspondingly, the height of the i-n step gaps is identified by the vertical coordinate z 1; synchronously, the contour of the model at the vertical coordinate z1 is acquired, and the transverse dimension a1 of the contour of the model at the preset lateral viewing angle is acquired.

S202: acquiring unknown data;

capturing, by an external detection device, a transverse dimension a2 of the printed entity at a vertical coordinate z1 at a preset lateral perspective; the lateral dimension a2 is the actual dimension of the corresponding print entity at that location.

S203: repairing and judging;

if a1= a2, stopping the repairing operation, and if a1 ≠ a2, continuing to execute the repairing operation;

specifically, if a1= a2, it indicates that the size of the gap between the corresponding steps of the print object is consistent with the theoretical model size, and the repair operation may not be required.

Specifically, if a1 ≠ a2, it indicates that the print entity does not match the theoretical model size at the corresponding step gap, and the repair job needs to be executed.

It should be noted that, because the computer can reasonably scale the printing track according to the difference of the materials when generating the main body code, referring to fig. 1 of the accompanying drawings, in each layer of the printed entity obtained by actual printing, the widest part is larger than the theoretical size, and the narrowest part (i.e. the position of the step gap) is smaller than the theoretical size, and the printed entity can be repaired by the subsequent surface treatment process; thus, when a1 ≠ a2, it is actually a2< a 1.

S204: generating a patching file;

scaling the model contour based on the difference value of a1 and a2 to obtain a patching track, and generating a patching file comprising a vertical coordinate z1 and the patching track through a driver adapted to a patching device;

specifically, the scaling data is obtained according to the comparison between the a1 size of the entity model at the vertical coordinate z1 and the a2 size of the model at the vertical coordinate z1, the scaling data is used for scaling the model contour of the model at the vertical coordinate z1, the theoretical contour of the printing entity 100 at the vertical coordinate z1 is obtained in a virtual mode, the theoretical contour can be used for obtaining the contour data theoretically related to the step gap 200, namely the repairing track, and the repairing equipment can be guided to perform the repairing operation of the step gap 200 by using the repairing track. Specifically, the scaling means takes into account the property of more uniform shrinkage of the material, and specifically, in FDM printing, the outer shell of the mold has the same wall thickness, so that the curing shrinkage of the outer wall of each layer of the printed entity 100 is more uniform, and therefore, the dimensional change of the whole contour can be reflected by the change of one of the lateral dimensions.

S205: repairing the equipment drive;

and driving the patching equipment to act through the patching file, so that the patching equipment performs FDM patching operation on the outer surface of the printing entity 100 on a vertical coordinate z 1.

Specifically, the property of the repair job of the repair device is the same as that of the FDM print job printed by the FDM, the FDM print job is responsible for printing the printing entity 100 of the model, and the repair device repairs the step gap 200 between the printing entities 100 of two adjacent layers in the printed printing entity 100.

In particular, regarding the FDM printing method provided in the embodiment of the present invention, in view of implementation convenience, the external detection device includes the measurement light curtain 14 that is driven to move by the detection drive assembly, and the repair device includes the repair hot-melt extrusion head 17 that is driven to move by the repair drive assembly.

Specifically, the measuring light curtain 14 is a high-precision light curtain with higher technical requirements derived from a safety light curtain, and is measured by a single set or multiple sets of sensors. The measuring light curtain 14 is a special photoelectric sensor, and like a common correlation photoelectric sensor, includes two parts, namely an emitter and a receiver, which are separated from each other and oppositely arranged, and is shaped like a long tube. The detection light generated by the emitter of the measuring light curtain 14 generates a light array at a fixed interval along the length direction to form a light curtain, and the function of monitoring and measuring the overall dimension of an object is realized by matching a controller and software thereof in a scanning mode. In the embodiment of the present invention, the detection plane of the measurement light curtain 14 is arranged along the horizontal direction, and the detection driving assembly drives the measurement light curtain 14 to move vertically, so that the application requirements of the FDM printing method in the embodiment of the present invention can be met.

Fig. 4 is a schematic three-dimensional structure diagram of an FDM printer according to an embodiment of the present invention, fig. 5 is a schematic front view structure diagram of the FDM printer according to an embodiment of the present invention, and fig. 6 is a schematic integrated module diagram according to an embodiment of the present invention.

Correspondingly, the embodiment of the invention also provides an FDM printer, which comprises a printer main body, wherein the printer main body is a DELTA FDM printer and comprises a cylindrical processing platform, a hot-melting extrusion head 11 and a motion driving assembly for driving the hot-melting extrusion head 11 to move; specifically, the hot-melt extrusion head 11 is generally disposed on the moving platform 3, and the hot-melt extrusion head 11 and the moving platform 3 are in a stationary integrated combined structure.

In a specific implementation, the printer body according to the embodiment of the present invention further includes a base 10, which can be regarded as a constant fixed reference, for fixing other components.

The motion driving assembly comprises three groups of driving units which are uniformly distributed around the circumference of the processing platform; each group of driving units comprises an upright post 6, a sliding block 5 and a connecting rod group 4, wherein the sliding block 5 is in sliding fit with the corresponding upright post 6, and two ends of the connecting rod group 4 are respectively connected with the hot melting extrusion head 11 and the sliding block 5; specifically, the movement of each slider 5 on the corresponding upright 6 needs to be controlled by the corresponding driving module, and since the embodiment of the present invention does not relate to an improvement on the driving module, the structure of the driving module can be implemented with reference to the prior art, and the embodiment of the present invention is not additionally limited, in the drawings, the driving module is not illustrated in the drawings in order to avoid the occlusion of lines.

A preset circumferential area on the top surface of the processing platform is a working area 2; specifically, the size of the working area 2 is determined by the length of the connecting rod in the connecting rod group 4, and the larger the length of the connecting rod is, the larger the working area 2 is under the condition of meeting the requirement of the basic length of the connecting rod, but in practical implementation, the working area 2 is limited by the size of the processing platform, and the size of the working area 2 cannot exceed the size of the top surface of the processing platform. In an embodiment of the invention the working area 2 is smaller than the top surface of the processing platform.

Specifically, the FDM printer of the embodiment of the present invention further includes a rotation driving device 15, an external detection device, and a repair device;

the rotary driving device 15 is used for driving the processing platform to rotate around the axis of the processing platform;

the external detection equipment comprises a detection driving component and a measurement light curtain 14, the measurement width of the measurement light curtain 14 is greater than or equal to the diameter of the working area 2, the measurement detection driving component drives the measurement light curtain 14 to move up and down, and the measurement end of the measurement light curtain 14 faces one side of the processing platform; in particular, in cooperation with the rotary drive device 15, the measuring light curtain 14 is used to obtain a transverse dimension a2 of the vertical position z1 of the printing entity 100 in a preset lateral viewing angle.

The repairing device comprises a repairing driving assembly and a repairing hot-melt extrusion head 17, wherein the repairing driving assembly drives the repairing hot-melt extrusion head 17 to move, and an extrusion tail end 18 of the repairing hot-melt extrusion head 17 faces one side of the processing platform.

Specifically, compared with the FDM printer in the prior art, the FDM printer of the embodiment of the present invention is added with the rotation driving device 15, the external detection device, and the repair device; specifically, the rotation driving device 15 may enable the processing platform to rotate, that is, the rotation driving device 15 may provide a rotation degree of freedom for the printing entity 100, which may simplify the structure of the external detection device and the repair device. In addition, can know through the structure of DELTA FDM printer, stand evenly distributed is around processing platform, because interfere the relation, and external equipment is difficult to repair the entity of printing on the processing platform in the position that the stand set up, consequently, rotates through driving the processing platform, can make the rotation that the entity of printing on the processing platform can be corresponding to make the surface structure that the entity of printing and stand are relative can rotate to the noninterference position on, reduce the operation degree of difficulty of repairing the operation.

The operation of the rotation driving device 15 for driving the machining platform to rotate should be incorporated into the basic print code.

Further, the external detection device and the repair device are integrated in an integrated module to simplify the structure of the FDM printer. In particular, embodiments of the present invention provide a possible implementation manner of the integral module for reference.

Specifically, the integrated module comprises a lifting driving component, a lifting platform 9, a measuring light curtain 14, a telescopic driving unit and a repairing hot-melting extrusion head 17;

the lifting platform 9 is in sliding fit with the upright 6, and the lifting driving assembly drives the lifting platform 9 to move along the upright 6;

the measuring light curtain 14 is fixedly arranged on the lifting platform 9;

the telescopic driving unit comprises a telescopic guide block 16 and a telescopic driving assembly, the telescopic guide block 16 is fixedly arranged on the lifting platform 9, the repairing hot-melt extrusion head 17 is in sliding fit with the telescopic guide block 16, and the telescopic driving assembly drives the repairing hot-melt extrusion head 17 to move towards or away from the working area 2 in a translation manner. Theoretically, the repairing driving assembly of the embodiment of the invention needs to drive the repairing hot-melt extrusion head to reach the height position of each step gap in the printing entity and enable the extrusion tail end of the repairing hot-melt extrusion head to be close to the corresponding step gap; in the embodiment of the invention, the basic functions required by the repair driving component can be realized by combining the telescopic driving unit and the lifting platform 9,

in the embodiment of the invention, the lifting driving component in the integrated module can be a motor screw rod component, and the lifting platform 9 can move along the vertical direction with high precision by driving the driving screw rod 8 through the lifting motor 7; the measuring light curtain 14 comprises an emitting component 12 and a receiving component 13, and the emitting component 12 and the receiving component 13 are arranged on the lifting platform 9 in a matching way; the arrangement of the telescopic guide block 16 and the telescopic driving assembly can enable the repairing hot-melt extrusion head 17 to translate along the telescopic guide block 16, and the repairing hot-melt extrusion head 17 can repair the step gap 200 of the printing entity 100 on the processing platform 1 by combining the rotary motion of the processing platform 1.

It should be noted that, due to the limitation of repairing the solid structure and the moving direction of the hot-melt extrusion head 17, the gap of the partial printing solid 100 cannot be repaired.

Specifically, the telescopic driving assembly may be a high-precision linear driving element such as a linear motor, specifically, the telescopic driving assembly may be disposed on the lifting platform 9, or may be disposed outside the lifting platform 9 to reduce the load weight of the lifting platform 9, and the structure of the telescopic driving assembly is not shown in the figure, and may be implemented by referring to the prior art.

Further, the measuring light curtain 14 is fixedly arranged on the bottom surface of the lifting platform 9; the telescopic guide block 16 is fixedly arranged on the bottom surface of the lifting platform 9. Specifically, in the embodiment of the present invention, the measuring light curtain 14 and the telescopic guide block 16 are fixedly disposed on the bottom surface of the lifting platform 9, and the top surface of the lifting platform 9 is a flat surface, so that when the printer fails, if the lifting platform 9 collides with the printer main body (mainly a hot melt extrusion head and its related driving structure) due to interference, the top surface of the lifting platform 9 collides with the hot melt extrusion head and its related driving structure, the measuring light curtain 14 and the repairing device can be protected. Furthermore, a buffer material may be provided on the top surface of the lifting platform 9.

Further, the height of the measuring end of the measuring light curtain 14 is higher than the height of the extrusion end 18 of the repairing hot-melt extrusion head 17, and by the arrangement mode, the height difference between the height of the measuring end of the measuring light curtain 14 and the height of the extrusion end 18 of the repairing hot-melt extrusion head 17 is reasonably set, so that on one hand, repeated lifting movement of the part of the lifting platform 9 can be avoided, and on the other hand, the measuring light curtain 14 and the repairing hot-melt extrusion head 17 can simultaneously operate (when the measuring light curtain 14 performs relatively late repairing operation, the repairing hot-melt extrusion head 17 performs relatively early repairing operation).

Further, the lifting platform 9 is slidably fitted on the upright 6 of each of the three sets of driving units;

the middle part of the lifting platform 9 is provided with a through groove matched with the outer wall of the processing platform, and the lifting platform 9 surrounds the outer wall of the processing platform.

Specifically, the operation principle of the FDM printer of the embodiment of the present invention is: the hot-melt extrusion head 11 and the rotary driving device 15 perform operation according to the basic printing code, and after the number of layers of the printing entity 100 printed by the hot-melt extrusion head 11 exceeds a certain value, the lifting of the lifting platform 9 is used for driving the measuring light curtain 14 to move to a preset position height to obtain the transverse dimension of the printing entity 100, and the visual angle direction of the printing entity 100 measured by the measuring light curtain 14 is ensured to be consistent according to the feedback of the rotary driving device 15; and obtaining a repair file after corresponding data processing, and controlling the action of the telescopic driving assembly through the repair file so as to enable the repair hot-melt extrusion head 17 to act to execute FDM repair operation.

It should be noted that, because the direction of the extrusion end 18 of the repairing hot-melt extrusion head 17 according to the embodiment of the present invention is fixed, there is a certain limitation on the structure of the solid model to be repaired, in a specific implementation, the model adaptability of the FDM printer may be improved by providing a plurality of sets of repairing devices according to the embodiment of the present invention, and the repairing driving component may also be replaced by a six-axis manipulator, so as to better repair the step gap 200 of the printing entity 100.

In summary, the embodiment of the invention provides an FDM printing method and an FDM printer, the FDM printing method supplements real-time repair work on the basis of the original FDM printing method to repair the printed entity 100 of the model, so that the surface of the printed entity 100 of the model can be smoother, the speed of the model surface post-processing process can be increased, and the production efficiency can be improved; the shrinkage change condition of the step gap 200 is obtained by combining the FDM printing characteristic and utilizing the mode of measuring the transverse dimension by the measuring light curtain 14, so that the implementation is convenient; this FDM printer fully combines the structural feature of DELTA 3D printer, and the structural correlation structure who fuses into rotary driving equipment 15, outside check out test set and repair equipment in DELTA 3D printer has organically for this FDM printer structure is comparatively compact, has good convenience of use.

The FDM printing method and the FDM printer provided in the embodiments of the present invention are described in detail above, and the principle and the embodiment of the present invention are explained in detail herein by applying specific examples, and the description of the above embodiments is only used to help understanding the method and the core idea of the present invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, there may be variations in the specific embodiments and the application scope, and in summary, the content of the present specification should not be construed as a limitation to the present invention.

Claims

1. An FDM printing method comprising:

the repair operation comprises the following steps:

2. The FDM printing method of claim 1 wherein the external detection device includes a measurement light curtain that is driven in motion based on a detection drive assembly.

3. The FDM printing method of claim 1 wherein the repair apparatus comprises a repair hot melt extrusion head that is driven in motion by a repair drive assembly.

4. An FDM printer comprises a printer main body, wherein the printer main body is a DELTA FDM printer and comprises a cylindrical processing platform, a hot-melt extrusion head and a movement driving assembly for driving the hot-melt extrusion head to move;

characterized in that it is used to implement the FDM printing method according to claim 1, the FDM printer further comprises a rotation driving device, an external detection device and a repair device;

5. The FDM printer of claim 4, wherein the external detection device and repair device are integrated in a single module.

6. The FDM printer of claim 5, wherein the integrated module comprises a lift drive assembly, a lift platform, the measurement light curtain, a telescoping drive unit, and the repair hot melt extrusion head;

the measuring light curtain is fixedly arranged on the lifting platform;

7. The FDM printer of claim 6, wherein the measurement light curtain is secured to a bottom surface of the lift platform;

8. The FDM printer of claim 6, wherein the measurement end height of the measurement light curtain is higher than the extrusion tip height of the repair hot melt extrusion head.

9. The FDM printer of claim 6 wherein the lift platform is a sliding fit on a column of each of the three sets of drive units;