CN109130171B - Polymer multi-material multi-laser flexible additive manufacturing system and method - Google Patents

Abstract

The invention belongs to the field of wire material laser additive manufacturing, and discloses a polymer multi-material multi-laser flexible additive manufacturing system and method. The system comprises a plurality of modules, wherein each module correspondingly forms different areas in a single sliced layer, each module comprises a laser emitting unit, a plurality of robots, a wire supply unit and an extrusion unit, the wire supply unit and the extrusion unit are matched with each robot, and the laser emitting unit and the extrusion unit are separately arranged, so that extrusion and melting are separately carried out to avoid the blockage of a spray head of the extrusion unit; the extrusion unit is arranged at the tail end of the robot, the robot carries the extrusion unit to reach a preset position to realize the conveying of wires, each robot conveys one wire, the multiple robots send the wires according to a preset track and a preset sequence, and the sent wires are melted under the action of the laser emission unit to realize the forming of multiple materials of each sliced layer. The invention solves the problem of easy blockage of the spray head, improves the flexibility of a manufacturing system and realizes the forming of large-size products.

Description

Polymer multi-material multi-laser flexible additive manufacturing system and method

Technical Field

The invention belongs to the field of wire material laser additive manufacturing, and particularly relates to a polymer multi-material multi-laser flexible additive manufacturing system and method.

Background

Fused Deposition Modeling (FDM) is an important polymer additive manufacturing technology, and has many advantages of additive manufacturing technology, such as manufacturing of parts without geometric restrictions, shortening of product development and manufacturing cycle, and material saving. In the FDM forming process, the polymer wire is conveyed to a nozzle by a wire feeding mechanism and heated to a molten state, and is solidified and formed in air after being extruded.

At present, the FDM technology has the advantages of low running cost, wide forming materials, simple post-treatment, etc., but as an important polymer additive manufacturing method, it still has the following disadvantages: (1) the phenomenon of blockage of the thermal spray head often occurs in the printing process, which is mainly caused by mismatching of wire feeding rate and wire melting rate, and the unmelted wire penetrates into the melted material which is melted but not extruded yet, so that the melted material overflows to a gap at the feeding end to be cooled and solidified, thereby causing the blockage of the spray head; (2) the printing nozzle always remains molten materials, and the materials are solidified and left at the nozzle after cooling, and because the printing nozzle is generally 0.4mm and is a key part of the printing nozzle, the residual materials are difficult to clean, the nozzle is damaged due to improper cleaning operation, and the printing precision is seriously influenced; (3) if the printed part has a complex structure and a large size, the printing nozzle can work at a high temperature (the common printing temperature of ABS and PLA is about 200 ℃) for a long time, which affects the service life of the printing nozzle; (4) the FDM forming needs to extrude the molten material from a spray head, so that the forming speed is low, and the FDM forming is not suitable for manufacturing large-sized workpieces; (5) extruding the wires into a vertical direction, depositing the wires in a molten state point by point, line by line and plane by plane under the action of gravity, and finishing the forming of the product in the height direction by a method that a lifting platform descends, wherein an FDM printing spray head; (6) most of the current FDM printers are in an inherent single-nozzle mode, and only one material can be formed. With the development of science and technology and the strategic needs of the country, the formation of multiple materials has become a hot point of research.

CN107116220A discloses an electric field driven molten metal spray deposition 3D printing apparatus and its working method, which is directed to the preparation of metal multi-materials; CN206733600U discloses a device for realizing multi-material-level composite 3DP by a single nozzle, which mainly uses ceramic powder or hydrogel as a printing material, and the use is limited to the biomedical material forming field, so that the additive manufacturing research of polymer multi-material is less, and the polymer multi-material is in a relatively blank state; CN104118121A discloses an anti-blocking printing nozzle of an FDM printer, which is characterized in that a thin heating aluminum block, a T-shaped preheating aluminum block and a constant temperature aluminum block are added, so that the heating space is greatly reduced, the melting of wire materials is fast, and the problem of nozzle blocking is solved to a certain extent; in addition, in the FDM technology and even the whole additive manufacturing field, the integral forming of large-sized products is always an urgent problem to be solved, mainly because the range in which the laser generated by the laser can act is limited.

Disclosure of Invention

Aiming at the defects or the improvement requirements in the prior art, the invention provides a polymer multi-material multi-laser flexible additive manufacturing system and a method, which improve the manufacturing system and the manufacturing method in the fused deposition process, wherein the segmented slice layer divided in the forming process is divided into a plurality of regions to realize the segmented forming, simultaneously, the forming unit and the processing sequence corresponding to each forming region are set, and the extruding unit and the laser emitting unit are separately arranged, so that the polymer wire is sent out and is separated from the melting phase, and the problems that a common nozzle of FDM equipment is easy to block, difficult to clean, short in service life and the like are solved; the wire feeding device is driven by the robots to convey different types of wires, so that the flexibility, the accuracy and the stability of the machining process are improved, the problems of forming of multiple materials and difficulty in forming of large-size products are solved, and the flexibility of a manufacturing system is greatly improved.

To achieve the above object, according to one aspect of the present invention, there is provided a polymer multi-material multi-laser flexible additive manufacturing system, characterized in that,

the system comprises a plurality of modules, wherein after each sliced layer of a product to be formed is divided into a plurality of areas, each module correspondingly forms different areas so as to realize the sectional forming of the product to be formed, and each area can be spliced together seamlessly;

each module comprises a laser emitting unit, a plurality of robots, a wire supply unit and an extrusion unit, wherein the wire supply unit and the extrusion unit are matched with each robot, and the laser emitting unit and the extrusion unit are separately arranged, so that extrusion and melting are separately carried out, and the extrusion unit is prevented from being blocked; the extruding unit is arranged at the tail end of the robot, the robot carries the extruding unit to reach a preset position to realize conveying of wires, each robot conveys one wire, the plurality of robots send wires according to a preset track and a preset sequence, and the sent wires are melted by laser emitted by the laser emitting unit, so that the melting and forming of multiple wires of each sliced layer are realized.

Further preferably, the lower end of the extrusion unit is provided with a traction mechanism, the traction mechanism comprises a traction plate and a group of fixed pulleys arranged oppositely, the wire penetrates out of the fixed pulleys arranged oppositely, and the traction plate is used for connecting the fixed pulleys with the extrusion unit.

Further preferably, the laser emission unit preferably employs CO₂The laser device adjusts parameters of the laser device in real time according to different wires conveyed by the robot, so that the laser device meets the requirements of melting of different wires on laser energy.

Further preferably, the robot preferably adopts a multi-axis robot, so that mutual noninterference during cooperative work among different robots is ensured, and the flexibility of the manufacturing system is improved, wherein the number of the robots is preferably 2-6, and the number of the laser emission units is preferably 1-3.

Further preferably, the system further comprises a controller, and the controller is respectively connected with the robot, the laser emitting unit, the wire supplying unit and the extruding unit in each module, so that the cooperative work of all the components is realized.

Further preferably, the system further comprises an elevating platform, and the elevating platform descends the thickness of one sliced layer by layer to realize layer-by-layer forming of the product to be formed.

According to another aspect of the invention, there is also provided a method of additive manufacturing of a manufacturing system as described above, characterised in that the method comprises the steps of:

(a) constructing a three-dimensional model of a product to be formed, slicing the three-dimensional model in layers to obtain two-dimensional data of a plurality of slice layers, carrying out voxel slicing on each slice layer to obtain a data point set of each layer, and carrying out voxel slicing on all slice layers to obtain a space data point set of the whole product to be formed; dividing a data point set in each sliced layer into a plurality of areas, selecting required wires corresponding to the areas according to the divided areas and installing the wires on the wire supply unit, and setting the motion tracks and wire supply sequences of different robots in each area according to the divided areas;

(b) for each slicing layer, the robots in different areas carry the wire feeding unit to feed wires according to the set motion track, the laser emission unit melts the sent wires so as to realize the melt forming of the wires in different areas, the forming of a single slicing layer is finished after the melt forming of the wires in all different areas is finished, and all the areas can be spliced together in a seamless mode;

(c) and (c) descending the lifting platform by the thickness of one sliced layer, and repeating the step (b) until the formation of all sliced layers is completed, thereby obtaining the required product.

In general, compared with the prior art, the above technical solution contemplated by the present invention can achieve the following beneficial effects:

1. according to the invention, each sliced layer is processed in a partitioning manner, the corresponding robot, the extrusion unit and the wire feeding unit in each area are correspondingly matched, and the forming of each area is realized through the synergistic effect among the robots in each unit, so that the forming of a single sliced layer is finally completed, and the method is not limited by the size of a product in theory and is particularly suitable for processing large-size products;

2. according to the invention, a multi-module design is adopted, and the wire feeding unit and the laser emission unit are separately arranged in each module, so that the feeding and melting of wires are separately carried out, and the extrusion unit is prevented from being blocked in the feeding process of the wires, thus the cleaning difficulty of the extrusion unit is reduced, and the service life of the extrusion unit is prolonged;

3. the invention adopts a mode that the tail ends of a plurality of robots are provided with the extrusion units to realize the wire feeding process of the robots, realizes the forming of products containing a plurality of materials by arranging different wires in different robots, simultaneously adopts the robots to carry the extrusion units to move together, has high degree of freedom, can realize the processing process of almost any track or angle, and improves the flexibility of the manufacturing system.

4. The invention adopts laser to melt the wire, so that the energy is concentrated, the high-temperature-resistant high-performance polymer (such as PEEK material) can be easily melted, and the problem that the high-temperature-resistant high-performance polymer is difficult to form is greatly improved.

Drawings

FIG. 1 is a schematic diagram of an apparatus configuration for a polymeric multi-material multi-laser flexible additive manufacturing system constructed in accordance with a preferred embodiment of the present invention;

FIG. 2 is a schematic diagram of an apparatus configuration for a modular polymer multi-material multi-laser flexible additive manufacturing system constructed in accordance with a preferred embodiment of the present invention;

FIG. 3 is a schematic diagram of the construction of two six-axis robots within the same module constructed in accordance with the preferred embodiment of the present invention;

FIG. 4 is a schematic diagram of a galvanometer structure in a laser emitting unit constructed in accordance with a preferred embodiment of the present invention;

FIG. 5 is a schematic structural view of a filament supply unit and an extrusion unit constructed in accordance with a preferred embodiment of the present invention;

fig. 6 is a schematic structural view of a table constructed in accordance with a preferred embodiment of the present invention.

The same reference numbers will be used throughout the drawings to refer to the same or like elements or structures, wherein:

1-robot 3-laser emission unit 31-laser 32-lens 33-X-axis galvanometer motor 34-X-axis galvanometer 35-Y-axis galvanometer motor 36-Y-axis galvanometer 4-lifting table 51-wire supply unit 52-extrusion unit 53-traction mechanism 531-fixed pulley 532-traction plate 7-controller 8-working table 81-support 82-bolt 83-connecting joint

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. In addition, the technical features involved in the embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

Fig. 1 is a schematic diagram of an apparatus structure of a polymer multi-material multi-laser flexible additive manufacturing system constructed in accordance with a preferred embodiment of the present invention, and as shown in fig. 1, a polymer multi-material flexible additive manufacturing apparatus includes a plurality of modules, each module for forming a different region in a sliced layer; in the embodiment, two robots 1 are adopted in one module to respectively convey different types of wires, a laser emitting unit 3 is arranged above the forming table, each robot is provided with an extruding unit 52 and a wire supplying unit 51 in a matching manner, and the number of the robots, the wire supplying units, the extruding units and the laser emitting units can be increased according to needs in practice.

The robot has high degree of freedom, can ensure that the free end of the arm of the robot can finish the motion of any angle or track in space, and each robot is controlled by a linkage program installed in the controller, and the robots are coordinated to work and do not interfere with each other.

The laser emitting unit is used as a heat source for processing the wire materials and is used for melting the wire materials, the polymer has higher absorptivity for laser generated by the laser, and when the types of the materials are changed, the parameters of the laser can be changed in real time to adapt to the requirements of different materials. The position of the laser in the laser emitting unit is fixed above the Z-axis lifting table, preferably CO₂Laser and laser galvanometer scanning system, and its parametersThe method can be adjusted in real time according to different materials, so that the proper processing temperature can be obtained in real time when multiple material parts are switched.

The upper table top of the Z-axis lifting table is the forming bottom surface of the product and is parallel to the ground.

Fig. 2 is a schematic structural diagram of an apparatus of a modular polymer multi-material multi-laser flexible additive manufacturing system constructed according to a preferred embodiment of the present invention, as shown in fig. 2, the system comprises two robots 1, a laser emitting unit 3, a Z-axis lifting table 4, a wire supplying unit 51, an extruding unit 52, a controller 7, a workbench 8, and the like. In the embodiment, the controller 7 is respectively connected with the two robots 1, the laser emitting unit 3, the Z-axis lifting table 4, the wire supply unit 51 and the extrusion unit 52, is used for controlling the cooperative work of the two parts, does not interfere with each other, and has the characteristics of integration and modularization; the extrusion unit is driven by the robot, so that the number of the extrusion unit and the number of the extrusion unit are equal, the number of the lasers is set according to the number of the divided areas in each sliced layer, and each forming area contains one laser.

In the forming process, the slicing layer is divided into a plurality of different areas, so that a large-size product can be formed, but in consideration of the forming practice and the processing efficiency, the number of laser emitting units is preferably 1-3, and the number of robots is preferably 2-6.

Fig. 3 is a schematic structural diagram of two six-axis robots in the same module, constructed according to the preferred embodiment of the present invention, as shown in fig. 3, both the two robots are six-axis, and both the robots have the same structure and working principle, and the robots are six-axis, which means that the robot arm has six degrees of freedom, and six arrows in the figure respectively indicate the directions of rotation of the six axes, and the robot arm can adapt to the processing of almost any angle and trajectory, and can meet the requirement of actual forming.

Fig. 4 is a schematic diagram of a galvanometer structure in a laser emitting unit constructed according to a preferred embodiment of the present invention, and as shown in fig. 4, the laser emitting unit 3 is composed of six parts, i.e., a laser 31, a lens 32, an X-axis galvanometer motor 33, an X-axis galvanometer 34, a Y-axis galvanometer motor 35, and a Y-axis galvanometer 36. The galvanometer structure ensures that the intensity of laser on a plane is equal, a beam of laser is emitted, and the position with equal intensity forms a spherical surface (or named cambered surface) instead of a plane, and has the characteristics of quick and accurate scanning.

FIG. 5 is a schematic structural view of a filament supplying unit and an extruding unit constructed in accordance with a preferred embodiment of the present invention, as shown in FIG. 5, the extruding unit 52 is provided at the end of the filament supplying unit 51, a filament is wound around the filament supplying unit 52, the filament is extruded from the extruding unit 52, and the end of the filament extruding unit is provided with a traction mechanism including a traction plate and a set of fixed pulleys 531 oppositely arranged for "holding" the filament to ensure a controllable moving track of the filament; be less sliding friction between pulley and the silk material, guarantee that the silk material can be smoothly and be guided to waiting to take shape the department without destruction, these two fixed pulleys all pass through the bolt fastening on the traction plate 532, and traction plate 532 and silk material extrusion unit pass through the bolt fastening on support 81. The traction mechanism ensures that the wire can not move randomly after being extruded from the nozzle of the extrusion unit, but is guided to the position to be formed, thereby ensuring the stability of the processing process and being beneficial to improving the size precision and the shape precision of the product.

FIG. 6 is a schematic structural view of a table constructed in accordance with a preferred embodiment of the present invention, as shown in FIG. 6, the end of the robot 1 is connected to the table, and the table is provided with a connection joint 83 for connecting the table 8 and the robot, a bracket 81 for fixing the wire extruding unit, and a bolt 82 for connecting the bracket 81 to the table.

The above is a detailed description of the whole apparatus structure, and the specific processing steps are as follows:

(1) introducing a three-dimensional model of the product into a controller 7, and firstly slicing the model in layers to determine the forming height of each layer; carrying out voxel slicing on each layer to obtain a data point set of each layer, obtaining a space data point set of the product and position information of each point by slicing the layers and voxel slicing results, and setting corresponding materials at corresponding data points according to the requirements of the product to obtain material information; dividing each slice layer into a plurality of areas (area 1, area 2 … … area n) so as to determine the robot corresponding to each area and further generate the working instruction of each robot, wherein the voxel slice is a point for dividing the three-dimensional model of the product into space, namely the model is regarded as consisting of infinite points in space;

(2) and (3) for the spatial data point set determined in the step (1), setting corresponding materials at corresponding positions according to the requirements of the product, namely storing material information by taking 'unit points' as a unit, and generating a processing code which can be identified by the robot after obtaining the spatial data information and the material information of the product model.

(3) The controller 7 simultaneously controls the extrusion unit driven by the robot 1 to enable wires to be smoothly extruded and guided to a position to be formed through the wire traction mechanism, when a certain layer of a product is formed, according to the material and the position information of each layer obtained in the step (2), when a certain material is needed, the corresponding robot drives the extrusion unit to reach the position to be formed, and the laser emits laser to enable the wires to be melted; different robots are processed through a preset processing track and a preset processing sequence, and meanwhile, a laser adjusts relevant parameters in real time to enable the laser power to be adaptive to different materials; the forming of different forming areas is completed by respective robots and lasers together, the different forming areas can be connected in a seamless mode, after the point-to-line forming is achieved in each area according to the step, the melting forming of the wires in all the areas is completed, and finally the forming of a layer of slicing layer is completed.

(4) And (4) after each layer is formed in the step (3), lowering the Z-axis lifting platform 4 by the same height according to the thickness of the layered slice in the step (1), continuing to form the next layer, and repeating the processes to obtain the whole product.

It will be understood by those skilled in the art that the foregoing is only a preferred embodiment of the present invention, and is not intended to limit the invention, and that any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the present invention.

Claims (6)

1. A polymer multi-material multi-laser flexible additive manufacturing system is characterized in that,

the system comprises a plurality of modules, wherein after each sliced layer of a product to be formed is divided into a plurality of areas, each module correspondingly forms different areas so as to realize the sectional forming of the product to be formed;

each module comprises a laser emitting unit (3), a plurality of robots (1), and a wire supply unit (51) and an extrusion unit (52) which are matched with each robot, wherein the laser emitting unit (3) and the extrusion unit (52) are separately arranged, so that the extrusion and the melting are separately carried out, and the blockage of a spray head of the extrusion unit is avoided; the extrusion unit (52) is arranged at the tail end of the robot (1);

the method comprises the steps that three-dimensional models of part products to be formed are sliced in layers to obtain two-dimensional data of a plurality of slice layers, voxel slicing is conducted on each slice layer to obtain a data point set of each layer, and after voxel slicing is conducted on all slice layers, a space data point set of the whole products to be formed is obtained; dividing a data point set in each sliced layer into a plurality of areas, wherein according to the divided areas, the robot (1) carries the extrusion unit to reach a preset position to realize the conveying of wires, each robot conveys one wire, the robots send the wires according to a preset track and a preset sequence, and the sent wires are melted under the action of laser emitted by the laser emission unit to realize the melting forming of multiple wires in each sliced layer;

the lower extreme of extruding unit (52) is provided with drive mechanism, and this drive mechanism includes traction plate (532) and sets up a set of fixed pulley (531) that set up relatively, and the silk material is followed wear out between the fixed pulley that sets up relatively, the traction plate be used for with the fixed pulley with extrude the unit connection.

2. A manufacturing system as set forth in claim 1, characterized in that the laser in the laser emitting unit (3) uses CO₂The laser device adjusts parameters of the laser device in real time according to different wires conveyed by the robot, so that the laser device meets the requirements of melting of different wires on laser energy.

3. A manufacturing system according to claim 1, wherein the robot (1) is a multi-axis robot to improve the flexibility of the manufacturing system, wherein the number of the robots is 2-6, and the number of the laser emitting units is 1-3.

4. A manufacturing system according to claim 1, further comprising a controller (7) connected to the robot, the laser emitting unit, the filament supplying unit and the extruding unit in each module, respectively, so as to realize the cooperative work of the components, wherein the controller (7) comprises a linkage program for controlling the multiple robots to cooperate, so as to ensure that the robots cooperate with each other without mutual interference.

5. A manufacturing system according to claim 1, characterized in that the system further comprises an elevator table (4) by means of which the layer-by-layer forming of the product to be formed is achieved by lowering the thickness of one sliced layer by layer.

6. A method of additive manufacturing of the manufacturing system of claim 5, comprising the steps of:

(a) constructing a three-dimensional model of a product to be formed, slicing the three-dimensional model in layers to obtain two-dimensional data of a plurality of slice layers, carrying out voxel slicing on each slice layer to obtain a data point set of each layer, and carrying out voxel slicing on all slice layers to obtain a space data point set of the whole product to be formed; dividing a data point set in each sliced layer into a plurality of areas, selecting required wires corresponding to the areas according to the divided areas and installing the wires on the wire supply unit, and setting the motion tracks and wire supply sequences of different robots in each area according to the divided areas;

(b) for each slicing layer, the robots in different areas carry the wire feeding unit to feed wires according to the set motion track, the laser emission unit melts the sent wires so as to realize the melt forming of the wires in different areas, the forming of a single slicing layer is finished after the melt forming of the wires in all different areas is finished, and all the areas can be spliced together in a seamless mode;

(c) and (c) descending the lifting platform by the thickness of one sliced layer, and repeating the step (b) until the formation of all sliced layers is completed, thereby obtaining the required product.

Images