CN211591316U

CN211591316U - 3D printing device for large-scale additive manufacturing

Info

Publication number: CN211591316U
Application number: CN201922038747.7U
Authority: CN
Inventors: 陈祺睿
Original assignee: Individual
Current assignee: Individual
Priority date: 2019-11-22
Filing date: 2019-11-22
Publication date: 2020-09-29
Anticipated expiration: 2029-11-22

Abstract

The embodiment of the utility model discloses 3D printing device for large-scale vibration material disk relates to 3D and prints technical field. The material melting extrusion mechanism adopts an extrusion mode of a counter-rotating conical double-screw structure, the double-screw extrusion mechanism is driven in a direct connection mode, the integration level of a driving structure is improved, the counter-rotating conical double-screw structure extruder can be applied to a 3D printer, the tail-end printing head is improved aiming at the fact that the thermal expansion pressure component of a melting material is not controlled by a screw in a screw gap, the printing head is connected with a melting material flow control mechanism, the printing head is of a variable caliber structure, throttling control over the melting fluid can be achieved, control accuracy and real-time performance are further improved, and requirements of a high-efficiency large FDM3D printing process are met.

Description

3D printing device for large-scale additive manufacturing

Technical Field

The embodiment of the utility model provides a 3D prints technical field, concretely relates to 3D printing device for large-scale vibration material disk.

Background

Technical background of the manufacturing industry of large products: all products serve human life and production, the size of adults is generally one meter to two meters, the size of the products below one meter can be defined as small size, one meter to two meters are medium size, and the size of more than two meters is defined as large size by human scale.

In basic principle, the current industrial manufacturing method of the real object only has three process modes, namely material reduction manufacturing, equal material manufacturing and material addition manufacturing.

Reducing material manufacturing: in the age of stone products, the desired part is obtained by knocking a stone with another stone and subtracting the redundant part, and the finished product is formed by cutting a whole material with a cutter of a modern machine tool to obtain a part of the material. The material reduction manufacturing needs to prepare a piece of material larger than the finished product firstly, and then remove ten to ninety percent of the material, when the size of the finished product is small, the shape is simple, the absolute quantity of the removed and wasted material is not too large, when the size of the finished product is large, and when the size of the finished product is complex, the waste is very large, labor and time are wasted, the interference of the cutter is serious when the material is removed, and the cutter has inaccessible parts due to the obstruction of the three-dimensional structure of the finished product. The complexity is limited. But because the processing is carried out at the normal temperature of the solidified material of the substance, no substance phase change exists before and after the processing, and a more accurate finished product can be obtained. The disadvantages are as follows: waste of material, moderate efficiency, tool interference, and is particularly severe in large scale and complex structures. The advantages are that: the deformation at normal temperature is small, the stress is small, and the accuracy is high.

And (3) material preparation: from pottery to bronze era, fluid or liquid is injected into a mould, and a finished product with the volume equal to that of a mould cavity is obtained after cooling or sintering, and the finished product belongs to the class-material manufacturing from modern various injection molding and casting processes. The total volume of the mould is more than six times of that of the product, when the product enters a medium-large size, the volume weight cost of the mould is increased sharply, and meanwhile, the mould interference exists even though the material is not removed in the equal-material manufacturing process, and the part which can not be separated and demoulded is blocked by the three-dimensional structure of the finished product. Therefore, if a complex finished product is to be produced, the product is designed to be split into a plurality of unnecessary parts which are respectively machined and then assembled. And the manufacturing of the materials requires that the mold is prepared firstly, the early investment is high, but the high batch production efficiency can be obtained. But also saves raw materials. The disadvantages are as follows: the method has the advantages of high input threshold, long process period, large temperature change, phase change, large stress, large deformation, low overall precision and serious large-scale and complicated structure. The advantages are that: the mass production efficiency is high.

Additive manufacturing: electroplating, surfacing and spraying belong to additive manufacturing, but are generally not suitable for manufacturing of whole parts, and are generally used for repairing or other auxiliary processes, and an overall additive manufacturing process, such as 3D printing, is only recently performed, and a finished product is built by adding materials layer by layer. The core principle of 3D printing, which is one of the main technologies of additive manufacturing, is dimension reduction, the printing process is performed on a 2-dimensional surface, the 3-dimensional spatial interference problem does not exist, a complex 3-dimensional model is decomposed into a plurality of 2-dimensional sheet-like layers by special software, and the layers have thicknesses, but are thinner in the thickness direction relative to the whole body and can be approximately considered as 2-dimensional. The most important advantage is that the mould is directly formed by stacking layer by layer from nothing to nothing without the initial investment cost of the mould and preparing a blank larger than a finished product. And is insensitive to the complex structure of the product, since three dimensions have been reduced to two dimensions. However, as described above, the reduced material and the equal material are both surfaces of the whole material, and the 3D printing is a surface which is cut into the inside of the material and can be printed, and is far larger than the original surface area, so that the efficiency of the 3D printing is much lower than that of the former two methods at the same moving speed. The disadvantages are as follows: the efficiency is very low. Large temperature variation, stress and deformation. This is particularly true in the case of large products. The advantages are that: the complexity limit is very small, the internal and external integrated processing is realized, the material is saved, the early investment is very small, and the process period is short.

The prior art background that the 3D printing process is large-scale: with the economic development and the technical progress, particularly the development of the computer technology information technology in recent times, products are more and more complex, the variety is more and more, the batch of single products is less and less, the defects of material reduction and equal material manufacturing are more and more obvious, and particularly in the field of complex and light-weight products. 3D printing in this case has a principal advantage for complex products. Meanwhile, blanks larger than finished products are not required to be prepared, and materials are saved. And a mold is not required to be prepared in advance, so that the fixed investment is saved. The advantages emerge gradually, while the inefficient defects do not differ too much in absolute terms in efficiency at small sizes due to the smaller cardinality.

However, any 3D printing process is a comprehensive system of multiple technologies, and after the molding size is increased, the complementary technology cannot be matched with the molding size, and the size above meter level and the size at decimeter level are 10 times in size, but the cubic meter is 1000 times of the cubic decimeter by calculating the effective molding volume, so that the volume of the material to be processed by the printing equipment in the same time theoretically needs to be improved by nearly thousand times, and if reasonable efficiency is to be kept, the improvement is obviously not possible by a simple amplification structure.

Therefore, most of the existing 3D printing technology doors are only suitable for small products, namely, the size level from decimeter to meter, and even if the size of the 3D printing technology doors is barely reached, the printing is realized by adopting thin walls, low-density filling and other modes of sacrificing mechanical properties, the actual effective printing volume is very small, the environmental space size of human life is matched with the size of human body 1-2 meters, such as houses, furniture, automobiles, ships and the like, the internal space is a multiple relation of the human body size, and if the size of the 3D printing technology doors cannot reach the size of the meter used in daily life, the product size designed according to the height of people cannot enter the high-value mainstream market.

The following will briefly describe the reason principle that the currently mainstream SLA/DLP, SLS and FDM3D printing processes can not produce large-size products efficiently.

1. SLA/DLP is a 3D printing technique using a light-curing (hardening) resin as a raw material, and is different from DLP in the way of using light. SLA uses UV light beam to scan photocuring resin and obtains the shape of printing the layer, can regard as the process of point to line, line to face shaping gradually, and DLP uses the projection principle of similar projecting apparatus, throw the required light of a printing layer and solidify the resin, compare SLA technique and has skipped the process of point to line, line to face, DLP is more faster than SLA on the individual layer shaping speed, DLP has also got rid of the required high-precision optics deflection mirror system of SLA, therefore DLP's cost is lower, at present mass market mostly adopts DLP's technology to do photocuring 3D and prints.

The DLP technology is difficult to realize large-scale, because the projection resolution adopted by the DLP technology is limited (usually 1920 x 1080), the projection resolution is about 0.1mm when the DLP technology is used in a decimetric scale, after the DLP technology is large-scale, the volume is enlarged by 1000 times, the area of a single layer is enlarged by 100 times, in order to keep the size of the single pixel to be 0.1mm, the total pixel quantity of the DLP is also enlarged by 100 times, namely the resolution is required to reach 19200 x 10800, otherwise, the edge of a forming layer is provided with sawteeth (similar to sawteeth after picture enlargement), and the prior art cannot achieve the extremely high resolution. Even if high precision is not required, efficiency is difficult to improve in the case of large size, a photo-curing resin material used in the photo-curing technology must be cured by reaction of light, the thickness of each layer cannot be too thick in order to ensure sufficient curing of the resin material, otherwise the layer thickness is relatively too thin during molding of a large size object due to a drop in attenuation efficiency of light because of a sharp increase in scattering error of light, resulting in a large total number of layers and a sharp decrease in overall molding efficiency. The light-cured material has high production cost, dark reaction (curing under the condition of no light), is not durable (easy to decompose), has toxicity and insufficient mechanical property after being formed, has limited variety and cost performance due to the fact that the material must have photosensitivity and is difficult to select high-performance engineering resin which is mature and cheap in the market, the price is calculated according to grams, large-scale products have large material consumption and sensitive price, and the weight of objects commonly used by people is 10kg-50kg (such as sofas, chairs, tables and the like), so the light-cured material is not suitable for large-scale production in technical principle, economy and practicability.

2. SLS Process (Selectivity)LaserSintered) isA method for preparing the productMetalThe SLS process is similar to SLA and is a point-to-line and line-to-surface gradual forming process, and the whole forming process is linear, so that the forming volume is increased, and the forming speed of a single piece is reduced by 3 times. Most of metal or thermoplastic resin can be used in an SLS process after being made into powder, the raw material needs additional powder processing cost which is several times of the raw material cost after being powdered, the powder of the material can cause the surface of an SLS formed product to form powder particles, air is arranged in the powder, the gas escapes during laser welding, the volume is shrunk, the stress is large, and the stress cracking is easy to occur when the size is large. The SLS process allows the material powder to fill the entire molding space, with the unsintered material being the support, so the SLS process can be used without printing a support structure separately, with little waste of powder material.

However, SLS processes require heating of the material powder to a temperature slightly below the melting temperature of the material when printing the product, thereby reducing the required output power of the laser and reducing the internal stresses that result from gradual cooling due to non-monolithic fabrication. After enlargement, the volume is enlarged 1000 times, and the volume is about 12m after enlargement³(2m 3m 2m), it takes tens of tons to fill the whole molding space with the plastic material powder, and even tens of tons to one hundred tons if the metal powder is used, it is necessary to heat the material and keep the temperature to 100 degrees or more. In order to solve the problem of material powder generation after large-scale production, the original mechanical structure design and process of the SLS process become very complicated, the total cost of materials is very high, and the energy consumption is also very large.

The SLS process uses the laser power and is closely related to the forming speed, the maximum power of the SLS process is generally between 0.4kw and 1kw, according to the principle of geometric amplification, the product volume is amplified by 1000 times, theoretically, the maximum power of the SLS process is also amplified by 1000 times correspondingly, otherwise, the SLS process is equivalent to using a tiny light spot to carve a picture which is increased by thousand times, the efficiency is unacceptably low, or the maximum power of a matched laser needs 400kw to 1000kw, according to the current laser technology, the common power is below 6kw, and 400kw can only be realized in the military field, so that the SLS process is difficult to realize at present.

The SLS printing layer height also has a large limitation because the principle is to sinter or melt the powder to form a solid state by using the high temperature generated by the focused laser focal spot, and the heat conduction is spontaneously diffused to the surrounding powder, if a deeper sintering thickness (layer height) is required, the heat diffusion can cause uncontrollable sintered line edges. Therefore, the size of the apparatus is not economically large in technical principle, and is not suitable for practical use.

3. The FDM process (fused deposition modeling), also called fuse deposition, the existing small FDM process mainly uses thermoplastic plastic wires with the diameter of about 1mm-3mm as printing materials, the printing head (2) melts the wires to coat and form the shape of each layer, the technology required by the FDM process is the simplest of all 3D printing process types, except for a moving structure, only a wire feeding mechanism and a heating head (printing head) are needed, the FDM process is compared with the SLS process and the DLP process, the FDM process does not use expensive materials or expensive technologies, the modeling principle is simpler, theoretically, as long as a printing line which is increased by ten times is used, the volume increment can be obtained under the condition that the original moving speed is not changed, the surface precision is sacrificed, but the precision is not a main problem in the large additive manufacturing field, on one hand, products with large size such as furniture, the requirements for the overall size precision of houses, lamps, decoration ornaments and the like are not high, large products on the two aspects need surface paint coating and other processes, the surface finish is determined by the coating process, the efficiency is the main problem when the size reaches the magnitude of several meters, FDM improves the line width and the layer height by improving the material flow, the forming volume efficiency can be greatly improved, and the FDM process has the possibility of large-scale production.

The small FDM process is a forming mode based on wires, a printing nozzle is coated and formed back and forth, the whole forming process is linear and is a process of gradually forming a body from a point to a line, from the line to a surface and from the surface, the volume is increased in three directions of length, width and height, the diameter of a printing line determines the increment of two directions, the movement speed determines the increment of a third direction, the increments of the three directions all need the equal proportion increment of material flow, and theoretically, the increment is 3 times of the average side length increment of a product, so that the extrusion efficiency of the printing line is greatly improved when the FDM is large.

In this case, the use of the filamentous material is impossible, the typical side length of the forming volume of the existing FDM printer using the filamentous material is about 0.1-1 meter, the typical side length of 1-10 meters is required for large-scale 3D printing and is basically 10 times, the conversion volume is 1000, the diameter of the wire needs to be amplified by 10 times and reaches 10mm-30mm, the wire is not a wire but a rod, the extrusion speed of the material is also amplified by 10 times, and as the diameter of the wire of the material becomes large, the wire becomes difficult to bend, the allowed bending diameter becomes very large, the wire is difficult to bend into a coil, the production is not easy, and additional processing cost is required. And the thermal conductivity of the material is limited, when the diameter of the wire is increased, the area of the outer surface of the wire is increased by a square, the volume is increased by a cube, the melting heating mode of a small machine only heats the outer surface of the wire, the melting efficiency of the wire is seriously reduced, and the heating principle of a printing head of the small machine is not applicable any more. The small-size conventional FDM printer uses crowded material gear and silk material surface meshing roll to produce and extrudes thrust, and after silk material line footpath became thick 10 times, the silk material sectional area enlargies and is close to 100 times, and extrusion speed need improve 10 times simultaneously, and the extrusion resistance of silk material becomes very big, and the intensity of silk material epidermis is difficult to bear the thrust of crowded material gear, leads to the epidermis to burst, and crowded material gear skids the idle running. The feeding mechanism of the small-sized machine and the melting structure of the printing head are not suitable after being enlarged.

In comprehensive analysis, the conventional small FDM process has certain practical value in small products, and the principle of the process can realize large-scale production, but the conventional melt extrusion mechanism can not meet the requirement of large-scale production.

The limitation of large-scale existing 3D printing process is as follows: the FDM technology realizes large-scale operation at a few of domestic and foreign companies to a certain extent, a gantry motion structure (similar to a gantry machining center) is generally adopted, a movable head type (printing head motion) motion structure is adopted, and a movable table type structure commonly used by the gantry machining center is adopted, so that a printing platform and a printing object are moved by the movable table structure, the motion inertia is far larger than the movable head type, and repeated acceleration and deceleration motion in 3D printing is not facilitated. The material melting and extruding mechanism is arranged on a lower probe shaft (Z axis), a single-screw extruder similar to an injection molding machine is generally used as the material melting and extruding mechanism, and granular raw materials are used as raw materials. In order to achieve a certain material extrusion flow rate, the material melting and extruding device arranged at the tail end of a moving structure has large volume and weight, so that the rigidity of a mechanical moving structure for installing and bearing the melting and extruding device must be designed to be strong enough, the inertia of the whole moving structure is large, products to be printed are complex and have local details, a printing head needs more short-distance reciprocating motion, a printing mechanism must be accelerated and decelerated repeatedly, and the moving structure has high motion inertia due to the weight of an extruder and the mechanism, so that the average acceleration is low, the average motion speed is low, the energy consumption is high, the printing quality is reduced, and the mechanical abrasion is accelerated. On the contrary, the weight of the extrusion device is reduced, the whole motion structure is lightened, the lighter melting extruder causes the material extrusion efficiency to be low, the extrusion flow is insufficient, and the flow and the weight are contradictory in structural design. Although the framework realizes the large-scale FDM process size, the movement speed and the discharge flow rate cannot be simultaneously improved, and the overall printing efficiency is still not high.

In the prior art devices capable of extruding 10kg of material per hour, which have a self weight of about 100 and 200 kg, i.e. a flow to weight ratio of less than 1, of about 0.1 to 0.05, the average movement speed can only reach 4000 mm/min, and thus the printing efficiency is low. Therefore, various performances of the melt extrusion device basically determine the system performance of the whole 3D printer, and directly influence the comprehensive forming efficiency of large FMD3D printing.

Large FDM printers typically use a single screw extruder in the plastics industry, and a brief analysis of the use of existing screw extruders in large FDM3D printing follows.

The single-screw extruder is simple in structure and easy to install and use, the high-performance double-screw extruder is complex in structure and large in size, printing speed can be increased only by light weight requirements of large-scale 3D printing, and therefore the single-screw extruder is difficult to be used for large-scale 3D printing, and the single-screw extruder is widely adopted and researched in the large-scale FDM3D printing industry at present. No case or literature has been found for large 3D printers using twin screw extruders.

The existing conical counter-rotating twin-screw extruder is very large in structure, except for necessary structures such as twin screws, machine barrels and heating sleeves, a thrust bearing device, a transmission system, a twin-screw synchronous mechanism, a driving and speed reducing mechanism, a base and the like have large volume and weight, and the existing conical counter-rotating twin-screw extruder is very not beneficial to high-mobility operation in a 3D printing process.

In addition, in the process of large-scale 3D printing, the movement and flow control are uniformly controlled by a master control system, the flow of the printing head must strictly correspond to the movement track and speed of the printing head according to the command of the master control, when the printing head moves at a variable speed, the change rate of the flow is strictly synchronous according to the command of the master control and the change rate of the movement speed, and the response speed of the printing flow which is instantaneously changed along with the master control command has a high requirement, otherwise, the line width and the line height of the printing line are out of control (larger or smaller), and the deviation is generated with the set value of the program command in the master control system. Moreover, for a printing scene which moves at a constant speed but continuously changes the line width and the line height, even a printing scene which moves at a variable speed and changes the line width and the line height, the requirements on the accuracy of flow control and real-time response are higher. In summary, even if the deviation is weak, according to the principle of 3D printing, the final accumulated error will be increased, which will cause a great influence on the appearance of the printed product, and even cause printing failure. Accurate flow control must therefore be achieved in large FDM3D printing processes. The existing conical counter-rotating double-screw extruder has a long transmission chain and is difficult to realize accurate transmission.

In summary, the existing conical counter-rotating twin-screw extruder has the important defects of too large volume and weight, too long transmission chain and the like, and certainly, the existing conical counter-rotating twin-screw extruder cannot be independently used for a 3D printing system because the hot melt material, besides the driving force of the extruder, also has the pressure generated by thermal expansion which is not controlled by the extruder, and also needs to be opened and closed at the tail end and controlled in a throttling way, and needs to be improved aiming at the characteristics of the 3D printing process. In order to realize an efficient large-scale FDM printing process, the following requirements must be satisfied simultaneously: the device has the advantages of small volume and weight, high-pressure and high-flow extrusion, high-precision tail end flow control, real-time flow change following instructions and good material plasticizing and exhausting effects.

Obviously, the extrusion device in the existing plastic industry or the extrusion mechanism in the existing 3D printing industry can not realize the extrusion device.

Disclosure of Invention

Therefore, the embodiment of the utility model provides a 3D printing device for large-scale vibration material disk makes has used the extrusion mode of counter-rotating toper double-screw structure, has improved control accuracy and real-time, and it is required to satisfy the large-scale FDM3D printing technology of efficient.

In order to achieve the above object, the embodiment of the present invention provides the following technical solutions:

according to the embodiment of the utility model, this 3D printing device for large-scale additive manufacturing includes material melt extrusion mechanism and printer head, the printer head is connected with molten material flow control mechanism, and printer head and material melt extrusion mechanism fixed connection, material melt extrusion mechanism's extrusion opening and printer head's molten material input port communicate; the material melting and extruding mechanism comprises a melting shell, a driving conical screw rod, a driven conical screw rod and a melting heater, wherein the driving conical screw rod and the driven conical screw rod are arranged in the melting shell and are meshed with each other, the driving conical screw rod is connected with a melting and extruding power source through a melting speed reducer, the driving conical screw rod is connected with the driven conical screw rod through a synchronous transmission mechanism and drives the driven conical screw rod to rotate, and the melting heater is arranged on the outer side of the melting shell.

Furthermore, the synchronous transmission mechanism comprises a driving gear and a driven gear which are meshed with each other, the driving gear is fixed on a screw shaft of the driving conical screw, and the driven gear is fixed on a screw shaft of the driven conical screw.

Furthermore, the driving gear and the driven gear are arranged in a synchronous box shell, the synchronous box shell is arranged between the melting shell and the melting speed reducer, and a bearing group which is sleeved on the shaft of the driving conical screw and the shaft of the driven conical screw is further arranged in the synchronous box shell. The bearing group is a combined bearing of a radial bearing and a thrust bearing.

Furthermore, the extrusion opening is arranged at the lower end of the melting shell, the printing head is fixed on one side of the lower end of the melting shell, and the upper end of the melting shell is provided with the feeding opening.

Furthermore, the lower end of the printing head is provided with a printing nozzle, the molten material flow control mechanism comprises a material control rod arranged in a lifting mode and a lifting mechanism for driving the material control rod to lift, and the lower end of the material control rod is arranged at the printing nozzle. The lifting of the material control rod is utilized to realize the flow regulation of printing and the switching of the caliber of the nozzle, and the structure is simple.

Furthermore, the lifting mechanism comprises an electric cylinder and an electric cylinder servo motor which are connected, and the electric cylinder is fixedly connected with the upper end of the material control rod.

Furthermore, the lower end of the material control rod is provided with a transverse flow channel and a vertical flow channel, the transverse flow channel transversely penetrates through two sides of the material control rod, the lower end of the vertical flow channel penetrates through the material control rod, and the upper end of the vertical flow channel is communicated with the transverse flow channel. More accurate adjustment can be realized through horizontal runner and vertical runner, and when the material control lever was in printing nozzle top completely, the bore of printing nozzle was printout bore promptly, and in the material control lever lower extreme got into printing nozzle, the material was exported behind horizontal runner and vertical runner in proper order, and vertical runner bore was printout bore promptly, continues to move down when the material control lever just can close printing nozzle completely.

Further, the lower end of the printing head is provided with a tail end heater.

Furthermore, conveying heaters are arranged at the extrusion port and the molten material conveying port.

The utility model discloses mainly make practical innovation to the vibration material disk manufacturing process of the large-scale product of centering.

The embodiment of the utility model provides a have following advantage:

the embodiment of the utility model provides an innovative mode of extruding that has used incorgruous rotatory toper double screw structure, and adopt the mode drive double screw extrusion mechanism that directly links, initiative conical screw passes through synchronous drive mechanism and connects and drive driven conical screw rotatory, make one-tenth, the integrated level of drive structure has been improved, make incorgruous rotatory toper double screw structure extruder can be applied to the 3D printer, to in the screw rod clearance, except the mechanical pressure who extrudes, the thermal energy pressure component of melting material does not receive the factor of screw rod control, terminal printer head has been improved, it is connected with melting material flow control mechanism to beat printer head, make and beat printer head and be variable bore structure, can be to melting fluid throttle control, further improvement control accuracy and real-time, it is required to satisfy the large-scale FDM3D printing technology of efficient.

The axes of the two screws of the conical double-screw extrusion structure have a certain included angle, and the screws are conical, and the diameters of the screws are gradually reduced from large to small and gradually compress a molten material. The conical double-screw type is compared with a parallel double-screw type, the center distance of the screw is not fixed, the axis of the screw has a certain included angle, the farther away from the head of the screw is, the larger the center distance of the screw is, and the larger the diameter of the screw is, so that the driving design of the screw is not difficult as the parallel screw, the center distance of the two axes is gradually increased from a small end to a large end, larger installation spaces are reserved for gears and gear shafts in a transmission system and radial bearings and thrust bearings for supporting the gear shafts, larger-specification radial bearings and thrust bearings can be installed, the closer the shaft diameter of the conical screw to the driving end is, the larger the driving torque can be transmitted easily. Therefore, the conical double-screw extrusion structure is easier to realize large working torque, large load bearing capacity and large extrusion flow. The mode of the counter-rotating has forced conveying characteristics, and meanwhile, the volume and the weight are kept small, and the application of 3D printing is facilitated.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below. It should be apparent that the drawings in the following description are merely exemplary, and that other embodiments can be derived from the drawings provided by those of ordinary skill in the art without inventive effort.

The structure, ratio, size and the like shown in the present specification are only used for matching with the content disclosed in the specification, so as to be known and read by people familiar with the technology, and are not used for limiting the limit conditions that the present invention can be implemented, so that the present invention has no technical essential significance, and any structure modification, orientation change, ratio relation change or size adjustment still falls within the scope that the technical content disclosed in the present invention can cover without affecting the function that the present invention can produce and the purpose that the present invention can achieve.

Fig. 1 is a schematic view of a 3D printing apparatus for large-scale additive manufacturing according to embodiment 1 of the present invention;

fig. 2 is a schematic view of a material melt extrusion mechanism according to embodiment 1 of the present invention;

fig. 3 is a schematic view of a print head according to embodiment 1 of the present invention;

FIG. 4 is an enlarged view of a portion of FIG. 3 at A, showing a material control lever in a state I;

fig. 5 is a state diagram ii of the material control lever according to embodiment 1 of the present invention;

fig. 6 is a state diagram iii of the material control rod according to embodiment 1 of the present invention;

fig. 7 is a schematic view of an actual application of the 3D printing apparatus for large-scale additive manufacturing according to embodiment 1 of the present invention;

fig. 8 is a schematic view of an actual application of the 3D printing apparatus for large-scale additive manufacturing according to embodiment 2 of the present invention;

FIG. 9 is an enlarged view of a portion of FIG. 8 at B;

in the figure: 1-material melt extrusion mechanism 2-printing head 3-melt reducer 4-melt extrusion power source 5-melt heater 6-feed inlet 7-extrusion outlet 8-molten material input port 9-transmission heater 10-tail end heater 11-electric cylinder 12-electric cylinder servo motor 13-power source controller 14-temperature controller 15-master controller 16-melt shell 17-driving conical screw 18-driven conical screw 19-bearing group 20-driving gear 21-driven gear 22-synchronous box shell 23-fixed seat 24-material control rod 25-heat insulation pad 26-printing nozzle 27-transverse flow channel 28-vertical flow channel 29-raw material bin 30-industrial robot 31 -a travelling gantry machine 32-a feed pipe.

Detailed Description

The present invention is described in terms of specific embodiments, and other advantages and benefits of the present invention will become apparent to those skilled in the art from the following disclosure. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention. In the present specification, the terms "upper", "lower", "left", "right", "middle", and the like are used for the sake of clarity only, and are not intended to limit the scope of the present invention, and changes or adjustments of the relative relationship thereof are also considered to be the scope of the present invention without substantial changes in the technical content.

Referring to fig. 1-2, the 3D printing device for large-scale additive manufacturing includes a material melt extrusion mechanism 1 and a printing head 2, the printing head 2 is connected with a melt material flow control mechanism, the printing head 2 is fixed on one side of the lower end of the material melt extrusion mechanism 1, and an extrusion port 7 of the material melt extrusion mechanism 1 is communicated with a melt material input port 8 of the printing head 2. The embodiment of the utility model provides a with material melt extrusion mechanism 1 and 2 fixed connection of printer head, and set up the molten material flow control mechanism who is used for controlling output flow in printer head 2, material melt extrusion mechanism 1 adopts twin-screw extrusion mechanism, the screw rod has the compulsory transport characteristic, but the molten material has expansion pressure, the material has broken away from the control of screw rod when being close to the export, the pipeline material of transmission process and molten material itself also have elasticity, under the effect of thermal expansion pressure, also have certain pressure under the condition that the screw rod does not move, therefore only carry out flow control through the screw rod, when continuous unchangeable extruded material, thermal expansion pressure is in the stable state, therefore the flow is stable, but 3D printed product has certain complexity usually, in the printing process, the flow is the break-make and the variation of size repeatedly, when the screw rod stall, or during variable speed motion, the actual flow of terminal printing nozzle 26 can not respond to the change of instruction immediately under the thermal expansion power effect of melting material, but after waiting thermal expansion pressure to consume completely, the flow just can be stabilized again, leads to actual flow and instruction to produce the hysteresis, and the real-time of flow is difficult to guarantee, so the utility model discloses a control cooperation of terminal throttle control and screw rod, just can solve the flow and be not only the volume in the space accurate, also accurate in time, really realize large-scale FDM3D and print.

The material melt extrusion mechanism 1 in this embodiment includes a melt housing 16, a screw extrusion mechanism and a melt heater 5, the screw extrusion mechanism is rotatably disposed in the melt housing 16, the melt heater 5 is disposed outside the melt housing 16, and the screw extrusion mechanism is connected to a melt extrusion power source 4 for driving the screw extrusion mechanism to rotate through a melt reducer 3. The lower end of the melting shell 16 is provided with an extrusion opening 7, and both sides of the upper part of the melting shell 16 are respectively provided with a feeding opening 6.

The screw extrusion mechanism comprises a driving conical screw 17 and a driven conical screw 18 which are meshed with each other, the upper end of the driving conical screw 17 is connected with a driving gear 20, the upper end of the driven conical screw 18 is connected with a driven gear 21, the driving gear 20 is meshed with the driven gear 21, and the upper parts of the driving conical screw 17 and the driven conical screw 18 are respectively connected with a bearing 19. The driving conical screw 17 is connected with a melt extrusion power source 4 through a melt reducer 3. The screw extrusion mechanism can also be a single screw structure driven by a hydraulic motor or other structures capable of generating extrusion pressure. The melt extrusion power source 4 is a servo power source, and the servo power source is matched with the double screws to achieve better extrusion effect and efficiency. The driving gear 20 and the driven gear 21 are arranged in a synchronous box shell 22, the synchronous box shell 22 is arranged between the melting shell 16 and the melting extrusion power source 4, and a bearing set 19 sleeved on screw shafts of the driving conical screw 17 and the driven conical screw 18 is further arranged in the synchronous box shell 22. In order to facilitate the assembly and maintenance of the integrated synchronization and support mechanism, the synchronization box housing 22 is divided into two parts by taking a plane formed by the axes of the two screws as a parting plane, and lubricating grease can be injected into the synchronization box housing 22 to lubricate the bearing set 19 and the gears.

The embodiment of the utility model provides an on being applied to large-scale 3D printer with toper double screw extrusion mechanism, the concrete improvement lies in the drive structure of melting extruder, has simplified the structure that complicated screw rod of traditional extruder, lazytongs, reducing gear box, multistage link to each other, improves the mode for directly driving. In the structure of the utility model, no unnecessary transmission axis body, thrust support bearing group, radial bearing and the like exist between the screw rod and the high-precision speed reducer, and the direct mounting is on the screw rod shaft, so that the whole driving structure is more compact, the volume is smaller, and the weight is lighter. The different-direction double-screw extruding structure is different from the conveying mechanism of a single-screw extruding structure used in the current 3D printing industry. The solid conveying process in the single-screw extrusion structure is friction drag, the melt conveying process is viscous drag, and the magnitude of the friction coefficient between the solid material and the metal surface and the viscosity of the melt material determine the strength of the conveying capacity of the single-screw extruder to a great extent. In the single-screw structure, a spiral passage exists from the feeding hole 6 to the final discharging hole, which means that the single screw has a lower pressure building limit on the material, when the pressure of the melt reaches a certain degree, the melt can leak and release pressure from the spiral passage and other gaps, so that the single-screw structure does not form effective positive displacement conveying on the material any more, the final output flow cannot be continuously increased, and the output flow cannot correspond to the rotating speed of the motor. The meshing structure of the meshing type counter-rotating double-screw extrusion mechanism is similar to a gear pump and a double-screw pump in the principle of forcedly conveying molten fluid materials, a section of double C-shaped closed chambers can be formed by the meshing structure, the number of the C-shaped closed chambers is the same as the number of turns of screw threads, when the screws rotate, shafts of the double C-shaped closed chambers move forwards (towards a discharge port), the screws rotate for one turn, and the closed chambers move forwards for one lead, so the materials are forcedly pushed forwards by the mutually meshed threads, and the degree of forcedly conveying the materials depends on the meshing clearance between the screw ridge of one screw and the screw groove of the other screw and the matching clearance between the screws and screw jackets. The embodiment of the utility model provides an adopted the crowded structure of incorgruous rotatory toper double screw of closely meshing, the less fit clearance of screw rod and screw rod overcoat, the maximum possible reduction hourglass flow phenomenon obtains the biggest positive displacement transport effect. The maximum output flow under the conditions of the driving force limit and the mechanical limit of the screw can be realized.

According to the 3D printing principle, the internal filling volume accounts for about 90% of the total volume, only the shell curved surface influencing the appearance effect of the printed product is formed, and the internal filling does not influence the appearance effect of the printed product, so that the line width and the line height (layer height) can be increased in the printing process, and the internal filling is rapidly completed at the maximum flow. For a part of the plane perpendicular to the horizontal plane in the outer surface or a curved surface with small curvature change and approaching the vertical horizontal plane, the printing can be rapidly carried out by using a larger layer height and a larger flow rate, and the appearance effect (curved surface fitting effect) of the product is the same as that of the small layer height. A larger flow rate therefore means a higher average efficiency 3D printing.

The extrusion port 7 and the molten material input port 8 are provided with transmission heaters 9, the lower end of the printing head 2 is provided with a tail end heater 10, the melting heater 5 and the transmission heaters 9 are connected to a temperature controller 14, the material is kept in a proper temperature environment all the time, and 3D printing is finally achieved after the material is melted, transmitted and discharged from the printing head 2. The molten material flow control mechanism and the melt extrusion power source 4 are connected with a power source controller 13 to control the extrusion pressure of the molten material, the flow rate of the material or the cut-off flow rate. The power source controller 13 and the temperature controller 14 are connected with a master controller 15.

Referring to fig. 3, the lower extreme that beats printer head 2 is equipped with print nozzle 26, the utility model discloses the innovative extrusion mode that has used counter-rotating toper double screw structure of embodiment, twin-screw synchronization structure and bearing structure have been improved, make one-tenth, the integrated level of drive structure has been improved, and regard as accurate drive mode with servo drive, make counter-rotating toper double screw structure extruder can be applied to the 3D printer, to in the screw rod clearance, except the mechanical pressure who extrudes, the thermal expansion pressure component of melting material does not receive the factor of screw rod control, terminal printer head 2 that beats has been improved, it is connected with melting material flow control mechanism to beat printer head 2, can be to melting fluid throttle control, further improvement control accuracy and real-time, satisfy the large-scale FDM3D printing process of efficient and need.

The molten material flow control mechanism includes a material control rod 24 which is provided in the print head 2 to be lifted and lowered, and a lifting mechanism which moves the material control rod 24 to be lifted and lowered, and the lower end of the material control rod 24 is provided at the print nozzle 26. Elevating system is including electronic jar servo motor 12 and electronic jar 11 that from top to bottom connect gradually, and electronic jar 11 is connected with material control rod 24 upper end, and the structure is very simple, in order to avoid beating printer head 2 in the heat transfer of molten material to electronic jar 11, originally be equipped with heat insulating mattress 25 between electronic pole of stand and the printer head 2. Of course, the embodiment of the present invention provides an elevating system that can also adopt other power sources that can be precisely controlled. One side of the printing head 2 is provided with a fixed seat 23 for connecting the material melt extrusion mechanism 1.

Referring to fig. 4-6, a transverse flow passage 27 and a vertical flow passage 28 are formed at the lower end of the material control rod 24, the transverse flow passage 27 transversely penetrates through two sides of the material control rod 24, the lower end of the vertical flow passage 28 penetrates through the material control rod 24, and the upper end of the vertical flow passage 28 is communicated with the transverse flow passage 27. The lower end of the material control rod 24 is provided with a transverse flow channel 27 and a vertical flow channel 28, and the position of the material control rod 24 is controlled by the electric cylinder 11, so that the printing head 2 has at least two output calibers and can be completely closed.

When the material control lever 24 is in states i and ii, there is a path for material to flow from the chamber of the printhead 2 to the print nozzle 26, and the printhead 2 is in an open state. When material control lever 24 is in state iii, there is no material flow path from the chamber to print nozzles 26 and printhead 2 is in a closed state. Specifically, when the position of the material control lever 24 is in the state i, a certain gap exists between the material control lever 24 and the print nozzle 26, and the molten material flows into the print nozzle 26 from the gap, and the aperture of the print nozzle 26 is in the maximum aperture state as the final output aperture of the material. When the position of the material control lever 24 is in the state ii, there is no gap between the material control lever 24 and the print nozzle 26, and the molten material flows out only from the horizontal flow channel 27 and the vertical flow channel 28, and the caliber of the vertical flow channel 28 at this time is used as the final output caliber of the material.

The melting extrusion power source 4 drives the driving conical screw 17 and the driven conical screw 18 to rotate through the melting speed reducer 3, solid particle raw materials entering from the feeding hole 6 are heated into fluid, the material is fully plasticized through the rotation of the screws and extrusion pressure to the molten material is generated, the molten material is conveyed into the printing head 2 through a molten material conveying pipe, the electric cylinder servo motor 12 drives the material control rod 24 to lift through the electric cylinder 11, the opening degree of the printing nozzle 26 is further adjusted, and the flow of the material is adjusted or the printing nozzle 26 is directly closed.

Referring to fig. 7, the 3D printing apparatus in the present embodiment is applied to an industrial robot 30, a raw material bin 29 is disposed on one side of the industrial robot 30, the raw material bin 29 is connected to a feeding port 6 of a material melt extrusion mechanism 1 through a feeding pipe 32, the material melt extrusion mechanism 1 is fixed on a robot arm of the industrial robot 30, and two printing heads 2 are fixed on two sides of the material melt extrusion mechanism 1. The device is generally suitable for 3D printing application of medium-high speed and medium-small flow, can be integrated on a loading arm of the industrial robot 30 by using a light extrusion device, and is suitable for 3D printing products of medium size and small size.

The utility model discloses 3D printing device has following advantage:

1. reducing the total weight of a melt extrusion apparatus

The structure of a large-scale melt extruder in the traditional industry is optimized, so that the conical double-screw extruder can be applied to a large-scale 3D printer, the driving structure of the melt extruder is specifically improved, the complex structure of a screw, a synchronous mechanism, a reduction gearbox and multistage connection of the traditional extruder is simplified, and the improvement is a direct-drive mode. The embodiment of the utility model provides an in, the screw rod to and high-accuracy speed reducer between not have unnecessary transmission axis body, thrust support bearing group, journal bearing etc. direct mount epaxial at the screw rod, make whole drive structure compacter, the volume is littleer, weight is also lighter.

2. Increasing the output flow of a melt extrusion apparatus

The different-direction double-screw extruding structure is different from the conveying mechanism of a single-screw extruding structure used in the current 3D printing industry. The solid conveying process in the single-screw extrusion structure is friction drag, the melt conveying process is viscous drag, and the magnitude of the friction coefficient between the solid material and the metal surface and the viscosity of the melt material determine the strength of the conveying capacity of the single-screw extruder to a great extent. In the single-screw structure, a spiral passage exists from the feeding hole 6 to the final discharging hole, which means that the single screw has a lower pressure building limit on the material, when the pressure of the melt reaches a certain degree, the melt can leak and release pressure from the spiral passage and other gaps, so that the single-screw structure does not form effective positive displacement conveying on the material any more, the final output flow cannot be continuously increased, and the output flow cannot correspond to the rotating speed of the motor.

The meshing type counter-rotating double-screw extruder is similar to a gear pump and a double-screw pump in the principle of forcedly conveying molten fluid materials, a section of double C-shaped closed chambers can be formed by a meshing structure, the number of the C-shaped closed chambers is the same as the number of turns of screw threads, when the screws rotate, shafts of the double C-shaped closed chambers move forwards (towards a discharge port), the screws rotate for one turn, and the closed chambers move forwards by a lead, so that the materials are forcedly pushed forwards by the mutually meshed threads, and the degree of forcedly-displacing and conveying depends on the meshing gap between the screw ridge of one screw and the screw groove of the other screw and the matching gap between the screws and screw jackets.

The utility model discloses the crowded structure of incongruous rotatory toper double screw of closely meshing that adopts, the less fit clearance of screw rod and screw rod overcoat, the maximum possible reduction hourglass flow phenomenon obtains the biggest positive displacement and carries the effect. The maximum output flow under the conditions of the driving force limit and the mechanical limit of the screw can be realized.

3. Accurate flow control

3D printing process has very high requirement to the stability of the extrusion flow of material, the embodiment of the utility model provides an incorgruous toper two xuan extrusion structures that adopt have the compulsory transport characteristic of extremely low hourglass, therefore mechanical structure possesses the condition of accurate control flow, can calculate out the relation function of rotational speed and extrusion capacity according to this characteristic. The utility model discloses use servo drive mode, cooperation high accuracy planetary reducer directly drives the structure with synchronous case and constitutes numerical control screw extruder, and the screw shaft becomes the numerical control axle, realizes accurate control flow and rapid instruction response ability, and this is that the single screw rod that generally adopts in the current large-scale FDM3D printing field extrudes the structure and does not have.

4. Real-time flow control

Because the servo motor controls the flow rate by pressure, the screw has a forced conveying characteristic, but the molten material has expansion pressure, the material is separated from the control of the screw when approaching the extrusion port 7, the pipeline material and the molten material in the transmission process have elasticity, and under the action of the thermal expansion pressure, the screw does not move and has certain pressure, so the flow rate is controlled only by the screw, when the extrusion material is continuously unchanged, the thermal expansion pressure is in a steady state, and the flow rate is stable, but 3D printing products generally have certain complexity, during the printing process, the flow rate is repeatedly switched on and off and has a change in size, when the screw stops rotating or moves in a variable speed, the actual flow rate of the tail end printing nozzle 26 does not immediately respond to the change of a command under the action of the thermal expansion force of the molten material, but after the thermal expansion pressure is completely consumed, the flow just can be stabilized again, leads to actual flow and instruction to produce the hysteresis, and the real-time of flow is difficult to guarantee, so the utility model discloses a terminal throttle control and servo motor control's screw rod cooperation, just can solve the flow and be not only the space volume accurate, also accurate in time.

The position of the material control rod 24 is controllable, and when the position of the material control rod 24 transitions from state i to state ii, the cross-sectional area of the material flow conduit formed by the material control rod 24 and the print nozzle 26 decreases as the material control rod 24 moves towards the print nozzle 26, and increases. When the position of the material control rod 24 is transited from the state ii to the state iii, the sectional area of the material flowing channel formed by the transverse flow channel 27 and the printing nozzle 26 is gradually reduced along with the movement of the material control rod 24 towards the printing nozzle 26, otherwise, the sectional area is increased, the flow resistance is changed in real time in cooperation with the flow regulation of the extrusion device, the flowing flow is not only related to the pressure but also related to the resistance, and therefore, the continuous accurate real-time regulation of the tail end of the printing output flow is finally realized under the control of the control system software.

5. Improving the effect of material output by a melt extrusion device

In 3D printing process applications, the extrusion effect of the melt extrusion device on the material directly determines the final printing effect. Two main factors affecting the material effect are the plasticizing degree and the impurity removal degree (moisture, air, low molecular weight vaporized impurities, etc.). If the plasticizing degree of the material is insufficient during extrusion, the material is unevenly distributed and has loose multiple layers, and finally, the mechanical property of a printed product is poor. If the impurity removal degree is not enough when the material is extruded, particularly when moisture and air are not completely removed, the molten material containing gas and moisture enters a normal-temperature normal-pressure state (after being extruded from a printing nozzle), the pressure is suddenly reduced, the moisture in the material can be vaporized, so that the printing line expands, and after water vapor is discharged, the printing line shrinks, so that the printing line width and the line height are uncontrollable, the printing line has more air holes, and the printing effect is seriously reduced.

Compared with a single-screw structure commonly used in the industry, the double-screw extruding structure has good mixing, stirring, plasticizing and impurity discharging effects, a printing line is compact and uniform in plasticizing, and the printing effect is good. Due to the mixing and stirring characteristics of the double-screw extruding structure, various auxiliary agents such as a toughening agent, a plasticizer, a filling agent, glass fibers, carbon fibers and the like can be added into a main material, so that the main material is modified and enhanced or other properties are added, the counter-rotating double-screw extruder has the forced extruding characteristic, powdery raw materials can be used, and the double-screw extruding structure has the advantage of material selection diversity compared with a single-screw extruding structure.

6, the printing head with high integration can realize the sealing and the caliber switching

6.1 opening and closing of print nozzles

The small FDM3D printer uses a wire printing mode, is simple in structure and only comprises a heating head and a wire extruding device. The printing head 2 cannot be completely closed during or after printing is completed, and only negative pressure generated during short-distance retraction of the printing line is used for pumping the fluid material back into the printing nozzle, but the negative pressure cannot be continued, so that if the fluid material is not printed again in a short time, part of the fluid material overflows from the printing nozzle 26 and remains in other positions of a product, and the printed product has local defects. Such defects are reduced in the case of compact printers due to the relatively small size of the product. But to large-scale 3D printing, the volume increase is 1000 times, and its defect also will be enlarged, consequently any unnecessary material remains all can't ignore to large-scale printer, the utility model discloses beat fine solution of printer head 2 and printed the problem that the in-process material spills over, when not needing output material, material control rod 24 penetrates in printing nozzle 26, and material control rod 24 outer wall only has minimum fit clearance with printing nozzle 26 inner wall, and the clearance is less than the overflow limit value of molten material, makes the material unable overflow.

6.2 bore switching of print heads

In a large FDM3D printing process, the nozzle aperture of the printing head 2 is not a fixed size, but a plurality of nozzles with different apertures are provided, and the flow control of the nozzles with different apertures in cooperation with extrusion can realize the line width and line height of different output printing lines. According to the foregoing analysis, it is generally only necessary that the exterior curved surface (visible to the human eye) of the printed product have some appearance effect, while the interior (not visible to the human eye) solid portion thereof is generally not required unless the product has special requirements for its interior structure. A larger bore nozzle, i.e. a larger flow rate, is used for filling the interior of the printed product. The printing line is widened and heightened to reduce the density of the reciprocating filling line of the current printing layer, the principle of the printing line is similar to that a painting brush is used for coloring a graph with a certain area, the painting brush with a wider pen point can use fewer reciprocating times and shorter total path length to color the graph, the reciprocating acceleration and deceleration times can be reduced for 3D printing, the average movement speed of printing can be improved, the path length is also reduced, and therefore the forming speed of a printing product is improved. The contradiction between the efficiency and the appearance quality is greatly optimized.

In the current FDM3D printing field, the current variable caliber of the printing head 2 in the industry is realized by a structure of a plurality of independent printing nozzles with different calibers, the printing head 2 is required to be shifted when different printing nozzles are switched, and the printing nozzle after replacement is moved to the position of the printing nozzle before replacement so as to continue printing. If a plurality of independent printing nozzles are at the same height relative to the printing object plane, the printing is interfered, and therefore the unused printing nozzles need to be lifted to a higher position to avoid scratching the surface of the printing layer. Finally, the structure of the existing multiple print heads 2 becomes complex, the integration level is poor, and the total weight is increased due to the structure of the multiple independent print heads 2, so that the printing device is not suitable for high-speed and high-efficiency printing.

The embodiment of the present invention provides a concentric nesting mode for the structure of the printing head 2 and the material control rod 24, and a vertical flow channel 28 with a smaller bore is embedded inside the printing nozzle 26. In the example, the nested structure is a dual-aperture nest, and can also be a multi-aperture nest. It is not necessary to shift the position of the print head 2 during switching of the print head 2 because all the printing nozzles are concentric. The novel printing head 2 is hidden inside the current printing nozzle along with the material control rod 24 in the unused state except for the outermost (also the maximum caliber) printing nozzle, so that the problem of printing interference does not exist, and the problem of scratching the surface of the printing layer does not occur. The novel structure beat printer head 2 and realize printing nozzle 26's the closure and printing nozzle 26's bore switching, improved the integrated level, reduced weight, improved printing efficiency.

Example 2

Referring to fig. 8-9, the utility model discloses 3D printing device installs on walking machine tool 31, and the 3D who is applicable to high-speed, large-traffic, high motion stability prints and uses, can use the structure of external large-scale extruder, is fit for jumbo size or super large-size 3D and prints the product. The material melting and extruding mechanism 1 is fixed on a machine tool base, one side of a row frame type machine tool 31 is provided with a raw material bin 29 for supplying materials to the material melting and extruding mechanism 1, a melting material conveying pipe is arranged along the machine frame, and the printing head 2 is arranged on a row frame which can move horizontally and vertically.

Although the invention has been described in detail with respect to the general description and the specific embodiments, it will be apparent to those skilled in the art that modifications and improvements can be made based on the invention. Therefore, such modifications and improvements are intended to be within the scope of the invention as claimed.

Claims

1. A3D printing device for large-scale additive manufacturing, its characterized in that: the 3D printing device comprises a material melt extrusion mechanism (1) and a printing head (2), wherein the printing head (2) is connected with a melt material flow control mechanism, the printing head (2) is fixedly connected with the material melt extrusion mechanism (1), and an extrusion port (7) of the material melt extrusion mechanism (1) is communicated with a melt material input port (8) of the printing head (2); the material melting and extruding mechanism (1) comprises a melting shell (16), a driving conical screw (17), a driven conical screw (18) and a melting heater (5), wherein the driving conical screw (17) and the driven conical screw (18) are arranged in the melting shell (16) and are meshed with each other, the driving conical screw (17) is connected with a melting and extruding power source (4) through a melting speed reducer (3), the driving conical screw (17) is connected through a synchronous transmission mechanism and drives the driven conical screw (18) to rotate, and the melting heater (5) is arranged on the outer side of the melting shell (16).

2. The 3D printing device for large scale additive manufacturing of claim 1, wherein: the synchronous transmission mechanism comprises a driving gear (20) and a driven gear (21) which are meshed with each other, the driving gear (20) is fixed on a screw shaft of the driving conical screw (17), and the driven gear (21) is fixed on a screw shaft of the driven conical screw (18).

3. The 3D printing device for large scale additive manufacturing of claim 2, wherein: the driving gear (20) and the driven gear (21) are arranged in a synchronous box shell (22), the synchronous box shell (22) is arranged between the melting shell (16) and the melting speed reducer (3), and a bearing group (19) which is sleeved on a screw shaft of the driving conical screw (17) and the driven conical screw (18) is further arranged in the synchronous box shell (22).

4. The 3D printing device for large scale additive manufacturing of claim 1, wherein: the extrusion opening (7) is arranged at the lower end of the melting shell (16), the printing head (2) is fixed on one side of the lower end of the melting shell (16), and the upper end of the melting shell (16) is provided with the feeding opening (6).

5. The 3D printing device for large scale additive manufacturing of claim 1, wherein: the lower extreme of printer head (2) be equipped with print nozzle (26), fused material flow control mechanism is including material control lever (24) and the elevating system that drives material control lever (24) lift that goes up and down the setting, and the lower extreme setting of material control lever (24) is in print nozzle (26) department.

6. The 3D printing device for large scale additive manufacturing of claim 5, wherein: the lifting mechanism comprises an electric cylinder (11) and an electric cylinder servo motor (12) which are connected, and the electric cylinder (11) is fixedly connected with the upper end of the material control rod (24).

7. The 3D printing device for large scale additive manufacturing of claim 5, wherein: the material control rod is characterized in that a transverse flow channel (27) and a vertical flow channel (28) are formed in the lower end of the material control rod (24), the transverse flow channel (27) transversely penetrates through two sides of the material control rod (24), the lower end of the vertical flow channel (28) penetrates through the material control rod (24), and the upper end of the vertical flow channel (28) is communicated with the transverse flow channel (27).

8. The 3D printing device for large scale additive manufacturing of claim 1, wherein: the lower end of the printing head (2) is provided with a tail end heater (10).

9. The 3D printing device for large scale additive manufacturing of claim 1, wherein: conveying heaters (9) are arranged at the extrusion port (7) and the molten material input port (8).