CN110682533A - FDM that prints towards complicated work piece 3D spouts a mechanism - Google Patents

Abstract

The invention discloses an FDM spinning mechanism for 3D printing of complex workpieces. The FDM spinning mechanism includes a spinning feeding system installed above and a spinning spinning system fixed below it; in the spinning feeding system, optimized For the L-shaped connector connected with the throat, a fan speed controller is installed on the side of the connecting frame, and an elongated throat is designed in the wire output system to print complex workpieces. The spinneret mechanism can not only effectively solve the problem of FDM 3D printers printing complex workpieces, but also further solve the problem that the filaments in current 3D printing are easily thermally expanded, resulting in nozzle blockage. The invention expands the application range of FDM three-dimensional printing while improving the printing efficiency and the precision of the printed product, and has higher economic benefits.

Description

An FDM spinneret mechanism for 3D printing of complex workpieces

technical field

The invention relates to an FDM spinning mechanism for 3D printing of complex workpieces, and belongs to the technical field of equipment components in the field of 3D printing.

Background technique

Fused Deposition Modeling (FDM) 3D printing technology is one of the traditional technologies in the field of 3D printing. It is welcomed by many users because of its easy-to-implement manufacturing method of layer-by-layer fuse formation, which can be used to print various physical models. Even utility artifacts. The spinneret is the core component of this printing equipment. At present, the traditional spinneret with a combination of a short throat and a large heating block is usually used on the market. Since this spinneret mechanism is prone to interference with the workpiece, it is only suitable for 2.5-axis printing processes, and cannot be used for multi-axis unsupported 3D printing of complex workpieces. Unsupported 3D printing of complex workpieces is one of the important development trends of current 3D printing technology. Therefore, the multi-axis unsupported 3D printing technology for complex workpieces designs a spinneret structure with less interference and stable performance, which plays an important role in the development of FDM 3D printing technology.

SUMMARY OF THE INVENTION

In order to solve the problems of insufficient existing technology and the like, the purpose of the present invention is to provide an FDM spinning mechanism for 3D printing of complex workpieces, which effectively solves the problems of printing complex workpieces and preventing wire clogging in multi-axis printing, and is a multi-axis printing mechanism. Such problems in 3D printing provide an effective solution. The invention has the characteristics of low cost, high processing efficiency, and strong operability.

In order to achieve the above object, the present invention adopts the following technical solutions:

An FDM spinning mechanism for 3D printing of complex workpieces, including a wire feeding system and a wire discharging system; the wire feeding system includes a connecting frame, a compression screw, a compression block, a compression spring, a fastening bolt, an adjustment screw, A feeding gear, a pinch wheel and a stepping motor; the wire discharging system includes a throat, a nozzle and a heating block; the wire feeding system also includes a cooling fan for reducing the temperature of the throat.

Further, it also includes an L-shaped connector, the L-shaped connector is composed of a vertical plate and a horizontal plate; the vertical plate is provided with a through hole, the outer side of the vertical plate is fixed on one side of the connecting frame, and the stepping motor is fixed on the On the other side of the connecting frame, its output shaft passes through the through hole, and the end of the output shaft exposed through the through hole is fixed with a feeding gear; the geometric center of the pressing block is hinged with the inner side of the vertical plate, and the longitudinal direction of the pressing block is There is a pressing screw running through, the fastening stud is fixed on the upper surface of the horizontal plate, the adjusting screw longitudinally penetrates the horizontal plate and the fastening stud in sequence, and a pressing spring is connected between the adjusting screw and the pressing screw; There is a pressing wheel; there are longitudinal through holes on the horizontal plate, which are used to pass through the PLA wire.

The stepping motor drives the feeding gear to drive, and the feeding gear, the pressing wheel, the pressing block and the pressing spring together feed the wire into the wire discharging system below to realize the wire feeding action. On the one hand, the compression spring is used for manual wire changing, and on the other hand, it prevents the wire from jumping during the feeding process. The compression spring is sleeved on the compression screw on the compression block and the fastening stud fixed on the adjustment screw on the L-shaped connector. By tightening/releasing the compression screw, the horizontal plate of the compression block and the L-shaped connector can be changed. The effective distance of the compression spring can be adjusted by tightening/releasing the adjusting screw. The geometric center of the pressing block is fixed on the vertical plate of the L-shaped connector, which can be manually pressed/relaxed, and the pressing wheel is fixed on the pressing block to push the wire to the feeding gear to facilitate wire feeding.

Further, a front air guide cover and a rear air guide cover are respectively provided at the front and rear of the cooling fan, the front wind guide cover is fixed to the horizontal plate, the cooling fan is fixed to the front wind guide cover, and the rear wind guide cover is fixed to the front wind guide cover.

Further, it also includes a fan speed regulator, which is fixed on the connecting frame, and the fan speed regulator is electrically connected to the cooling fan.

The fan speed regulator is connected to one side of the connecting frame, which plays an important role in the heat dissipation process. Printing complex workpieces has extremely high process requirements, so parameters such as printing speed are different in different time periods, and wire blockage may occur in any link, so the open governor can adjust the temperature of the fan at various time periods, At the same time, technicians can also manually adjust according to the printing conditions to ensure that the temperature of the nozzle is always within the appropriate range.

Further, a straight pipe is installed in the longitudinal through hole, the upper end of the straight pipe extends below the feeding gear and the pressing wheel, and the lower end is connected with the throat.

The wire will enter the newly connected straight-through pipe under the action of the feeding gear. Because the wire itself is plastic, it is entangled when purchased, so the manual wire change is often blocked in the wire-feeding system. The straight-through pipe guarantees After the wire is extruded by the feeding gear, it smoothly enters the L-shaped connector and the wire outlet system below, and the lower part is connected with the throat through a thread.

Further, the length of the straight pipe below the longitudinal through hole is 1/5 of the length of the throat.

Since the throat is an elongated throat, it is made of 304 stainless steel to ensure the strength, but because it is too long and the rigidity is not enough, the straight-through pipe has been extended down to 1/5 of the throat length, which improves the lengthened type without reducing the printing range. The stiffness of the throat.

Further, the upper part of the throat pipe is connected with the straight pipe, and the lower part is connected with the heating block. The length of the throat is suitable for printing complex workpieces, such as cladding. Printing on the basis of the existing matrix material is prone to adverse phenomena such as interference. Especially as a complex workpiece, the printing of a single matrix will take a long time. If there is an accident due to later cladding, the work efficiency will be greatly reduced. Therefore, the length of the elongated throat pipe of the present invention is 3 to 5 times that of the existing throat pipe on the market, and it is made of 304 stainless steel. Blocks the heat transfer of the heating block upwards and prevents the nozzle from clogging. There are two symmetrical rectangular planes milled above the heat blocking slot with a milling cutter, which is convenient for fixing the throat to the heating block and the L-shaped connector with a wrench, making the throat connection more stable. A Teflon tube runs through the inside of the elongated throat, the lower part of which is communicated with the nozzle, and the printing wire is smoothly guided to the nozzle and melted in the nozzle.

Further, the outside of the heating block is a rectangular solid, and the volume is half of the existing heating block, which can effectively reduce the interference. There are two hollow circular cones on the upper surface, and one of the circular cones is provided with a thread matching the external thread of the throat. Internal thread is used for thread connection with the throat pipe; heating holes are opened on the surface of the heating block below the other round table, and the heating rod is inserted into the heating block successively through the round table and the heating hole from top to bottom. Slow, prevent throat blockage, on the other hand can reduce its overall thickness. The heating block is made of aluminum alloy material, and the temperature sensor and the heating block are fixed by hexagon socket screws; the heating rod is locked by the tip tightening screw, and the temperature sensor and heating rod are respectively connected to the temperature controller and the relay through the wire. The given temperature heats the temperature of the heating block to a certain temperature.

Beneficial effects achieved by the present invention: the spinning system is comprehensively optimized from top to bottom, effectively solving the problem of printing complex workpieces and preventing wire clogging in multi-axis printing. The manufacturing precision and processable range of 3D printing have high economic benefits.

Description of drawings

Fig. 1 is the axial side view of the spinning system; Fig. 2 is the front view of the spinning system; Fig. 3 is the top view of the spinning system; Fig. 4 is the front view of the spinning system; Fig. 5 is the side view of the spinning system; Fig. 6 is the L type Axonometric view of the connector; Figure 7 is a front view of the L-shaped connector; Figure 8 is a sectional view of the L-shaped connector; Figure 9 is a front view of the wire feeding system; Figure 10 is a sectional view of the wire feeding system; Figure 11 is a section view of the heating part; 12 is the axonometric view of the heating block;

Symbols and meanings in the figure:

1-connecting frame, 2-pressing screw, 3-pressing block, 4-pressing spring, 5-fastening stud, 6-cooling fan, 7-fan governor, 8-feeding gear, 9- Pinch wheel, 10-stepper motor, 11-L-type connector, 12-adjustment screw, 13-rear air guide, 14-front air guide, 15-PLA wire, 16-Teflon conduit, 17- Extended throat, 18-nozzle, 19-heating block, 20-tip set screw, 21-heating rod, 22-temperature sensor, 23-hexagon socket head screw, 24-first hollow round table, 25-second hollow round table , 26- heat block slot, 27- rectangular plane.

Detailed ways

The technical solution of the present invention will now be fully described with reference to FIGS. 1-12 . The following descriptions are only a part of the implementation examples of the present invention, but not all. Based on the implementation cases in the present invention, all other implementation cases obtained by those skilled in the art without creative work fall within the protection scope of the present invention.

As shown in Figures 1-12, the present invention discloses a design of an FDM spinning mechanism for 3D printing of complex workpieces. This mechanism includes two parts: the wire feeding system and the wire feeding system. The wire feeding system is connected to the control system, and the lower end is connected to the wire feeding system. During the printing process, the drive shaft of the stepping motor drives the rotation of the feeding gear, and the PLA wire is compressed during the printing process. Under the combined action of the wheel and the feeding gear, it is forced to move downward, and this process realizes the continuous supply of printing raw materials.

As shown in Figures 4-8, the wire feeding system includes a stepper motor 10, a pressing block 3, a pressing wheel 9, a pressing screw 2, a pressing spring 4, and an L-shape which are sequentially connected to the connecting frame 1. The connecting piece 11, the adjusting screw 12, the fan speed regulator 7, the front and rear air guide covers 13-14 and the cooling fan 6; the output end of the stepping motor 10 is fixed with the feeding gear The feeding gear rotates, the other end of the feeding gear is connected to the pressing wheel 9 and the pressing block 3 in turn, and the feeding gear 8, the pressing wheel 9 and the pressing block 3 realize the wire feeding action under the pressure;

At the same time, the compression spring 4 is respectively wound on the compression screw 2 of the compression block 3 and the fastening stud 5 of the L-shaped connector, and the fastening stud 5 of the L-shaped connector is locked by the adjustment screw 12. The preload force can be adjusted by tightening/releasing the pressing screw 2 of the pressing block 3, and the moving length of the pressing block can be adjusted by tightening/releasing the adjusting screw 12 to control the clearance between the pressing wheel 9 and the feeding gear 8.

For printing complex workpieces, the problem of heat dissipation during the printing process is particularly important. In order to maximize the heat dissipation efficiency, the present invention adds a fan speed controller 7 to the wire feeding system, which is fixed on one side of the connecting frame 1, and outputs signals in real time through the control system to control the output voltage. The wind speed changes all the time. At the same time, the air guide cover of the fan has also been structurally designed. Under this structure, the heat at the throat above the heating block can be rapidly reduced to avoid wire blockage during the printing process.

One side of the L-shaped connector is fixed with the adjusting stud, and the other side is connected with the elongated throat, and the cooling fan and the air guide cover are also fixed on it. The PLA wire will enter the newly connected straight pipe port downward by the action of the feeding gear, and smoothly enter the wire outlet system through the straight pipe port.

The lower end of the wire feeding system is connected to the wire discharging system.

9 to 12 , the filament output system specifically includes: the nozzle 18 is connected to the heating block 19, and the heating block conducts heat to the nozzle to complete the melting of the PLA filament 15. The heating rod 21 and the temperature sensor 22 pass through the inner hexagon. The screws 23 are fixed on the heating block 19, and are respectively connected to the relay and the temperature controller through wires to realize heating and to realize constant temperature control of the heating block. The four heat blocking grooves at the nozzle 18 of the elongated throat 17 can effectively block the heat transfer. There are two symmetrical rectangular planes milled with a milling cutter above the heat blocking groove, which is convenient to use a wrench to fix the throat to the heating fast and the connecting piece. There is a Teflon conduit 16 inside the elongated throat 17, which can prevent the heat from being transferred to the PLA wire inside the elongated throat, effectively preventing the wire from being blocked due to thermal expansion inside the elongated throat. The temperature sensor 22 detects the temperature, When the heating rod 21 heats the heating block 19 to complete the printing process, the temperature of the nozzle portion is constant, and the joint action of the components realizes the complete printing work.

This embodiment provides two heat dissipation methods and one heating method. One is that the elongated throat pipe is made of 304 stainless steel, and four heat blocking grooves of equal distance and equal width are opened at the connection with the heating block. , which can block the heat transfer from the source and prevent the nozzle from clogging.

The other is to add a speed-adjustable cooling fan to the wire feeding system. The air guide hood has the best heat dissipation effect above the heating block after system analysis, so as to avoid the temperature of the heating block rising too much due to excessive heat dissipation. slow. The fan speed regulator is connected with the control system, and the wind speed is adjusted in real time by the control board, which can ensure the manufacturing precision of the workpiece during the printing process.

Among them, the heating method is that the designed heating block is made of aluminum alloy, and the heating rod is changed from the traditional insertion from the right to the upper insertion, which reduces the mass and volume of the heating block, can effectively reduce the interference in work, and improve the work efficiency. At the same time, put thermal insulation glue on the outside of the heating block to reduce heat loss and increase its life.

The combination of the two heat dissipation methods and heating methods solves the problems of inability to print complex workpieces or low printing accuracy in the existing multi-axis 3D printing, and further solves the existing uneven heat dissipation of the throat and nozzle, which leads to easy blockage. wire problem. While improving the printing efficiency, the invention improves the manufacturing precision and the processable range of the three-dimensional printing, and has higher economic benefits.

The above description of the disclosed embodiments enables any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (10)

1. An FDM spinning mechanism for 3D printing of complex workpieces comprises a yarn feeding system and a yarn discharging system; the wire feeding system comprises a connecting frame, a compression screw, a compression block, a compression spring, a fastening bolt, an adjusting screw, a feeding gear, a compression wheel and a stepping motor; the wire outlet system comprises a throat pipe, a nozzle and a heating block; the filament feeding system is characterized by further comprising a cooling fan and a fan speed regulator, and the cooling fan and the fan speed regulator are used for reducing the temperature of the throat pipe.

2. The FDM spinning mechanism for 3D printing of complex workpieces as claimed in claim 1 further comprising L-shaped connectors, wherein the L-shaped connectors are composed of vertical plates and horizontal plates; a through hole is formed in the vertical plate, the vertical plate is fixed to one side of the connecting frame, the stepping motor is fixed to the other side of the connecting frame, the output shaft of the stepping motor penetrates through the through hole, and a feeding gear is fixed to one end, exposed out of the through hole, of the output shaft; the geometric center of the pressing block is hinged with the inner side surface of the vertical plate, a pressing screw penetrates through the pressing block longitudinally, the fastening stud is fixed on the upper surface of the transverse plate, the adjusting screw penetrates through the transverse plate and the fastening stud longitudinally and sequentially, and a pressing spring is connected between the adjusting screw and the pressing screw; a pressing wheel is arranged below the pressing block; the transverse plate is provided with a longitudinal through hole for passing through the PLA silk material.

3. An FDM spinning mechanism for 3D printing of complex workpiece as claimed in claim 2 wherein, front and back of the heat dissipation fan are set with front wind guiding cover and back wind guiding cover respectively, the front wind guiding cover is fixed on the cross plate of the L-shaped connecting piece, the heat dissipation fan is fixed on the front wind guiding cover, the back wind guiding cover is fixed on the front wind guiding cover.

4. An FDM spinning mechanism for 3D printing of complex workpiece as claimed in claim 2 wherein the longitudinal through hole is installed with a straight through pipe, the upper end of the straight through pipe extends to below the feeding gear and the pinch roller, the lower end is connected with the throat.

5. An FDM spinning mechanism for 3D printing of complex workpiece as claimed in claim 4 wherein the length of the straight through pipe under the longitudinal through hole is 1/5 of throat length.

6. An FDM spinneret mechanism facing to 3D printing of a complex workpiece according to claim 1 wherein the throat is elongated and has a length of 120-180 mm.

7. An FDM spinning mechanism for 3D printing of complex work piece according to claim 1 wherein the throat has heat blocking slots above the junction with the heating block.

8. The FDM spinning mechanism for 3D printing of complex workpieces as claimed in claim 1, wherein the heating block has heating holes on its top surface for inserting heating rods into the heating block from top to bottom.

9. The FDM spinning mechanism for 3D printing of complex workpieces according to claim 8, wherein a first hollow circular truncated cone and a second hollow circular truncated cone are arranged on the upper surface of the heating block, the first hollow circular truncated cone is located above the heating hole, and an internal thread matched with an external thread of the throat pipe is arranged in the second hollow circular truncated cone.

10. An FDM spinning mechanism for 3D printing of complex workpiece as claimed in claim 1 wherein the heating block is 15-20 mm long and wide and 5mm thick.

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