CN220146689U - Desktop level granule 3D printer - Google Patents

Abstract

The utility model discloses a desktop-level particle 3D printer, which comprises a base, an electric cabinet and a double-layer portal frame, wherein the double-layer portal frame is fixed on the base, the electric cabinet wraps the double-layer portal frame and is fixed on the base, a slidable Y-axis assembly is arranged on the base below the double-layer portal frame, a liftable Z-axis assembly is arranged between the double-layer portal frames, a slidable X-axis assembly is arranged on the Z-axis assembly, a detachable extrusion device is arranged on the X-axis assembly, a printing platform is arranged on the Y-axis assembly, plastic particles are melted by the extrusion device and extruded from a nozzle, printing is carried out on the printing platform, 3D printing can be carried out by using various conventional plastic particles and composite modified material particles, the traditional mode that a plastic wire is used as a raw material for printing is changed, and printing capability and printing speed are greatly improved.

Description

Desktop level granule 3D printer

Technical Field

The utility model relates to the field of small 3D printing equipment, in particular to a desktop grade particle 3D printer.

Background

Traditional small-size 3D printer of desktop level basically wholly uses the linear consumptive material of plastics, carries a heating region with the wire rod through gear structure pay-off extrusion mechanism, extrudes after melting, and one section is put away in proper order layer by layer and is realized 3D entity's printing shaping, and the type quantity of consumable material that can print is few, and printing ability and printing speed have all received serious restriction.

At present, in large-scale 3D printing equipment, the industry at home and abroad directly uses a screw type industrial extruder as an extrusion head in the 3D printing equipment, an extrusion screw and a charging barrel of a plasticizing system are parts with the diameter of more than D30, particles are fed into the plasticizing system from one end through the equipment, the screw rotates to move, fluid extrusion is realized at the other end through the cooperation of a three-section area of the screw and a heating system, and a die head structure is matched, so that the 3D printing function taking plastic particles as raw materials is completely realized.

For small 3D printing apparatuses, it is also desirable to use a similar copy reduction means to achieve 3D printing of particles as a raw material, but after only the extruder is designed to be copy reduced by a 3D printer, there are the following problems: an elongated screw rod with the diameter below 20mm (the length of a thread groove is more than 25 times of the diameter) is difficult to process and realize, and is extremely easy to bend, break and discard in machining; the screw groove depth of the screw rod with small specification is smaller, so that raw material particles are more difficult to enter the screw groove space, and extrusion flow break occurs.

At present, small and medium-sized plastic particle 3D printers with fewer numbers in the market basically have the problems of unstable extrusion, easy interruption of equipment printing, limited supported particle consumable types, low printing qualification rate and the like, and the particle 3D printing function is difficult to realize completely, and the miniaturization of the particle 3D printing equipment is always in an exploration stage, so that the problems in the prior art are solved.

Disclosure of Invention

In order to make up the defects of the prior art, the utility model aims to provide a desktop grade particle 3D printer which is provided with a small printing extrusion device, can realize the rapid switching of the extrusion device, is provided with a platform pressing plate device, and realizes the fixed printing of various materials.

The utility model is realized by the following technical scheme:

the utility model provides a desktop level granule 3D printer, includes base, electrical cabinet and double-deck portal frame, double-deck portal frame is fixed on the base, electrical cabinet parcel double-deck portal frame just fixes on the base, be equipped with slidable Y axle subassembly on the base of double-deck portal frame below, be equipped with liftable Z axle subassembly between the double-deck portal frame, be equipped with slidable X axle subassembly on the Z axle subassembly, be equipped with detachable extrusion device on the X axle subassembly, extrusion device includes shell, motor fixed plate and magazine fixed plate, be fixed with the motor on the motor fixed plate, be fixed with the storage box between motor fixed plate and the magazine fixed plate, the bottom of magazine fixed plate is fixed with the heater cylinder, the bottom of heater cylinder is equipped with the nozzle, the feed opening has been seted up to the intermediate position of magazine fixed plate, the heater cylinder top be equipped with the feed inlet, the storage box with the heater cylinder is linked together through feed opening and feed inlet, the output shaft of motor passes the motor fixed plate downwards to be connected with detachable extrusion device, the screw rod is equipped with the screw rod in the screw rod is stretched into with the screw rod, the screw rod is stretched into with the side of the heater cylinder, the screw rod is stretched into by the screw rod, the side is stretched into by the heater cylinder, the printer platform from the side.

Further preferably, a heat insulation pad is fixed between the top end of the heating cylinder and the fixing plate of the material box, the heating cylinder is divided into an upper cylinder, a middle cylinder and a lower cylinder, the upper cylinder and the middle cylinder adopt an empty-avoiding structure, the lower cylinder is a thickened cylinder, 2 cooling fins are fixed on the outer side wall of the upper cylinder, and a heating fin and 1 temperature thermocouple are fixed on the outer side wall of the lower cylinder.

Further preferably, the feed inlet is funnel-shaped, and 1-6 inclined slots are formed in the side wall of the feed inlet.

Further optimally, the spiral rod is provided with spiral grooves with equal depth, the outer diameter of the spiral rod is 8-16 mm, and the length of the spiral groove section is 8-15 times of the outer diameter of the spiral rod.

Further preferably, the upper end of the screw rod is provided with a plurality of positioning grooves, the top of the screw rod is provided with an internal threaded hole, an adjusting screw is arranged in the internal threaded hole, a coupler is arranged between the screw rod and an output shaft of the motor, the coupler is connected with the screw rod and the output shaft of the motor, and the adjusting screw is positioned between the screw rod and the output shaft of the motor and used for adjusting the size of a gap between the lower section of the screw rod and the nozzle.

Further preferably, the printing platform comprises a supporting plate, a heating aluminum plate and a toughened glass plate, wherein the supporting plate is fixed on the Y-axis assembly, the heating aluminum plate is fixed above the supporting plate, dense and evenly distributed screw holes are formed in the periphery of the heating aluminum plate, and the toughened glass plate is arranged above the heating aluminum plate.

Further preferably, the Y-axis assembly comprises a first motor, a first driving wheel, a first auxiliary wheel, first sliding rails, first sliding blocks and a connecting plate, wherein the first auxiliary wheel and the first driving wheel are respectively arranged at the front end and the rear end of the base, the first motor is fixed at the bottom of the base, a driving shaft of the first motor is connected with the first driving wheel, two sides of the first driving wheel and two sides of the first auxiliary wheel are respectively provided with a first sliding rail, 2 first sliding blocks are respectively arranged on the first sliding rails, the supporting plate is fixed on the first sliding blocks, the connecting plate is fixed at the bottom of the supporting plate, a synchronous belt is arranged between the first driving wheel and the first auxiliary wheel, and the connecting plate is relatively fixed with the synchronous belt.

Further preferably, the Z-axis assembly comprises a second motor, a screw rod, an arched lifting plate, lifting frames, second sliding blocks and second sliding rails, 4 second sliding rails are arranged on the outer side of the double-layer portal frame, the sliding blocks are fixed at two ends of the arched lifting plate, 2 arched lifting plates are respectively clamped on the vertical frames on two sides of the double-layer portal frame through the sliding blocks and the sliding rails, screw holes are formed in the arched lifting plate, 2 second motors which are symmetrical to each other are fixed between the vertical frames on two sides of the double-layer portal frame, the screw rods are fixed on output shafts of the second motors, the screw rods penetrate through the screw holes on the arched lifting plates, the top ends of the screw rods are connected with the double-layer portal frame in a rotating mode, and 2 lifting frames are fixed between the arched lifting plates.

Further preferably, the X-axis assembly comprises a fixing plate, a third sliding block, a third sliding rail, a third motor, a second driving wheel, a second auxiliary wheel and a second connecting plate, wherein the third sliding rail is fixed on the lifting frame, the bottoms of two ends of the fixing plate are respectively fixed with the third sliding block, the fixing plate is arranged between 2 lifting frames in a sliding mode through the third sliding block and the third sliding rail, the second driving wheel and the second auxiliary wheel are respectively arranged on an arched lifting plate, the third motor is fixed at the bottom of the arched lifting plate where the second driving wheel is located, a synchronous belt is arranged between the second driving wheel and the second auxiliary wheel, and the second connecting plate is fixed at the bottom of the fixing plate and is fixed with the synchronous belt.

Further preferably, the fixing plate is fixed with an electrical plug-in housing, the fixing plate is provided with an L-shaped fixing plate, the extrusion device is detachably fixed on the fixing plate through the L-shaped fixing plate, and the left side of the extrusion device is fixed with an electrical plug-in connector matched with the electrical plug-in housing.

The beneficial effects of the utility model are as follows:

1. the desktop grade particle 3D printer can use various conventional plastic particles and composite modified material particles to carry out 3D printing, changes the traditional mode of printing by taking plastic wires as raw materials for a small 3D printer, and greatly improves the printing capability and the printing speed.

2. The utility model designs the extrusion device special for the desktop grade particle 3D printer, solves the problem of limitation of the required space and particle diameter of the desktop grade 3D printer plasticizing system, enables particles to smoothly enter the heating cylinder, realizes plasticizing and stable output of conventional plastic and modified particles (particle diameter is 3-5 mm) thereof, has compact integral structure and attractive appearance, and can realize the process from plastic particles to plasticizing extrusion in a minimum space.

3. This 3D printer has designed extrusion device's quick change structure, and convenient quick dismantlement reload still can realize that multiple printing granule raw materials exempts from to debug, exempt from the quick switch of clearance if being equipped with a plurality of printheads.

4. According to the 3D printer, the double-layer gantry frame structure device is used, stable rigidity is provided, and meanwhile, the gravity center of the printing extrusion device is arranged in the frame, so that unbalanced load force is eliminated, the accuracy of motion control is improved, and the use abrasion of a motion assembly is slowed down.

5. The printing platform is provided with the dense screw holes, and the printing pieces of various materials can be pressed and fixed by matching with the pressing strips, so that the deviation of the printing pieces is prevented.

Drawings

Fig. 1 is a schematic perspective view of the present utility model.

Fig. 2 is a perspective view of the interior of the present utility model.

Fig. 3 is a schematic view of an electrical connector housing and electrical connector on an extrusion device according to the present utility model.

FIG. 4 is a schematic view showing the internal perspective structure of the extrusion device of the present utility model with the outer casing removed.

Fig. 5 is a schematic perspective view of fig. 4 with the cartridge removed.

Fig. 6 is a schematic cross-sectional structure of fig. 5.

Fig. 7 is a schematic perspective view of a heating cartridge.

Fig. 8 is a schematic cross-sectional structure of the heating cartridge.

Fig. 9 is a schematic perspective view of a screw rod.

FIG. 10 is a schematic view of the structure of the Z-axis assembly and the X-axis assembly of the present utility model.

Fig. 11 is a disassembled view of fig. 10.

FIG. 12 is a schematic view of the structure of the Y-axis assembly and printing platform of the present utility model.

Fig. 13 is a front view of fig. 12.

FIG. 14 is a schematic view of a print using a molding to secure the print in accordance with the present utility model.

In the figure:

1. a base; 2. an electrical cabinet;

3. an extrusion device; 30. a nozzle; 31. a housing; 32. a motor; 33. a feed hopper; 34. a storage box; 35. a heating cylinder; 36. a motor fixing plate; 37. a magazine fixing plate; 38. a coupling; 39. a screw rod; 311. an electrical plug housing; 312. an electrical connector; 352. a cylinder is arranged; 353. a middle cylinder; 354. a lower cylinder; 355. an inner cylinder; 356. a feed inlet; 357. a chute; 3511. a heat insulating mat; 3512. a heat sink; 3513. a heating sheet; 3514. a temperature thermocouple; 371. a feed opening; 391. an adjusting screw; 392. a thread groove; 393. a positioning groove; 394. an internal threaded hole;

4. a Z-axis assembly; 41. an arcuate lifting plate; 42. a second motor, 43, a lead screw; 44. a second slide rail; 45. a second slider; 47. a screw hole; 48. lifting the frame;

5. a Y-axis assembly; 51. a first slide rail; 52. a first slider; 55. a first auxiliary wheel; 56. a first main wheel; 58. a first motor; 59. a connecting plate;

6. an X-axis assembly; 61. a fixing plate; 62. a third slide rail; 63. a third slider; 64. a third motor; 65. a second driving wheel; 66. a second auxiliary wheel; 611. a second connecting plate; 612. an L-shaped fixing plate;

7. a double-layer portal frame;

8. a printing platform; 81. tempered glass plate; 82. heating the aluminum plate; 83. a support plate;

9. printing a piece; 91. a print base; 93. briquetting; 94. pressing strips;

A. and an empty-keeping structure.

Detailed Description

In order to clearly illustrate the technical features of the present solution, the present utility model will be described in detail below with reference to the following detailed description and the accompanying drawings. In the description of the present utility model, it should be noted that the directions or positional relationships indicated by the terms "left", "right", "front", "rear", "inner", "outer", etc. are based on the directions or positional relationships shown in the drawings, are merely for convenience of describing the present utility model and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present utility model.

As shown in fig. 1 and 2, the utility model provides a desktop grade particle 3D printer, which comprises a base 1, an electric cabinet 2 and a double-layer portal frame 7, wherein the double-layer portal frame 7 is fixed on the base 1, the electric cabinet 2 wraps the double-layer portal frame 7 and is fixed on the base 1, a slidable Y-axis component 5 is arranged on the base below the double-layer portal frame 7, a liftable Z-axis component 6 is arranged between the double-layer portal frames, a slidable X-axis component 6 is arranged on the Z-axis component, a detachable extrusion device 3 is arranged on the X-axis component, a printing platform 8 is arranged on the Y-axis component, the X-axis component and the Z-axis component drive the extrusion device to move up and down, the Y-axis component drives the printing platform to move back and forth, the extrusion device melts and extrudes plastic particles, and prints on the printing platform.

As shown in fig. 3 to 7, the extruding device 3 includes a housing 31, a motor fixing plate 36 and a material box fixing plate 37, a motor 32 is fixed on the motor fixing plate, a material storage box 34 is fixed between the motor fixing plate 36 and the material box fixing plate 37, a heating cylinder 35 is fixed at the bottom of the material box fixing plate 37, a nozzle 30 is arranged at the bottom of the heating cylinder, a feed opening 371 is arranged at the middle position of the material box fixing plate, a feed opening 356 is arranged at the top of the heating cylinder, the material storage box is communicated with the heating cylinder through the feed opening 371 and the feed opening 356, an output shaft of the motor 32 passes through the motor fixing plate 36 downwards and is connected with a screw rod 39, a middle lower section of the screw rod passes through the feed opening 371 and stretches into the heating cylinder 35, a feed hopper 33 is fixed above the side of the material storage box 34, and the feed hopper is communicated with the material storage box. In actual operation, the feeder hopper passes through the hose connection automatic feed machine, and plastic granules automatically fed to the feeder hopper in, then fall into the storage box, the hob rotates and presses the plastic granules into the heating cylinder to progressively go deep into by the heating cylinder melting, extrude from the nozzle. Wherein, a discharging door (not shown) is arranged at the bottom of the feeding hopper 33, which is convenient for cleaning or replacing the residual materials.

As a preferred embodiment, as shown in fig. 4 and 5, a heat insulation pad 3511 is fixed between the top end of the heating cylinder 35 and the material box fixing plate 37, the heating cylinder is a metal component, the metal conducts heat quickly when the lower end of the heating cylinder heats, and the heat insulation pad is arranged between the two components, so that heat can be prevented from being uploaded to other mechanical components such as the material box 34, excessive heat uploading is reduced, and blanking faults caused by early melting of plastic particles are caused.

As shown in fig. 6, 7 and 8, the heating cylinder 35 is divided into an upper cylinder 352, a middle cylinder 353 and a lower cylinder 354, and 2 cooling fins 3512 are fixed on the outer side wall of the upper cylinder to accelerate the heat dissipation of the upper cylinder; the upper cylinder 352 and the middle cylinder 353 adopt a clearance structure, so that heat transfer is reduced; the heating plate 3513 and 1 temperature thermocouple 3514 are fixed on the outer side wall of the lower cylinder 354, the heating plate heats, the temperature thermocouple measures the temperature, the lower cylinder adopts a thickened design, the outer diameter of the cylinder body of the lower cylinder is 3.5-6.5 times of that of the inner cylinder 355, the characteristics of high-energy heat accumulation and enhanced heat preservation are achieved, the temperature fluctuation in the lower cylinder is reduced, and the high-temperature constant-temperature control is conveniently realized; the bottom section of the heating cylinder 35 is heated, the heat uploading is reduced in the middle section, the upper section dissipates heat, the temperature is controlled in a multi-position auxiliary mode, the temperature of the heating cylinder is gradually increased from top to bottom, and extrusion faults caused by early melting of plastic particles due to overheating of the upper section of the heating cylinder are avoided.

As a preferred embodiment, as shown in fig. 7 and 8, the feeding port 356 is funnel-shaped, and the side wall of the feeding port is provided with 1-6 chute 357, which expands the feeding space of the feeding port, so that the plastic particle raw material with conventional particle size (3-5 mm) can smoothly enter the heating cylinder, and the conveying capability of the extrusion device to the plastic particles is improved.

As a preferred embodiment, as shown in FIG. 9, the screw rod is provided with a screw groove 392 with equal depth, the outer diameter of the screw rod is 8-16 mm, the length of the screw groove section is 8-15 times of the outer diameter of the screw rod, the screw groove is of an R groove structure, and the screw rod has the advantages of small volume, light weight, small resistance, smooth conveying and feeding and the like, and has stable extrusion control and no flow break.

As a preferred embodiment, as shown in fig. 6 and 9, the upper end of the screw rod 39 is provided with a plurality of positioning grooves 393, the top of the screw rod is provided with an internal threaded hole 394, an adjusting screw 391 is arranged in the internal threaded hole, a coupler 38 is arranged between the screw rod 39 and the output shaft of the motor 32, the coupler is connected with the screw rod and the output shaft of the motor, the adjusting screw 391 is positioned between the screw rod 39 and the output shaft of the motor 32 and is used for adjusting the size of a gap between the lower section of the screw rod 39 and the nozzle 30, and according to the types, viscosity, temperature and pressure reaction characteristic conditions of plastic particles, the distance of the gap can be changed to achieve the purpose of controlling the melt flow resistance and flow, so that the plasticization and stable extrusion of various different plastic particles by using the same plasticization system can be realized.

As a preferred embodiment, as shown in fig. 12, 13 and 14, the printing platform 8 includes a support plate 83, a heating aluminum plate 82 and a tempered glass plate 81, the support plate 83 is fixed on the Y-axis assembly 5, the heating aluminum plate 82 is fixed above the support plate, dense and uniformly distributed screw holes (not shown) are formed in the periphery of the heating aluminum plate, the tempered glass plate 81 is arranged above the heating aluminum plate 82, a base is printed on the tempered glass plate, then a product is printed, a pressing block 93 is placed under the condition that the printing path is not obstructed in the continuous printing process, the position of the pressing block is freely selected according to the structural size of the printed product (the position and the number of the pressing block are adjusted), then a pressing bar 94 with a proper length is selected for fixing, 2 layers or 3 layers of pressing blocks can be used in a matched mode, the pressing blocks are reliably locked, and the phenomenon that the bottom layer is deformed and separated from the tempered glass due to larger shrinkage internal stress in the upper layer plastic cooling process is effectively avoided.

As a preferred embodiment, as shown in fig. 12 and 13, the Y-axis assembly 5 includes a first motor 58, a first driving wheel 56, a first auxiliary wheel 55, a first sliding rail 51, a first sliding block 52 and a connecting plate 59, where the first auxiliary wheel and the first driving wheel are respectively disposed at front and rear ends of the base 1, the first motor 58 is fixed at the bottom of the base, a driving shaft of the first motor is connected with the first driving wheel 56, two sides of the first driving wheel and the first auxiliary wheel are respectively provided with a first sliding rail 51, each of the first sliding rails is provided with 2 first sliding blocks 52, the supporting plate 83 is fixed on the first sliding block, the bottom of the supporting plate is fixed with the connecting plate 59, a synchronous belt (not shown) is disposed between the first driving wheel 56 and the first auxiliary wheel 55, the connecting plate 59 is relatively fixed with the synchronous belt, and the first motor drives the supporting plate to slide back and forth on the base through the synchronous belt.

As a preferred embodiment, as shown in fig. 2, 10 and 11, the Z-axis assembly 4 includes a second motor 42, a lead screw 43, an arched lifting plate 41, lifting frames 48, a second sliding block 45 and a second sliding rail 44, 4 second sliding rails 44 are disposed on the outer side of the double-layer gantry 7, two ends of the arched lifting plate 41 are respectively fixed with sliding blocks 45,2, the arched lifting plates are respectively clamped on the vertical frames on two sides of the double-layer gantry 7 through the sliding blocks 45 and the sliding rails 44, screw holes 47 are disposed on the arched lifting plate 41, 2 second motors 42 which are symmetrical to each other are fixed between the vertical frames on two sides of the double-layer gantry, the lead screw 43 is fixed on the output shaft of the second motor 42, the lead screw passes through the screw holes 47 on the arched lifting plates, the top end of the lead screw is rotationally connected with the double-layer gantry, 2 lifting frames are fixed between the arched lifting plates 41, extrusion devices 3 and 2 second motors 42 are respectively clamped on the vertical frames, and the lifting plates drive the extrusion devices to move up and down between the double-layer gantry frames through the lifting frames.

As a preferred embodiment, as shown in fig. 2, 3, 10 and 11, the X-axis assembly 6 includes a fixing plate 61, a third slider 63, a third sliding rail 62, a third motor 64, a second driving wheel 65, a second auxiliary wheel 66 and a second connecting plate 611, the third sliding rail 62 is fixed on the lifting frame 48, the bottoms of two ends of the fixing plate 61 are respectively fixed with a third slider 63, the fixing plate is slidably disposed between the 2 lifting frames 48 through the third slider and the third sliding rail 62, the second driving wheel 65 and the second auxiliary wheel 66 are respectively disposed on an arcuate lifting plate, a third motor 64 is fixed at the bottom of the arcuate lifting plate 41 where the second driving wheel is located, a synchronous belt (not shown) is disposed between the second driving wheel 65 and the second auxiliary wheel 66, the second connecting plate 611 is fixed at the bottom of the fixing plate 61 and is fixed with the synchronous belt, the third motor rotates to drive the extruding device to slide left and right between the lifting frames, which sets the center of gravity of the extruding device inside the frame, thereby eliminating the load force, and improving the precision of motion control and wear of the motion assembly.

As a preferred embodiment, as shown in FIG. 3, the fixing plate 61 is fixed with an electrical plug housing 311, the fixing plate is provided with an L-shaped fixing plate 612, the extruding device 3 is detachably fixed on the fixing plate 61 through the L-shaped fixing plate, and an electrical plug 312 adapted to the electrical plug housing 311 is fixed on the left side of the extruding device, so that the extruding device can be conveniently and rapidly detached, and if a plurality of printing heads are provided, the rapid detachment and switching of various printing particle raw materials without debugging and cleaning can be realized.

The desktop grade particle 3D printer can use various conventional plastic particles and composite modified material particles to carry out 3D printing, changes the traditional mode of printing by taking plastic wires as raw materials for a small 3D printer, and greatly improves the printing capability and the printing speed.

The present utility model is not described in detail in the present application, and is well known to those skilled in the art. Finally, it is noted that the above embodiments are only for illustrating the technical solution of the present utility model and not for limiting the same, and although the present utility model has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications and equivalents may be made thereto without departing from the spirit and scope of the technical solution of the present utility model, which is intended to be covered by the scope of the claims of the present utility model.

Claims (10)

1. The utility model provides a desktop level granule 3D printer, includes base, electric machine case and double-deck portal frame, double-deck portal frame is fixed on the base, electric machine case parcel double-deck portal frame just fixes on the base, its characterized in that: a sliding Y-axis assembly is arranged on the base below the double-layer portal frames, a lifting Z-axis assembly is arranged between the double-layer portal frames, a sliding X-axis assembly is arranged on the Z-axis assembly, a detachable extrusion device is arranged on the X-axis assembly,

the extrusion device comprises a shell, a motor fixing plate and a material box fixing plate, a motor is fixed on the motor fixing plate, a material storage box is fixed between the motor fixing plate and the material box fixing plate, a heating cylinder is fixed at the bottom of the material box fixing plate, a nozzle is arranged at the bottom of the heating cylinder, a feed opening is arranged at the middle position of the material box fixing plate, a feed inlet is arranged at the top of the heating cylinder, the material storage box is communicated with the heating cylinder through the feed opening and the feed inlet, an output shaft of the motor downwards passes through the motor fixing plate and is connected with a screw rod, the middle and lower sections of the screw rod pass through the feed opening and extend into the heating cylinder, a feed hopper is fixed above the side of the material storage box and is communicated with the material storage box,

the Y-axis assembly is provided with a printing platform, the spiral rod rotates to press plastic particles into the heating cylinder, the plastic particles gradually go deep into the heating cylinder to be melted, the plastic particles are extruded from the nozzle, and printing is performed on the printing platform.

2. The desktop grade granule 3D printer of claim 1, wherein: the heating device is characterized in that a heat insulation pad is fixed between the top end of the heating cylinder and the fixing plate of the material box, the heating cylinder is divided into an upper cylinder, a middle cylinder and a lower cylinder, the upper cylinder and the middle cylinder adopt an empty-avoiding structure, the lower cylinder is a thickened cylinder body, 2 cooling fins are fixed on the outer side wall of the upper cylinder, and a heating fin and 1 temperature thermocouple are fixed on the outer side wall of the lower cylinder.

3. The desktop grade granule 3D printer of claim 1, wherein: the feeding hole is funnel-shaped, and 1-6 chute are arranged on the side wall of the feeding hole.

4. The desktop grade granule 3D printer of claim 1, wherein: the spiral rod is provided with spiral grooves with equal depth, the outer diameter of the spiral rod is 8-16 mm, and the length of the spiral groove section is 8-15 times of the outer diameter of the spiral rod.

5. The desktop grade granule 3D printer of claim 1, wherein: the upper end of hob is equipped with a plurality of constant head tanks, and the internal thread hole has been seted up at hob top, internal thread hole is equipped with adjusting screw, be equipped with the shaft coupling between the output shaft of hob and motor, the output shaft of shaft coupling connection hob and motor, adjusting screw is located the output shaft centre of hob and motor for the size of clearance between hob hypomere and the nozzle is adjusted.

6. The desktop grade granule 3D printer of claim 1, wherein: the printing platform comprises a supporting plate, a heating aluminum plate and a toughened glass plate, wherein the supporting plate is fixed on the Y-axis assembly, the heating aluminum plate is fixed above the supporting plate, dense and evenly distributed screw holes are formed in the periphery of the heating aluminum plate, and the toughened glass plate is arranged above the heating aluminum plate.

7. The desktop grade granule 3D printer of claim 6, wherein: the Y-axis assembly comprises a first motor, a first driving wheel, a first auxiliary wheel, a first sliding rail, a first sliding block and a connecting plate, wherein the first auxiliary wheel and the first driving wheel are respectively arranged at the front end and the rear end of the base, the first motor is fixed at the bottom of the base, a driving shaft of the first motor is connected with the first driving wheel, two sides of the first driving wheel and two sides of the first auxiliary wheel are respectively provided with a first sliding rail, 2 first sliding blocks are respectively arranged on the first sliding rail, the supporting plate is fixed on the first sliding blocks, the connecting plate is fixed at the bottom of the supporting plate, a synchronous belt is arranged between the first driving wheel and the first auxiliary wheel, and the connecting plate is relatively fixed with the synchronous belt.

8. The desktop grade granule 3D printer of claim 1, wherein: the Z-axis assembly comprises a second motor, a lead screw, an arched lifting plate, lifting frames, second sliding blocks and second sliding rails, 4 second sliding rails are arranged on the outer side of the double-layer portal frame, the sliding blocks are fixed at the two ends of the arched lifting plate, 2 arched lifting plates are respectively clamped on the vertical frames on the two sides of the double-layer portal frame through the sliding blocks and the sliding rails, screw holes are formed in the arched lifting plate, 2 second motors which are symmetrical to each other are fixed between the vertical frames on the two sides of the double-layer portal frame, the lead screw is fixed on an output shaft of the second motor, the lead screw penetrates through the screw holes on the arched lifting plate, the top ends of the lead screw are rotationally connected with the double-layer portal frame, and 2 lifting frames are fixed between the arched lifting plates.

9. The desktop grade granule 3D printer of claim 8, wherein: the X-axis assembly comprises a fixing plate, a third sliding block, a third sliding rail, a third motor, a second driving wheel, a second auxiliary wheel and a second connecting plate, wherein the third sliding rail is fixed on the lifting frame, the bottoms of two ends of the fixing plate are respectively fixed with the third sliding block, the fixing plate is arranged between 2 lifting frames in a sliding mode through the third sliding block and the third sliding rail, the second driving wheel and the second auxiliary wheel are respectively arranged on an arched lifting plate, the third motor is fixed at the bottom of the arched lifting plate where the second driving wheel is located, a synchronous belt is arranged between the second driving wheel and the second auxiliary wheel, and the second connecting plate is fixed at the bottom of the fixing plate and is fixed with the synchronous belt.

10. The desktop grade granule 3D printer of claim 9, wherein: the electric plug-in type extrusion device comprises a fixing plate, and is characterized in that an electric plug-in shell is fixed on the fixing plate, an L-shaped fixing plate is arranged on the fixing plate, the extrusion device is detachably fixed on the fixing plate through the L-shaped fixing plate, and an electric plug-in connector matched with the electric plug-in shell is fixed on the left side of the extrusion device.