WO2017113169A1

WO2017113169A1 - Metering extrusion device for 3d printer

Info

Publication number: WO2017113169A1
Application number: PCT/CN2015/099824
Authority: WO
Inventors: 陈名乔
Original assignee: 深圳万为智能制造科技有限公司
Priority date: 2015-12-30
Filing date: 2015-12-30
Publication date: 2017-07-06
Also published as: CN106515018A

Abstract

A metering extrusion device for a 3D printer, comprising a wheel shaft (1), a case (2), and several baffle plates (31). Several cavities (23) are provided within the case (2) of the metering extrusion device, eccentric wheels (12) are respectively inscribed in the cavities (23), and when viewed from the axial direction of a rotating shaft (11), at least two eccentric wheels (12) are uniformly distributed on the rotating shaft (11); slurries extruded by each eccentric wheel (12) compensate for each other in amount, thereby reducing the fluctuation of the total amount of the extruded slurries, so that the metering extrusion device may implement more precise control over flow output.

Description

Metering extrusion device for 3D printer

Technical field

[0001] The present invention relates to the field of 3D printing technology, and in particular to a metering and extrusion device for a 3D printer.

[0002]

BACKGROUND

[0004] A 3D printer, also known as a three-dimensional printer, is a cumulative manufacturing technology, a machine for rapid prototyping, which is based on a digital model file and can be bonded using special wax, powdered metal or plastic. Material, a three-dimensional object is produced by printing a layer of bonding material. At this stage, 3D printers are used to manufacture products. The technique of constructing objects by layer-by-layer printing. The principle of the 3D printer is to put the data and raw materials into the 3D printer, and the machine will build the products layer by layer according to the program.

[0005] The metering and extrusion device in the prior art 3D printer is driven by a roller or a gear, and the output of the roller device is relatively uniform, and is mainly used for printing of a wire, so the selection range is relatively narrow, too soft, too soft, and brittle. The material can not be used, and its driving force is based on the friction between the roller and the wire. It is easy to slip and the output is not accurate. The way in which the gear meshes to convey the melted slurry is to use the gear gap to convey one by one. The amount of output of the material changes periodically, making it impossible for the 3D printer to accurately control the amount of print of the slurry. In the case of inaccurate metering extruders, it is impossible to spray the slurry of the precise outer diameter.

SUMMARY OF THE INVENTION

The present application provides a metering extrusion device in which the amount of slurry extruded is a constant value.

[0008] In one embodiment, a metering extrusion device for a 3D printer is provided, comprising:

[0009] an axle, comprising a rotating shaft and at least two eccentric wheels, in the axial direction of the rotating shaft, at least two eccentric wheels and the like are eccentrically spaced and evenly distributed on the rotating shaft;

[0010] The casing is provided with a plurality of cavities for accommodating the eccentric wheels; the casing is provided with a total feeding hole and a total discharging hole, and the plurality of cavities respectively are provided with the sub-feeds communicating with the total feeding holes a hole and a separation hole communicating with the total discharge hole; the eccentric wheel is cut into the cavity body, and the eccentric wheel forms an extrusion cavity with the cavity;

And at least two isolation mechanisms including a partition and a telescopic member, the partition being movably mounted by the telescopic member In the cavity of the chassis, the partition plate is disposed between the split feed hole and the split discharge hole. Under the action of the expansion member, the partition plate is always in contact with the eccentric wheel, and the split feed hole and the split discharge hole are isolated.

[0012] Further, the axle includes four eccentric wheels, and the angle between the vertical line of the center point of the eccentric wheel to the central axis of the rotating shaft and the vertical line of the center points of the other three eccentric wheels to the central axis of the rotating shaft respectively It is 90°, 180. And 270. .

[0013] Further, the angle between the center line of the adjacent two eccentric wheels to the vertical line of the central axis of the rotating shaft is 90°.

[0014] Further, the chassis includes an upper cover and a lower cover, and the upper cover and the lower cover are fixed together, and the upper cover and the lower cover are combined to form a plurality of cavities for accommodating the eccentric.

[0015] Further, the upper cover is provided with a total feeding hole, a total discharging hole, a sub-feeding hole and a separating material hole, and the upper cover is provided between the feeding hole and the discharging hole for accommodating the isolation mechanism. a groove, the partition is fixed in the groove by a telescopic member

The spacer is always in contact with the eccentric under the extrusion of the telescopic member.

[0016] Further, the telescopic member is a spring, and the partition plate is provided with a groove or a ridge for mounting the telescopic member.

[0017] According to the above-mentioned embodiment, the metering and extrusion device for a 3D printer has a plurality of cavities in the casing of the metering and extruding device, and an eccentric wheel is respectively cut in the cavity, and viewed from the axial direction of the rotating shaft, at least The two eccentric wheels are evenly distributed on the rotating shaft, and the amount of slurry extruded by each eccentric wheel complements each other, which reduces the fluctuation of the total amount of the total extruded slurry, so that the metering and extrusion device can more accurately control the flow output. , to meet high precision 3D printing.

[0018]

BRIEF DESCRIPTION OF THE DRAWINGS

1 is a schematic exploded view of a metering extrusion device of an embodiment 3D printer;

2 is a schematic exploded view of a metering extrusion device of an embodiment 3D printer; [0021] FIG.

[0022] FIG. 3 is a cross-sectional view of a metering extrusion apparatus of an embodiment 3D printer;

4 is a schematic exploded view of a metering extrusion apparatus of an embodiment 3D printer. [0023] FIG.

[0024]

DETAILED DESCRIPTION

The present invention will be further described in detail below with reference to the accompanying drawings.

[0027] This embodiment provides a metering and extrusion device for a 3D printer for driving printing of a molten material of a 3D printer. The metering extrusion device can also be used for feeding other equipment. [0028] As shown in FIG. 1 and FIG. 2, the embodiment provides a metering and extrusion device for a 3D printer, which includes an axle 1, a chassis 2, and four isolation mechanisms 3. The axle 1 and the isolation mechanism 3 are respectively mounted on the chassis 2.

[0029] Preferably, the axle 1 includes a rotating shaft 11 and four eccentric wheels 12, and the four eccentric wheels 12 are uniform in size, that is, the diameter and the thickness are equal. The four eccentric wheels 12 are equally spaced on the rotating shaft 11, and the four eccentric wheels 12 are eccentrically spaced and evenly distributed on the rotating shaft 11 as seen from the axial direction of the rotating shaft 11. The rotary shaft 11 and the four eccentric wheels 12 are of a one-piece structure and are formed by grinding. The angle between the center line of the adjacent two eccentric wheels 12 to the vertical line of the central axis of the rotating shaft 11 is 90°, and the vertical line of the center point of any one of the eccentric wheels 12 to the central axis of the rotating shaft 11 and the center points of the other three eccentric wheels 12 are The angles of the vertical lines of the central axis of the rotating shaft 11 are 90°, 180° and 270°, and the four eccentric wheels 12 are uniformly on the rotating circumference, and the arrangement order of the four eccentric wheels 12 on the rotating shaft 11 can be arbitrarily changed. In other embodiments, an arbitrary number of eccentric wheels of 4 may be provided on the axle 1 .

[0030] The cabinet 2 includes an upper cover 21 and a lower cover 22, and the upper cover 21 is fixed to the lower cover 22 by screws. The upper cover 21 and the lower cover 2 2 are combined to form four cavities 23 for mounting and accommodating the axle 1 , and four eccentric wheels 12 are arranged corresponding to the four eccentric wheels 12 , and the four cavities 23 are arranged equidistantly in a straight line. .

[0031] The upper cover 21 is provided with a total feed hole 211 and a total discharge hole 212. The total feed hole 211 is connected to the feeding device, and the other end is connected to the four chambers 23 through the four sub-feed holes 213 for introducing the melted slurry into the cavity 23. The total discharge port 212 is connected to the nozzle device, and the other end is connected to the four chambers 23 through the four discharge holes 214, respectively, for squeezing the melted slurry into the nozzle device for feeding. Preferably, the total feed holes 211 and the total discharge holes 212 of the upper cover 21 are symmetrically arranged symmetrically, and the feed holes 213 and the split holes 214 are symmetrically arranged symmetrically, and the apertures are equal to ensure smooth conduction of the inlet and outlet. The symmetrical setting is beneficial to the mold or processing production and reduces the production cost.

[0032] The upper cover 21 is further provided with four recesses 215 for mounting the isolation mechanism 3, and the recesses 215 are located between the split feed holes 213 and the split holes 214, and are in communication with the cylindrical cavity 231, four The position of the recess 215 in the four cylindrical cavities 23 1 is uniform. In other embodiments, in order to install the isolation mechanism 3, the upper cover 21 is provided with a through groove, and the isolation mechanism 3 is mounted in the through groove in cooperation with the cover. The cover and the through groove are combined with the groove 215 structure of the embodiment.

[0033] As shown in FIG. 3, the mounting shaft 吋, the rotating shaft 11 of the axle 1 is mounted on the upper cover 21 and the lower cover 22 of the casing 2, and both ends of the rotating shaft 11 are rotatably mounted by bearings. One end of the rotating shaft 11 passes through the casing 2 and is connected to the output end of the external driving device. [0034] The four eccentric wheels 12 are respectively accommodated in the four cavities 23, and the eccentric 12 and the cavity 23 are always kept in in-situ contact, and the thickness of the eccentric 12 is slightly smaller than the width of the cylindrical cavity 231, so that The eccentric 12 forms an extrusion chamber in the cavity 23.

[0035] The isolation mechanism 3 includes a partition 31 and a telescopic member 32. Preferably, the telescopic member 32 is a spring, and the partition plate 31 is movably fixed to the recess 215 by a spring. The partition plate 31 partially protrudes into the cavity 23 to contact the eccentric 12, and the partition plate 31 has no gap with the recess 215. . During the eccentric rotation of the eccentric wheel 12, under the elastic pressing action of the spring, the partition plate 31 is always in contact with the eccentric wheel 12, so that the partition plate 31 divides the eccentric wheel 12 into an extrusion chamber in the cavity 23 to be separated into a feed. The space between the cavity and the discharge chamber, the feed chamber and the discharge chamber are alternately changed to realize the extrusion

[0036] Preferably, in order to facilitate the installation of the partition 31, the partition 31 is provided with a groove or a rib, and the partition 31 is connected to the spring by a groove or a rib.

[0037] The metering and extrusion device of the 3D printer provided by the embodiment has four chambers 23 in the casing 2 of the metering and extruding device, and the eccentric wheel 12 is respectively cut in the four chambers 23, and an eccentricity The angle between the vertical line of the center point of the wheel 12 to the central axis of the rotating shaft 11 and the vertical line of the center points of the other three eccentric wheels 12 to the central axis of the rotating shaft 11 are 90°, 180° and 270°, respectively, that is, in the axial direction of the rotating shaft 11 Above, the four eccentric wheels 12 are evenly distributed on the rotating shaft, and the total amount of materials extruded by the four eccentric wheels 12 in the uniform driving unit is constant, so that the metering and extruding device can accurately control the flow output, satisfying High precision 3D printing.

[0038] In other embodiments, the total feed hole 211, the total discharge hole 212, the split feed hole 213, the split discharge hole 214, and the isolation mechanism 3 are disposed on the lower cover 22, which can also realize material introduction and extrusion. Out.

[0039] The total discharge opening of one metering extrusion device may be connected to a plurality of nozzle devices, or one metering extrusion device may correspond to one nozzle device, and the number of metering and extrusion devices may be set according to actual needs. The 3D printer equipped with the above-mentioned metering and extruding device can control the rotary feeding of the metering and extruding device through the controller, and the controller can control the rotation speed of the metering and extruding device and the extrusion material to accurately control the amount of the output material. High precision printing.

[0040] The four eccentric wheels compensate each other, so that the principle that the coextruded slurry is constant at any engraving is as follows: [0041] As shown in FIG. 4, the large circle is A, and the small circle is B. The big circle is fixed, and the small circle rotates around the point A, doing eccentric motion. Point C is the intersection of the small circular symmetry axis and the large circular symmetry axis, and the intersection of the large circular symmetry axis and the small circle. The length of AB is the eccentricity. The line CD is an isolating device, separating the two sides Hey.

[0042] Calculation process:

[0043] Let the radius of the large circle be R, the radius of the small circle be r, the value of the angle P be alfa (radian), and the value of the angle N be beta, and the expression of the instantaneous area of the extrusion region is:

[0044] S = large circle area - small circle area - area enclosed by three points of CDE

[0045] Area enclosed by three points of CDE = sector ADE-fan BCE-triangle ABC

[0046] Therefore:

[0047] S = large circle area - small circle area - (fan ADE - sector BCE - triangle ABC)

[0048] That is:

[0049] s=(pi*R*R-pi*r*r)-(alfa/(2*pi)*pi*R*R-(alfa+beta)/(2*pi)*pi*r* R-0.5*(Rr)*r*sin(al fa+beta) ); (Equation 1)

[0050] The relationship between alfa and beta can be obtained by the sine theorem

[0051] beta=asin((R-r)/r *sin(alfa) ); (Equation 2)

[0052] Simultaneous equations 1 and 2, eliminate beta. The function F(alfa) with R as an independent variable relative to alfa is obtained, and R and r are constants.

[0053] That is: S = F (alfa) value range: [0, 2 * PI]

[0054] This function represents the correspondence between the area of the extrusion cavity and the angle alfa

[0055] Deriving this unary function, Sd = F' (alfa) value range: [0, 2*PI]

[0056] This function represents the relationship between the velocity of the area change in the extrusion chamber and the angle alfa, that is, the flow velocity of the fluid as a function of alfa.

[0057] Using four identical devices, the initial angles of each device are: 0, PI/2, PI, 3pi/2

[0058] That is, the flow velocity of the fluid and the function of alfa are:

[0059] Sd = F'(alfa);

[0060] Sdl = F'(alfa+pi/2);

[0061] Sd2 = F'(alfa+pi);

[0062] Sd3 = F'(alfa+3*pi/2);

[0063] Then the four synthesis speeds are:

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Claims

Claim

A metering extrusion device for a 3D printer, characterized by comprising:

An axle, comprising a rotating shaft and at least two eccentric wheels, in the axial direction of the rotating shaft, at least two of the eccentric wheels are equicentrically spaced and evenly distributed on the rotating shaft;

a chassis provided with a plurality of cavities for accommodating the eccentric wheels; the chassis is provided with a total feeding hole and a total discharging hole, and a plurality of the cavities are respectively provided with the total feeding holes a sub-feed hole of the communication and a separation hole communicating with the total discharge hole; the eccentric is cut into the cavity, and the eccentric wheel and the cavity form an extrusion cavity;

And at least two isolation mechanisms including a partition and a telescopic member, the partition being movably mounted in the cavity of the chassis by the telescopic member, the partition being disposed at the sub-feed hole and the sub-division Between the discharge holes, under the action of the telescopic member, the partition plate is always in contact with the eccentric wheel, and the sub-feed holes and the separation holes are isolated.

A metering and extrusion apparatus for a 3D printer according to claim 1, wherein said wheel shaft includes four eccentric wheels, and one of said four eccentric wheels is centered on said eccentric wheel center point The angle between the vertical line of the axis and the vertical line of the other three eccentric center points to the central axis of the rotating shaft is 90°, 180° and 270°, respectively.

A metering and extrusion apparatus for a 3D printer according to claim 2, wherein an angle between the center points of the two eccentric wheels adjacent to the central axis of the rotating shaft is 90°. A metering and extrusion apparatus for a 3D printer according to claim 3, wherein said chassis comprises an upper cover and a lower cover, said upper cover and said lower cover being fixed together, said upper cover and lower cover A plurality of cavities for accommodating the eccentric are combined.

The metering and extrusion device for a 3D printer according to claim 4, wherein the upper cover is provided with a total feed hole, a total discharge hole, a sub-feed hole and a discharge hole, a cover is provided between the feed hole and the discharge hole for receiving the groove of the isolation mechanism, and the partition plate is fixed in the groove by a telescopic member, under the extrusion of the expansion member The baffle is always in contact with the eccentric.

A metering and extrusion apparatus for a 3D printer according to claim 5, wherein said telescopic member is a spring, and said spacer is provided with a groove or a rib for mounting said telescopic member.