NL1043229B1

NL1043229B1 - 3d printer and support system and element therfor

Info

Publication number: NL1043229B1
Application number: NL1043229A
Authority: NL
Inventors: Arnoud Koorevaar Martijn
Original assignee: Arnoud Koorevaar Martijn
Priority date: 2019-04-10
Filing date: 2019-04-10
Publication date: 2020-10-20

Abstract

The present invention relates to a 3D printer provided with a printer head suspended by arms, connected at least with the print head in a manner forming a parallelogram construction deflectable within the plane thereof and included angularly moveable relative to the print head via a semi spherical ball joint, the ball connected to the end of a arm and received by a joint accommodated by the print head, characterized in that the ball (10) is included at radial distance from the arm (2). The opposite end of the rod (2) may be accommodated within the printer in a corresponding manner, the ball (10) at the opposite end of the arm included at a radial opposite side of the arm (2).

Description

3D PRINTER AND SUPPORT SYSTEM AND ELEMENT THERFOR

[0001] The present invention relates to an improvement in a so-called 3D printer system, in particular of the so-called delta type, such as the Kossel-Rostock - https://reprap.org/wiki/Rostock -, which type in itself is widely known per se, more in particular to an improvement in the suspension system of the printer head thereof.

[0002] So called 3D printers are generally known, including the so-called delta type of 3D printers. One example of such is provided by patent publication CN104669624A. Another by website publication https://www.deltarocket.be/deltarocket-pro/. In the known 3D printers the print head may be supported directly, e.g. as in the delta-rocket pro or by a so called effector plate, also denoted carrier plate, e.g. as known from patent publication CN106042386A. In either case the support comprises three pairs of arms, alternatively denoted rods, forming a flexible parallelogram construction in their connection to the print head.

[0003] In the first mentioned prior art document the connection of an arm with the print head, directly or via a carrier plate, is formed by a universal ball and socket joint, alternatively denoted spheroid joint. Such joints are normally connected to the end of a rod, typically light weight carbon rods, e.g. by screwing a threaded part of the ball joint longitudinally into the rod. However, spherical ball joints may also take the form of so called magnetic ball joints as is e.g. made public by patent publication CN207842056U. Where the latter overcomes the problem of a constrained amount of freedom within the ball-joint, in that the socket and hence shaft protrudes through the ball at diametrically opposing sides, the magnetic connection may turn out to be limited in printing forces or acceleration forces to be withstood, i.e. handled by the joint.

[0004] As to the latter, it should be mentioned that, in order to move to print head over the object and-or object table for supporting the object to be printed, each pair of arms is individually driven upwardly or downwardly. To this end, a typical construction provides that the upper ends of a pair of rods is connected to a slider, guided by a vertical stand of the printer, and driven by a motor via a drive means such as a belt as in above patent publication CN104669624A, and such as a screw spindle as in above secondly cited

2- patent publication CN10642386A. Yet other manners of driving the print head are known, e.g. from patent publication US2016332378A1, in which the arms are moved by spherically shaped beams, driven via a gear rack and causing the parallelogram construction of a pair of arms to move both in Z direction as well in the XY plane, the latter with the advantage of a relatively large reach over the support platform, typically up to the edge thereof.

[0005] The present invention seeks to further improve upon the known solutions, in particular to provide for a reliable and accurate 3D print head support system with large angular degree of freedom of articulation, without the disadvantages of the know designs, i.e. without the ball joint failing or causing a drive motor to skip under high printing pressure or acceleration in displacement of the printing head during printing.

[0006] Another object of the invention is to provide a printer that is capable of printing with a high degree of reliability and accuracy in space or in other circumstances of reduced availability of gravitational force.

[0007] Yet another object of the invention is to provide for a 3D print head support system that does not cause one or more of the print head displacement drive motors to skip, thereby e.g. loosing relative positional information, or being adversely affected by sudden loss of counter force.

[0008] Again another object of the present invention is to provide for an easily replaceable print head or effector plate carrying the same.

[0009] Also, the invention provides for realizing a printer head suspension design featuring a controlled, i.e. constant and predictable amount of wearing of ball joints as applied in a 3D printer head.

[0010] In the present invention freedom of movement of the ball bearing within it's socket is provided by at least at one end including the ball with radial displacement relative to the projection of the suspension rod. At the top end the suspending rod's projection passes the ball support at it's upper side, and at the down end the projection passes the lower side of the ball support. In this manner, with forces emanating from relatively heavy weight or from relatively high speed of rod displacement tend to even more firmly press a ball into its socket, meaning that the suspension rods stay in place under such conditions.

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[0011] Various aspects of the invention and an embodiment of the relevant part of the invention will by ways of example be described and illustrated along the figures in the drawings, depart from the general and wide spread knowledge of 3D printing systems, in which:

[0012] FIG. 1 is a perspective view of the suspension and drive of a printer head of a 3D printer in accordance with the present invention, included in shown part of a 3D printer structure known per se;

[0013] FIG. 2 within the same 3D printer structure environment, now presented from side elevation, sets forth a side view of a suspension and suspension rod according to the invention, featuring a so-nominated Z-design in the ball bearing support of the invention;

[0014] FIG. 3 in a close up perspective view displays the connection of a pair of suspension rods to the printer head, in this example to a carrier plate therefore;

[0015] FIG. 4 in a closer view and in side elevation, and with the printer head removed from the carrier plate, represents part of the 3D printer part and invention from yet a different perspective.

[0016] In the drawings the following references will be used: 1 drive connector 2 pair of rods (2a and 2b) 3 effector or support or carrier plate (for print head) 4 support rim or surface (of drive connector 1) 5 rod end with radial displaced ball bearing 6 bracket (joining a pair of rod ends, supporting hooking point 7) 7 hooking point (radial displaced in form of outward protruding eye) 8 spring (spiral spring by way of example only) 9 socket 10 ball, semi-sphere 11 ball arm 12 print head

[0017] FIG. 1 is a perspective view of the suspension and drive of a printer head of a 3D printer in accordance with the present invention. Such printers are commonly known in the art, typically as so-called delta printers. The drive of the printer head in such printer is

-4- performed by moving each one of the three pairs of suspension arms up and down individually in a controlled manner. Since the pairs of arms are connected at each end to the print head and a driver plate or yoke by means of a ball joint, in a manner in which each pair forms a parallelogram structure, the 3D print head is effectively moved in the X-Y plane if one or more of the driver plates is moved up or down. This up or down movement is normally performed by a drive belt connected to the driver plate and driven by an electric motor, e.g. at the bottom of a pillar that guides the driver plate to which a pair of arms is connected, as may e.g. be taken from above cited prior art. Alternative drives however equally apply the same principle, e.g. as in the case of a mechanical drive arm included in between pillars of a printer, driving the parallelogram pair of suspension arms. The connection of an arm is usually formed by a so called universal ball joint provided with a through hole for connection to a shaft, often in the form of a bolt. Alternatively the arms may be connected via a spherical or magnetic ball joint. The latter type of joints features a larger degree of freedom of movement within the joint, however is limited in transfer of force as at large accelerations, due to the limited amount of magnetic force available for holding the sphere within the joint.

[0018] The suspension arms 2 as provided by the present invention and in the figures however depart from a different, new principle at realizing such desired large amount of swiveling freedom of the joint. As may be most clearly seen in FIG. 2, the ball 10 of the ball joint connection with joint 9 is connected to it's suspension arm at some radial distance thereof. In this example it is connected via a shaft or screw, alternatively also denotable as pin and ball arm 11. These are oriented largely transverse to , at least under an angle with the axis of the suspension rod 2a. At it's other end 5, a suspension arm 2 is provided with a ball in the same manner, however with the ball 10 and ball arm 11 oriented in opposite direction and at the opposite radial side of the rod 2, e.g. as at rod 2a in FIG. 2. In this manner a large degree of angular movement of the ball is attained within the joint, certainly compared to that freedom of movement of a universal joint, however without the limitation in transferable force as is brought along by magnetic ball joints.

[0019] FIG. 1 displays the design in accordance with the invention, featuring a driving or connector plate 1, functionally comparable to a so-called slider in known designs. The connector plate at it's side wall facing the print head is provided with a rim 4, sufficiently large for supporting and bolting on or otherwise connecting a joint 9. Rod ends 5 are mutually interconnected in articulating manner by a bracket 6, the ball arm 10 in this

-5- embodiment simultaneously being provided as, or also having the function of articulating shaft. The bracket or connecting strip 6 may at least at the location of articulating connection be embodied U shaped, e.g. be produced as part from a U shaped profile. Where not required for the functioning of the present suspension system, a ball joint interaction of this invention is according to a sophistication of it's design provided with a spring load or spring force, urging ball and joint to one another. In this manner the connection, though secured by gravity and by a force emanating between non-depicted extruder and print head via a non-depicted hollow filament guide, may be provided with an at least mostly defined load or force, thereby providing equally distributed wear and accurate articulation of ball in joint. In the depicted embodiment the spring force is provided by means of a spring element 8 acting between bracket 6 and driver plate 1, centrally in between it's two articulating connections 5. This may generate a constant force in all range of motion.

[0020] As e.g. provided by FIG3 and FIG. 4, the parallelogram construction according to the present invention is identical at both ends 5 of a rod 2a and 2b, except for the orientation of the ball arms 11 to be oriented inverted. The spring element 8 is in the example of this depicted embodiment provided as a spiral spring. At the print head side, the spring element is connected between bracket 6 and the print head 12, and at the drive plate, alternatively denoted slider side between bracket 6 and rim 4 of the drive plate 1. In the example of this embodiment the print head 12 is connected to the bracket via carrier plate 3, also denoted as effector plate. Preferably the spring element 8 is designed to line up with the joints 9, so as to have the spring force acting in line with the axis of the joint, which in this example coincides with that of a cylindrical body into which at one of the axial ends the joint is provided. In order to provide such line up the bracket 6 is provided with a hooking point 7, here in the form of an eyed bolt bolted into the bracket, locating the attachment of the spring element off side from the bracket 6, so as to position the spring element 8 in a manner to cause the spring force to be aligned in the above said desired manner.

[0021] The figures each per se and in conjunction explicitly illustrate that the three parallelogram constructions hook up at a downward facing side of a portion of the print head or the effector plate as in this illustrated embodiment. Conversely, the so called Z- arms according to the present invention, at the drive plate or slider, hook up at an upward

-6- facing portion thereof. The invention is however not limited to this use of the here disclosed Z-arms principle, hence equally includes e.g. the kinematic inverse use thereof.

[0022] As may be further regarded disclosed is the advantageous use of and design for the spring elements 8, which may provided with a hook element, for hooking up to the print head 12, i.e. the carrier plate 3 there of. In order to have the spring force optimally in line with the force acting on the ball joint the spring element is at the print head side and the slider side respectively, provided with a hooking point located in line with the joint positions.

[0023] The design of the present invention has the advantage that the print head, at least carrier 3 therefore be easily detached, i.e. taken out of its hooking function. This construction according to a further elaboration of the present invention allows easily and quickly exchanging a print head 12, or carrier plate 3 with print head as the case may be. The latter is strongly desirable if not highly important for raising up-time of the printer system, e.g. in cases of required print head exchange for reason of either failure or replacement for accommodating a different type or diameter of to be printed material filament and nozzle diameter.

[0024] In a further elaboration of this advantageous aspect, the slider 1 and, or only the print head, at least the carrier plate 3 therefore, may be provided with an indentation 13, allowing the spring element 8 to protrude through the carrier plate an be aligned with the two joints. In further elaboration of such alternative, the hooking function is embodied by a cylindrical element attached to spring 8, e.g. in an eyed end thereof, hooking to the carrier plate 3 and moveable in radial direction or at least in the X-Y plane against some spring force. The cylindrical or barrel like element hooks to the upper surface of effector plate 3 and allows for easy detaching of spring 8 by finger movement of the cylinder and spring associated therewith laterally to the side edge of the effector plate.

[0025] In a further elaboration of the invention, ball arm 11 protrudes into and is attached to ball 10 and may also include or be embodied by way of a bolt. The arm may in an alternative design be received by each of the flanges connecting to the base side of a U- shaped bracket 6 by way of bores therein. In such particular embodiment the bores are provided with cylindrical receivers, fittingly receiving arm 11 and providing the same with directional, i.e. orientation stability. The arm is then secured in place by way of a washer and nut construction. The connection of bracket and rod may in such design be provided by way of an eyed bolt, screwed into an end cap secured on to the end of a rod

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2. This may e.g. be in the form of a light weight, hollow and carbon material based rod 2, the bolt secured in place by a nut. Preferably washers are applied at both sides of the bolt eye, in between bolt and receiving element . Such a design is relatively simple and economic, and provides for a secure movement within the plane of the parallelogram only. Finally, a bolt may be used to secure ball receiver, i.e. joint to the print head, or carrier plate as the case may be.

[0026] It is in particular remarked that while the examples for a ball joint are provided with the ball connected to the arm, and the hip or hollow semi-sphere at the print head or effector plate side, the skilled person easily realizes that the kinematic inversion thereof is may equally be embodied and hence equally forms part of the present invention.

[0027] It is remarked that any embodiment of the present invention need not be limited to the present example provided here. Rather the invention, while notwithstanding encompassing all details of the above description and details in the figures, is primarily defined by the definitions and circumscriptions in the following set of claims, included after below clauses, further summarizing and defining the invention. Clauses

1. A 3D printer provided with a printer head suspended by arms, connected at least with the print head in a manner forming a parallelogram construction deflectable within the plane thereof and included angularly moveable relative to the print head via a semi spherical ball joint, the ball connected to the end of a arm and received by a joint accommodated by the print head, characterized in that the ball (10) is included at radial distance from the arm (2).

2. Printer according to claim 1, in which the opposite end of the rod (2) is accommodated within the printer in a corresponding manner, the ball (10) at the opposite end of the arm included at a radial opposite side of the arm (2).

3. Printer according to any of claim 1 and 2, in which the ball (10) is connected to the arm (2) by a ball arm (11), connected or being part of the arm end while extending under and angle with the parallelogram arm (2). 4, Printer according to the preceding claim, in which the ball arm (11) extends at least virtually transverse thereto.

5. Printer according to any of the preceding claims, wherein the ends (5) of a pair of arms are interconnected by a bracket (6).

6. Printer according to the preceding claim, in which the bracket is U-shaped.

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7. Printer according to any of the preceding claims 5 to 6, in which the ball arm (11) is supported by at least two walls of the bracket, include at mutual distance.

8. Printer according to any of the preceding claims 5 to 7, in which the connection of a bracket (6) with a rod end is integrated with the ball connection by means of an eyed end (20) of the arm (2) through which the ball arm (11) protrudes.

9. Printer according to any of the preceding claims, in which the ball joint connection is secured by a spring element providing a spring load on to the connection.

10. Printer according to the preceding claim, in which the spring element is a singular spring element, included centrally in between two ball joint connections.

11. Printer according to any of the preceding claims 9 to 10, in which the spring element is included for exerting its spring force in line with the orientation of a joint (9) of a ball joint connection, in particular vertically.

12. Printer according to any of the preceding claims 9 to 11, in which the print head or carrier plate carrying a print head is included demountable in the printer by way of a detachable hooked connection of the spring element with the print head or carrier plate.

13. Printer according to any of the preceding claims 9 to 12, in which the spring element is embodied as a helical spring.

14. Printer according to any of the preceding claims 12 to 13, in which the hook connection is provided in the form of a cylindrical element connected in transverse orientation to the spring element.

15. Printer according to any of the preceding claims 9 to 12, in which the print head or carrier plate is at its edges provided with a cut-out for freely, at least partly accommodating a spring element therein.

Claims

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1. A 3D printer comprising a print head suspended from arms, connected to at least the print head in such a way that they form a parallelogram structure, which is pivotable in its plane, and angle-pivotable with respect to the print head received via a hemispherical ball joint, in which the ball is connected to the end of an arm and received in a cup housed in the printhead, characterized in that the ball (10) is received radially from the arm (2).

The printer of claim 1, wherein the opposite end of the rod (2) is similarly received in the printer, the ball (10) or the cup at the opposite end of the arm being received on a radially opposite side of the printer. the arm (2).

A printer according to any one of claims 1 and 2, wherein the element of the ball joint (10) is connected to the arm (2) by a ball arm (11), connected or forming part of the arm end, extending at an angle to the parallelogram arm (2).

A printer according to the preceding claims, wherein the ball arm (11) extends at least substantially transversely thereto.

Printer according to any one of the preceding claims, wherein the ends (5) of a pair of arms are interconnected by a bracket (6).

Printer according to the preceding claims, wherein the bracket is U-shaped.

A printer according to any one of the preceding claims 5-6, wherein the ball arm (11) is supported by at least two spaced apart walls of the bracket.

A printer according to any one of the preceding claims 5-7, wherein the connection of a bracket (6) with a rod end is integrated with the ball connection by means of an eyelet end (20) of the arm (2), where the ball arm (11) through.

A printer according to any one of the preceding claims, wherein the connection in the ball joint is secured by means of a spring element which provides a spring load on the connection.

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The printer of the preceding claims, wherein the spring element is a single spring element centrally received between two ball joint connections.

Printer according to any one of the preceding claims 9-10, wherein the spring element is included for exerting its spring force in line with the orientation of a hinge (9) of a ball and socket joint, in particular vertically.

12. Printer as claimed in any of the foregoing claims 9-11, wherein the printhead or carrier plate carrying a printhead is accommodated in the printer in a detachable manner by means of a releasable hook connection of the spring element to the printhead or carrier plate.

Printer according to any one of the preceding claims 9-12, wherein the spring element is designed as a coil spring.

Printer according to any of the preceding claims 12-13, wherein the hook connection is provided in the form of a cylindrical element connected in transverse orientation to the spring element.

15. Printer as claimed in any of the foregoing claims 9-12, wherein the print head or carrier plate is provided at its edges with a recess for freely, at least partially receiving a spring element therein.