Device for producing a three-dimensional object using a pressure generating unit

Abstract

The invention relates to a device for producing a three-dimensional object (50) from solidifable material in a liquid phase. Said device comprises at least one preparation unit for preparing the solidifiable material in the liquid phase, at least one pressure generating unit (60) for generating a pressure in the liquid phase and at least one discharge unit (12) for discharging the solidifiable material through an outlet opening. Said pressure generation unit comprises a rotation motor and an axial movement motor (10) for moving conveyor means, said rotation motor being arranged behind the axial movement motor (10) when viewed from the discharge unit (12). The invention also relates to a device for providing high forces at low speeds.

Claims

1. A device for the production of a three-dimensional object from solidifiable material which is either present in fluid form in the starting state or can be liquefied, comprising at least one preparation unit for the provision of the solidifiable material in a fluid phase, at least one discharge unit for delivering the solidifiable material through an outlet opening, at least one pressure generating unit for generating a pressure on the fluid phase, wherein the pressure generating unit comprises a rotation motor incorporating a rotor and an axial movement motor for axially moving a spindle and a conveying means, wherein the rotation motor is arranged behind the axial movement motor as seen from the discharge unit, wherein the spindle passes through the axial movement motor and is fixedly connected to the rotor of the rotation motor in mutually non-rotatable manner at one end, so that a rotary movement of the rotor also leads to a rotary movement of the spindle and vice versa, and is connected in releasable manner to the conveying means at the other end, wherein axes of the rotation motor and of the axial movement motor are mutually aligned, wherein the rotation motor is blockable in one direction of rotation by a free-wheel device mounted in a housing of the rotation motor, wherein the axial movement motor carries on its back the separate rotation motor.

2. A device in accordance with claim 1, wherein the rotation motor is an electromechanical dispensing motor for the rotation of the conveying means which is in the form of a feed screw, and wherein the electromechanical axial movement motor is an electromechanical axial movement motor for the axial movement of the feed screw and comprises a stator and a hollow rotor for driving the spindle of a spindle drive and a nut cooperating therewith which spindle passes through the rotor.

3. A device in accordance with claim 1, further comprising at least one material storage device for the fluid phase which is connected to the pressure generating unit for generating the pressure on the fluid phase in the material storage device.

4. A device in accordance with claim 1, wherein the discharge unit for a sequential discharge of the solidifiable material in the form of drops comprises an outlet opening in direction of the three-dimensional object to be manufactured.

5. A device in accordance with claim 3, wherein the preparation unit is a plasticizing unit for preparing the solidifiable material into plastified or plastifiable material, which plasticizing unit is directly coupled to the material storage device that is subjectable to the pressure.

6. A device in accordance with claim 1, wherein the housing of the rotation motor in the form of a dispensing motor is mounted on a housing of the axial movement motor for the purposes of countering a torque of the free-wheel device.

7. A device in accordance with claim 1, wherein the rotation motor is mounted in axially moveable manner on guides which form a torque support and are fixed to a housing of the axial movement motor.

8. A device in accordance with claim 1, wherein the axial movement motor is a hollow shaft motor through which the spindle passes.

9. A device in accordance with claim 2, wherein the nut of the spindle drive of the axial movement motor is mounted in the rotor of the axial movement motor or is formed by the rotor of the axial movement motor.

10. A device in accordance with claim 1, wherein a planetary gear drive is accommodated in the axial movement motor.

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) The invention is explained in greater detail hereinafter with the aid of an exemplary embodiment. Therein:

(2) FIG. 1 shows a device for the production of a three-dimensional object in a three-dimensional view,

(3) FIG. 2 a longitudinal section through the pressure generating unit,

(4) FIG. 3 a longitudinal section through the pressure generating unit and the plasticizing unit.

DETAILED DESCRIPTION

(5) The invention is now described exemplarily in more detail with reference to the accompanying drawings. However, the exemplary embodiments are concerned only with examples which are not intended to limit the inventive concept to a certain arrangement. Before the invention is described in detail, it should be pointed out that it is not limited to the particular components of the device or the particular processing steps, since these components and processes can vary. The expressions used herein are only intended to describe special embodiments and are not used restrictively. In addition, if the singular or indefinite articles are used in the description or in the Claims, then this also includes a plurality of these elements, insofar as the general context does not make something else clear.

(6) The Figures show a device for the production of a three-dimensional object 50 consisting of solidifiable material which, in the starting state, is present in either a fluid phase or being such that it can be liquefied. The production of the object is preferably effected by means of the sequential delivery of drops 70. To this end for example, individual drops 70 can be delivered sequentially from an outlet opening 12b of a discharge unit 12 so that the object 50 is built up layer by layer on an object carrier 13 which is moveable in the coordinate directions of the area. The object carrier 13 is guided in moveable manner relative to the outlet opening 12b of the discharge unit on a mounting 40.

(7) The solidifiable material is a plastified material, e.g. silicone or a plastifiable material such as plastics or else materials in powdered form, wherein it depends in essence, on the solidifiable material being present in the starting state either in a fluid phase or being such that it can be liquefied. The material could also be a material which is reversibly meltable when heated and is thus recyclable. Any other desired materials can also be used insofar as these materials are plastifiable by the device and above all, in that they are capable of being discharged by at least one discharge unit 12. Above all however, materials can also be processed by the device such as those which are usually employed in the field of injection molding in large quantities, this thereby contributing to the satisfactory production of the articles that are to be manufactured thereby.

(8) The device comprises at least one preparation unit for the preparation of the solidifiable material into the fluid phase and for the supply thereof—especially if the material is already present as a liquid, and possibly too if it is to be kept in this state—, and which, in the exemplary embodiment, is formed by a plasticizing unit 11 known in the field of injection molding. In the exemplary embodiment, this plasticizing unit is directly coupled to a material storage device 12c in the discharge unit 12 which can be subjected to pressure and which, in accord with FIG. 3, could merely be in the form of a channel. If necessary, an indirect coupling is also possible as long as care is taken to ensure that the high pressures are controlled in an appropriate manner. The discharge unit 12 serves for delivering the solidifiable material through a preferably clockable outlet opening 12b in the direction of the three-dimensional object 50 that is to be manufactured or the associated object carrier 13.

(9) At least one pressure generating unit 60 produces the pressure on the fluid phase in the material storage device 12c, this pressure being necessary particularly in the case where the material is delivered in drop-like manner so that the corresponding drops, or rather, properly speaking, droplets, can be formed. Basically however, the device is suitable for delivering the material with great force at very low speeds. The discharge unit 12 and the pressure generating unit 60 are preferably connected together by the plasticizing unit 11. They form a system in which, or within which, the pressure is brought to bear on the fluid phase. Discharge unit 12 and mounting 40 are fixed to one another. The pressure generating unit 60 is attached to the discharge unit 12 and is moveably mounted in relation to this connection. Thus, the larger unit for reason of size, namely, the pressure generating unit 60 is mounted such as to be moveable relative to the smaller, correspondingly rigid unit consisting of the discharge unit 12 and the mounting 40 for the object carrier 13. Consequently, despite the high pressures and possibly high temperatures, precision within the region where the drops 70 are delivered is ensured.

(10) Preferably, discharge unit 12 and mounting 40 are fixed onto a machine table 15 which is preferably of stiff construction in order to also keep the movements here as small as possible. In accordance with FIGS. 1 and 3, the axial movement motor 10 of the pressure generating unit is preferably moveable over the support 25 on the machine table 15, namely, it is supported such as to be moveable axially along the machine table, whilst the discharge unit 12 is supported on the machine table 15 by the support 28. In turn, the mounting 40 for the coordinate table of the object carrier 13 is then securely fixed to the machine table 15 so as to produce a rigid connection between the mounting 40 and the discharge unit 12 via the machine table 15.

(11) The pressure generating unit 60 comprises a rotation motor, the electromechanical dispensing motor 14, and an axial movement motor 10 for moving a conveying means, wherein the conveying means is preferably a feed screw 26 which is accommodated in the plasticizing unit 11. In accordance with FIG. 3, the dispensing motor 14 is arranged behind the axial movement motor 10 as seen from the discharge unit 12. This arrangement was chosen because of the high forces that have to be applied by the axial movement motor, these forces regularly lying within a range of between 50 and 100 MPa. Due to the selected arrangement, these forces can be applied to the discharge unit 12 or the material storage device 12c located therein via the shortest path. The pressure generating unit 60 is effective to produce a constant pressure by the forward movement of the conveying means or the feed screw 26, respectively, on the one hand, whilst on the other hand, the synthetic material is prepared as required as a melt due to the cooperation between the feed screw 26 and the plasticizing unit 11 produced by the rotation of the feed screw in the plasticizing unit.

(12) The axial movement of the feed screw 26 is produced by the axial movement motor which comprises a stator 20 and a hollow rotor 21 for driving a spindle 16 which passes through the rotor. The spindle 16 of the spindle drive device is operatively connected to a nut. The rotation of the feed screw 26 is effected by a separate drive motor 18 of the dispensing motor 14 which is employed simultaneously with the axial movement motor and the system for regulating the dynamic pressure used for the purposes of producing the object. The axes of the drive motor 18 of the dispensing motor 14 and the axial movement motor 10 are aligned with one another.

(13) The spindle 16 of the axial movement motor 10 is fixedly connected to a rotor 22 of the drive motor 18 and is releasably connected to the conveying means or the feed screw 26. In order to ensure the mutually independent operation of the two motors, the dispensing motor 14 is in this respect blockable in one direction of rotation by a free-wheel device 19 mounted in a housing 18a of the drive motor 18. For the purposes of countering the torque of the free-wheel device, the housing 18a of the drive motor 18 is mounted via a torque support 27 on the housing 23 or the housing casing 23a of the axial movement motor 10.

(14) The axial movement motor 10 is formed by a hollow shaft motor through which the spindle 16 passes. The nut of the spindle drive of the axial movement motor 10 is mounted in the rotor 21 of the axial movement motor or is formed by the rotor 21 as in the embodiment in accordance with FIG. 2. In addition, the rotor 21 and the spindle 16 are operatively coupled to one another by planetary gears 17 in the exemplary embodiment.

(15) In accordance with FIG. 3, the feed screw 26 is fixed to the front end of the spindle 16 in releasable manner via a feed screw coupling 29, i.e. on the left-hand side of the axial movement motor in FIG. 3.

(16) When generating pressure and supplying the plastifiable material, the device works as follows:

(17) In the exemplary embodiment, the axial movement of the feed screw 26 is produced in accord with FIG. 3 by the spindle 16 of the axial movement motor 10 with the aid of the rotationally driven rotor 21 which simultaneously forms the nut of the spindle drive. The transmission from the rotor 21 to the spindle 16 is effected via the intermediary of the planetary gears 17. The spindle can only produce an axial force when it is experiencing a torque counter-acting force corresponding to its spindle ratio. This torque counter-acting force is developed by the dispensing motor 14 in the main direction of the force, i.e. to the left in FIG. 3 during the movement of the feed screw 26, the dispensing motor being supported by means of a torque support 27 on the housing 23 for the axial movement motor 10. The torque support 27 forms guide means along which the dispensing motor 14 is mounted in axially moveable manner during the movement of the conveying means. For the backward movement of the feed screw, the torque counter-acting force is made available by an appropriately regulated active energizing with current. Basically, due to the fixed connection of the spindle 16 of the axial movement motor 10 to the rotor 22 of the drive motor 18, the rotary movement of the dispensing motor also leads to a rotary movement of the spindle 16 and vice versa. The spindle 16 can convert the rotation into a linear movement if a torque support corresponding to the desired feeding force is provided in correspondence with the spindle pitch thereof. For this torque supporting process, a free-wheel device 19 is integrated into the drive motor 18 of the dispensing motor 14 for building up the pressure, i.e. for the movement of the feed screw 26 to the left in FIG. 3, whilst the dispensing motor 14 is active for the reverse direction of the feed screw 26.

(18) The free-wheel device is provided in order to decouple the movement of the axial movement motor from the dispensing motor 14 and it blocks or can block the dispensing motor 14 in one direction of rotation, i.e. a unidirectional rotation prevention means. The free-wheel device 19 is mounted on the housing 18a of the drive motor 18 of the dispensing motor 14. For its part, this mounting is in turn mounted via the torque support 27 on the housing 23 or the housing casing 23a of the axial movement motor 10.

(19) It is self-evident that this description can be subjected to the most diverse modifications, changes and adaptations which fall within the range of equivalents to the attaching Claims.