EP3347191A1

EP3347191A1 - Method and device for applying fluids

Info

Publication number: EP3347191A1
Application number: EP16781276.7A
Authority: EP
Inventors: Bastian HEYMEL; Josef Grasegger; Ingo Ederer
Original assignee: Voxeljet AG
Current assignee: Voxeljet AG
Priority date: 2015-09-09
Filing date: 2016-09-08
Publication date: 2018-07-18
Also published as: CN108025498B; CN108025498A; US10882110B2; WO2017041779A1; DE102015011503A1; US20180339452A1

Abstract

The invention relates to a method and a device for applying fluids, particularly in a method for producing three-dimensional shaped parts, wherein a coating device (5) comprising a blade (1), a fluid outlet and a reservoir (2) is provided, and the blade is displaced across the working field such that it can implement a rotational movement type vibration, said vibration occurring as the result of a stroke by a linear actuator (4).

Description

METHOD AND DEVICE FOR APPLYING FLUIDS

The invention relates to a device and a method for applying fluids, in particular in a method for producing three-dimensional objects.

European Patent EP 0 431 924 B1 describes a method for producing three-dimensional objects from computer data. In this case, a particulate material is applied in a thin layer by means of coater (recoater) on a platform and this selectively printed by means of a print head with a binder material. The particle area printed with the binder bonds and solidifies under the influence of the binder and optionally an additional hardener. Subsequently, the build platform is lowered by one layer thickness or the coater / printhead unit is raised and a new layer of particulate material is applied, which is also selectively printed as described above. These steps are repeated until the desired height of the object is reached. The printed and solidified areas create a three-dimensional object (molded part).

This object made of solidified particulate material is embedded after its completion in loose particulate material and is subsequently freed from it. This is done for example by means of a nipple. Thereafter, the desired objects remain, which are then affected by powder deposits, e.g. be freed by manual brushing.

1

CONFIRMATION COPY 3D printing based on powdered materials and the introduction of liquids with a printhead is the fastest method among the layering techniques.

This process can be used to process various fluids, such as particulate matter, including, but not limited to, natural biological raw materials, polymeric plastics, metals, ceramics and sands.

Similarly, other powder-based rapid prototyping processes, such as e.g. the selective laser sintering or the electron beam sintering in each of which also a loose particulate material is applied in layers and selectively solidified by means of a controlled physical radiation source.

In addition, there are also other methods, such as the fused-Deposiiton-Modeling Fused (FDM) - layer construction method, in which each of the cross sections of the component are constructed by a liquid, outside a nozzle solidifying medium, the position of the build platform by one layer thickness to the last Position is changed and these steps are repeated until the component is finished

In the following, all these methods are summarized under the term "three-dimensional printing process" or 3D printing process.

These methods sometimes use different options for layering. In some methods, the particulate material required for the entire layer is presented to a thin blade. This is then moved over the building area and sweeps out the submitted material and smoothes it. Another type of layer application is the continuous presentation of a small volume of particulate material during the movement of the blade. For this purpose, the blade is usually attached to the underside of a movable silo. Directly above or next to the blade, an adjustable gap is provided, through which the particulate material can flow out of the silo. The excitation of the outflow is done by the introduction of vibrations in the silo blade system.

Conventional coaters with the principle of operation of vibrating blades usually serve only for the application of a particular material. The vibration is generated by an eccentric mechanism. In a material / parameter change, such as the change in the vibration amplitude, the vibrating blade, or the oscillating mechanism must be mechanically adjusted by means of relatively complex external mechanisms. State of the art here is the replacement of eccentrics to change the vibration amplitude. The coater angle can be adjusted by means of rotation of the entire coater or mechanical change in the distance between the coater and the eccentric.

It was therefore an object of the present invention to provide an apparatus and a method with which a simple and reliable adjustment of the vibration amplitude is possible. A further object of the present invention was to provide a device and a method with which a simple adjustment of the coater angle, possibly during a coating process, is possible.

Brief summary of the disclosure

In one aspect, the disclosure relates to a method for applying fluids, in particular in a method for producing three-dimensional models, by means of a device on a construction field, wherein a coater, comprising a blade, a fluid outlet and a reservoir, is provided and wherein the blade is moved over the construction field such that it can perform a vibration in the manner of a rotary movement and wherein the vibration is effected by a stroke generating linear actuator.

In a further aspect, the disclosure also relates to a device for applying fluids, in particular in a method for producing three-dimensional models, on a construction field, wherein a coater, comprising a blade, a fluid outlet and a reservoir, is provided, and wherein the blade over the Construction field is moved so that it can perform a vibration in the manner of a rotary motion and wherein a stroke generating linear actuator is provided for generating the vibration.

In yet another aspect, the disclosure relates to a fluid application coater, particularly in a method of making three-dimensional models, to a construction field comprising a blade, a fluid outlet, and a reservoir, and wherein the blade is movable over the construction field to provide it can perform a vibration in the manner of a rotational movement and is provided for generating the oscillation of a stroke generating linear actuator.

Brief description of the figures

Figure 1: Schematic representation of a coater with a vibrating blade according to the prior art in the stationary (Fig. La) and oscillating state (Fig. Lb).

Figure 2: Schematic representation of a coater with a vibrating blade according to a preferred embodiment of

present invention. Figure 3: Schematic representation of a coater with a vibrating blade according to a preferred embodiment of

present invention, wherein the coater is shown at a first angle (Fig. 3a) and after an angular adjustment with a second angle (Fig. 3b).

Figure 4: Schematic representation of a coater with a closure according to another preferred embodiment of the invention.

Figure 5: Schematic representation of the coater with a

Closure of Fig. 4, wherein a swinging position (Fig. 5a) and a closing position (Fig. 5b) are shown.

Figure 6: Schematic representation of the compression of the fluid via an adjustment of the coater angle.

Figure 7: Schematic representation of the coater filling in a in a straight, vertical (Fig. 7a) and a tilted position (Fig. 7b).

Figure 8: Schematic representation of the coater in operation and in a lifted state.

Detailed description

In the following some terms are defined in more detail. Otherwise, for the terms used, the meanings known to those skilled in the art are to be understood.

For the purposes of the invention, "3D printing processes" are all processes known from the prior art which include the construction of components in enable three-dimensional shapes and are compatible with the described process components and devices.

For the purposes of the invention, "selective binder application" or "selective binder system application" can be carried out after each particle material application or, depending on the requirements of the molding and for the optimization of the molding production, also take place irregularly, i. non-linear and parallel after each particle material application. "Selective binder application" or "Selective binder system application" can thus be adjusted individually and in the course of the production of moldings.

"Shaped body" or "component" in the sense of the invention are all three-dimensional objects produced by means of the method according to the invention and / or the device according to the invention, which have a dimensional stability.

As an "apparatus" for carrying out the method according to the invention, any known 3D printing apparatus can be used which includes the required components. Conventional components include coater, building field, means for moving the building field or other components, metering device and heating means, and other components known to those skilled in the art. which are therefore not detailed here.

As "fluids" it is possible to use all flowable materials known for 3D printing, in particular in powder form, as slag or as liquid, for example, sands, ceramic powders, glass powders and other powders of inorganic materials, metal powders, plastics, wood particles, Fiber materials, celluloses and / or lactose powder as well as other types of organic, powdery materials The particulate material is preferably a dry free-flowing powder, but also a cohesive, cut-resistant powder can be used. This cohesiveness can also result from the addition of a binder material or an auxiliary material.

"Construction field" is the plane or, more broadly, the locus on which or in which the bed of particulate material grows during the construction process by repeated coating with particulate material.The construction field is often passed through a floor, the building platform, through walls and an open deck surface Building level, limited.

The "printhead" is composed of various components, including the print modules, which are aligned relative to the printhead, and the printhead is oriented relative to the machine, allowing the location of a nozzle to be mapped to the machine coordinate system.

"Coater" or "recoater" is the unit by means of which the fluid is applied to the construction field. This can consist of a fluid reservoir and a fluid application unit, according to the present invention, the fluid application unit comprises a fluid outlet and a coater blade.

"Blade" "vibrating blade" or "coater blade" in the context of the invention is the component that levels the applied fluid.

"Fluid outlet" in the sense of the invention is the opening by means of which the fluid is applied to the building field, The "fluid outlet" has at least one outflow gap, but may also comprise a plurality of outflow gaps. The "fluid outlet" may preferably be unitary with one or two fluid reservoirs.

The "reservoir" or "fluid reservoir" or "reservoir" here is the receptacle of the fluid. that he resonates when swinging the blade, or not. There are versions in which the blade forms part of the reservoir.

A "linear actuator" is to be understood to mean an actuator for generating the vibration of the blade, whose suspension points execute an approximately linear, oscillating motion relative to one another.

The "stroke" is to be understood as meaning the maximum linear movement of the actuator, whereby the stroke also serves to achieve an angular adjustment of the coater blade or of the coater, or possibly a closure of the fluid intake to reach.

"Angle adjustment" in the sense of the invention is the adjustment of the angle between the construction field and the coater blade or the "coater angle" is the angle including the construction field normal and the joining line of the fulcrum blade The coater oscillation takes place around this line as a zero line.

A vibration in the manner of a rotary movement in the context of the invention is the movement of the blade or coater blade over a pivot point, preferably this movement is generated by an actuator.

Various aspects of the invention are described below.

The invention relates in one aspect to a method for applying fluids, in particular in a method for producing three-dimensional molded bodies, by means of a device on a construction field, wherein a coater, comprising a blade with a fluid outlet and a reservoir, is provided and wherein the blade over the construction field is moved so that they one after the manner of a rotary motion can perform and wherein a generation of the vibration is carried out by a stroke generating linear actuator.

With a method according to the present invention, the swinging range of the blade is widened. This is achieved by the use of a linear actuator, which can freely controllably generate a swing stroke.

Due to the free controllability of the stroke, a simple adjustment of the oscillation amplitude is possible. For prior art coaters, this requires complex kinematics or a change in articulation (e.g., eccentricity).

According to a preferred embodiment of the invention, the actuator can produce a stroke that is at least 3 times as large as the amplitude of oscillation, then the stroke can easily be changed to produce larger oscillation amplitudes, but can also serve to achieve an angular adjustment of the coater blade or of the coater if necessary, to achieve a closure of the fluid intake.

Preferably, in a method according to the invention, the stroke of the actuator Huberzeugung electrically, electrodynamically, electrostatically, pneumatically, hydraulically and / or mechanically generated. This can also be done using mechanical lever systems, if necessary.

According to one embodiment of the invention, an articulation of the coater on the device takes place at at least one pivot point. Such an embodiment has proven to be advantageous because the vibration can be generated relatively easily.

Preferably, in an inventive method, an adjustment of a coater angle to the construction field without displacement of Anlenkungspunkten and possibly even during a coating process done. The adjustment of the coater angle could be done by moving a start position of the actuator.

This is advantageous because the angle of the coater to the construction field for the coating result is very important and must be adapted for different materials. In the case of coaters of the prior art, the entire coater must be pivoted or the articulation points displaced for its adjustment.

According to a preferred embodiment of the invention, therefore, the adjustment of the coater angle can also take place during the operation of the device or the coating process.

By choosing a large stroke, it is even possible according to the present invention for the coater blade to be lifted from the building field by pivoting the blade. It is this no additional lifting device or a reduction of the construction field necessary to achieve a sufficient distance.

According to a particularly preferred embodiment of the present invention, a coating in both directions of travel is possible. This is possible because the coater angle can be easily adjusted, and thereby an adjustment of the coater angle is easily possible depending on the direction of movement and thereby coating can take place in both directions.

In a further aspect, the present invention relates to a device for applying fluids, in particular in a method for producing three-dimensional molded bodies, on a construction field, wherein a coater, comprising a blade and a reservoir, is provided and wherein the blade above the construction field so movable is that it can perform a vibration in the manner of a rotational movement and wherein for generating the vibration is provided a stroke generating linear actuator.

Preferably, the actuator is designed such that it can generate at least 3 times as large a stroke compared to a vibration amplitude.

This Huberzeugung can be achieved by means of electrical, electro-dynamic, electrostatic, pneumatic, hydraulic and / or mechanical systems.

Preferably, the coater is hinged to the device at at least one pivot point.

According to a further preferred embodiment of the invention, a corresponding counterpart for closing an opening of the coater is provided at an outer, the actuator opposite region of the maximum amplitude of oscillation of the blade corresponding counterpart. By pivoting the coater, it is now possible to close the coater opening and thereby enable a targeted application at certain locations and / or to prevent inadvertent leakage of the reservoir.

In a further aspect, the present invention relates to a coater for applying fluids, in particular in a method for producing three-dimensional molded bodies, to a construction field, comprising a blade and a storage container, and wherein the blade is movable above the construction field in such a way that it follows a vibration Can perform type of rotational movement, wherein a stroke generating linear actuator is provided for generating the vibration.

Preferred embodiments will be described below. In the following, the present invention will be explained in more detail by means of examples which represent preferred embodiments.

A schematic representation of a coater with a prior art vibrating blade in the stationary and oscillating state is shown in FIG.

A coater (5) comprising a blade (1), a fluid outlet and a reservoir (2) are articulated to an articulation (6), a pivot point (3) on a device for producing three-dimensional molded parts. Fig. La) shows the dormant state and Fig. Lb) hinted the oscillating state. The oscillation amplitude is determined by the eccentric. Since the vibration should be a relatively small, the amplitude of motion is determined by the eccentric as small.

In Fig. 2, a coater (5) with a vibrating blade (1) according to a preferred embodiment of the present invention is shown schematically. In the embodiment shown, the coater (5) is also articulated to the device via a pivot point (3). The storage container (2) is arranged above the blade (1) and oscillates according to this embodiment with the blade (1). The Huberzeugung now takes place here via a linear actuator (4), which in turn via a pivot point (6) on the blade (1) or the coater (5) is articulated. By exciting the actuator (4) no vibration can be generated, which can be relatively easily selected differently and thus results in an extended vibration range.

According to this embodiment shown, everything that is arranged below the fulcrum (3) vibrates. So it swing reservoir or reservoir (2) and blade (1). The oscillation of the reservoir (2) is not absolutely necessary according to the present invention. Indeed no vibration of the reservoir (2) serve to achieve a better fluidization of the fluid.

A schematic representation of a coater with a vibrating blade according to a preferred embodiment of the present invention is shown in FIG. In this case, the coater is shown with a first angle (FIG. 3 a) and after an adjustment with a second angle (FIG. 3 b). Watch here is that the oscillating oscillating motion is the same in both versions. These oscillating movements are relatively small movements (8). To adjust the angle of the blade (1) or the coater (5), a large actuator movement (7) can be performed and then oscillate around this turn the oscillation.

The pivot point (3) takes over the leadership and stabilization of the blade movement. Its rigidity and backlash significantly affect the coating result.

4 is a schematic representation of a coater (5) with a closure (9) according to another preferred embodiment of the invention. 5 is a representation of the coater (5) with a closure (9) from FIG. 4, wherein an oscillating position (FIG. 5a) and a closing position (FIG. 5b) are illustrated.

Due to the possibility of a relatively large stroke of the linear actuator (4), the coater (5) can pivot to the left so far that it can be closed in a "closure station" (9).

A schematic representation of the compression of the fluid via an adjustment of the coater angle is shown in FIG. The fluid here exits from the storage container (1) over the blade (2) to the construction field (600) below the blade and is deflected by the blade inclined at the applicator angle (601) from the original layer thickness (602) to the final layer thickness (602). 603). According to the present invention, it is possible to achieve an improvement in the coating filling. Fig. 7 shows a schematic representation of the coater filling in a in a straight, vertical (Fig. 7a) and a tilted position (Fig. 7b).

It has been found that by selective tilting of the reservoir (2) during filling, the bulk cone in the reservoir can be changed so that after the subsequent straightening for coating the bulk cone (10) has a significantly better shape and thereby the undesirable effect the particle material after the fluidization (by switching the coater (5)) over the reservoir rim runs, is greatly reduced.

By a short oscillation of the reservoir (2) in a tilted position, it is additionally possible to further optimize the pour cone (10) and / or throw some particulate material before the coater (5) is returned to its angular position for coating (Fig. 7).

A lifting of the coater blade (2) by a distance (801) from the construction field (600) takes place, for example, by pivoting the blade. This is shown in FIG. On the left is the peeler (5) shown in operation and right in a lifted state. In the case of the conventional coater, a lifting device or a lowering of the construction field is necessary in order to achieve a sufficient distance. According to the preferred embodiment shown, the blade (1) can now be easily swiveled by the actuator, namely so far that a distance (801) to the construction field (600) is achieved. LIST OF REFERENCE NUMBERS

blade

reservoir

Fulcrum coater

Huber procreation

coaters

articulation

Actuator movement for angle adjustment

vibration

shutter

angle of repose

Baufeld

Beschichterwinkel

layer thickness

final layer

Abhebedistanz

Claims

claims

1. A method for applying fluids, in particular in a method for producing three-dimensional molded bodies, by means of a device on a construction field, wherein a coater comprising a blade, a fluid outlet and a reservoir, is provided and wherein the blade is moved over the construction field such in that it can execute a vibration in the manner of a rotary movement,

characterized in that

the vibration takes place by means of a stroke by a linear actuator.

2. The method according to claim 1,

characterized in that

the actuator compared to the amplitude of vibration can produce a stroke at least 3 times as large.

3. The method according to any one of the preceding claims,

characterized in that

a Huberzeugung electrically, electrodynamically, electrostatically, pneumatically, hydraulically and / or mechanically.

4. The method according to any one of the preceding claims,

characterized in that

An articulation of the coater takes place on the device at least one pivot point.

5. The method according to any one of the preceding claims, characterized in that

an adjustment of a coater angle to the construction field without displacement of articulation points and possibly during a coating process takes place.

6. The method according to claim 5,

characterized in that

the adjustment of the coater angle by moving a start position of the actuator takes place.

7. The method according to any one of the preceding claims,

characterized in that

a coating in both directions of travel is possible.

8. A device for applying fluids, in particular in a method for producing three-dimensional molded body, on a construction field, wherein a coater, comprising a blade, a fluid outlet and a reservoir, is provided and wherein the blade is movable over the construction field such that they can perform a vibration in the manner of a rotational movement,

characterized in that

for generating the oscillation, a linear actuator producing a stroke is provided.

9. Apparatus according to claim 8,

characterized in that

the actuator compared to a vibration amplitude can produce at least 3 times as large stroke, preferably

characterized in that for Huberzeugung electrical, electrodynamic, electrostatic, pneumatic, hydraulic and / or mechanical systems are provided, preferably

characterized in that

the coater is hinged to the device at at least one pivot point, preferably

characterized in that

on an outer, the actuator opposite region of the maximum amplitude of oscillation of the blade corresponding counterpart for closing an opening of the coater is provided.

10. A coater for applying fluids, in particular in a method for producing three-dimensional molded bodies, on a construction field comprising a blade, a fluid outlet and a reservoir and wherein the blade is movable over the construction field such that they perform a vibration in the manner of a rotary movement can

characterized in that