EP3554835A2

EP3554835A2 - Method and device for additive manufacturing of a three-dimensional object and three-dimensional object

Info

Publication number: EP3554835A2
Application number: EP17829145.6A
Authority: EP
Inventors: Sarah Sitz; Henrik Wolfgang Behm; Karim Bahroun
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2016-12-16
Filing date: 2017-12-08
Publication date: 2019-10-23
Also published as: WO2018108732A2; DE102016225227A1; CN110035902A; WO2018108732A3

Abstract

The invention relates to a method (300) for additive manufacturing of a three-dimensional object (1), in particular a seal and/or coating, from an elastomer in the liquid phase, in particular from a liquid silicone rubber (20), the elastomer being sprayed (301) onto a substrate (30), preferably onto a workpiece and/or onto another elastomer.

Description

Description title

Method and apparatus for the additive manufacturing of a three-dimensional object and a three-dimensional object

State of the art

The invention is based on a method, a device and a product according to the preamble of the independent claims.

From WO 2008/044884 AI is a laminating film, in particular a

Coating film, made of plastic / Teflon-silicon and a process for its preparation with improved bond strength between plastic or Teflon with silicone rubber known.

Disclosure of the invention

Against this background, a method for the additive manufacturing of a three-dimensional object, a device for the additive manufacturing of a three-dimensional object, and a three-dimensional object are presented with the approach presented here. The measures listed in the dependent claims advantageous refinements and improvements of the method specified in the independent claims or the device are possible.

It is a process for the additive manufacturing of a three-dimensional object, in particular a seal and / or a coating, of a liquid-phase rubber, in particular of a

Liquid silicone rubber, wherein the rubber is applied to a substrate, preferably on a workpiece and / or on another rubber,

is sprayed on.

In this case, a three-dimensional object can be understood as meaning components of any geometry and / or shape. In particular, it can also be understood to mean flat components, such as surface seals, foils and / or coatings, which have a small expansion or thickness in a direction perpendicular to the surface of the component, compared to an expansion in a plane parallel to a surface of the component , In particular, they may also be understood to mean elongated components, such as sealing beads, sealing cords and / or, which have a small expansion or thickness in two directions perpendicular to the direction parallel to the surface compared to an expansion in one direction parallel to a surface of the component of the component. A liquid silicone rubber may be understood to mean a silicone rubber and / or a silicone elastomer, in particular still uncrosslinked, which is in liquid form. In this case, spraying can be understood as meaning that the liquid silicone rubber is distributed in droplets in a gas stream, for example applied to a substrate. In particular, it may be understood that a plurality of droplets of the liquid silicone rubber are simultaneously applied or discharged onto the substrate.

The method has the advantage that in a comparison to a sequential

Austragungs- or construction process, a large amount of liquid silicone rubber can be discharged in a short time.

It is expedient if the elastomer is sprayed by an injector, in particular a high-pressure injector, such that a droplet size of sprayed droplets on the substrate and / or a distance between the sprayed-on droplets on the substrate can be adjusted. Because this can further increase the efficiency of the process. In particular, a residual flowability of the liquid silicone rubber can be adjusted by the droplet size and / or the distance between the sprayed-on droplets. This improves a

Degree of crosslinking of the liquid silicone rubbers and thus can be improved mechanical properties as well as a denser material structure improved resistance to aging and permeation of media can be achieved.

The droplet size depends on the injector used. Due to a flow behavior that can be assumed to be watery at high shear, which arises in such a type of dosage form, the droplet size may assume values that are in the range of small water droplets, such. one

Drop radius from 0.05 mm to 0.25 mm. Droplets with high flowability can assume droplet radii in the range of about 0.5 mm. At a pressure of 50-100 MPa, the liquid silicone rubber is affected by shear rate gradients of up to 10 ⁴ s ^-1 , at which the liquid silicone rubber assumes the flow behavior of a low-viscosity liquid (10 Pa * s).

In this case, a high-pressure injector can be understood to be an injector which discharges a liquid silicone rubber and / or liquid auxiliary under pressure or high pressure via a nozzle or sprays it onto a substrate. Under pressure or high pressure can be understood a pressure range, for example, greater than 1 bar, preferably greater than 100 bar, more preferably greater than 500 bar and most preferably greater than 1000 bar.

Furthermore, it is advantageous if before and / or during the spraying of the

Elastomers, in particular of the liquid silicone rubber, a plasma treatment and / or a UV light treatment of the aufzusprühenden elastomer. Because this can cause a curing reaction of the elastomer during a

Spraying operation, i. during a flight from the injector to the substrate. Therefore, the sprayed elastomer or the sprayed elastomer droplets better stick together. As a result, a material strength of the three-dimensional object can be significantly improved. A plasma treatment may be understood as meaning a functionalization of the elastomer and / or the substrate, in particular a surface of the elastomer and / or of the substrate, with a plasma. The resulting in a plasma reactive particles and resulting UV radiation can advantageously on a

Material surface are steered and a targeted treatment of the surface be used. In particular, in the case of polymeric or elastomeric plastics, this can expediently be followed by postcrosslinking of the surface, removal of weakly adhering low molecular weight compounds on the surface, physical modification, such as roughening of the surface by particle bombardment and chemical activation by production of functional groups or by oxidation of the surface Surface can be achieved. When using layer-forming precursors, a coating of the elastomer and / or the substrate, in particular a surface of the elastomer and / or the substrate can take place.

In a further embodiment of the invention, it may be advantageous if the elastomer, in particular the liquid silicone rubber, is introduced into a plasma, in particular into a plasma jet, and through the plasma, in particular through the plasma jet, onto the substrate and / or to another Elastomer is applied. Thus, the discharged, sprayed liquid silicone rubber droplets can be targeted by the plasma jet to the substrate and / or on an already

Apply discharged and possibly cured elastomer. Furthermore, depending on a Aufsprührate, a Aufsprühdrucks and / or a

Plasma parameters, in particular a plasma composition and a plasma intensity or a plasma temperature, the droplet size and / or the distance between the sprayed droplets and thus adjust the residual fluidity of the liquid silicone rubber even more precisely.

Furthermore, it is expedient if before and / or during the spraying of the

Elastomers, in particular of the liquid silicone rubber, a plasma treatment and / or a UV light treatment of the substrate takes place. As a result, an improved adhesion between the sprayed liquid silicone rubber and the substrate, in particular with different material components, such as elastomer plastic, elastomer metal and / or elastomeric ceramic / glass systems, can be achieved.

Furthermore, it is advantageous if after spraying the elastomer,

in particular the liquid silicone rubber, a plasma treatment and / or a UV-light treatment of the sprayed-on elastomer takes place. Because of this, a degree of crosslinking of the liquid silicone rubber can be further increased.

Furthermore, the residual flowability of the liquid silicone rubber can be controlled by

Plasma temperature and / or by another heat source, the

Substrate can temper, positively influence.

In a further alternative embodiment it can be provided that an auxiliary material, in particular metal particles and / or layer-forming precursors, is supplied to the elastomer before and / or during the spraying of the elastomer. This can significantly improve the material strength of the three-dimensional object. In addition, mechanical, thermal, optical and / or electrical properties of the three-dimensional object can thereby be varied in a targeted manner. For example, it is conceivable that the component to be manufactured becomes electrically conductive and / or opaque by adding aluminum, silver and / or gold particles. Excipient may also be understood to mean a filler or a plurality of fillers, for example silicates, talc, aluminum and aluminum compounds, boronitrites, soot particles, conductive carbon blacks and graphites.

Furthermore, it is advantageous if, by means of a control unit, a flowability of sprayed droplets of elastomer is set as a function of parameters of a spraying process, in particular a spraying pressure, a spraying rate, a plasma parameter, in particular a plasma intensity, and / or a UV light intensity. Because this allows the droplet size and / or the distance between the sprayed droplets and thus the

Adjust the residual fluidity of the liquid silicone rubber even more precisely. A

Viscosity of the liquid silicone elastomer may advantageously be in a range from 5 Pa * s to 100 Pa * s.

The advantages mentioned above apply equally to one

Device for the additive manufacturing of a three-dimensional object made of an elastomer.

It is particularly advantageous if the device for carrying out a

Method for the additive manufacturing of a three-dimensional object from a Elastomer a spraying device, in particular an injector, for spraying an existing in liquid phase elastomer, in particular a

Liquid silicone rubber, on a substrate, wherein the device further comprises a plasma unit and / or a UV light unit for the treatment of the elastomer and / or the substrate before, during and / or after a Aufsprühvorgang. Because this can be compared to a sequential Austragungs- or

Build-up process a large amount of liquid silicone rubber can be discharged in a short time.

It is also expedient if the device has a drive unit which is adapted to move the spray device relative to the substrate and / or to the already sprayed on elastomer and / or the substrate relative to the

To move spray device. Thus, any desired three-dimensional component can be produced in a targeted manner.

In that the device has an addition unit which is adapted to the elastomer before and / or during the spraying of the elastomer

Adjuvant, in particular metal particles and / or layer-forming precursors, such as e.g. Hexamethyldisiloxane (HMDSO), trimethylaluminum, trimethylindium, etc., can provide material properties of the three-dimensional object

be changed significantly. For example, by adding

Aluminum, silver and / or gold particles the mechanical, thermal,

optical and / or electrical properties of the three-dimensional object are selectively changed.

It is furthermore advantageous if the device has a control unit that is set up to have a flowability of sprayed-on droplets of elastomer in

Dependence on parameters of a spraying process, in particular one

Aufsprühdrucks, a Aufsprührate, a plasma parameter, in particular a plasma intensity, and / or set a UV light intensity. Because of this, the droplet size and / or the distance between the sprayed-on droplets and thus the residual fluidity of the liquid silicone rubber can be set even more precisely. The aforementioned advantages also apply in a corresponding manner to a three-dimensional object, which is produced in particular by one of the aforementioned methods.

Embodiments of the invention are illustrated in the drawings and explained in more detail in the following description. Show it:

1 is a schematic representation of an apparatus for additive manufacturing of a three-dimensional object made of an elastomer according to one

Embodiment; and

2 shows a schematic illustration of a method for the additive manufacturing of a three-dimensional object made of an elastomer according to one

Embodiment;

In the following description of favorable embodiments of the present invention are for the in the various figures

represented and similar elements acting the same or similar

Reference numeral used, wherein a repeated description of these elements is omitted.

1 shows a schematic representation of a device 100 for additive manufacturing of a three-dimensional object 1 made of an elastomer according to one exemplary embodiment. The device 100 has an injector unit 10, which serves as a spray device for a liquid silicone rubber 20. The

Liquid silicone rubber 20 is supplied to the injector unit 10 and discharged under pressure or high-pressure from a nozzle 11 of the injector unit 10 onto a substrate 30. The liquid silicone rubber 20 can in this case be discharged as finely atomized droplets 21.

Furthermore, the device 100 may have a plasma unit 40 for generating and guiding a plasma 41 or a plasma jet 43. Of the

Plasma jet 41 can exit from the plasma unit 40 through a plasma nozzle 42. The plasma 41 may, for example, from supplied gases, such as For example, nitrogen, oxygen and / or precursors such as HMDSO or from a combination of the aforementioned substances produced.

In an alternative embodiment, the plasma unit 40 and / or the plasma nozzle 42 may be arranged adjacent to the nozzle 11 of the injector unit 10 such that the finely atomized droplets 21 from the

Liquid silicone rubber 20 are introduced into the plasma jet 43 and sprayed with the plasma jet 43 on the substrate 30 and discharged. In this case, depending on a spraying pressure, a spraying rate and / or a plasma parameter, a size of the droplets 21 and / or a distance of the droplets

Droplets can be adjusted on the substrate 30. Here are small ones

Droplets which are sprayed on the substrate 30 at great distances from one another have a lower residual flowability than large droplets 21, which are sprayed onto the substrate 30 at small distances from one another. Thus, small droplets 21 that are applied slowly and therefore have more time for crosslinking through the plasma 41 are more likely to build up a coarse component structure, whereas large droplets 21 that are applied quickly and therefore have less time for crosslinking by the plasma 41 , are more suitable for filling up the coarse component structure, for filling pores and for improving a surface quality of the component.

Alternatively or additionally, the device 100 may comprise a UV light unit 45 which irradiates a region 31 on the substrate 30 and / or on the already sprayed-on droplets 21 of the liquid silicone rubber 20 with UV light and thus on the one hand the surface 32 of the substrate 30 and / or. or the already sprayed droplets 21 of the liquid silicone rubber 20 activated and on the other hand, the already sprayed droplets 21 of the

Liquid silicone rubber 20 further crosslinked. In a further alternative embodiment it can be provided that the device 100 has an addition unit 50, the metal particles and / or layer-forming precursors to the finely divided, from the nozzle 11th

discharged droplets 21 of liquid silicone rubber 20 can give.

As a result, the material strength of the three-dimensional object 1 can be significantly improved. Furthermore, this can be targeted mechanical, thermal, optical and / or electrical properties of the three-dimensional object to be changed 1.

The substrate 30 can in this case be mounted on a workpiece carrier 35 which can be moved in three spatial directions. Alternatively or additionally, the

Injector 10 and / or the plasma unit 40 or the nozzle 10 and / or the plasma nozzle 42 may be designed to be movable.

The device can furthermore have a control unit 60, which activates the injector unit 10 via a control signal 101 and via it the

Can set Aufsprühdrucks and / or the Aufsprührate the liquid silicone rubber 20. Furthermore, the control unit 60 via another

Control signal 351 drive the workpiece carrier 35 and move the workpiece carrier 35 and thus also the substrate 20 located thereon in all three spatial directions. In particular, it can be provided that the workpiece carrier 35 is moved in a direction 34 under the nozzle 11 or the plasma nozzle 42. Furthermore, the control unit 60 can control the plasma unit 40 via a further control signal 401 and thus set, for example, a temperature of the plasma 41. Alternatively or additionally, the control unit 60 can control the UV light unit 45 via a further control signal 451 and thus set, for example, a UV light intensity.

The control unit 60 may in this case receive sensor signals 61, which may include, for example, process parameters 62 such as spray pressure, spray rate,

Plasma parameters and / or UV light intensity and a relative distance between the workpiece carrier 35 and the substrate 30 and the nozzle 11 include. From these process parameters, the control unit 60

for example, using a previously determined algorithm and / or by comparing the process parameters 62 in a table in one

Memory unit of the control unit 60 stored values (look-up table)

Plasma unit 40, the UV light unit 43, the workpiece carrier 35 and / or the injector 10 to control, so that by the sprayed droplets 21 from the liquid silicone rubber 20, a three-dimensional object 1, such as

For example, a sealing lip or a sealing bead arises. The

Process parameters 62 via sensors that on the injector 10, at the plasma unit 40, on the UV light unit 45 and / or on the

Workpiece carrier 35 or on the nozzle 11 and / or the plasma nozzle 42 are arranged to be received.

FIG. 2 shows a schematic representation of a method 300 for additively manufacturing a three-dimensional object 1 according to one exemplary embodiment. In a first method step 301, a liquid silicon rubber 20 is sprayed onto a region 31 of a surface 32 of a substrate 30 as an droplet 21 through an injector unit 10. In a second

Process step 302, which can take place at the same time as or after the first method step 301, involves curing or crosslinking the liquid silicone rubber 20 sprayed onto the substrate 30 and / or already discharged liquid silicone rubber 20, whereby a three-dimensional object 1 gradually forms.

Alternatively or additionally, a treatment of the region 31 of the surface 32 of the substrate 30 or of the already discharged liquid silicone rubber 20 by a plasma 40, a plasma jet 43 and / or by UV light may optionally take place before or during the first process step 301.

Furthermore, alternatively or additionally, during the first method step 301 or the second method step 302, the liquid silicone rubber 20 can be introduced into the plasma 40 and / or into the plasma jet 43, so that it is targeted to the surface 32 of the substrate 30 and / or the already

sprayed liquid silicone rubber 20 and thereby causing a crosslinking reaction of the sprayed droplets 21 of the

Liquid silicone rubber 20 is already initiated in flight from a nozzle 11 of the injector 10 to the substrate 30. Alternatively or additionally, this treatment can be carried out with UV light of a UV light unit 43

Furthermore, alternatively or additionally, after the first method step 301 or after the second method step 302, a treatment of the region 31 of the surface 32 of the already discharged liquid silicone rubber 20 by a plasma 40, a plasma jet 43 and / or by UV light can take place Residual fluidity of the sprayed droplets 21 of the liquid silicone rubber 20 to influence.

Claims

claims

1. A method (300) for the additive manufacturing of a three-dimensional object (1), in particular a seal and / or a coating, of a liquid-phase rubber, in particular of a liquid silicone rubber (20), characterized in that the rubber is applied to a substrate ( 30), preferably on a workpiece and / or on a further rubber, sprayed (301) is.

2. The method (300) according to claim 1, characterized in that the elastomer by an injector unit (10), in particular a

Hochdruckinjektor, is sprayed such that a droplet size sprayed droplets (21) on the substrate (30) and / or a distance between the sprayed droplets (21) on the substrate (30) is adjustable.

3. The method (300) according to claim 1 or 2, characterized in that before and / or during the spraying of the elastomer a

Plasma treatment and / or a UV light treatment of

to be sprayed on the elastomer.

4. Method (300) according to one of the preceding claims, characterized in that the elastomer is introduced into a plasma (41), in particular into a plasma jet (43), and through the plasma (41), in particular through the plasma jet (43), is applied to the substrate (30) and / or to another elastomer.

5. The method (300) according to any one of the preceding claims, characterized in that before and / or during the spraying (301) of the elastomer, a plasma treatment and / or a UV light treatment of the substrate (30). Method (300) according to one of the preceding claims, characterized in that after the spraying (301) of the elastomer, a plasma treatment and / or a UV light treatment of the

Sprayed elastomer occurs.

Method (300) according to one of the preceding claims, characterized in that before and / or during the spraying (301) of the elastomer, an auxiliary material, in particular metal particles and / or layer-forming precursors, is supplied to the elastomer.

Method (300) according to one of the preceding claims, characterized in that by a control unit (60) a flowability of sprayed droplets (21) made of elastomer in dependence on parameters of a spraying process, in particular a

Aufsprühdrucks, a Aufsprührate, a plasma intensity and / or a UV light intensity is set.

Device (100) for carrying out a method (300) for the additive manufacturing of a three-dimensional object (1) made of an elastomer, in particular according to one of claims 1 to 8, with a spraying device, in particular an injector unit (10), for

Spraying (301) a liquid-phase elastomer, in particular a liquid silicone rubber (20), onto a substrate (30) by a plasma unit (40) and / or a UV light unit (43) for treating the elastomer and / or the substrate (30) before, during and / or after a spraying process (301).

Device (100) according to claim 9, characterized by a

Drive unit adapted to move the spray device relative to the substrate (30) and / or to already sprayed elastomer and / or to move the substrate (30) relative to the spray device.

Device (100) according to claim 9 or 10, characterized by an adding unit (50) which is adapted, before and / or during the spraying (301) of the elastomer, to the elastomer an adjuvant, in particular metal particles and / or layer-forming precursors.

Device (100) according to one of claims 9 to 11, characterized by a control unit (60) which is adapted to a flowability of sprayed droplets (21) of elastomer depending on parameters of a spraying process (301), in particular a spraying pressure, a Aufsprührate, a Set plasma intensity and / or a UV light intensity.

Three-dimensional object (1), in particular a seal and / or coating, produced by a method (300) according to one of Claims 1-8.