Additive production component of an extruder

Abstract

The invention relates to an extruder comprising a plurality of components, in which a medium is kneaded, mixed and / or conveyed in the extrusion direction between the components, at least two of which at least partially engage with each other. According to the invention, at least one of the components is designed in a computer-aided manner, computer-aided production data is provided for the component, and the component is produced in an additive manner on the basis of the production data, the component produced in this way has at least one of the following functions: ideal medium dispersion, thermal homogenization with targeted temperature control of the medium, mechanical homogenization of the medium, and melting of the medium. The invention further relates to a method related thereto and to a component.

Description

Technical Field

[0001] The invention relates to an extruder comprising a plurality of components, wherein a medium is kneaded, mixed and / or conveyed in the extrusion direction between the components, at least two of which components at least partially mesh with one another. The invention also relates to a method for producing the components and to the components themselves. Background Art

[0002] Such devices are known from the prior art. For example, in the Internet publication on the Chemitechnik.de website, in a report by Thomas Malzahn on September 8, 2011, a device for dispersing plastic materials in planetary roller extruders and for selectively controlling their temperature is described.

[0003] The device of the planetary roller extruder is similar to a planetary gear transmission, which has a limited tooth width and a helical tooth section. When the central spindle rotates, the planetary spindles roll on the central spindle and the internally toothed rollers and revolve like planets. In this process, the material is caught, inserted into the corresponding tooth gap by the spindle teeth, rolled into a thin layer and conveyed forward by the helical teeth. Through this repeated thin layer rolling, precise temperature control and dispersion can be achieved throughout the entire production process.

[0004] With the aid of deep etching technology to produce the sleeve, it is possible to produce a sleeve with a particularly minimized wall thickness. The thin outer wall enables improved temperature control of the medium via the sleeve.

[0005] However, in the case of sleeves with twisted internal toothing, there are clear limitations in terms of production technology with regard to the toothing design (module, pitch change, targeted dwell phases, toothing with reverse pitch, etc.).

[0006] The space available for machining the inner surface of the barrel greatly limits the geometrical implementation possibilities.

[0007] This means that in flat-roller extruders the displacement unit cannot be implemented individually according to the requirements of the process technology, as is currently done in single-screw and twin-screw extruders.

[0008] The advantages of intermeshing components with different geometries over their length have already been disclosed in the publication "Plastics" 05 / 2005 by Carl Hanser Verlag. Therein a multi-zone screw is described in which a pair of screws is replaced by a central screw into which each of the small screws engages oppositely. Summary of the invention

[0009] The task of the present invention is to realize and simplify the manufacture of complex components in extrusion technology so as to realize the requirements of method technology and to minimize the manufacturing cost and production time of components. In addition, the task includes providing an extruder and a corresponding method for manufacturing such components by means of the manufactured components.

[0010] In conjunction with the preamble of claim 1, the solution to the object associated with the device is characterized in that at least one of the components is designed with the aid of a computer, computer-aided production data exist for the component, and the component is additively produced based on the production data, in such a way that the component produces at least one of the following functions:

[0011] Ideal medium dispersion,

[0012] Thermal homogenization with targeted temperature control of the medium,

[0013] Mechanical homogenization medium,

[0014] Melting medium.

[0015] A plurality of intermeshing components that can be produced according to the invention are conceivable. For example, the components of a planetary roller extruder can thus be significantly more adapted to the requirements of the process technology. The screw embodiment is similar to that of a single-screw and twin-screw extruder.

[0016] The important thing is that the invention allows the production of components which at least include the functions or combinations of functions specified in the claims. From components designed with the aid of computer-aided design (CAD), manufacturing data are also generated with the aid of a computer, which are now used for additive production of components, similar to the production of components with the aid of numerical control (CNC). In additive production, material is applied layer by layer and thus a three-dimensional object is produced.

[0017] Additive production (also known as 3D printing) allows the production of very complex components, since the accessibility of the connection points does not have to be taken into account when assembling the individual components. The conventional consideration of the manufacturability of the component also plays a secondary role, since additive production creates the possibility of producing very complex embodiments using this method.

[0018] According to a further development, the profile and / or geometry varies over the length of the additively produced component. This has the advantage that the conveying behavior can be influenced in such a way that different residence times can be achieved within the component section. In particular, in PWE, work is usually carried out with gaps in the toothing. The planetary spindle can move freely within this gap. With the possibilities described here, the freedom of movement of the planetary spindle can be limited. In addition, it is advantageous that different method steps, such as pressure increase, melting, thermal and mechanical dispersion, can be achieved over the length of the screw in a single-screw or twin-screw extruder, similar to a multi-zone screw.

[0019] According to a further development, the profile that changes over the length of the additively produced component includes a changing toothing, wherein the pitch of the toothing can change continuously, linearly, gradually, decreasingly or abruptly. This has the advantages of a compact design and flexible implementation of the method specifications.

[0020] Advantageously, the invention is implemented in a planetary roller extruder comprising a planetary roller, a central spindle and a plurality of planetary spindles, the planetary spindles meshing at least partially both with the central spindle and with the planetary rollers.

[0021] Different pitches can be used within the planetary roller system, or even opposite pitches. The transition can be smooth or abrupt, which is only possible with the additive production method according to the invention. The basic geometry can remain constant, but can also be changed, so that a change in the toothing module is achieved. However, completely different designs are also conceivable with additive production.

[0022] According to a further improvement, it is proposed to partially implement the planetary spindle without toothing so that it only has a conventional, for example cylindrical geometry there. The planetary spindle is then still safely guided in the system, but significantly smaller intermediate spaces are created, which can be beneficial for meeting the required functionality according to the invention.

[0023] The previously known state stages can also be realized on the planetary main shaft by means of a large diameter barrel section. Advantageously compared to the prior art, in the state stages realized on the planetary main shaft by means of a large diameter barrel section, a dynamic state stage which can be significantly easier to clean can therefore be realized by means of the present invention.

[0024] But the planetary spindle can also be complex in structure and be completely or partially hollow.In addition, therefore, can produce bigger volume and realize better mixing, but the toothing is maintained here.

[0025] This of course applies to one planetary axis as well as to multiple planetary axes.

[0026] According to a further development, the additively produced components according to the invention can be provided with a number of openings which can be used as temperature control channels, for injection, for degassing or for other functions. The embodiment of such openings is hardly subject to any restrictions here. Conventional holes are always cylindrical and straight; with additive production, the diameter of these holes can be varied or they can be curved, i.e. adapted to the requirements of the desired function. Another advantage is that no additional seals are required. For example, air or water can be conveyed through these openings, or they can be used for measurement technology.

[0027] The solution to the object of the method is specified in claim 9 .

[0028] For the functions to be fulfilled, care must be taken to ensure that they are fulfilled within a certain time window, since, depending on the material used, this can be damaged if the time required to fulfill the function is too long. Thus, for example, certain plastics can be thermally damaged if the residence time is too long, or if foods are mixed with fats in the extruder, these foods cannot be used.

[0029] The solution to the object with regard to the product is specified in claim 10 .

[0030] Ideally, the computer-aided geometry is created with the aid of targeted flow simulations. These flow simulations can be repeated several times in order to improve the geometry in a flexible process. Only in this way can it be ensured in advance that the desired goals are achieved in the best possible way: homogeneous melting, cooling and heating, and dispersion.

[0031] Advantageous further developments emerge from the dependent claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The device according to the invention is schematically shown in the drawing.

[0033] Figure 1 An extruder is shown symbolically.

[0034] Figure 2 A planetary roller extruder is schematically shown,

[0035] Figure 3 Shown in accordance with Figure 2 A cross-sectional view of

[0036] Figure 4 Schematically shows two meshing complex components, and

[0037] Figure 5 A partial cross-sectional view showing a complex structure of a planetary roller component,

[0038] Figure 6The complex structure of the planetary roller components with planetary spindles but without complete toothing is shown as an example.

[0039] Figure 7a -d shows by way of example an embodiment of a complex planetary spindle. DETAILED DESCRIPTION

[0040] Figure 1 An extruder 1 is shown which has a first component 2 , which is shown here by way of example as an extruder housing composed of a plurality of sleeves, and a second component 3 , which is also by way of example an extruder screw which is rotated by means of a drive 5 .

[0041] The medium is supplied to the extruder 1 via the filling hopper 4 , is kneaded, mixed in the intermediate space between these components and / or is conveyed in the extrusion direction 6 to the end of the extruder 1 , where it is further processed.

[0042] Figure 2 An extruder 1 is shown by way of example, which is designed as a planetary roller extruder 7. Here, the first component 2 of the extruder 1 is a planetary drum 8 and the second component 3 is a planetary spindle 10. The planetary spindle 10 meshes with the planetary roller 8 by means of its toothing 11, so that the two components mesh with each other. In addition, the planetary spindle 8 also meshes with the central spindle 9, so that in this exemplary embodiment, even three components mesh with each other.

[0043] Figure 3 and Figure 2 Basically consistent, the same components are also marked with the same reference numerals. A planetary roller extruder is also shown here, but in a sectional view. In this sectional view, the following embodiment is shown, in which the toothing 11 changes on the length of the components 2 and 3. Here, for example, three different toothings A, B and C are reproduced, which are marked with reference numerals 12, 13 and 14. Such a complex embodiment can only be manufactured very expensively. Regarding the external geometry, as required in the planetary spindle 10 or the central spindle 9, this is still achievable in some cases. Regarding the internal geometry, as required in the planetary roller 8, classical manufacturing (turning, corrosion, etc.) encounters its limitations due to lack of accessibility. Additive manufacturing does not have this limitation, because through the layered structure, almost every conceivable contour can be manufactured here.

[0044] Figure 4 The first component 2 is again shown meshing via a toothing with the second component 3. The two components 2, 3 have different toothings A, B and C, which are also denoted by the reference numerals 12, 13 and 14.

[0045] In accordance with Figure 5In the view of FIG. 8 , only a sectional view of the planetary roller 8 is shown. Thus, the complex construction with very different toothings of the central spindle 9 and the planetary spindles 10 can be seen. Here, too, the different toothings A, B and C are marked with reference numerals 12 , 13 and 14 .

[0046] In all the figures showing the planetary roller extruder 7, only one planetary spindle 10 is shown for the sake of illustration. Of course, the present invention also includes embodiments in which a plurality of planetary spindles 10 are arranged around the central spindle 9 and mesh with the central spindle 9 and, if necessary, also with the planetary rollers 8. A plurality of modules shown in this way can be arranged in series one after the other in the extrusion direction and thus provide an extruder 1 of very complex construction.

[0047] Planetary roller extruders usually use intermeshing tooth geometries with a pitch, which are usually referred to as helical toothing.

[0048] The profile and lead of these geometries are usually substantially constant over the length of the component. It is known to completely or partially remove individual teeth or multiple teeth. It is also known to introduce additional geometries (hub shafts).

[0049] exist Figure 6 A geometry is schematically shown in which the components, such as Figures 2 to 5 , there is no constant lead. Identical components are also marked with the same position number. Different leads can be used within a planetary roller system, or they can also have opposite leads. The transition can be smooth here, but also abrupt, which can only be achieved via an additive manufacturing process. Here, the basic geometry can remain constant, but can also be changed, and for example the tooth module can be changed, but can also be designed completely differently, as shown here. This embodiment is only an example, but a large number of freely configurable geometries are conceivable. It is thus possible to create a simple circular geometry in the planetary spindle, which then no longer engages with each other (position 15), that is, no longer meshes with each other, just as any other geometry can be mapped, as long as the kinematics of the rotating parts allow this.

[0050] exist Figure 7a 1 shows a planetary spindle 10 with a cavity 16 in which an additional spindle 17 is located. The additional spindle 17 is integrated into the planetary spindle 10 and is suspended therein, as it were. Due to additive manufacturing, the planetary spindle 10 can be integral and closed on both sides, since the additional spindle 17 does not have to be installed. This creates a larger volume in order to achieve improved mixing. The toothing is retained here.

[0051] The inner contour can be freely designed here, in particular using adaptive methods:

[0052] This design is a necessary requirement for adaptive manufacturing methods, but is not limited to planetary roller extruder components. It is also conceivable to combine such hollow shapes with common geometries such as on extruder screws, so as to be used, for example, in shearing and mixing components.

[0053] List of reference numerals:

[0054] 1 Extruder

[0055] 2 The first component of the extruder

[0056] 3. The second component of the extruder

[0057] 4 Filling hopper

[0058] 5. Drive

[0059] 6 Extrusion direction

[0060] 7 Planetary Roller Extruder

[0061] 8 planetary rollers

[0062] 9 Central spindle

[0063] 10 Planetary spindles

[0064] 11 teeth

[0065] 12 tooth part A

[0066] 13 tooth B

[0067] 14 tooth C

[0068] 15 The geometry of 10 that no longer meshes

[0069] Cavity in 1610

[0070] 17 Additional spindle

Claims

1. An extruder (1) comprising a plurality of components, wherein: Kneading, mixing and / or conveying a medium in an extrusion direction (6) between components (2, 3), wherein at least two components at least partially mesh with each other, characterized in that at least one of the components (2, 3) is designed with the aid of a computer, computer-aided production data exist for the component (2, 3), and the component (2, 3) is additively produced based on the production data, so that the component produced in this way satisfies at least one of the following functions: Ideal medium dispersion, Thermal homogenization with targeted temperature control of the medium, Mechanical homogenization medium, Melting medium.

2. The extruder according to claim 1, characterized in that The contour and / or geometry can vary over the length of the additively produced component (2, 3).

3. The extruder according to claim 2, characterized in that The profile which varies over the length of the additively produced component (2, 3) comprises a varying toothing (11).

4. The extruder according to claim 3, characterized in that The toothing (11) which varies over the length of the additively produced component (2, 3) comprises a pitch, wherein the pitch varies continuously, linearly, gradually, decreasingly or abruptly.

5. The extruder according to claim 1, characterized in that The extruder (1) is a planetary roller extruder (7) comprising a planetary roller (8), a central spindle (9) and a plurality of planetary spindles (10), each planetary spindle (10) at least partially meshing with both the central spindle (9) and the planetary roller (8).

6. The extruder according to claim 5, characterized in that The planetary spindle (10) is partially free of toothing and therefore only has conventional geometries there.

7. The extruder according to claim 5, characterized in that The planetary main shaft (10) is of complex construction and is completely or at least partially hollow.

8. Extruder according to one of the preceding claims, characterized in that The components (2, 3) have one or more openings which can be used as temperature control channels, for injection, for degassing or for other functions.

9. Method for producing a component for an extruder according to claim 1, characterized in that The components (2, 3) are designed with the aid of a computer, thereby generating computer-aided production data, and the components (2, 3) are additively manufactured based on the production data, so that the components produced in this way satisfy at least one of the following functions: Ideal medium dispersion, Thermal homogenization with targeted temperature control of the medium, Mechanical homogenization medium, Melting medium.

10. The extruder component according to claim 1, characterized in that: The components (2, 3) are designed with the aid of a computer, and therefore computer-aided production data exist, and the components (2, 3) are additively manufactured based on the production data.

11. The component according to claim 10, characterized in that The components (2, 3) have one or more openings which serve as temperature control channels, for injection, for degassing or for other functions.

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