FOAM TOOL

Description

[0001] The invention relates to a foaming tool for processing foamable plastic particles, with at least one region forming at least one section of a cavity.

[0002] Such foaming tools are well known in the art. They are used, for example, as automatic molding machines for producing or molding molded parts from foamable plastic particles. Such automatic molding machines have at least one foaming tool, so that they comprise, for example, two plates that can be moved toward or away from each other in a stroke-like manner. A cavity is thus formed between such foaming tools, which defines a mold cavity in which the foamable plastic particles can be molded. In the context of this application, a foaming tool is also understood to mean a component of a tool that forms a section of a cavity.

[0003] For production, the foamable and / or pre-foamed plastic particles are introduced into the cavity and formed into their original volume, for example, by means of hot steam, swelling or expansion. This allows the use of materials without an active blowing agent. The surface or surface structure of the cavity determines the surface structure of the molded part after production. It is possible to select the surface of the cavity according to the surface requirements of the resulting molded part, so that after demolding, the molded part has the corresponding surface formed by the foaming tool.

[0004] DE19744165 discloses a foaming tool according to the preamble of claim 1.

[0005] In the production of such foaming tools and their surface structures, it is known to introduce corresponding surface structures into the surfaces of the foaming tools using subtractive processes such as milling, erosion, etching, or laser ablation. Forming processes such as embossing are also known. One disadvantage of this is that material is lost during the subtractive or forming process. The foaming tools must therefore be manufactured with an excess dimension, which must then be subsequently removed or reshaped.

[0006] Furthermore, the known methods impose a limitation on the achievable geometries or surface structures of the surface of the foaming tools.

[0007] The invention is therefore based on the object of providing an improved foaming tool.

[0008] The object is achieved by a foaming tool of the type mentioned at the outset, in which the features of claim 1 are provided according to the invention.

[0009] The invention is therefore based on the finding that the surface structure, or at least part of the surface structure, of the cavity-forming region is produced by an additive process. This makes it possible to build the surface structure additively, so that no subtractive or reshaping post-processing process is necessary to introduce the desired surface structure into the foaming tool or to provide the foaming tool with the corresponding surface structure.

[0010] On the one hand, this ensures that material waste can be reduced, since the additive process only applies the material required to create the surface structure to the workpiece or existing surface. This makes it possible to produce foam tools with a finished final contour or at least a near-final shape. Of course, it is not impossible to rework a surface structure produced using additive processes.

[0011] In addition, surface structures can be realized that cannot be produced using conventional manufacturing methods or processes. The limitations of previous processes regarding the surface structure of the area forming the cavity do not apply to additive processes, so that a multitude of options are available for forming the surface structure of the foaming tool. In particular, surface structures are possible that are not accessible to subtractive or forming processes. For example, it is thus possible to produce structures such as channels close to the surface, i.e. close beneath the surface of the area forming the cavity, thus enabling more direct temperature control of the cavity. Such closed channels, which are provided close to the surface of the cavity, cannot be realized using forming or subtractive manufacturing processes.

[0012] The additive manufacturing of the surface structure can apply to the entire cavity or only to a section of a cavity formed by the foaming tool. It is also possible to produce only a portion of the surface structure of the foaming tool's surface bordering the cavity using an additive process.

[0013] Any suitable foamable plastic particles can be used to produce the molded part, for example, thermoplastics, particularly those based on polyolefin or polystyrene. The molded part is formed by sintering the plastic particles.

[0014] According to a preferred embodiment of the invention, it can be provided that at least part of the surface structure is produced by means of laser beam melting and / or binder jetting and / or electron beam melting and / or fused deposition modeling and / or laser metal deposition. Accordingly, the aforementioned methods are particularly suitable for producing at least part of the surface structure of the region forming the cavity, wherein material is selectively applied and solidified to form the surface structure. In this way, any desired surface structures can be produced that cannot be achieved with conventional production methods. In the context of this application, binder jetting is understood to mean a production method in which build-up material, in particular powdered material, is at least partially fixed with a binder. The fixed build-up material can then be sintered, for example.Such manufacturing processes are also known under the name “inkjet technology”.

[0015] Particularly preferably, at least one part of the surface structure is produced by successive layer-by-layer selective exposure and the associated successive layer-by-layer selective solidification of building material layers made of a building material that can be solidified by means of an energy beam, in particular a powdered one. Accordingly, at least one part of the surface structure is produced by the layer-by-layer solidification of a mostly powdered building material. In this process, a layer of building material is alternately applied and then solidified in the desired areas by an energy beam. This creates the desired surface structure layer by layer, which is built up through the additive manufacturing process.

[0016] Furthermore, during the production of the foaming tool according to the invention, it can be provided that at least one part of the surface structure is produced directly during the production of the tool or subsequently. According to the first alternative, it can therefore be provided that the foaming tool, which forms at least a portion of the cavity, or has a region that forms at least a portion of the cavity, is also produced by an additive manufacturing process. In this case, the surface structure of the region forming the cavity, or at least a portion thereof, is produced or formed together with the production of the foaming tool.

[0017] According to the second alternative, it is also possible to modify the existing surface structure of an existing foaming tool using an additive manufacturing process or to apply a surface structure to the surface of the previously manufactured tool. Accordingly, the foaming tool can consist of a prefabricated base body to which at least part of the surface structure is applied using the additive process. Thus, structures that are not accessible to conventional manufacturing processes can be supplemented using an additive process.

[0018] In this case, it can preferably be provided that at least a portion of a surface structure of the region forming the cavity is formed separately from the foaming tool and can be connected or is connected to the region. According to this embodiment of the foaming tool according to the invention, at least a portion of a surface structure of the region forming the cavity can be formed or manufactured separately from the rest of the foaming tool. The at least a portion of the surface structure of the region forming the cavity can thus be introduced into the foaming tool in order to subsequently produce corresponding molded parts with the foaming tool, which are to receive the desired surface structure.

[0019] Particularly preferably, the foaming tool according to the invention can be provided with at least one part being designed as an insert which is inserted or can be inserted into a corresponding recess. In particular, it is possible to change the corresponding regions or parts of the surface structure of the foaming tool, so that different surface structures can be produced using the same foaming tool. For this purpose, inserts can be provided, for example, which are additively manufactured and have a certain, defined surface structure. By introducing such inserts into the foaming tool, it is possible to produce various molded parts with different surface structures. The various inserts can be changed if molded parts with a different surface structure are to be produced using the same foaming tool.

[0020] The foaming tool according to the invention can further be developed such that at least one part of the surface is subsequently applied to an existing component or an existing surface structure is supplemented by the at least one part. According to this embodiment of the invention, a certain hybrid construction is therefore proposed in which a defined surface structure is applied to an existing foaming tool or an existing surface structure is supplemented accordingly. This makes it possible to combine different manufacturing processes such that part of the foaming tool can be manufactured using conventional processes and only areas or parts of the surface or surface structure that cannot be manufactured using conventional processes, for example, are manufactured using additive processes. Of course, the proportion of production using additive manufacturing processes can be selected as desired.

[0021] According to a further preferred embodiment of the foaming tool according to the invention, at least one piece of information relating to at least part of the surface structure can be generated using CAD (computer-aided design) or at least one machine parameter. The at least one piece of information can particularly preferably be used to describe the surface structure, for example, to specify or create a geometric or three-dimensional model of the surface structure that the foaming tool is to have. It is also possible to generate the desired surface structure by appropriately adjusting structure-forming machine parameters.

[0022] According to a further preferred embodiment of the foaming tool according to the invention, it can be provided that at least one part of the surface structure is post-processed by at least one process step, preferably by an abrasive process and / or laser ablation and / or a chemical or electrical smoothing process and / or a compacting or micro-forming process. Accordingly, the at least one part of the surface structure that was additively produced according to the invention can be post-processed accordingly. By means of the post-processing processes or the at least one post-processing step, the surface structure or the surface of the foaming tool can be processed in a defined manner so that the surface has a defined quality. Blasting the surface with glass beads can be used in particular as a compacting or micro-forming process.

[0023] According to a preferred embodiment, at least one part of the surface structure of the cavity-forming region has at least two sub-regions with different surface structures. According to this embodiment, it is therefore possible to additively produce part of the surface structure of the cavity-forming region, with the surface structure being formed differently in at least two sub-regions of the part. In particular, various sub-regions can thus be produced that differ in their surface structure. Accordingly, any desired surface structures can be formed, which are subsequently transferred to the molded part during its production.

[0024] The foaming tool according to the invention is further developed in such a way that the surface structure forms or comprises at least one elevation and / or at least one depression in the surface of the foaming tool. In contrast to subtractive methods, it is thus possible not only to form a depression in the surface of the foaming tool, but also to apply an elevation. Naturally, both the application of the elevation and the formation of a depression can be combined as desired, so that the resulting surface structure can be either raised or recessed relative to the foaming tool.

[0025] A further development of the foaming tool according to the invention can consist in the at least one part having a surface structure such that a product manufactured using the foaming tool can be provided with at least one piece of information during production. The at least one piece of information can, for example, be or contain a motif or lettering, in particular relating to the production of the molded part. For example, it is thus possible to integrate a manufacturer's mark, a production date, or a batch number into the surface structure, so that the manufactured product also bears the information on its surface structure.

[0026] The invention also relates to a method for producing a foaming tool according to the invention with at least one region forming at least one portion of a cavity. Naturally, all advantages, details, and features relating to the foaming tool according to the invention are transferable to the method according to the invention.

[0027] Particularly preferably, the method according to the invention provides that at least one part of the surface structure is produced by successive layer-by-layer selective exposure and the concomitant successive layer-by-layer selective solidification of building material layers made of a building material that can be solidified by means of an energy beam, in particular a powdered one. In the manufacturing method according to the invention, a building material, in particular a powdered one, is thus applied layer by layer and subsequently exposed to an energy beam and thereby solidified. The desired surface structure is formed layer by layer through the selective exposure or solidification of the building material.

[0028] According to a preferred embodiment of the method according to the invention, it can be provided that at least one part of the surface structure is subsequently applied to an existing component or that an existing surface structure is supplemented by the at least one part. Accordingly, it is provided that the foaming tool according to the manufacturing method is designed as a hybrid component, wherein the desired surface structure or a part thereof is subsequently applied to the existing component or semi-finished product. It is also possible for the foaming tool to already have a defined surface structure, which is supplemented by the at least one part of the desired surface structure using the additive manufacturing method. Thus, a combination of conventional manufacturing methods and additive manufacturing methods is possible.

[0029] The invention will be explained in more detail below using exemplary embodiments with reference to the drawings. The drawings are schematic representations and show: Fig. 1 a foaming tool according to the invention according to a first embodiment; Fig. 2 the section II-II of the foaming tool according to the invention of Fig. 1 ; Fig. 3 a foaming tool according to the invention according to a second embodiment; and Fig. 4 a foaming tool according to the invention according to a third embodiment.

[0030] Fig. 1 shows a foaming tool 1 for processing foamable or pre-foamed plastic particles. The foaming tool 1 has a region 2 that forms a section of a cavity 3 or delimits the cavity 3. According to the Fig. 1In the first exemplary embodiment shown, the region 2 forming the cavity 3 has a part 4 with a surface structure 5 produced by an additive process. According to this exemplary embodiment, the surface structure 5 is produced by means of laser beam melting, wherein the surface structure 5 is produced by successive layer-by-layer selective exposure and the associated successive layer-by-layer selective solidification of building material layers from a powdery building material that can be solidified by means of an energy beam. Of course, all other additive manufacturing processes can be used to produce the foaming tool 1.

[0031] In the Fig. 1In the embodiment of the foaming tool 1 shown, the surface structure 5 is produced directly together with the production of the remaining foaming tool 1. An alternative separate production of the surface structure is shown, for example, in the second embodiment with reference to Fig. 3 shown.

[0032] The surface structure 5 has a plurality of elevations 6 and a plurality of depressions 7, which are produced by means of the additive manufacturing process. According to the invention, the surface structure 5 has two sub-regions 8, 9, wherein the surface structure 5 is differently developed in the two sub-regions 8, 9. The two sub-regions 8, 9 accordingly have a differently designed surface structure 5.

[0033] In Fig. 2 is the area II-II of Fig. 1Shown enlarged. The surface structure 5 is clearly formed by alternating elevations 6 and depressions 7. Furthermore, it can be seen that the surface structure 5 has near-surface channels 10 through which, for example, a working fluid can be conveyed to control the temperature of a molded part. The near-surface arrangement of the channels 10 is made possible by the use of the additive manufacturing process, although this would not be feasible using conventional manufacturing methods.

[0034] Fig. 3 shows a foaming tool 11 according to a second exemplary embodiment. The foaming tool 11 has a region 12 that forms a portion of a cavity 13. The region 12 has a part 14 with a surface structure 15 produced by an additive manufacturing process. The surface structure 15 also has elevations 6 and depressions 7.

[0035] Part 14 is designed as an insert and inserted into a corresponding recess 16 in the foaming tool 11. Of course, part 14 is detachable and can thus be removed from the foaming tool 11. Thus, various inserts can be accommodated in the recess 16, allowing different surface structures 15 to be introduced into the foaming tool 11 or allowing the part 14 to be replaced.

[0036] Fig. 4 shows a foaming tool 17 according to a third embodiment. The foaming tool 17 has a region 19 forming a section of a cavity 18, which has at least a part 20 of a surface structure 21. The part 20 of the surface structure 21 is produced by an additive process. The foaming tool 17 according to the Fig. 4The illustrated embodiment thus has three sub-regions 22 to 24, wherein the surface structure 21 in the sub-regions 22 and 24 is the same and differs from the part 20 of the surface structure 21 in the sub-region 23. In other words, the surface structure 21 in the sub-regions 22 and 24 differs from the surface structure 21 in the region 24.

[0037] The surface structure 21 in sub-regions 22 and 24 was produced together with the rest of the foaming tool 17 directly during its manufacture. Part 20 of the surface structure 21 in sub-region 23 was subsequently applied using an additive process. In other words, the surface structure 21 was supplemented by sub-region 23.

[0038] Of course, the individual embodiments shown in the individual exemplary embodiments can be combined with one another as desired. In particular, each of the embodiments shown can be provided with channels 10. It is also possible to divide the individual surface structures 5, 15, 21 into sub-regions as desired, or to produce these directly with the individual foaming tools 1, 11, 17 or subsequently and / or separately from them, for example as inserts. LIST OF REFERENCE SYMBOLS

[0039] 1 Foaming tool 2 Area 3 Cavity 4 Part 5 Surface structure 6 Raised portion 7 Recess 8 Sub-area 9 Sub-area 10 Channel 11 Foaming tool 12 Area 13 Cavity 14 Part 15 Surface structure 16 Recess 17 Foaming tool 18 Cavity 19 Area 20 Part 21 Surface structure 22 Sub-area 23 Sub-area 24 Sub-area

Claims

1. Foaming tool (1, 11, 17) for processing foamable plastic particles, having at least one portion of a cavity (3, 13, 18) forming region (2, 12, 19), wherein at least one part (4, 14, 20) of a surface structure (5, 15, 21) of the cavity (3, 13, 18) forming region (2, 12, 19) is produced by an additive method, wherein the surface structure (5, 15, 21) at least one elevation (6) and / or at least one recess (7) in the surface of the foaming tool (1, 11, 17) forms or comprises such, characterized in that the at least one part (4, 14, 20) has at least two sub-areas (8, 9, 22 - 24) with different surface structure (5, 15, 21), wherein the surface structure (5, 15, 21) alternately arranged elevations (6) and recesses (7).

2. Foaming tool according to claim 1, characterized in that the at least one part (4, 14, 20) of the surface structure (5, 15, 21) is produced by laser beam melting and / or binder jetting and / or electron beam melting and / or fused deposition modeling and / or laser metal deposition.

3. Foaming tool according to claim 1 or 2, characterized in that the at least one part (4, 14, 20) of the surface structure (5, 15, 21) is produced by successive layer-by-layer selective exposure and associated successive layer-by-layer selective solidification of building material layers from a solidifiable by means of an energy beam, in particular powdery, building material.

4. Foaming tool according to one of the preceding claims, characterized in that the at least one part (20) is formed as an insertion part which is inserted or insertable into a corresponding recess (16).

5. Foaming tool according to any one of the preceding claims, characterized in that the at least one part (4, 14, 20) of the surface structure (5, 15, 21) is produced directly together with the production of the foaming tool (1, 11, 17) or subsequently.

6. Foaming tool according to one of the preceding claims, characterized in that at least one part (4, 14, 20) of a surface structure (5, 15, 21) of the cavity (3, 13, 18) forming region (2, 12, 19) is formed separately to the foaming tool (1, 11, 17) and is connectable or connected to the region (2, 12, 19).

7. Foaming tool according to one of the preceding claims, characterized in that the at least one part (4, 14, 20) of the surface structure (5, 15, 21) is subsequently applied to an existing component or an existing surface structure (5, 15, 21) is supplemented by the at least one part (4, 14, 20).

8. Foaming tool according to one of the preceding claims, characterized in that at least one information concerning at least a part (4, 14, 20) of the surface structure (5, 15, 21) can be generated by means of CAD or by means of at least one machine parameter.

9. Foaming tool according to any one of the preceding claims, characterized in that the at least one part (4, 14, 20) of the surface structure (5, 15, 21) is post-processed by at least one process step, preferably by an abrasive method and / or laser ablation and / or a chemical or electrical smoothing method and / or a compacting or microforming method.

10. Foaming tool according to any one of the preceding claims, characterized in that the at least one part (4, 14, 20) has a surface structure (5, 15, 21) such that a product produced by means of the foaming tool (1, 11, 17) can be provided with at least one information during production.

11. Method for producing a foaming tool (1, 11, 17) according to any one of the preceding claims, having at least one portion of a cavity (3, 13, 18) forming region (2, 12, 19).

12. Method according to claim 11, characterized in that the at least one part (4, 14, 20) of the surface structure (5, 15, 21) is produced by successive layerwise selective exposure and associated successive layerwise selective solidification of building material layers from a solidifiable by means of an energy beam, in particular powdery, building material.

13. Method of claim 11 or 12, characterized in that the at least one part (4, 14, 20) of the surface structure (5, 15, 21) is subsequently applied to an existing component or an existing surface structure (5, 15, 21) is supplemented by the at least one part (4, 14, 20).