Method for producing injection molding element by additive manufacturing

Abstract

A method for producing a three-dimensional object includes specifying reference-object information which describes data of a reference object, determining load information which describes at least one load value in a specific load situation inside the reference object described by the reference-object information, determining load regions having load values that deviate from a reference-load value inside the reference object described by the reference-object information, on the basis of the load information, determining object information which describes geometrically structural data of the object to be produced, on the basis of the load information and of the boundary condition information, and producing the three-dimensional object.

Claims

1. A method for the manufacture of a tool element for an injection molding tool, the method comprising: providing, to a control device, an item of reference object information describing geometrically structural data of a reference object with specified external dimensions; providing, to the control device, at least one item of boundary condition information describing: at least one geometrically structural boundary condition of the tool element; and at least one closed external contour of the tool element; determining an item of load information describing at least one load value in a particular load situation within the reference object described by the reference object information; determining load regions with load values deviating from a reference load value within the reference object described by the reference object information using the load information; determining an item of object information describing geometrically structural data of the tool element based on the load information and the boundary condition information; and manufacturing, with the control device, the tool element based on the object information, wherein the tool element is at least in part additively constructed and comprises: a main body portion comprising: a first region having a solid form of a first density; a second region with mechanical load values deviating from reference mechanical load values, the second region having a lightweight structure of a second density lower in comparison with the first density; and an external form corresponding to the specified external dimensions and the at least one closed external contour of the reference object in at least the first and second regions; and a projecting portion projecting from a face of the main body portion, the projecting portion having a tempering channel structure in a region with thermal load values deviating from reference thermal load values, wherein the tempering channel structure is configured for flowing of a tempering medium therethrough for tempering of the tool element.

2. The method of claim 1, wherein the lightweight structure comprises at least one lightweight construction element and is additively constructed through successive, selective fusing in layers of the fusible construction material by an energy beam generated by a radiation generation device, wherein the at least one lightweight construction element comprises at least one of: a recess; a sandwich structure; a region with a density lower in comparison with other regions of the tool element; a region made of a fusible construction material having a lower density in comparison with another fusible construction material of the tool element; or a region with thinner walls in comparison with other regions of the tool element.

3. The method of claim 1, wherein the tempering channel structure is additively constructed through successive, selective fusing in layers of the fusible construction material by an energy beam generated by a radiation generation device.

4. The method of claim 1, wherein the lightweight structure is formed in a geometrically structural design through an interior of the tool element.

5. The method of claim 1, wherein the boundary condition information describes at least one non-changeable region of the tool element in view of geometrically structural data of the reference object described by the reference object information, and the tool element is manufactured with a region corresponding to the non-changeable region described by the boundary condition information.

6. The method of claim 1, wherein the boundary condition information describes at least one of: a solid external region of the tool element; or a solid internal region of the tool element; wherein the tool element is manufactured with at least one object region corresponding to at least one region described by the boundary condition information.

7. The method of claim 1, wherein the boundary condition information describes at least one connecting region for connecting the tool element to another object.

8. The method of claim 1, wherein the tool element is a pusher element.

9. The method of claim 3, wherein the projecting portion has an additively constructed reinforcing structure in a region corresponding to regions of the reference object deviating from mechanical reference load values.

10. The method of claim 1, wherein the tool element is entirely additively constructed.

11. The method of claim 1, wherein at least one object segment of the tool element is additively constructed on a base object body to form a hybrid object.

Description

(1) The invention is explained in more detail in terms of exemplary embodiments in the figures of the drawing. In the figures:

(2) FIG. 1 shows an illustration of the principle of an apparatus for carrying out a method according to an exemplary embodiment of the invention; and

(3) FIGS. 2-7 show illustrations of the principle of a method step of a method according to one exemplary embodiment of the invention.

(4) FIG. 1 shows an illustration of the principle of an apparatus 1 for carrying out a method according to an exemplary embodiment of the invention. The apparatus 1, and thereby the method that can be carried out with this, is used for the additive manufacture of a three-dimensional object 2, i.e., typically, an engineering component or an engineering component group, through successive, selective fusing in layers of a fusible construction material 3 by means of an energy beam 5 generated by a radiation generation device 4.

(5) The successive, selective fusing in layers of the fusible construction material 3 is done in such a way that the energy beam 5 generated by the radiation generation device 4 is guided by a beam deflection device 6 in a targeted manner to regions, corresponding to particular cross-sectional geometries to be fused, layer-related in each case, of the object 2 to be manufactured, of a layer of construction material formed by means of a coating device 7, movably mounted as suggested by the horizontally aligned arrow, in a construction chamber 8 of the apparatus 1.

(6) The selective fusing in layers of the fusible construction material 3, and accordingly the additive construction of the object 2, here takes place on a supporting device with a carrier mounted movably in a vertical direction. The carrier is, for example, mounted movably relative to the radiation generation device 4.

(7) The energy beam 5 used is electromagnetic radiation, i.e. a laser beam, referred to more briefly as a laser. The radiation generation device 4 used is accordingly a laser generation device for generating a laser beam. The method can accordingly be a selective laser sintering method, known for short as an SLS method, for carrying out selective laser sintering processes for the additive manufacture of three-dimensional objects 2, or a selective laser melting method, known for short as an SLM method, for carrying out selective laser melting processes for the additive manufacture of three-dimensional objects 2.

(8) The fusible construction material 3 used can, for example, be a metal powder (mixture) that is fusible by means of the energy beam 5, i.e. for example an aluminum or steel powder, and/or a plastic powder (mixture) that is fusible by means of the energy beam 5, i.e. for example a polyetheretherketone powder.

(9) In addition to the above-described functional components, i.e. the radiation generation device 4, the beam deflection device 6, and the coating device 7, the apparatus 1 of course comprises further functional components which are not illustratedsince they are not important for the explanation of the principle described hereinwhich are typically necessary or useful for carrying out additive construction processes.

(10) The selective fusing in layers of the fusible construction material 3 takes place on the basis of structural data. The structural data describes, in general, the geometrical, or geometrically structural form of the particular object 2 to be additively manufactured. The structural data is stored in at least one control device (not illustrated) belonging to the apparatus 1, which controls the respective additive construction process or the functional components of the apparatus 1 necessary for the respective additive construction process.

(11) An exemplary embodiment of the method, in which an object 2 in the form of a tool pusher element for an injection molding tool is manufactured, is explained in more detail with reference to FIGS. 2-7.

(12) In the first step of the method, an item of reference object information describing data of a solidly constructed reference object illustrated in FIG. 2, and at least one item of boundary condition information describing an in particular geometrically structural boundary condition of the object 2 actually to be manufactured by means of the method, is prepared or provided. The reference object information describes data of the reference object.

(13) Corresponding data contains a specified geometrically structural design, i.e. in particular a specified external contour, of the reference object. The reference object information accordingly describes the geometrically structural design of the reference object, i.e., in particular, design data, such as CAD data, of the reference object. The geometrically structural design, i.e. in particular also the mass, of the reference object is typically specified with respect to an object-specific field of application or use.

(14) As explained, in addition to the reference object information, an item of boundary condition information is also prepared or specified. The boundary condition information describes a variety of boundary conditions affecting the object 2 to be manufactured. Boundary conditions can be geometrically structural parameters or structural-physical parameters or properties of the object 2 to be manufactured. Particular geometrically structural parameters or particular structural-physical parameters or properties are accordingly specified through the boundary condition information, which should (necessarily) be given at least at one object segment of the object 2 to be manufactured, or at the entire object 2 to be manufactured.

(15) Corresponding boundary conditions define at least one geometrically structural parameter of at least one external (exposed) object segment of the object 2 to be manufactured, such as a surface, a side face, a bottom face etc., and/or at least one internal (not exposed) object segment of the object 2 to be manufactured, or geometrically structural parameters of the entire object 2 to be manufactured.

(16) Corresponding boundary conditions can, alternatively or in addition, define at least one structural or physical parameter of at least one external (exposed) object segment of the object 2 to be manufactured and/or at least one internal (not exposed) object segment of the object 2 to be manufactured or at least one structural or physical parameter of the entire object to be manufactured. Corresponding structural or physical parameters are, in particular, mechanical parameters such as mass, density, hardness, strength or bending strength, stiffness or bending stiffness, elasticity, plasticity (ductility), toughness and/or tribological parameters such as the coefficient of friction, resistance to wear and/or optical-acoustic parameters such as light and/or sound absorption or light and/or sound reflection, and/or thermal parameters such as thermal expansion, thermal conductivity, (specific) heat capacity, high-temperature strength, low-temperature toughness and/or electrical parameters such as electrical conductivity, electrical resistance, of at least one object segment of the object to be manufactured or of the entire object 2 to be manufactured.

(17) The boundary condition information can, for example, describe or define two-dimensional or three-dimensional regions of the object 2 to be manufactured that must not or cannot be changed in view of the geometrically structural data of the reference object described by the reference object information. The object 2 is then manufactured with regions corresponding to the non-changeable regions described by the boundary condition information.

(18) The boundary condition information can, for example, describe or define a closed external contour of the object 2 to be manufactured. The object 2 is then manufactured with a closed external contour corresponding to the closed external contour described by the boundary condition information.

(19) The boundary condition information can, furthermore, describe or define for example external and/or internal regions, which are to have solid form, of the object 2 to be manufactured. The object 2 is then manufactured external and/or internal regions that are to have solid form, corresponding to the external and/or internal regions that are to have solid form described by the boundary condition information.

(20) The boundary condition information can, furthermore, describe or define at least one object-specific functional region or element in view of a use as intended of the object 2 to be manufactured, for example a connecting region or a connecting element for connecting the object 2 to a further object. The object 2 is then manufactured with a functional region or functional element corresponding to the at least one functional region or functional element described by the boundary condition information.

(21) In the exemplary embodiment explained with reference to FIGS. 2-7, it is in particular described or defined by the boundary condition information that (i) a front tip 9 (shown in FIG. 2 at the corresponding object segments of the reference object) of the object 2 must be formed cohesively at least with the object segments 10, 11, (ii) the geometrically structural design of the object segment 11 must be retained, (iii) the (exposed) external faces of the object 2 must be closed, and (iv) the object 2 must not be shortened in its geometrically structural design in comparison with the reference object. It is furthermore defined through the boundary condition information that (v) the object 2 should be manufactured in such a way that mechanical loads acting on it when used as intended are absorbed, in particular as compressive loads, (vi) the region of the tip 9 of the object 2 must be provided with a tempering channel structure close to its contour, and (vii) all the object segments not necessary for the tempering of the object 2, in particular holes, may be removed.

(22) In a second step of the method that follows the first step, an item of load information describing at least one load value in at least one particular load situation within the reference object described by the reference object information is determined (cf. FIG. 3).

(23) The load information describes load values which at least one reference object segment, or the entire reference object, experiences in particular load situations, and thus the behavior (load behavior) of at least one reference object segment or of the entire reference object in particular load situations. In corresponding load situations this involves, for example, load scenarios in accordance with intended use of the object 2 to be manufactured, i.e. load situations to which the object 2 to be manufactured is typically exposed when used as intended.

(24) The load information can, in general, describe a mechanical and/or a climatic and/or a fluidic and/or a thermal load situation, in particular when the object 2 to be manufactured is used as intended. The load information is prepared through suitable algorithms, for example by means of a computer-based simulation, e.g. an FEM simulation. In other words, the load information contains data of a simulation, e.g. an FEM simulation, cf. FIG. 3.

(25) It can be seen from FIG. 3 that only a small proportion of the reference object is mechanically loaded under the given mechanical load situation. It can therefore be estimated with reference to FIG. 3 that a comparatively high potential for the reduction of construction material, and thus a comparatively high potential for the reduction of the weight of the object 2, is possible.

(26) In a third step of the method following the second step, load regions with load values deviating from a specifiable or specified reference load value within the reference object are determined using the load information or in the load information. The load values determined in the second step of the method within the reference object in the load situation under consideration in each case are accordingly compared individually, in groups, or as a whole with at least one reference load value. It is thus determined through matching or comparison whether corresponding load values within the reference object are located above or below a corresponding reference load value. A reference load value can refer to an upper and/or lower load limit value. Upper or lower load limit values are typically defined through object-specific, and in particular material-specific, characteristic parameters.

(27) The determination of corresponding load regions with load values deviating from a reference load value within the reference object with reference to the load information or in the load information is performed using suitable algorithms, for example by means of a computer-based simulation, e.g. an FEM simulation.

(28) An FEM simulation of the of the geometrically structural design of the reference object after an adjustment of it to the load situation is shown in FIG. 4. The different hatchings show different loads. A corresponding CAD model is shown in FIG. 5. It can be seen that the geometrically structural design of the reference object has been changed significantly in comparison with that shown in FIG. 2. Although it is true that a significant reduction in weight or material is possible in this way, the above-mentioned boundary conditions are not, however, fulfilled.

(29) In a fourth step of the method following the third step, an object information describing geometrically structural data of the the object 2 to be manufactured is determined on the basis of the load information and of the boundary condition information. Corresponding geometrically structural data contains the geometrically structural design of the object 2 to be manufactured, cf. FIG. 6. The boundary conditions described or defined by the boundary condition information are incorporated in the geometrically structural design of the object 2 to be manufactured. The load values described by the load information are, equally, incorporated in the object information.

(30) It can be seen in FIG. 6 that the object information describes design data, e.g. CAD data, of the object 2 to be manufactured. This design data is converted into the geometrically structural form, i.e. in particular the layer-related cross-sectional geometries, of the structural data describing the object 2 to be manufactured.

(31) It can further be seen in FIG. 6 that in those regions of the object 2 to be manufactured that correspond to the load regions of the reference object in which load values deviate from corresponding reference load values, particular additively constructed external and/or internal structures are formed, which handle the respective deviation of the respective load values from corresponding reference load values.

(32) In a fifth step of the method following the fourth step, the object 2 is manufactured on the basis of the object information. The object 2 is here, at least in those load regions with load values deviating from the reference load value, additively manufactured through successive, selective fusing in layers of a fusible construction material. In the exemplary embodiment, the entire object 2 is additively constructed.

(33) In load regions with load values deviating from the reference load value, the object 2 is manufactured with an additively constructed lightweight structure 12 comprising at least one lightweight construction element. Through the specific additive construction of the lightweight structure 12, the object 2 is specifically manufactured, in regions which correspond to corresponding load regions of the reference object which exceed or fall short of particular reference load values, with additively constructed structures which bring about a reduction in weight or material through a (local) reduction in density. The lightweight structure 12 is formed in regions of the object 2 that are subject to very little mechanical stress. A recess, a sandwich structure, a region with a density that is lower in comparison with other regions of the manufactured object 2, a region made of a fusible construction material 3 having a lower density in comparison with another fusible construction material 3 of the manufactured object 2, or a region with thinner walls in comparison with other regions of the manufactured object 2 can, for example, be formed as the lightweight construction element of an appropriate lightweight structure 12.

(34) In load regions with load values deviating from the reference load value, the object 2 is manufactured with an additively constructed tempering channel structure (not illustrated), through which a tempering medium for tempering the manufactured object 2 can flow. Through the specific additive construction of suitable tempering channel structures, the object 2 can be specifically manufactured, in regions which correspond to corresponding (thermal) load regions of the reference object which fall short of or exceed particular (thermal) reference load values, with additively constructed structures which, when a tempering medium flows through them, bring about a tempering of the object 2. Tempering channel structures are typically formed in thermally stressed regions of the object 2. A targeted tempering, i.e. cooling or heating, of the object 2 can be achieved through suitable tempering channel structures.

(35) In load regions with load values deviating from the reference load value, the object 2 is manufactured with a reinforcing structure 13 comprising at least one additively constructed reinforcing element. Through the targeted additive construction of the reinforcing structure 1, the object 2 can be manufactured in a targeted manner, in regions which correspond to corresponding (mechanical) load regions of the reference object which fall short of exceed particular (mechanical) reference load values, with additively constructed structures which bring about an increase in the mechanical strength of the object 2 through a (local) reinforcement. A ribbed element can, for example, be formed as a reinforcing construction element, cf. FIG. 6. The reinforcing structure 12 can be formed three-dimensional longitudinal and/or transverse ribbing.

(36) In load regions with load values deviating from the reference load value, the object 2 can be manufactured with an additively constructed bionic structure (not illustrated) that comprises at least one bionic element which describes at least one biological, in particular animal and/or vegetable structure, and/or is derived from at least one biological, in particular animal and/or vegetable structure. An animal structure, wherein external and/or internal animal structures and/or animal-generated structures are used as animal structures, and/or a vegetable structure, wherein external and/or internal vegetable structures and/or vegetables-generated structures are used as vegetable structures can be formed as the bionic element.

(37) Additively formed structures, i.e. in particular lightweight structures 12 and/or tempering channel structures and/or reinforcing structures 13 and/or bionic structures can extend in two or three dimensions, in the form of a network in some cases, through the object 2. Suitable additively formed structures can extend (only) through the interior of the object 2, so that they are not visible from the outside. Suitable structures can, in addition to their respective original function, of course also affect (further) physical properties of the object 2. This can, for example, be found in the case of a potentially three-dimensional ribbed structure inside the object 2, which on the one hand (in comparison to a solid formation) entails a reduction in material, and on the other hand entails a mechanical reinforcement of the object 2.

(38) The method allows the object 2 to be manufactured, in particular with regard to particular load situations of the object 2, in a targeted, additive manner, i.e. in particular with additively constructed structures. The construction the object 2 is based on the prior determination of specific load regions in the reference object which, as described, are evaluated with respect to particular reference load values, i.e. are compared with corresponding reference load values. In this way it is possiblewith reference to a specific load situationfor regions to be determined which are formed in a particular manner with a view to the specific load situation, i.e. for example with particular structures, i.e. in particular in an optimized manner. This can, as explained, refer, for example, to a formation of mechanical reinforcing structures and/or a formation of mechanical weakening structures, i.e. for example structures that save weight or material, and/or a formation of tempering channel structures, etc.

(39) The object 2 is thus optimized with a view to a particular application situation or a particular load situation, which significantly improves the structural properties of the object 2 from various points of view, e.g. mechanical stability, weight etc. It is here, in particular, possible for an appropriate optimization to take place only in the interior of the object 2. The external dimensions, or the external contour, i.e. (to a large extent) the external shape of the object 2 can be retained (as compared with the reference object).

(40) A further advantage of the method is that the objects 2 to be manufactured according to the method can be entirely additively constructed. In particular with a view to the manufacture of engineering objects, i.e. for example tool elements for injection molding tools, such as for example tool insert elements, pusher elements etc., which until now have comprised a base object body to be held ready in a store, which in future are provided with at least one object segment formed additively on the base object body (hybrid object), storage space, storage time, storage work etc. can be saved through the direct, additive manufacture of the object 2.

(41) Finally, FIG. 7 shows an illustration of an FEM simulation of the object 2 that has been manufactured or is to be manufactured on the basis of the object information. The different hatchings show different loads. It can be seen that a support structure of the object 2 is loaded in a similar manner to that illustrated in FIG. 4. The lightweight structure 12 is to a large extent unloaded. The lightweight structure 12 is, however, appropriate for accepting particular loads that arise during operation of the object 2, for example when clamping the object 2 into a clamp.

(42) With the exemplary embodiment explained with reference to FIGS. 2-7, the weight of the object 2 can be reduced by more than 50% with the same geometrically structural design and the same functionality as compared with the (solid) reference object. A further reduction in the weight of the object 2 could be achieved by adjusting particular boundary conditions.

LIST OF REFERENCE SIGNS

(43) 1 Apparatus 2 Object 3 Construction material 4 Radiation generation device 5 Energy beam 6 Beam deflection device 7 Coating device 8 Construction chamber 9 Tip 10 Object segment 11 Object segment 12 Lightweight structure 13 Reinforcing structure