DE102023129227A1 - Method for producing a component having at least one cavity as well as a projectile and manufacturing device for this purpose - Google Patents

Abstract

The invention relates to a method for producing a component having at least one cavity, in which an injection molding material is first introduced into an injection molding cavity (4) of an injection molding tool (5) at at least one material injection point and then a projectile (1) is used to produce the cavity by injecting a Fluids are pressed into the injection molding cavity (4) at a fluid injection point along a displacement path through the injection molding material present in the injection molding cavity (4), so that part of the injection molding material is forced out of the injection molding cavity (4). It is provided that the projectile (1) is asymmetrical with respect to its longitudinal axis (7) which runs through a center of gravity (9) of the projectile (1), and the longitudinal axis (7) is defined by a discontinuity point (12) of the projectile on the side facing away from the fluid injection point Projectile (1) and / or a geometric center of gravity of a front side (11) of the projectile (1). The invention further relates to a projectile (1) and a manufacturing device (2) for producing a component having at least one cavity.

Description

The invention relates to a method for producing a component having at least one cavity, in which an injection molding material is first introduced into an injection molding cavity of an injection molding tool at at least one material injection point and then a projectile is introduced to produce the cavity by injecting a fluid into the injection molding cavity at a fluid injection point along a Displacement path is pressed by the injection molding material present in the injection molding cavity, so that part of the injection molding material is forced out of the injection molding cavity. The invention further relates to a projectile and a manufacturing device for producing the component.

For example, the publication is from the prior art DE 10 2008 215 592 B3 known. This describes a projectile for a casting device for producing hollow cast objects, the casting device comprising a cavity, a filling device for filling flowable casting material into the cavity, a displacement device with which the projectile is used to move into the material filled into the cavity, preferably through This can be driven through, wherein the projectile extends along a projectile longitudinal axis and wherein the projectile has a non-rotationally symmetrical cross section at least in an axial contour portion of its longitudinal extent.

Furthermore, the publication discloses DE 10 2010 015 452 B3 a method for injection molding a molded part that has at least two sections with different outer diameters, wherein a cavity located inside the molded part is created by driving a projectile in the direction of a longitudinal axis of the molded part through the still molten injection moldable material in a conveying direction, for which purpose A pressurized fluid is introduced into the cavity located behind the projectile in the conveying direction, which advances the projectile in the conveying direction. In order to achieve wall thicknesses that are as constant as possible when the external dimensions of the molded part change, it is provided that a projectile is used which has at least one elastic or plastic section which is delimited by a space into which the pressure fluid can enter when the projectile is advanced, whereby the volume of the space can change depending on the fluid pressure, the pressure of the pressure fluid being controlled or regulated so that the space increases and/or decreases so that the effective outer diameter of the projectile assumes a predetermined value over the feed path in the conveying direction.

It is the object of the invention to propose a method for producing a component having at least one cavity, which has advantages over known methods, in particular enabling an injection molding process to be carried out reliably with high process reliability.

This is achieved according to the invention with a method for producing a component having at least one cavity with the features of claim 1. It is provided that the projectile is asymmetrical with respect to its longitudinal axis running through a center of gravity of the projectile and that the longitudinal axis runs through a point of discontinuity of the projectile on the side facing away from the fluid injection point and/or a geometric center of gravity of a front side of the projectile.

Advantageous embodiments with useful developments of the invention are specified in the dependent claims. It should be noted that the exemplary embodiments explained in the description are not restrictive; Rather, any variations of the features disclosed in the description, the claims and the figures can be realized.

The method described is used to produce the component, in particular using a corresponding manufacturing device that is provided and designed to implement the method. Basically, the component is manufactured by injection molding, namely by introducing the injection molding material into the injection molding cavity of the injection molding tool, which is part of the manufacturing device. The injection molding tool is in particular in the form of an injection mold, preferably as a multi-part injection mold, which can be opened or is opened to remove the manufactured component.

The injection molding material is introduced into the injection molding cavity at the at least one material injection point. There can only be a single material injection point or the introduction can take place at several spaced-apart material injection points. If this description refers to the material injection point or at least one material injection point, the statements are always equivalent and can be transferred analogously to several material injection points or to each of these several material injection points.

A thermoplastic is preferably used as the injection molding material. It can also be provided that the injection molding material is a composite material, in particular a fiber composite material. In In this case, the injection molding material has a matrix made of plastic, in particular thermoplastic, as well as reinforcing fibers, for example carbon fibers, glass fibers, aramid fibers, basalt fibers or natural fibers. The injection molding material can have a metallic content to make it electrically conductive.

The component produced should have at least one cavity. There may only be a single cavity or there may be several cavities made in the component. These can be continuously spaced apart from one another or at least partially merge into one another. If we are talking about the cavity or the at least one cavity, the statements are equivalent and can also preferably be transferred to each of the several cavities, if they are present. The cavity is preferably a channel-shaped or tubular cavity and therefore has an elongated shape. The cavity can be designed to specifically adjust the stiffness of the component so that it improves the load-bearing capacity of the component. For example, the component is part of a battery of a motor vehicle, in particular it is in the form of a battery tray, battery tray cover or cooling plate.

In principle, the cavity could be produced during a process downstream of injection molding, for example using a chip-removing process. However, this is complex and also leads to a high demand for injection molding material. For this reason, it is intended to produce the cavity using the projectile during injection molding, i.e. while the injection molding material is in a flowable state in the injection molding cavity. For this purpose, the injection molding material preferably has a temperature which is higher than its glass transition temperature or crystallization temperature.

After the injection molding material has been introduced into the injection molding cavity, the projectile is displaced along the displacement path through the injection molding cavity and therefore through the injection molding material. The displacement path can be straight throughout. However, it is preferably provided that the displacement path has at least one curvature or bend. For example, it is provided that the displacement path is straight in some areas and curved in some areas, in particular a curved region of the displacement path is accommodated between two straight regions of the displacement path or vice versa.

By displacing the projectile, it displaces some of the injection molding material to form the cavity. This part of the injection molding material is forced out of the injection molding cavity by the projectile. For example, it is provided that the injection molding material is displaced as part of a mass push-back, so that it is guided out of the injection molding cavity through the sprue. Here, the projectile is preferably displaced out of the injection molding cavity via the sprue. It is then discharged from a hot runner of the injection molding tool into a cold runner. However, the injection molding material can alternatively be displaced by blowing it out.

The projectile is displaced by injecting the fluid into the injection molding cavity at the fluid injection point. The fluid pushes the projectile away from the fluid injection site and through the injection molding cavity, namely forming the cavity. It can be provided that the projectile remains in the injection molding cavity until the injection molding is completed and is consequently removed from the injection molding cavity together with the component. Alternatively, it is provided to use the fluid to force the projectile through the injection molding material and out of the injection molding cavity, so that after the injection molding has ended, the component is removed from the injection molding cavity or removed from the mold independently of the projectile.

Injection molding is carried out using the so-called projectile injection technology (PIT). More precisely, this is projectile-assisted injection molding, which is also known as projectile assisted injection molding (PAIM). Injection molding is carried out by metering and plasticizing the injection molding material, which is subsequently introduced into the injection molding cavity. In order to achieve reliable shaping of the component and a high level of process reliability, an additional pressing of the injection molding material is preferably provided, namely before the projectile is pressed through the injection molding material. It can also be provided that the injection molding material introduced into the injection molding cavity is first at least partially cooled before the projectile is displaced through it. The projectile consists, for example, of metal, ceramic or a polymer. In any case, a melting temperature of the material used for the projectile is higher than the temperature of the injection molding material with which it comes into contact.

In any case, however, the displacement of the projectile takes place before the component is removed from the mold, i.e. before it is removed from the injection molding cavity, in particular before the injection mold is opened for demolding. The cavity is formed by displacing the projectile through the injection molding material. The use of the projectile has the advantage part that a substantially constant wall thickness results at least along a straight displacement path when using a symmetrical projectile. Known projectiles for such a procedure usually have an outer contour which is symmetrical with respect to their longitudinal central axis. For example, when viewed in cross section, the projectile is continuously round or at least almost round along its longitudinal central axis.

At best, projectiles are known in which, starting from a round cross-section, webs extend in the radial direction outwards, which run in the longitudinal direction of the projectile. The webs therefore protrude in the radial direction over a base body of the projectile and run parallel to the longitudinal central axis of the projectile or of the base body. In this respect, they have their greatest extent in a direction that is aligned parallel to the longitudinal central axis of the projectile.

The projectile, which is completely round in cross-section, can only be used to create round cavities. It ensures a high level of process reliability because, due to its symmetrical design, it does not tilt during displacement through the injection molding material. However, if the projectile has the webs, these serve to form notches in the component. Due to the bars, the center of gravity of the projectile changes. Unless suitable constructive countermeasures are taken on the projectile, the injection molding process must be controlled in such a way that the projectile does not tilt. This results in a reduction in the speed at which the projectile can be pushed through the injection molding material.

In order, on the one hand, to make the shape of the cavity flexible and, on the other hand, to achieve a high level of process reliability, it is provided according to the invention that the projectile has the longitudinal axis, which runs through the center of gravity of the projectile. The projectile is designed asymmetrically with respect to this longitudinal axis. The projectile preferably has a contour that is closed in the circumferential direction and is therefore not interrupted. In particular, there are no notches or the like running in the axial direction with respect to the longitudinal axis on the outside of the projectile. This results in an extremely uniform wall thickness of the manufactured component. Furthermore, the longitudinal axis runs through the point of discontinuity of the projectile and/or the geometric center of gravity of the front of the projectile.

The asymmetrical shape of the projectile means, for example, that when viewed in cross-section it deviates greatly from a round shape, in particular its dimensions in the transverse direction are larger than its dimensions in the vertical direction. Preferably, the dimensions in the transverse direction are larger by a factor of at least 2, at least 3 or at least 4 than its dimensions in the vertical direction. For example, seen in cross-section, on the one hand it is flat across its entire width, while on the other hand - again in cross-section - it is continuously curved. Alternatively, the projectile is polygonal or polygonal in cross section. It preferably deviates from a square, in particular square, shape. For example, it is at least pentagonal or at least hexagonal.

The center of gravity of the projectile is to be understood in particular as a geometric center of gravity of the projectile, in particular in a cross section in which it has its largest dimensions in the radial direction with respect to the longitudinal axis. In this respect, the center of gravity can be the geometric center of gravity of the entire projectile, i.e. the volume center of gravity of the projectile, or alternatively the geometric center of gravity in a cross section of the projectile along its longitudinal axis, i.e. the center of gravity, preferably in a cross section in which the largest across the entire projectile Cross-sectional area or the largest cross-sectional area of the projectile is present.

It can be provided that the longitudinal axis is at least partially off-center in the projectile and accordingly cannot be referred to as the longitudinal central axis. Particularly preferably, the longitudinal axis is arranged parallel to a direction of displacement of the projectile along the displacement path. In other words, the projectile is pressed through the injection molding material in such a way that the longitudinal axis is always parallel to the direction of displacement of the projectile along the displacement path. Preferably, the projectile moves through the injection molding material in such a way that the center of gravity is always on the displacement path. The direction of displacement is to be understood in particular as a tangent of the displacement path in the center of gravity.

The point of discontinuity of the projectile is to be understood as an edge, a corner or a tip of the projectile. The point of discontinuity is not to be interpreted in a mathematical sense but rather in a technical sense. In this respect, it is a point at which several surfaces of the projectile or several edges of the projectile meet. The point of discontinuity of the projectile is preferably on its front side, i.e. on its side facing away from the fluid injection point. In particular, the discontinuity lies keitsstelle at a front end of the projectile, i.e. at the front of the projectile.

Alternatively or additionally, the longitudinal axis runs through the geometric center of gravity of the front of the projectile. The front is understood to mean a front end of the projectile, so the geometric center of gravity is on the side of the projectile facing away from the fluid injection point or at the front of the projectile. In particular, the geometric center of gravity is the geometric center of gravity in a cross section of the projectile on its front side.

During the displacement of the projectile along the displacement path, the point of discontinuity or the center of gravity is located at the front of the projectile, i.e. the injection molding material passes through it first. With the help of the described arrangement of the longitudinal axis, a high longitudinal stability of the projectile is achieved during its displacement through the injection molding material, so that tilting is almost impossible even at high displacement speeds and consequently a high level of process reliability is achieved.

A further development of the invention provides that a projectile is used as a projectile which has a base body and a guide web which projects beyond the base body in the radial direction with respect to the longitudinal axis and which completely surrounds the base body in the circumferential direction. The projectile has the base body and the guide bar. The guide web surrounds the base body completely and continuously in the circumferential direction with respect to the longitudinal axis and extends in the radial direction outwards from the base body, i.e. protrudes beyond the base body in the radial direction.

Preferably, the guide web protrudes evenly over the base body in the radial direction, i.e. has a certain extent in the radial direction throughout the circumferential direction. Accordingly, the guide web has the same shape as the base body, but is designed with larger dimensions in the radial direction. For example, the guide web protrudes beyond the base body in the radial direction by at least 1 mm, at least 2 mm or at least 4 mm. Additionally or alternatively, the projection is a maximum of 8 mm, a maximum of 6 mm or a maximum of 4 mm. In particular, the projection is from 1 mm to 8 mm, from 2 mm to 6 or approximately or exactly 4 mm.

The guide web preferably represents that part of the projectile which is furthest outward in the radial direction and in this respect defines the wall thickness of the component to be produced. The guide web preferably has dimensions in the axial direction which are at least 10%, at least 15% or at least 20% of a total extension of the projectile in the axial direction. Additionally or alternatively, the dimensions of the guide web in the axial direction are at most 30%, at most 25% or at most 20% of the total extension of the projectile in this direction.

The guide web is preferably delimited by a guide surface on its side located on the outside in the radial direction. The guide surface therefore closes the guide web in the radial direction to the outside. The guide surface can run continuously in the circumferential direction, for example it can be continuously curved throughout or it can be straight in sections and continuously curved in sections. However, it can also be provided that the guide surface is composed of several partial surfaces which adjoin one another at an angle in the circumferential direction. This means that two of the partial surfaces meet at an angle that is greater than 0° and less than 180°.

Preferably, the guide surface runs continuously in the circumferential direction in the axial direction parallel to the longitudinal axis, so that the guide web has the shape of a straight cylinder with any base area. However, it can also be provided that the guide surface is angled relative to the longitudinal axis. In this case, an angle of inclination of the guide surface with respect to the longitudinal axis is preferably identical throughout in the circumferential direction. Such a design of the projectile enables particularly reliable guidance during displacement along the displacement path and thus a high level of process reliability.

A further development of the invention provides that a fluid pressure of the injected fluid is adjusted depending on a position of the projectile with respect to the displacement path. For example, it is provided to set the fluid pressure to a specific target pressure, in particular to regulate it to the target pressure. This achieves a uniform movement of the projectile along the displacement path. The fluid pressure is particularly preferably set additionally or alternatively as a function of a geometry of the cavity. Additionally or alternatively, an input variable from the manufacturing device is included in the determination of the fluid pressure. The fluid pressure is particularly preferably adjusted using artificial intelligence, for example using an artificial neural network and/or deep learning. The procedure described once again enables a particularly high level of process reliability.

A further development of the invention provides that the projectile is arranged in the injection molding cavity before the injection molding material is introduced into the injection molding cavity. This means that the projectile is coated with the injection molding material while it is being introduced. After the injection molding material has been introduced, the projectile is already in its starting position at the beginning of the displacement path and can be displaced along the displacement path from there. Alternatively, it is provided that the projectile is only inserted into the injection molding cavity after the injection molding material has been introduced, in particular through a corresponding recess. Both variants enable the cavity to be reliably created using the projectile.

A further development of the invention provides that the projectile is arranged in the injection molding cavity in such a way that a fluid injector of the injection molding tool used to inject the fluid engages in a guide recess of the projectile. Injecting the fluid to displace the projectile along the displacement path is accomplished using the fluid injector. The fluid enters the injection molding cavity through this. In order to achieve reliable alignment of the projectile, it has the guide recess. The projectile is arranged in such a way that the fluid injector is present in the guide recess.

Preferably, the guide recess is designed such that the projectile is supported on the fluid injector in the radial direction. After arranging the fluid injector in the guide recess, the fluid injector rests on the projectile at several points spaced apart from one another in the circumferential direction, so that it is reliably held in a form-fitting manner in the radial direction. For example, two of these points are diametrically opposed to each other.

The guide recess is preferably designed symmetrically with respect to the longitudinal axis, so the longitudinal axis runs centrally through the guide recess. As a result, the projectile is driven by the fluid at its center of gravity, so that, together with the further described design of the projectile, tilting of the projectile is reliably prevented. The procedure described enables reliable alignment of the projectile and thus a high level of process reliability.

A further development of the invention provides that the projectile is inserted into a recess in the injection molding tool that surrounds the fluid injector and is adapted to the shape and/or dimensions of the projectile. The depression is made in a wall of the injection molding tool that delimits the injection molding cavity. The recess encloses the fluid injector, so the fluid injector is arranged in the recess and extends, for example, starting from a bottom of the recess in the direction of a mouth opening of the recess, via which it merges into the injection molding cavity. The fluid injector preferably projects out of the recess into the injection molding cavity.

In order to achieve particularly reliable positioning of the projectile, the projectile is inserted into the recess. Here, the recess is adapted to the projectile, namely adapted to its shape and/or dimensions. This means that, when viewed in cross section, a shape of the depression corresponds to the shape of the projectile. This preferably also applies to the dimensions. The recess is particularly preferably designed in such a way that the projectile inserted into it is held in a form-fitting manner in the radial direction by resting against an edge delimiting the recess. Once again, a particularly reliable positioning of the projectile is achieved.

A further development of the invention provides that, in addition to the cavity, at least one further cavity is produced in the component, in particular by means of a further projectile and/or by injecting the fluid. The production of the multiple cavities in the component has already been pointed out. Both the cavity and the further cavity are part of these several cavities. The cavity and the further cavity can be manufactured in the component at a continuous distance from one another. However, it can also be provided that they merge into one another at least in some areas.

The further cavity is produced, for example, using the further projectile, which is preferably designed analogously to the projectile already explained. It can be provided that the further projectile is identical to the projectile. Alternatively, it has a different shape and/or other dimensions in order to produce cavities of different shapes or dimensions. The further projectile is also preferably pressed through the injection molding material due to the injection of the fluid, namely along a further displacement path which is at least partially spaced from the displacement path. However, it can also be provided that the further cavity is produced solely by injecting the fluid, i.e. without the use of the further projectile. In any case, a flexible shape of the component is implemented.

A further development of the invention provides that at least one insert in the injection molding cavity is encapsulated and/or back-injected with the injection molding material. The insert is inserted into the injection molding cavity before the injection molding material is introduced. The insert preferably consists of a material that is different from the injection molding material. For example, it is made of metal. With the help of the insert, the properties of the component can be specifically adjusted, in particular its rigidity. The insert is preferably pretreated in such a way that the injection molding material forms a better bond with it. For example, a surface of the insert is thermally treated, in particular using a plasma.

The invention further relates to a projectile for producing a component having at least one cavity, in particular for carrying out the method according to the statements in this description, the projectile being intended and designed to be arranged in an injection molding cavity of an injection molding tool, into which at least an injection molding material can be introduced into a material injection point, and to produce the cavity by injecting a fluid into the injection molding cavity at a fluid injection point along a displacement path through the injection molding material present in the injection molding cavity, so that part of the injection molding material is forced out of the injection molding cavity. It is provided that the projectile is asymmetrical with respect to its longitudinal axis running through a center of gravity of the projectile and that the longitudinal axis runs through a point of discontinuity of the projectile on the side facing away from the fluid injection point and/or a geometric center of gravity of a front side of the projectile.

The advantages of such a design of the projectile or such a procedure for producing the component have already been pointed out. Both the projectile and the method for producing the component can be further developed in accordance with the statements in this description, so that reference is made to this in this respect.

A further development of the invention provides that a guide web projects continuously over a base body of the projectile in the radial direction with respect to the longitudinal axis in the circumferential direction. Such a design of the projectile has already been pointed out. The guide web serves to reliably guide the projectile along the displacement path in the radial direction with respect to the longitudinal axis. The guide web protruding beyond the base body serves in particular as a sealing web and prevents excessive flow of the injection molding material past the projectile. This design of the projectile enables the component to be produced with a particularly small wall thickness.

A further development of the invention provides that the guide bar protrudes evenly over the base body. In this respect, the guide web has a constant distance from the base body in the radial direction over the circumference of the base body. This reliably prevents the projectile from tipping.

Finally, the invention relates to a manufacturing device for producing a component having at least one cavity, in particular for carrying out the method according to the statements in this description, the manufacturing device being provided and designed to first introduce an injection molding material into an injection molding cavity of an injection molding tool at at least one material injection point and then to produce the cavity, pushing a projectile by injecting a fluid into the injection molding cavity at a fluid injection point along a displacement path through the injection molding material present in the injection molding cavity, so that a portion of the injection molding material is forced out of the injection molding cavity.

It is provided that the projectile is asymmetrical with respect to its longitudinal axis running through a center of gravity of the projectile and that the longitudinal axis runs through a point of discontinuity of the projectile on the side facing away from the fluid injection point and/or a geometric center of gravity of a front side of the projectile. With regard to the advantages and possible advantageous developments, reference is once again made to the further statements in this description.

The features and combinations of features described in the description, in particular the features and combinations of features described in the following description of the figures and/or shown in the figures, can be used not only in the combination specified in each case, but also in other combinations or on their own, without the scope of to abandon invention. Embodiments which are not explicitly shown or explained in the description and/or the figures, but which emerge from the explained embodiments or can be derived from them are therefore also to be considered to be included in the invention.

• 1 eine schematische erste Darstellung eines Projektils in einer ersten Ausführungsform,
• 2 eine schematische zweite Darstellung des Projektils in der ersten Ausführungsform,
• 3 eine schematische erste Darstellung des Projektils in einer zweiten Ausführungsform,
• 4 eine schematische zweite Darstellung des Projektils in der zweiten Ausführungsform, sowie
• 5 eine schematische dritte Darstellung des Projektils in der zweiten Ausführungsform.

The invention is explained below with reference to the exemplary embodiments shown in the drawing explained in more detail without restricting the invention. This shows:

• 1 a schematic first representation of a projectile in a first embodiment,
• 2 a schematic second representation of the projectile in the first embodiment,
• 3 a schematic first representation of the projectile in a second embodiment,
• 4 a schematic second representation of the projectile in the second embodiment, as well
• 5 a schematic third representation of the projectile in the second embodiment.

The 1 shows a schematic representation of a projectile 1 in a first embodiment, which is used in a manufacturing device 2 for producing a component, not shown. A fluid injector 3 of the manufacturing device 2 is shown, which is used to introduce a fluid into an injection molding cavity 4 of an injection molding tool 5 of the manufacturing device 2, which is only indicated. The manufacturing device 2 is used to produce the component in which a cavity is produced using the projectile 1. For this purpose, an injection molding material is first introduced into the injection molding cavity 4 and the projectile 1 is then pushed along a displacement path through the injection molding material present in the injection molding cavity 4.

Before being displaced along the displacement path, the projectile 1 is arranged in the injection molding cavity 4 in such a way that the fluid injector 3 engages in a guide recess 6 of the projectile 1. The fluid injector 3 and the guide recess 6 are preferably designed such that the fluid injector 3 is held in a form-fitting manner in the radial direction with respect to a longitudinal axis 7. In order to further improve the positioning of the projectile 1, there is a recess 8 in the injection molding tool 5, into which the projectile 1 is inserted before it is displaced along the displacement path.

The projectile 1 has a center of gravity 9, which is present here as a geometric center of gravity in a cross section of a back side 10 of the projectile 1. The center of gravity 9 lies on the side of the projectile 1 facing the fluid injector 3 or in the corresponding cross section with respect to the longitudinal axis 7. The longitudinal axis 7 runs through the center of gravity 9. It runs in a direction in which the projectile 1 has its largest dimensions. In particular, it cuts both the back 10 and a front 11 of the projectile 1.

The longitudinal axis 7 aligned in this way intersects a point of discontinuity 12 of the projectile 1, which is present on its front side 11, i.e. the side of the projectile 1 facing away from the fluid injector 3. In the exemplary embodiment shown, the point of discontinuity 12 is formed by an edge of the projectile 1. For example, the longitudinal axis 7 cuts this edge in the middle. The edge preferably runs parallel to a transverse axis of the projectile 1, in the direction of which the projectile 1 has its second largest dimensions. The transverse axis is perpendicular to the longitudinal axis 7 and also perpendicular to a vertical axis. The projectile 1 has a length in the direction of the longitudinal axis 7, a width in the direction of the transverse axis and a height in the direction of the vertical axis. The length is greater than the width and the height, the width is less than the length and greater than the height, and the height is less than the length and less than the width.

The projectile 1 has a base body 13 and a guide web 14 which projects beyond the base body 13 in the radial direction with respect to the longitudinal axis 7. The guide web 14 is delimited on the outside in the radial direction by a guide surface 15, which is present here as the lateral surface of a straight cylinder. The guide web 14 is preferably arranged on the back 10 of the projectile 1 or forms it. In this respect, the guide surface 15 surrounds the center of gravity 9 in the circumferential direction.

The 2 shows a schematic second representation of the projectile in its first embodiment. It is clear that the projectile 1 has several guide recesses 6 for several fluid injectors 3. The guide recesses 6 both open into a recess 16, which is made on the back 10 of the projectile and accommodates both guide recesses 6. The recess 16 is delimited in the radial direction outwards by an edge 17, which is continuous in the circumferential direction. The edge 17 is formed by the guide web 14; in particular, when viewed in the axial direction, it overlaps the guide surface 15. The arrow 18 indicates a direction of displacement of the projectile 1 along the displacement path already mentioned. The direction of displacement is arranged parallel to the longitudinal axis 7 along the entire displacement path.

The 3 shows a schematic representation of the projectile 1 in a second embodiment and, in some areas, the manufacturing device 2. The second embodiment of the projectile 1 is similar to its first embodiment, so reference is made to the above statements and only the differences are pointed out below. These are mainly in the shape practice of the projectile. While in the first embodiment the guide surface 15 had a continuous or at least largely continuous course in the circumferential direction, the course is now discontinuous. The guide surface 15 is composed of several partial surfaces, with two of these partial surfaces meeting one another at an angle that is greater than 0° and smaller than 180°.

In particular, when viewed overall, the guide web 14 is trapezoidal or at least almost trapezoidal. The point of discontinuity 12 is formed by a tip of the projectile 1, to which the base body 13 of the projectile 1 converges conically. It can be seen that the discontinuity point 12 corresponds to or lies in a geometric center of gravity of the front side 10 of the projectile 1. The longitudinal axis 7 runs through this geometric center of gravity. In the example shown, the longitudinal axis 7 runs both on the back 10 and on the front 11 in a respective cross section through the corresponding geometric center of gravity. At the same time, the longitudinal axis 7 is aligned parallel to the guide surface 15. This achieves particularly reliable guidance with a good seal at the same time.

It can be seen that the projectile is composed of several sections in the direction of the longitudinal axis 7, which are differently shaped. A first area is included in the guide web 14. A second area immediately follows the first area and is polygonal. Its dimensions decrease in the direction away from the guide web 14 in the axial direction. The second area is immediately followed by a third area, which is round in cross section. For example, the third area is conical or conical or - as shown - it is continuously round in cross section and has dimensions in the radial direction that decrease over its extent as the gradient increases.

The 4 again shows a schematic representation of the projectile 1 in its second embodiment. This also applies to the 5

REFERENCE SYMBOL LIST:

1

projectile

2

Manufacturing facility

3

Fluid injector

4

Injection molding cavity

5

Injection molding tool

6

Guide recess

7

Longitudinal axis

8th

deepening

9

main emphasis

10

back

11

front

12

discontinuity point

13

Basic body

14

Guide bridge

15

Guide surface

16

recess

17

edge

18

Arrow

QUOTES INCLUDED IN THE DESCRIPTION

This list of documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102008215592 B3 [0002]
• DE 102010015452 B3 [0003]

Claims (10)

Method for producing a component having at least one cavity, in which an injection molding material is first introduced into an injection molding cavity (4) of an injection molding tool (5) at at least one material injection point and then a projectile (1) is introduced to produce the cavity by injecting a fluid into the injection molding cavity (4) is pressed at a fluid injection point along a displacement path through the injection molding material present in the injection molding cavity (4), so that part of the injection molding material is forced out of the injection molding cavity (4), characterized in that the projectile (1) is displaced with respect to its center of gravity (9) of the projectile (1) running longitudinal axis (7) is asymmetrical and the longitudinal axis (7) through a discontinuity point (12) of the projectile (1) present on the side facing away from the fluid injection point and / or a geometric center of gravity of a front side (11) of the projectile (1). Procedure according to Claim 1 , characterized in that a projectile is used as the projectile (1), which has a base body (13) and a guide web (14) which projects beyond the base body (13) in the radial direction with respect to the longitudinal axis (7) and which supports the base body ( 13) completely surrounds in the circumferential direction. Method according to one of the preceding claims, characterized in that the projectile (1) is arranged in the injection molding cavity (4) in such a way that a fluid injector (3) of the injection molding tool (5) used to inject the fluid into a guide recess (6) of the projectile (1) intervenes. Method according to one of the preceding claims, characterized in that the projectile (1) is inserted into a recess (8) of the injection molding tool (5) which surrounds the fluid injector (3) and is adapted to the shape and/or dimensions of the projectile (1). Method according to one of the preceding claims, characterized in that in addition to the cavity, at least one further cavity is produced in the component. Method according to one of the preceding claims, characterized in that at least one insert part in the injection molding cavity (4) is encapsulated and/or back-injected with the injection molding material. Projectile (1) for producing a component having at least one cavity, in particular for carrying out the method according to one or more of the Claims 1 until 6 , wherein the projectile (1) is intended and designed to be arranged in an injection molding cavity (4) of an injection molding tool (5), into which an injection molding material can be introduced at at least one material injection point, and for producing the cavity by injecting a fluid into it Injection molding cavity (4) at a fluid injection point along a displacement path through the injection molding material present in the injection molding cavity (4), so that part of the injection molding material is forced out of the injection molding cavity (4), characterized in that the projectile (1) with respect to its through a center of gravity (9) of the projectile (1) is asymmetrical and the longitudinal axis (7) is defined by a point of discontinuity (12) of the projectile (1) on the side facing away from the fluid injection point and/or a geometric center of gravity of a front side ( 11) of the projectile (1). Projectile after Claim 7 , characterized in that a guide web (14) projects continuously over a base body (13) of the projectile (1) in the radial direction with respect to the longitudinal axis (7) in the circumferential direction. Projectile according to one of the preceding claims, characterized in that the guide web (14) projects evenly over the base body (13). Manufacturing device (2) for producing a component having at least one cavity, in particular for carrying out the method according to one or more of the Claims 1 until 6 , wherein the manufacturing device (2) is intended and designed to first introduce an injection molding material into an injection molding cavity (4) of an injection molding tool (5) at at least one material injection point and then to produce the cavity a projectile (1) by injecting a fluid into the injection molding cavity (4) at a fluid injection point along a displacement path through the injection molding material present in the injection molding cavity (4), so that part of the injection molding material is forced out of the injection molding cavity (4), characterized in that the projectile (1) is positioned with respect to its center of gravity of the projectile (1) is asymmetrical and the longitudinal axis (7) is defined by a point of discontinuity (12) of the projectile (1) located on the side facing away from the fluid injection point and/or a geometric center of gravity of a front side (11) of the projectile ( 1) runs.

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