Method and apparatus for manufacturing a cartridge case

Abstract

The present invention provides a method for manufacturing a cartridge case by joining its components. The method comprises: providing a base and a case made of the same or different materials; aligning the base and the case in a device using positioning aids; providing a gap between the base and the case; enclosing the area to be joined with an annular field former; passing a current through the field former to induce currents in at least a first electrically conductive component, thereby generating a Lorentz force; accelerating the first component from the field former towards the second component, forming a material-bonded connection between the components.

Description

[0001] The present invention relates to a method for manufacturing a cartridge case according to independent claim 1. Preferred embodiments are specified in the description and the dependent claims.

[0002] Traditionally, cartridge cases are manufactured by mechanically forming a single piece of metal made of brass, steel, or other alloys. This process requires numerous forming, annealing, and cleaning steps, which is time-consuming, space-consuming, and expensive.

[0003] The present invention differs from known methods in particular in that the cartridge case is manufactured from two separate components – a base and a sleeve – by means of kinetic acceleration towards each other and the resulting metallurgical bond formed upon contact of the components. In contrast to conventional welding processes, this enables the joining of different materials without significant heat input.

[0004] The method described in US10866073B2 for manufacturing multi-part sleeves uses thin sheets that are formed over a die. The present invention differs from this method in the use of prefabricated components and the metallurgical bond achieved by accelerating one component onto another.

[0005] In contrast to the electrical resistance welding using a roller electrode described in GB113601A, the present invention uses the Lorentz force generated by, for example, a magnetic pulse to create a material-bonded connection, in particular without heat input.

[0006] The present invention thus offers a simplified manufacturing process for cartridge cases that enables the combination of different materials and creates a high-strength bond without impairing the material properties.

[0007] According to one aspect of the present invention, a method for manufacturing a cartridge case by joining its components is provided. The method can include providing two components, in particular a base and a case. The base and the case can be made of the same or different materials. The method can further include aligning the base and the case in a device using positioning aids. A gap can be provided between the base and the case. The area to be joined can be enclosed by an annular field former. The method can further include passing a high current through the field former to induce high currents in a first electrically conductive component, i.e., the case or the base, thereby generating a Lorentz force.This allows the first component to be accelerated away from the field former towards the second component, thereby forming a material-locking / substance-locking connection between the components.

[0008] According to a further aspect of the present invention, the base and the case can be made of different materials, selected from the group comprising steel, brass, titanium, aluminum, and other non-ferrous alloys. This can allow for optimization of the material properties for different areas of the cartridge case, such as hardness at the base and ductility at the case mouth. The component to be accelerated should be selected such that a Lorentz force can be exerted on it by the rifling.

[0009] According to another aspect of the present disclosure, the base and the sleeve can be prefabricated using different manufacturing processes. This can enable flexible manufacturing, whereby, for example, the base can be produced by machining and / or the sleeve by deep drawing.

[0010] According to another aspect of the present disclosure, the positioning aids may comprise a plastic holder or a gripper on a robot arm. Alternative positioning aids may be mechanical clamping devices or magnetic holders.

[0011] According to another aspect of the present disclosure, the current frequency and current intensity used in the magnetic pulse method can be approximately 15 kHz and 250 kA. These parameters can be adjusted depending on the material and geometry of the components to be joined, with the frequency ranging from 1 to 100 kHz and the current intensity ranging from 10 to 1000 kA.

[0012] According to another aspect of the present disclosure, the gap between the base piece and the sleeve can be created by the geometry and orientation of the components relative to each other. Alternatively, the gap can be created by additional spacers or adjustable positioning elements in the device.

[0013] According to another aspect of the present disclosure, the process may further include applying a coating to at least one of the components, base piece or sleeve, before or after the joining process to improve corrosion protection. The coating may consist of various materials, such as nickel, chromium, polymers, or oxide layers.

[0014] According to another aspect of the present disclosure, a device for manufacturing a cartridge case is provided. The device may include a feature that can be configured to align a base and a case within one another at a radial distance. The device may further include positioning aids that can be configured to assist in aligning the base and the case within the device. An annular field former may be included in the device, which may be configured to enclose an area to be joined. The device may further include, or be connected to, a power source that can be configured to conduct a current through the field former. A control unit may be included in the device, which can be configured to control the joining process for joining the base and the case to form a material joint.

[0015] According to a further aspect of the present invention, the positioning aids can comprise at least one (plastic) holder, a clamping device, or a gripper on a robot arm. Alternative positioning aids can be optical sensors or laser systems for the precise alignment of the components.

[0016] According to another aspect of the present disclosure, the current source can be configured to generate a current with a frequency of approximately 15 kHz and a current intensity of approximately 250 kA. The current source can be adapted to generate different frequencies and current intensities, depending on the specific requirements of the materials to be joined.

[0017] According to another aspect of the present disclosure, the device may further comprise a coating application unit which may be configured to apply a coating to at least one of the parts, base piece or sleeve, before or after the joining process. The coating application unit may employ various coating technologies, such as spray coating, electroplating, or plasma deposition. Fig. Figure 1 shows a sectional view of a cartridge case assembly and an electromagnetic field former, according to aspects of the present invention.

[0018] The present invention relates to a method for manufacturing cartridge cases by metallurgical bonding of separate components. This method can offer a multitude of advantages, particularly with regard to the flexibility of material selection and the quality of the resulting bond.

[0019] In some embodiments, the method may involve the use of two components, in particular a base and a case, which may be made of the same or different materials. This flexibility in material selection can make it possible to optimize the material properties for different areas of the cartridge case, such as hardness at the base and ductility at the case mouth.

[0020] In some embodiments, the method may involve aligning the base piece and the sleeve in a fixture using positioning aids. This can enable precise alignment of the components, resulting in a high-quality connection.

[0021] In some embodiments, the method may involve passing a current through an annular field former to induce (high) currents in a first electrically conductive component. This can generate a Lorentz force that accelerates the first component away from the field former towards the second component, potentially forming a material-bonded connection between the components.

[0022] In some embodiments, the method may further include applying a coating to at least one of the components, base piece or sleeve, before or after the joining process to improve corrosion protection.

[0023] Overall, the presented method for manufacturing cartridge cases or parts thereof using the method according to the invention can offer improved flexibility in material selection, high quality of the resulting compound and improved corrosion resistance.

[0024] With reference to Fig. Figure 1 shows a sectional view of a cartridge case assembly and an (electro)magnetic field former. The assembly comprises a base piece 1 and a sleeve 2, positioned for connection. An annular field former 3 is shown, enclosing the area where the base piece 1 and the sleeve 2 are to be joined.

[0025] In some embodiments, the base piece 1 and the sleeve 2 can be made of the same or different materials. For example, the base piece 1 can be made of steel and the sleeve 2 of brass, titanium, aluminum, or other non-ferrous alloys. In other embodiments, both the base piece 1 and the sleeve 2 can be made of the same material, for example, steel or brass.

[0026] The base piece 1 and the sleeve 2 can be aligned in a device using positioning aids. These positioning aids can include, for example, a plastic holder or a gripper on a robot arm. In some embodiments, the device can be configured to hold the base piece 1 and the sleeve 2 in a specific orientation to ensure an optimal connection.

[0027] A gap can be provided between the base piece 1 and the sleeve 2. This gap can serve as an acceleration path for the joining process between the base piece 1 and the sleeve 2, which promotes a particularly durable connection of the components. In some embodiments, the gap can be created by the geometry and orientation of the base piece 1 and the sleeve 2 relative to each other. In other embodiments, the gap can be created by additional spacers or adjustable positioning elements in the device.

[0028] With reference to Fig. Section 1 further describes the method. The annular field former 3 can be configured to enclose a region of the cartridge case parts that are to be joined. In some embodiments, the field former 3 can conduct a (high) current to induce high currents in a first electrically conductive component. This is intended to generate a Lorentz force that accelerates the first component away from the field former 3 towards the second component, thereby forming a material-locked / compound bond between the components.

[0029] In some embodiments, the first component can be the base piece 1 or the sleeve 2. The choice of which component is accelerated may depend on the specific material properties and the requirements of the connection. For example, in some cases the base piece 1 can be accelerated if it is made of a material with high electrical conductivity and ductility, while in other cases the sleeve 2 can be accelerated.

[0030] In principle, it is also conceivable that both components are accelerated towards each other. The use of a second field former can be advantageous in this case, with the cartridge case components being positioned between the first and second field formers.

[0031] In some embodiments, the inner part, for example the bottom piece 1 ( Fig.1) be supported by a mandrel to prevent unwanted deformation. This can be particularly important if the base piece 1 or the sleeve 2 is made of a soft or ductile material that could easily deform during the joining process.

[0032] In some embodiments, the device for manufacturing a cartridge case may include a feature configured to align the base piece 1 and the case 2 at a radial distance from each other. This can enable precise alignment of the components, resulting in a high-quality and stable connection. The device may further include positioning aids configured to assist in aligning the base piece 1 and the case 2 within the device. These positioning aids may, for example, include a plastic holder or a gripper on a robot arm. In other embodiments, the positioning aids may be mechanical clamping devices or magnetic holders.

[0033] The acceleration of the first component can be adjusted to such a high degree that the oxide layer on both the first and second components is removed. This enables a metallurgical bond between the components within a very short time, for example, approximately 25 µs. In some embodiments, the resulting joint can be annular and have a width of a few millimeters. The width of the joint can be increased as required, particularly by adjusting the field dimensions and / or the degree of overlap of the sleeve parts to be joined.

[0034] In some embodiments, the cartridge case, due to the kinetic energy of the case part(s) being discharged during the joining process, does not experience a significant temperature increase and can be removed from the device. Therefore, no thermally induced changes in the material properties occur during this process, as the microstructure is essentially unaffected.

[0035] In some embodiments, the current frequency used in the inventive method can be in the range of 15 kHz and the current intensity can be in the range of 250 kA. In other embodiments, the current frequency and the current intensity can be adjusted depending on the material and geometry of the components to be joined. For example, the frequency can be between 1 and 100 kHz and the current intensity between 10 and 1000 kA, and is selected depending on the materials and the wall thickness of the cartridge case parts so that the accelerating Lorentz force provides a metallurgical bond. As a guideline, a velocity of approximately 200 m / s for the accelerating part at the moment of impact on the other component can be assumed. However, it should be noted that the velocity required for a metallurgical bond can be material-dependent.The speed information provided should therefore be understood as an illustration of the expected order of magnitude or guideline value and does not constitute a fixed value.

[0036] It should be noted that the descriptions in this text are merely exemplary and are not to be understood as limiting. All features from all embodiments can be interchanged or combined with one another, and each feature of each embodiment is disclosed independently of all other features of each individual embodiment.

[0037] In some embodiments, the device for manufacturing a cartridge case may include or be connected to a power source configured to conduct a (high) current through the field former 3. The power source may be capable of generating a current with a frequency of approximately 15 kHz and a current of approximately 250 kA. In other embodiments, the power source may be adjustable to generate different frequencies and currents, depending on the specific requirements of the materials to be joined. For example, the frequency may range from 1 to 100 kHz and the current from 10 to 1000 kA.

[0038] The device may further include a control unit configured to control the joining process for connecting the base piece 1 and the sleeve 2 to form a material joint. The control unit may be capable of controlling the current flow through the field former 3, monitoring and, if necessary, adjusting the positioning of the components, and monitoring and controlling the joining process as a whole.

[0039] The positioning aids can include a plastic holder or a gripper on a robot arm. These can serve to precisely align the base piece 1 and the sleeve 2 in the device and to hold them in position during the joining process. In other embodiments, the positioning aids can be mechanical clamping devices or magnetic holders.

[0040] The sleeve 2 advantageously has good electrical conductivity. This can help ensure that the currents induced by the field former 3 flow effectively in the sleeve 2 and generate a sufficient Lorentz force to accelerate the sleeve 2 towards the base piece 1.

[0041] The resulting joint can be ring-shaped and several millimeters wide. This can help to create a robust and tight connection between the base piece 1 and the sleeve 2. In other embodiments, the width of the joint can be adjusted, for example, by adjusting the dimensions of the field former 3 or the overlap of the parts to be joined.

[0042] In some embodiments, the base 1 and the sleeve 2 can be prefabricated before being positioned and joined in the device. This prefabrication can be achieved using various manufacturing processes. For example, the base 1 can be machined and the sleeve 2 deep-drawn. In other embodiments, the base 1 and the sleeve 2 can be manufactured using other suitable methods, such as casting, forging, or extrusion. The choice of manufacturing method may depend on the specific requirements for the components and the materials used.

[0043] In some embodiments, the method may include applying a coating to at least one of the components, base piece 1 or sleeve 2, before or after the joining process to improve corrosion protection. The coating may consist of various materials, such as nickel, chromium, polymers, or oxide layers. In other embodiments, the coating may also consist of other suitable materials that provide good corrosion protection. The coating may be applied, for example, by spray coating, electroplating, or plasma deposition. In some cases, the coating may also be applied by other suitable methods, such as dip coating or electrochemical deposition.

[0044] The device for manufacturing a cartridge case may, in some embodiments, include a coating application unit configured to apply a coating to at least one of the parts, base piece 1 or case 2, before or after the joining process. The coating application unit may employ various coating technologies, such as spray coating, electroplating, or plasma deposition. In other embodiments, the coating application unit may also employ other suitable coating technologies, such as dip coating or electrochemical deposition. The coating application unit may be configured to apply the coating uniformly and to a controlled thickness to the components to ensure optimal corrosion protection. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] US 10866073B2

[0004] GB 113601A

[0005]

Claims

[1] A method for manufacturing a cartridge case by combining its components, the method comprising: Providing two components, a base and a sleeve, wherein the base and the sleeve are made of the same or different materials; Aligning the base and sleeve in a device using positioning aids; Providing a gap between the base piece and the sleeve; Enclosing the area to be joined with a ring-shaped field former; Passing a current through the field shaper to induce currents in at least one first electrically conductive component, i.e., the sleeve and / or the base piece, thereby generating a Lorentz force. Acceleration of the first component from the field former towards the second component, forming a material-bonded connection between the components. [2] The method according to claim 1, wherein the base and the sleeve are made of different materials selected from the group comprising steel, brass, titanium, aluminium and other non-ferrous alloys. [3] The method according to claim 1 or 2, wherein the base and the sleeve are prefabricated using different manufacturing processes. [4] The method according to any one of claims 1 to 3, wherein the positioning aids comprise a plastic holder or a gripper on a robot arm. [5] The method according to any one of claims 1 to 4, wherein the gap between the base piece and the sleeve is created by the geometry and orientation of the components relative to each other. [6] The method according to any one of claims 1 to 5, further comprising the application of a coating to at least one of the components, base piece or sleeve, before or after the joining process to improve corrosion protection. [7] A device for manufacturing a cartridge case, the device comprising: a device configured to align a base piece and a sleeve within each other at a radial distance; Positioning aids configured to assist in aligning the base and sleeve in the device; a ring-shaped field former configured to enclose an area to be connected; a power source configured to conduct a high current through the field shaper; and a control unit that is configured to control the joining process to connect the base piece and the sleeve to form a material connection. [8] The device according to claim 7, wherein the positioning aids comprise at least a plastic holder, a clamping device or a gripper on a robot arm. [9] The device according to one of claims 7 or 8, wherein the power source is configured to generate a current with a frequency of approximately 15 kHz and a current strength of approximately 250 kA. [10] The device according to any one of claims 7 to 9, further comprising a coating application unit configured to apply a coating to at least one of the parts, base piece or sleeve, before or after the joining process.

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