Patent Application
20220355370
The present invention is in the field of mechanical engineering and foundry technology and general process engineering and can be used with particular advantage in series production.
It has long been known to produce components by casting in lost molds which can be removed after the casting process. Such components are also mass-produced in which the same or similar lost casting molds are mass-produced and used on the basis of models.
It is also already known to automatically produce lost casting molds in series, said lost casting molds being subsequently reused in an automatic casting process in series production of components/castings. The molds can be crushed and reused after their destruction.
Against the background of the prior art, the present invention is based on the object of creating a device and a method of the type mentioned at the beginning, with which the cost of manufacturing components can be reduced even further, wherein the flexibility in the selection of the shapes of components that can be produced should at least remain the same if not increased.
The object is achieved by means of the features of the invention by a device for producing components comprising a mold building device for producing lost casting molds and a casting device connected to the mold building device for casting components in the lost casting molds, in which the mold building device is suitable for the continuous layering of molding plates, wherein a respective at least three of said molding plates form a casting mold.
The mold building device in this case is basically suitable for producing parts of lost casting molds using a basic molding material. The casting molds in this case are composed of layered molding plates that can be produced individually within the mold building device or in an upstream facility and joined together into layer stacks in the mold building device. At least three such molding plates each form a casting mold. Complicated casting molds can also be assembled by using more than two molding plates, wherein each of the molding plates can have a simple design. Curved inner contours of the cavities in the casting molds can, for example, be assembled in stages. However, the molds within the individual molding plates can also be inclined or curved. Contours of the individual molding plates preferably run such that they can each be designed without undercuts.
After their production, the individual molding plates can, for example, be deburred or ground in order to ensure that different molding plates can be assembled without gaps. More than three molding plates, for example, at least five or ten molding plates, can also be used for a casting mold.
The molding plates can be produced within the mold building device or a separate facility using the basic molding materials sand, bauxite, chrome ore, ciphalite, artificial mullite, hollow spheres, expanded glass, ores, ceramic powder, artificial sand, metal particles, iron filings, copper filings, aluminum particles, steel particles or mixtures of said materials. Molding material binders can be used to hold the parts/particles of a single molding plate together. The following substances are suitable therefor: bentonite, binder clay, as chemical binders: inorganic water glass, furan resins, phenolic resins, cold box polyurethanes, acrylate binders, epoxy resins, polyester, polyvinyl, polyhydric alcohols, soluble polymer binders; in addition: salts, salt binders, cyanoacrylates, cellulose, acetate, sugar dextrose, cements, phosphate cement, gypsum, hemihydrates, quicklime, alginates, silicones, ethyl silicates, linseed oil binders, core oils, starch binders, coning sand binders, resols, novolaks, geopolymer binders.
In order to produce solid molding plates, the basic molding materials are mixed with the molding material binders and then solidified. The shaping can be done, for example, by blowing in, sieving, scattering, 3D printing with simultaneous structuring. A cuboid, cylindrical, prismatic or other shaped molding box can be used for shaping, wherein positive-locking elements for aligning different molding plates can be attached to one another during molding at the same time as the cavities of the casting mold.
The plates can be compacted by pressing, rolling, hydraulic or pressure hammering and hardened by heat, chemical reactions, radiation, gassing or the application of compressive force.
After the above treatments, the molding plates can be finished or generally filled with an additional material. The plates can be milled flat or ground and cooling irons can be inserted into the molding plates.
The individual molding plates can be structured using a variety of known processing methods, for example, suction, scratching, punching, fine blanking, embossing, milling, sawing, eroding, targeted local burning of the binder, core shooting, shaping using a tool, ultrasonic contouring, grinding, loosening by chemical solvents, drilling, debinding (by breaking the bond), 3D printing, wherein the processing can be single-sided, double-sided and each with or without undercuts.
The prefabricated molding plates are joined together into a layer stack within the mold building device. The individual layers/molding plates follow one another in a stacking direction in the joined-together stack. The stacking direction in this case can be arranged horizontally, so that the individual molded plates are arranged next to one another on a base. To form a stack, the molding plate to be added can be pushed against the already existing stack in the stacking direction. A molding plate can also be pushed into its position perpendicular to the stacking direction. The stacking direction in this case can run horizontally or vertically. It is also possible for a plurality of molding plates to be joined together outside the mold building device and inserted into a stack or a layer sequence inside the mold building device. Different molding plates can also be pushed into the stack from different directions within the mold building device. This can be useful, for example, if molding plates are manufactured at different points within the mold building device or are made available for joining together.
In principle, the individual molding plates can be moved within the mold building device by hydraulic or pneumatic slides or by electric slides. A drivable base can also be provided, on which the molding plates rest and are moved at least temporarily. Gravity can also cause molding plates to slip into their intended position on inclined planes.
Stacking of molding plates is thus possible within the mold building device, wherein at least three molding plates are brought together to form a layer stack. The stacking direction can be changed at times, so that a horizontal layer stack can adjoin a vertical layer stack.
Various molding plates are joined together within the individual layer stack, wherein at least two end plates are provided in each case, at which end plates the cavity of the respective casting mold to be shaped ends.
In addition, different casting molds can be produced in such a mold building device, in which different layer stacks are produced using respectively different sets of molding plates. Such a change of casting molds in continuous production is possible with extremely little effort, as only a single or a few molding plates are exchanged when stacking.
Provision can also be made for the mold building device to be suitable for producing molding plates individually, which each delimit a cavity of a casting mold on at least one, in particular on two of their sides.
In such a case, a plurality of casting molds are formed with a minimum number of molding plates by using the molding plates lying between the different casting molds for a plurality of casting molds at the same time.
It can also advantageously be provided for the mold building device to have an infeed device for moving individual molding plates to form a stack of molding plates, and an alignment element on which the molding plates can be aligned, and/or for the mold building device to have at least one tool for shaping positive-locking elements on the molding plates, wherein the positive-locking elements each enable the alignment of a molding plate on a molding plate directly adjacent thereto.
Such an infeed device can, on the one hand, have slides for pushing molding plates, but, on the other hand, said infeed device can also have gripping arms of robots. The molding plates can be placed on a common base in order to find a common alignment in a target position. A rail or edge can also serve as an alignment element. The molded plates can have positive-locking elements on the sides facing each other in order to align the molding plates with one another. Such positive-locking elements can have, for example, webs and grooves or pins and bores, cones and depressions and similar complementary geometric shapes.
The mold building device can be adapted to move, for example, slides for feeding molding plates along the stack in order to insert molding plates at different points in a layer stack. However, as part of the mold building device, a conveying element, for example, a conveyor belt, can also be provided, onto which the molding plates are pushed. Such a conveying element can, for example, also be designed elastically such that it automatically contracts behind the point at which the molding plates are joined together and thus exerts a compression effect on the molding plates for compression or for holding the stack together.
A conveying element can also be provided in the casting device downstream of the mold building device, which casting device moves the individual casting molds past a crucible or a spout for the melt, or such a crucible or a spout can be movable relative to the layer stack, or both, in order to fill the casting molds one after the other. Finally, it can also be provided that a demolding device is arranged downstream of the casting device.
The mold building device can also have a hydraulic, pneumatic, electric, or spring-driven device for pressing different molding plates together in the stacking direction. The molding plates can, for example, be glued, bolted or clamped to one another for their connection in order to join them together permanently to form casting molds.
Within the casting device, the crucible or a spout can be displaceable perpendicularly to the stacking direction and/or in the stacking direction in order, for example, to serve different feeders/sprues. A plurality of casting devices in the form of crucibles or pouring devices can also be provided.
In the demolding device downstream of the casting device, after the cast components have solidified, the molds can be destroyed or crushed, for example, by smashing using a hammer, tumbling, dissolving with solvents, ultrasound, shock waves, explosions or vibrations.
The produced components can then be removed by standard handling equipment such as cranes or robots, or by hand.
In addition to a device of the type explained above, the invention also relates to a method for producing castings, in which molding plates are first produced and automatically continuously layered in a mold building device, wherein each casting mold is formed by at least three molding plates delimiting a common cavity and wherein a casting material is poured into the casting molds within a casting device connected to the mold building device.
In particular, it can be provided that the mold building device is arranged in a fixed manner and that the individual molding plates are placed on a drivable conveying element, in particular a conveyor belt, and/or that the molding plates layered to form casting molds are moved relative to the casting device by means of a drivable conveying element.
It can be provided that a continuous conveying element, for example, in the form of a conveyor belt, is provided for moving molding plates within the mold building device and for their onward transport to and in the casting device. However, it can also be provided that an intermediate store or buffer for the casting molds is provided between the mold building device and the casting device in order to compensate for a temporary standstill of one of the two devices and to be able to continue operating the other device.
For this purpose, it can also be provided for an infeed device of the mold building device to move along the stack of molding plates and/or for a crucible of the casting device to move along the stack of molding plates in order to activate individual casting mold.
Both the mold building device and the casting device thus become more flexible, especially when the casting molds are lined up continuously and are moved on as a continuous row directly into the casting device.
The casting device can be movable at least with a melting crucible or a pouring device along the stacking direction or also perpendicular thereto in order to reach different pouring openings of the casting molds or to supply a plurality of casting molds with a casting material in one pass.
In order to reduce the number of molding plates to be handled and produced as much as possible, provision can also be made for individual molding plates to be used for a plurality of adjacent casting molds and/or for casting cores to be integrated into the molding plates.
Casting cores can also be integrated into the molding plates by suspending the casting cores on webs in recesses in the molding plates. This can be achieved, for example, by appropriate milling or other machining in which the webs remain between the cores and the outer parts of the molding plates.
Cores having materials different from the material of the molding plates, for example, having metal wires or carbon fibers, can also be suspended inside the molding plates. The corresponding wires, fibers or other strand-like elements can be pulled out of the castings after the casting process. In some cases, continuous openings created in this way in castings can be used practically, for example, by inserting electrical cables or light guides.
Provision can also be made for mold covers, each having at least one funnel and/or feeder, to be placed on one or more molding plates after layering such that the funnel and/or feeder is/are connected to at least one cavity of a casting mold.
Such a mold cover can have the shape of a plate or a cuboid, for example, and be provided with positive-locking elements for alignment with the molding plates. Such a mold cover can also have a U-shaped cross section, so that the legs of the U rest laterally on the molding plates and, on the one hand, can hold the molding plates together and, on the other hand, can align the mold cover on the molding plates.
In addition to a device for producing components and a corresponding method, the invention also relates to a layer stack, in particular a continuous layer stack, of molding plates that form a plurality of casting molds, wherein two, three or more molding plates form a casting mould and wherein at least one molding plate in each case forms a part of two casting molds that are directly adjacent to one another and delimits two cavities of different casting molds.
Such a mold stack implements a plurality of casting molds in the simplest possible way, using a number of molding plates that is kept as small as possible. Such a layer stack can also contain elements for holding the adjacent molding plates together, such as clamps, bolts or glue.
The invention is shown below using exemplary embodiments in figures of a drawing and then described.
The molding plates can be compressed and connected together in a compression device 1b in the stacking direction shown by the arrow 1c.
For this purpose, the individual molding plates can be provided, for example, with pins and bores which engage in one another and, on the one hand, serve for aligning adjacent molding plates with one another and, on the other hand, for connecting the molding plates to one another. The molding plates can also be connected to one another by means of continuous bolts or external clamps or glued to one another. The clamps can in each case overlap adjacent molding plates or a larger number than two molding plates.
Within the compression device 1b, slides or pivotable cheeks can be provided, which compress the layer stack in the stacking direction 1c.
The conveyor belt 39 moves in the direction 1c and transports the molding plates continuously or intermittently.
The infeed devices 28, 29 can also be driven, for example, along the conveyor belt 39 in the directions indicated by the arrow 1c and/or perpendicularly thereto (arrow 1d).
In addition to a device 1a for producing molding plates, the mold building device 1 can also process and feed additional or alternative molding plates, which are delivered prefabricated by a conveying device 41. Molding plates that are prefabricated and those manufactured in the mold building device 1 itself can also be joined together mixed within a layer stack and, for example, consist of different materials or have different dimensions, in particular different thicknesses.
The conveyor belt 39 can be, for example, a continuous conveyor belt and can be moved continuously or intermittently. It can be ensured by means of an intermittent movement, for example, that the infeed devices 28, 29 can insert the molding plates without gaps, in particular when the infeed devices cannot be moved along the conveyor belt 39.
The conveyor belt 39 or an alternative conveying element can have elasticity in the longitudinal direction, for example, so that said conveyor belt can exert a direction of compression in the stacking direction 1c on the molding plates placed thereon.
An interruption of the conveyor belt or a termination of a first conveyor belt, a bearing point and the start of a second conveyor belt can also be provided in the section 39a of the conveyor belt shown in dashed lines, for example, in order to be able to compensate for irregularities in the speed of equipping the conveyor belt with molding plates.
The same applies to the loop 39b of the conveyor belt, which makes it possible to store an increased stock of molding plates on the conveyor belt with a non-increased space requirement.
The section 39c of the conveyor belt passes through a casting device 2 in which a device for pouring molten casting material is provided, which device pours the casting material into molds formed by the molding plates. A pouring element in the form of a crucible can, for example, be movable along the conveyor belt 39c, as indicated by the arrow 2a, and/or also perpendicularly thereto, as indicated by the arrow 2b, in order to reach different feeders or casting funnels of the casting molds.
In the further course of the conveyor belt 39c, a demolding device 40 is provided behind the casting device 2, in which demolding device 40 the solidified castings are freed from the casting molds. This happens, for example, by smashing, shaking or chemically dissolving the material of the casting molds. The casting molds can also be acted upon by vibration, explosion, radiation, hammering or solvents. If planned, cores of the casting molds can also be removed by core marks after the crushing.
In another embodiment, not shown, the device can also do without a conveyor belt if the mold building device itself is movable and successively builds up a layer stack of molding plates. Such a mold stack can then be driven over using a transportable casting device in order to fill the casting molds with molten casting material. For continuous operation, the layer stack can form a closed line overall, for example, or said layer stack can be arranged along a finite path, wherein both the mold building device and the casting device start again at the other end of the layer stack after the end of travel on the layer stack. A multi-directional mold building device and casting device are necessary for this purpose.
For this purpose, as shown in
The intermediate space between the compression elements 36, 37 is also closed off by lateral delimiting elements, which are not shown in the figures, so that a box-shaped container is formed overall.
After filling in the molding material, which usually consists of a mixture of solid particles and binder material, a compression force can be exerted by the compression elements 36, 37, so that the molding material is compressed, compacted and solidified with the binder. The molding material can further be acted on by other means already described above, such as heat, radiation or the like, in order to solidify the molding material into a molding plate 3.
If the desired cavities have been introduced into the molding plate 3 from the side of the compression element 37, the compression elements 36, 37 can be brought closer together again, as is shown in
A finished molding plate provided with cavities is shown by way of example by the reference numeral 3 in
The recess 3a represents a part of a cavity of a casting mold created by joining together a plurality of molding plates.
The molding plates 4 and 5 can be pushed in, for example, from the other side of the conveyor belt 39 by the slides 29, 30. The various molding plates can be pushed in, for example, simultaneously because of the offset of the slides 28, 29, 30 relative to one another.
The molding plates 6, 7, 8 are already shown in the form of a layer stack on the conveyor belt.
The compression element 38 can regularly, for example, at equal intervals or controlled as required, press the molding plates 3, 4, 5 fed last against the already existing layer stack 6, 7, 8 in the stacking direction. The molding plates can then be clamped or glued together in order to hold them together.
It can be seen from
It can be seen from
A core 33 fastened to the molding plate 17 is shown as an example in the cavity 26 of the molding plates 16, 17, 18, 19.
On its underside, the molding plate 3 has a V-groove which runs in the stacking direction and interacts with a cross-sectionally V-shaped web 48 on the base 49. With a correspondingly identical arrangement of grooves on the undersides of the molding plates, said molding plates can be assembled into layer stacks of molding plates 3, 4, 5, wherein
The molding plates are then arranged thereon in a layer stack 3, 4, 5 corresponding to the layer stack having a cavity 27 shown in
The crushed material from the molding plates can be returned to the process and cyclically reused to produce new molding plates.
The presented device is thus able to carry out the entire process from the production of individual molding plates to the production of components by casting in an optimized manner and using the smallest possible number of molding plates. Molding plates of different dimensions and materials can be assembled into casting molds, wherein the selection of the molding plates used can be controlled ad hoc in the process. For example, molding plates having other recesses, external dimensions or more or less cooling properties, that is, controlled with regard to the thermal conductivity properties, can also be introduced into the layer stack in order to influence the cooling behavior of the melt during the production of the cast components.
For example, gravity casting or low-pressure casting can be implemented as the casting process.
In addition, components can be inserted into the individual molding plates, which components remain during the casting process and connect to the cast components or which can later be removed from the cast components in order to create targeted openings or complex recesses in the castings.
The inserted parts can, for example, also be strand-like elements made of fibers.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2019 217 038.2 | Nov 2019 | DE | national |
The present application is a national stage application of International Application No. PCT/EP2020/080709, filed Nov. 2, 2020, which claims priority to German Application No. DE102019217038.2, filed Nov. 5, 2019, the disclosures of which are hereby incorporated by reference in their entireties.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2020/080709 | 11/2/2020 | WO |
