Process for desanding a component

Abstract

The invention relates to a method for desanding a component cast using a sand mold and / or a sand core, in which sand adhesions are removed from a surface of the cast component by means of a laser device by aligning a laser beam onto the cast component (V2).

Description

[0001] The invention relates to a method for desanding a component cast using a sand mold and / or a sand core.

[0002] From WO 2018 / 152559 A1 it is known that in order to destroy a casting core or to core / desand workpieces that have been produced by means of a casting process, the workpieces can be set into vibration by striking them with a hammer, whereby the core is shattered and, if necessary, molding sand is removed from the workpiece.

[0003] Furthermore, EP 1 633 509 B1 discloses a method for the layered construction of models, in which different materials are applied layer by layer until a desired model is obtained, one of the materials being molding sand and the second material being a binder. The model is a casting mold or a casting core, and after casting such a mold, the casting is demolded by immersion in water or shaking.

[0004] Furthermore, DE 10 2007 045 649 B4 discloses a method for producing a mold and / or core for foundry purposes. A component can be cast using the described resulting mold and / or core. For a demolding or core removal step, the mold is removed mechanically, in particular by shaking, ultrasound, or tapping.

[0005] The object of the present invention is to provide a solution by means of which a cast component can be particularly effectively freed from sand adhesions.

[0006] This object is achieved according to the invention by the subject matter of the independent claim. Further possible embodiments of the invention are disclosed in the subclaims, the description, and the figures.

[0007] The invention relates to a method for desanding a component cast using a sand mold and / or a sand core. The method involves using a laser device to remove sand adhesions from a surface of the cast component by directing a laser beam onto the cast component. In sand casting or permanent mold casting of aluminum components, sand molds or sand cores are used to create cavities, internal and external contours, or even undercuts. Once the cast component has solidified, the requirement is to remove this sand from the component and its surface as quickly and completely as possible. This process is called coring and is often carried out as part of a hammering process or a shaker process, and thus by means of impulses or vibrations introduced into the component by hydraulic or pneumatic devices.During these hammering or shaking processes, the sand cores decompose or crumble due to vibration. To further remove sand from the surface of the component, a blasting process can be used, for example, with stainless steel balls, corundum, or similar blasting material. The sand must be completely removed, as any remaining sand residue, which may have penetrated or adhered to the component due to penetration, can become detached during subsequent use and potentially cause damage. For this reason, technical cleanliness requirements are included in many component specifications or drawings of the component to be cast.

[0008] Applying the laser beam using the laser device enables particularly reliable, complete removal of sand from the surface of the component. In particular, removing sand using the laser device allows for reliable removal of sand even from complex surface areas of the component, such as undercuts or pockets. This allows for a particularly good sand-free finish on the component.

[0009] In a possible further development of the invention, it is provided that the component is first vibrated in a coarse desanding process for coarse desanding and then the component is subjected to a fine desanding process in which the sand deposits are removed from the surface of the cast component by means of the laser device. This means that after casting, the component is first vibrated or oscillated in the coarse desanding process in order to remove the majority of the sand from the component. Any remaining sand deposits are then removed by means of the laser device. This allows the sand to be removed from the component particularly quickly, and additionally, thanks to the fine desanding process, the component is completely desanded particularly reliably.

[0010] In this context, it can be provided, in particular, that the component is vibrated by means of at least one hammer during the coarse sand removal process. This means that the component can be struck by the at least one hammer, causing the component to vibrate. By vibrating the component, the sand is shaken off the component. By hammering, a large portion of the sand can be shaken off the cast component particularly easily, reliably, and quickly.

[0011] In a further possible embodiment of the invention, it is provided that a fiber-based laser is used as the laser device for desanding. The fiber-based laser is a particularly small laser device, whereby a laser processing head of the laser device, which is configured to align the laser beam onto the cast component, can be moved particularly close to the component, or at least partially around respective edges of the component or at least partially into respective recesses of the component, whereby the laser beam can be guided particularly well into undercuts. As a result, these undercuts can be freed of sand particularly well using the laser device. A fiber laser is a special form of solid-state laser. A doped core of a glass fiber forms the active medium in a fiber laser.It is therefore a fiber optic cable with optical waveguide properties. The laser radiation transmitted through the laser-active fiber experiences very high amplification due to its great length.

[0012] In a further possible embodiment of the invention, it is provided that the cast component is heated at least in part by means of the laser device. In this case, the component can be heated at least in part by means of light pulses provided by the laser device, in that a local temperature increase is generated by the respective light pulses. This local temperature increase of the component creates micro-stress differences between the heated area of the component and the sand. In other words, cracks arise between the component and the sand adhering to the component due to the partial heating of the component. This partial heating of the component can lead to an expansion of the heated area of the component, thereby creating cracks between the component and the sand. As a result of these cracks between the component and the sand, the sand falls away from the surface of the component.For example, a laser with one to two kilowatts of power can be used, particularly an erbium fiber laser with a wavelength of 1,500 nanometers, a fan-shaped optics for a width of 15 millimeters, and a scanning or cleaning speed of approximately 20 millimeters per second. This allows the surface of the component to be scanned particularly quickly and over a large area using the laser beam provided by the laser device and to be heated in specific areas, allowing the surface to be cleaned particularly thoroughly of adhering sand.

[0013] In a further possible embodiment of the invention, the cast component is vibrated at least in part by the laser device. In other words, the component is vibrated at least in part by the laser beam provided by the laser device, thereby shaking off the sand from the surface of the component. This results in, in particular, a pulsed excitation of the surface of the cast component, which causes the contaminants, in particular the sand, to be loosened. This allows the sand to be removed from the surface of the component in a particularly gentle manner.

[0014] In this context, it can further be provided that, in order to set the cast component into vibration, at least one light pulse is emitted to the component by means of the laser device. The light pulse triggers a micro-shock on the surface of the component, whereby the sand is shaken off the surface of the component. In addition, the light pulse can heat the component at least in certain areas and thus locally, whereby the sand can be particularly effectively detached from the surface of the component due to the resulting micro-tensions between the heated surface of the component and the sand. The sand can thus be removed from the surface of the component particularly reliably.

[0015] In a further possible embodiment of the invention, the surface of the cast component is microstructured using the laser device. This means that the surface of the component is removed at least in certain areas using the laser device. Along with the material removal from the component, any sand adhering to the surface of the component is also removed. The sand is thus scraped off the surface of the component using the laser device. By microstructuring the surface, particularly stubborn sand deposits can be reliably removed from the component's surface.

[0016] In this context, it can be provided, in particular, that longitudinal grooves or V-shaped furrows are introduced into the surface of the component by means of the laser device. The longitudinal grooves or the V-shaped furrows can, in particular, have a width of ten to 50 micrometers. The surface of the component is thus restructured by means of the laser device in that micro-furrows are introduced into the surface of the component by means of the laser device. In this process, the material of the component, in particular aluminum, is melted and dust from the component falls off together with the sand as discharge during the grooving process. The longitudinal grooves can be introduced into the surface of the component particularly easily as a microstructure.The V-shaped grooves allow the sand to be removed particularly thoroughly from the surface of the component and the persistence of sand lines on the surface of the component after micro-grooving can be particularly well avoided.

[0017] In a further possible embodiment of the invention, a laser processing head of the laser device, which directs the laser beam onto the cast component, is guided by means of a numerical control. A numerical control is a device for controlling machines that reads control commands present as code on a data carrier and converts them into work or movement sequences. Due to the numerical control of the laser processing head, the laser device can be controlled particularly precisely and arranged in a wide variety of positions, similar to a CNC machine. This makes it possible to move the laser processing head so extensively that the entire surface of the component can be reached particularly reliably using the laser beam provided by the laser processing head.This ensures reliable desanding of the entire surface of the component.

[0018] Further features of the invention may emerge from the claims, the figures, and the description of the figures. The features and combinations of features mentioned above in the description, as well as the features and combinations of features shown below in the description of the figures and / or in the figures alone, can be used not only in the respective combinations specified, but also in other combinations or on their own, without departing from the scope of the invention.

[0019] The drawing shows in the only figure ( Fig. 1) a process diagram for a process for desanding a component cast using a sand mold and / or a sand core.

[0020] In Fig.1 shows a process diagram for a process for desanding a component cast using a sand mold and / or a sand core. The component is a component cast from aluminum, in particular a motor vehicle component. The process comprises a first process step V1 and a second process step V2. In the first process step V1, the component is subjected to a coarse desanding process for coarse desanding. Subsequently, in the second process step V2, the component is subjected to a fine desanding process, in which sand remaining on the surface of the component after the coarse desanding process is removed. In the coarse desanding process, the sand can be removed from the component in a hammering process or a shaker process, in particular by means of a hydraulic or pneumatic vibrating machine, by means of impulses or vibrations introduced into the component.Alternatively or additionally, the component can be subjected to a mechanical blasting process, a grinding process, a brushing process, a scraping process, or a water jet process during the coarse desanding process. In this case, the coarse desanding process involves coarse desanding of the component using hammer blows on various areas of the component, in which the component is vibrated at least in certain areas by the hammer blows. This can achieve a 98 to 99 percent sand-free state of the component. Following the coarse desanding process, an optical inspection system can be used to check for and document the sand-free state.

[0021] Following the coarse desanding process, the component undergoes the fine desanding process, in which the remaining sand deposits are removed from the surface of the cast component using a laser device. During the fine desanding process, the laser device directs a laser beam onto the cast component to remove the sand deposits. For cleaning or the removal of residual dirt, a numerically controlled laser processing head of the laser device can be used to direct the laser beam onto the component. In this case, the laser device is a fiber-based laser.This allows the laser device to quickly and reliably access all areas of the component's surface, especially any undercut on the component, and clean them locally using the laser beam. The laser processing head can be positioned at a short distance from the component's surface. During the fine desanding process using the laser device, the component's surface can be stimulated by a surface pulse triggered by the laser beam.

[0022] During the fine desanding process, the cast component can be heated at least in certain areas and / or vibrated at least in certain areas and / or microstructured at least in certain areas on its surface using the laser device. To vibrate the cast component during the fine desanding process, at least one light pulse can be emitted to the component using the laser device. During the microstructuring of the surface of the cast component, longitudinal grooves and / or V-shaped furrows can be introduced into the surface of the component using the laser device.

[0023] The described process is based on the realization that aluminum cast components, particularly for automotive applications, are becoming increasingly complex - in most cases to reduce weight and enhance integrated functions. This results in an increasing number of undercuts, pockets, and other areas that are either not accessible or difficult to access using conventional blasting processes that differ from laser processes. This is due, for example, to very flat beam angles that cannot produce any effect on the surface of the component. New sand materials for sand cores, such as inorganic binders or printed cores, are sometimes difficult to core, which means that core removal using a hammer system can often reach its limits. Excessive hammer energy introduced into the component can cause pre-damage or create cracks and possibly plastic deformation.As a result, such hammer systems are only suitable for coarse sand removal. Rework to remove residual sand / dirt is therefore necessary. Furthermore, minor process adjustments during the preceding casting process, for example, with regard to the casting temperature, can influence the adhesion or penetration of the sand into the component surface, thereby preventing reliable removal of the adhesions using hammer blows alone. Consequently, the described method provides for the removal of residual sand from the component surface using the laser device.

[0024] Overall, the invention shows how casting-related contamination on aluminum workpieces can be removed using the laser device. List of reference symbols V1 to V2 respective process steps QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This 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

[0000] WO 2018 / 152559 A1

[0002] EP 1 633 509 B1

[0003] DE 10 2007 045 649 B4

[0004]

Claims

[1] Method for desanding a component cast using a sand mold and / or a sand core, in which sand deposits are removed from a surface of the cast component by means of a laser device by directing a laser beam onto the cast component (V2). [2] Method according to claim 1, characterized by that the component is first vibrated in a coarse desanding process for coarse desanding (V1) and then the component is subjected to a fine desanding process in which the sand adhesions are removed from the surface of the cast component by means of the laser device (V2). [3] Method according to claim 2, characterized by that the component is vibrated in the coarse sanding process by means of at least one hammer (V1). [4] Method according to one of the preceding claims, characterized bythat a fiber-based laser is used as the laser device for desanding (V2). [5] Method according to one of the preceding claims, characterized by that the cast component is heated at least in part by means of the laser device (V2). [6] Method according to one of the preceding claims, characterized by that the cast component is vibrated at least in part by means of the laser device (V2). [7] Method according to claim 6, characterized by that in order to set the cast component into vibration, at least one light pulse is emitted to the component by means of the laser device (V2). [8] Method according to one of the preceding claims, characterized by that the surface of the cast component is microstructured by means of the laser device (V2). [9] Method according to claim 8, characterized bythat longitudinal grooves and / or V-shaped furrows are introduced into the surface of the component by means of the laser device (V2). [10] Method according to one of the preceding claims, characterized by that a laser processing head of the laser device, which directs the laser beam onto the cast component, is guided by means of a numerical control (V2).

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