AT504556A1 - DEVICE AND METHOD FOR MATERIAL PROCESSING - Google Patents

Description

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Apparatus and method for material processing

The invention relates to a device for processing solids, in particular for grinding and separating workpieces, as well as a method for operating such a device.

Such devices and methods are useful in many areas of material processing such as e.g. during grinding, polishing, milling etc. known.

A disadvantage of the known devices is in particular that the current materials, both the workpieces to be machined as well as the tools, make high demands on the environmental parameters such as temperature and cooling, otherwise threatened damage and thus economic losses and unprofitability by high reject rates. This is especially true for high speed grinding techniques.

It is therefore an object of the invention to provide an apparatus and a method for material processing, which can be operated material-friendly both for the tool and for the workpiece.

According to the invention, such a device comprises a housing, a working space which can be covered by a cover, and a grinding wheel arranged in the working space, wherein the working space is sealed off from the surroundings by means of the cover and can be evacuated.

According to the inventive method is provided to introduce a workpiece and a grinding wheel in the open working space of the device to close the working space by means of the cover to evacuate the working space by means of at least one vacuum pump to edit the workpiece, after completion of processing in the working space back pressure and remove the workpiece after opening the cover.

It is advantageous that results in a higher degree of efficiency of the entire cooling process, since the heating of the grinding wheel is omitted by friction with the ambient air. · «· ·································································································· ··· · 2

Furthermore, it is advantageous that thereby the operating costs can be reduced, since the operation and maintenance of a cooling system can be significantly reduced or even eliminated.

Further advantages of the inventively designed device can be seen from the dependent claims.

An advantageous embodiment of the device comprises a lock, which allows the introduction and removal of workpieces and tools in or out of the work space, without having to be evacuated each time.

The grinding wheel is advantageously at least partially made of a CFRP material, since the lower weight achieved thereby allows higher speeds.

The grinding wheel is preferably rotatably mounted on a shaft.

It is particularly advantageous that the shaft is driven by a suitable drive device so that the peripheral speed of the grinding wheel over 330 m / s, ie in the supersonic range, is located. As a result, cooling by zugefuhrtes coolant omitted in the best case.

Furthermore, by processing in a vacuum at supersonic speed of the grinding wheel advantageously the noise when driving over the sound barrier can be avoided.

An advantageous embodiment variant provides that the evacuation of the working space begins only when the grinding wheel has exceeded a peripheral speed of about 200m / s. The higher the peripheral speed, the more evacuated. This has the advantage that in the lower speed range, the vacuum pump does not yet go into operation and the available energy can be used to accelerate the grinding wheel faster to working speed.

An exemplary embodiment of an inventively designed device is shown below and explained in more detail in the accompanying description. It shows:

Fig. 1 is a highly schematic view of an exemplary embodiment of an inventively designed device for material processing. »· ♦ ♦ · ♦ ································································ • ··· · · 3

Devices for machining workpieces by grinding, milling, drilling and other machining methods have long been established in many fields of industry and craft. The increasing diversification of materials and the resulting broadly scattering material properties of workpieces and tools sometimes necessitates a redesign, adaptation and / or complete redesign of test benches, machine tools and equipment for machining workpieces.

New materials such as CFRP (carbon fiber reinforced plastic) offer e.g. In the production of grinding and cutting wheels, their lighter design and the resulting higher speeds make it possible to precisely process even brittle materials. The speeds can be so high that circumferential speeds of the grinding wheels can reach into the supersonic range. However, due to the higher speeds also thermal problems that require a high cooling capacity of the system and the tool, as well as the noise when driving over the sound barrier.

Cooling and the entire cooling periphery cause an immense share of process costs. The plant concept of an abrasive center, for example, becomes more expensive due to the cooling by approx. 20-30%. During the ongoing process, the cooling unit consumes up to 30% of the electrical connection power. Furthermore, the handling of the cooling media, whether it be coolants or oils, constantly high process costs for purchase, cleaning, filter disposal and disposal of the respective coolant. In addition, the grinding wheels heat up very much from peripheral speeds over 200m / s due to air friction.

The main problem of the cooling lies in the fact that at high peripheral speeds on the outer surface of a few microns thick air cushion forms, which can hardly be pierced by a liquid jet intended for cooling even at high pressures. Even with already known internally cooled grinding wheels, the cooling water jet directed from the inside outwards does not escape into the atmosphere due to the air film, but oscillates back and forth between the abrasive coating and the air film at least in the lower speed range up to approx. 100 m / s.

According to the invention, it is therefore provided that encapsulated grinding machines and closed grinding centers for high-speed grinding are provided with at least one ···························································································. · · ··········· • · ·· ·· · 4

Vacuum pump are equipped, the grinding process is thus carried out at least partially or almost completely in a vacuum.

The vacuum is preferably only generated when the peripheral speed of the grinding wheel 5 is already above a threshold value of, for example, 200 m / s. With increasing peripheral speed of the pressure is then further reduced or the working space 4 further evacuated. As a result, the energy available for the device 1 can be used to accelerate the grinding wheel 5. The evacuation begins only when the grinding wheel 5 rotates in the working speed range.

An embodiment of the invention is shown in FIG. 1 in a highly schematic view and will be explained below.

The device 1 comprises a per se known, single or multi-part housing 2, in which drive units and other necessary for the operation of the device elements can be accommodated. Furthermore, the device 1 has a tight-closing cover 3 of a working area 4. The cover 3 can be made of Plexiglas, for example, to give the person using the system the opportunity to monitor the machining process.

In the working area 4, for example, a CFRP grinding wheel 5 can be rotatably mounted on a shaft 6. With the grinding wheel, a likewise arranged in the work area 4 workpiece 7 is machined.

By sealing the cover 3, it is possible to produce in the work area 4, for example by appropriate arrangement of at least one vacuum pump 8 a negative pressure below 1 bar or approximately a vacuum, which offers several advantages: on the one hand eliminates the problem of air film in outdoor cooling , which results in a higher degree of efficiency of the entire cooling process. Furthermore, dust explosion during bursting of the CFRP basic body is prevented. The heating of workpiece and grinding wheel due to air friction is significantly reduced. The noise when driving over the sound limit at a corresponding peripheral speed of the grinding wheel 5 is also eliminated. Overall, even the entire cooling process can be reduced up to the elimination of the cooling at extremely high peripheral speeds («500m / s).

The machining is preferably carried out as follows: a workpiece 7 to be machined and a grinding wheel 5 are introduced into the still open working space 4 of the device 1. Then, the working space 4 is closed by means of the cover 3 and by means of the at least one vacuum pump 8 a negative pressure to vacuum produced. Now, the workpiece 7 can be processed in the desired manner. After completion of the processing, the ambient pressure is restored in the working space 4 and, after opening the cover, the workpiece 7 is removed.

Alternatively, the device 1 may also include an additional lock 9, which is accessible from the outside and connected to the working space 4 so that workpieces 7 can be introduced and removed from the working space 4 without releasing the vacuum and re-establishing a vacuum.

This is particularly suitable for smaller workpieces 7 in high quantities. The workpiece 7 is introduced into the lock 9 and this sealed against the environment. After opening a connection to the working space 4, the workpiece 7 is converted into this. The removal of a workpiece 7 from the working space 4 through the lock 9 takes place in the reverse order.

Claims (10)

1. Device (1) for machining materials, in particular for grinding, comprising a housing (2), a working space (4), which by a cover (3) can be covered, and in the working space (4) arranged grinding wheel (5), wherein the working space (4) through the cover (3) sealed against an environment and by at least one vacuum pump (8) is evacuated. 2. Apparatus according to claim 1, characterized in that with the working space (4) connectable externally accessible, tightly closable lock (9) is provided. 3. Apparatus according to claim 1 or 2, characterized in that the grinding wheel (5) consists at least partially of a CFRP material. 4. Device according to one of claims 1 to 3, characterized in that the grinding wheel (5) is rotatably mounted on a shaft (6). 5. Apparatus according to claim 4, characterized in that the shaft (6) by a suitable drive device is driven so that the peripheral speed of the grinding wheel (5) in the supersonic range is above 330 m / s. 6. Device according to one of claims 1 to 5, characterized in that the pressure in the working space (4) between p < 1 bar and p «0 bar. 7. Apparatus according to claim 6, characterized in that the pressure in the working space (4) from a peripheral speed of the grinding wheel (5) of over 200 m / s can be reduced such that with increasing peripheral speed of the grinding wheel (5), the pressure decreases. 8. A method for operating a device (1) for machining materials, in particular for grinding, wherein the device (1) a housing (2), a working space (4), which by a cover (3) can be covered, and a in wherein the working space (4) is sealed by the cover (3) from an environment and can be evacuated by at least one vacuum pump (8), characterized in that the method comprises the following method steps: ··· ···· ·· ·· t ··· · 7 - introducing a workpiece (7) and a grinding wheel (5) into the open working space (4), closing the working space (4) by means of the cover (3), evacuating the working space (4) by means of the at least one Vacuum pump (8), - machining the workpiece (7), setting the ambient pressure in the working space (4) to Bee processing, and opening the cover (3) and removing the workpiece (7). 9. The method according to claim 8, characterized in that the method may additionally and / or alternatively comprise the following method steps: introducing a workpiece (4) into the lock (9) instead of into the working space (4), - converting the workpiece (4 ) from the lock (9) into the partially or completely evacuated working space (4), machining the workpiece (4), - converting the workpiece (4) after processing from the working space (4) into the lock (9), and removing of the workpiece (4) from the lock (9). 10. The method according to claim 8 or 9, characterized in that the evacuation of the working space (4) from a peripheral speed of the grinding wheel (5) of more than 200 m / s begins.