EP0289875A1 - Method and device for cleaning work pieces - Google Patents

Abstract

The invention relates to a method and a device for cleaning foreign bodies, such as metal shavings or the like from a preceding metal- cutting production process, from work pieces. The work pieces (4) are dipped into a washing container (1, 2) and compressed air, which rises upwards in the washing liquid (20) due to buoyancy, is blown in at the bottom (19) becomes attached to foreign bodies (17) on the work piece (4) and drags the said foreign bodies with it upwards as a result of buoyancy. <IMAGE>

Description

The invention relates to a method for cleaning workpieces from foreign bodies such as chips or the like. by washing with a washing liquid in a washing container while blowing in compressed air or the like. below the workpieces, as well as a device for performing the method.

In the metalworking industry, especially in the machining of injection molded parts drilling, milling and turning leave metal chips on the machined workpieces, which have to be removed before further processing of the workpieces, which is usually done by washing the workpieces in a washing container. The washing liquid usually consists of water with cleaning additives, and the washing liquid in the washing container is pumped or the like to get to all surfaces, recesses, bores, etc. of the workpieces. kept moving. Especially when machining parts made of aluminum or aluminum alloys, foreign bodies such as chips can only be removed from angled bores and blind holes with great difficulty, so that manual subsequent cleaning using suitable brushes or cleaning syringes and using compressed air is usually used. Such manual post-cleaning is, however, associated with great effort and nevertheless does not provide sufficient certainty that the machined parts are free of chips and other foreign bodies, which can have an extremely disadvantageous effect, in particular when parts slide or move later in operation. Examples of such difficult-to-clean workpieces include engine blocks, cylinder heads, oil pump and water pump housings, intake manifolds and other parts from the automotive industry, which are particularly difficult to clean due to their complicated shape with a large number of tortuous channels, chambers, through and blind holes are, which has a particularly disadvantageous effect in series production.

From DE-GM 84 37 870 it is already known in a wash filled with a washing liquid inject the washing liquid at high pressure from the side using staggered nozzles and rotate the workpiece around an approximately horizontal axis or let it tumble. In this way, all sides of the workpiece should be reached by the nozzle jets. This known device works according to the so-called cavitation process, in which the water injected under high pressure forms vapor bubbles which implode when it hits the workpiece and are intended to entrain and loosen foreign bodies such as chips from the workpiece. However, this known method requires very high pumping capacities, and the removal of chips from bores and channels that are very difficult to access is usually unsatisfactory.

From FR-A 23 78 577 a method for washing fruit or vegetables is known, in which air is blown into a washing container with washing liquid from below and from the side in order to also make otherwise inaccessible areas of the fruit or to reach the vegetables with washing liquid. However, this known method has the consequence that the foreign substances dissolved during the swirling of the washing liquid are deposited again in other places, in particular because the washing water becomes increasingly dirty even after a few cleaning cycles.

The present invention has for its object a method and an apparatus for cleaning workpieces from foreign bodies such as chips or the like. preferred suggest that, even with complicated shapes of the workpieces, allows a flawless, largely automatic cleaning without the need for manual subsequent cleaning.

This object is achieved according to the invention by a method of the type mentioned at the outset, which is characterized in that washing liquid is pumped in via an inlet arranged in the lower region of the washing container and pumped out via an overflow of the washing container, and that in the region of the inlet the compressed air or the like . is introduced.

The invention evaluates the property of air or other gases to have a greater affinity for solids than for water or liquids, ie that the air (or gas) has the property of blowing into the wash liquid the foreign bodies in the bores, depressions and the like. bind the workpieces and rise due to the buoyancy forces in the washing liquid. The inventive concept described above already leads to an extremely good cleaning of the workpieces. The general principle of the use of rising air in the wash water can be used particularly advantageously in the case of particularly inaccessible and branched channels in the workpieces if, according to a further feature of the invention, the workpieces are moved in the wash tank about an approximately horizontal axis in such a way that in the Workpieces existing bores, channels or other recesses compared to the horizontal with their Openings are directed downwards or upwards in succession and the air or the like blown in below the workpieces. penetrates into the bores, channels or other depressions of the workpieces directed downward in the course of the rotation of the workpieces and thereafter or the like in the course of the further rotation while entraining the chips. flows out again. This principle can be used both in a cleaning process with a detergent circuit circulated via an overflow and without one.

By moving the workpieces around at least the horizontal axis, cavities and chambers such as e.g. Blind holes in the workpieces with their opening directed downwards at a certain point in time, so that the blown-in air rises into the blind holes, binds to the foreign bodies and, when the workpiece continues to rotate, z. B. 180 ° out of the then upward opening from the blind hole by buoyancy. This combination of measures achieves an extraordinarily high cleaning effect; this effect is of course also given with through holes and channels.

The invention also relates to a device for carrying out the method according to the invention. Such is characterized by a gear head arranged in the washing container, to which the workpieces can be fastened and which for generating movement of the workpieces at least about an approximately horizontal axis, in particular in the form of a wobble movement, is formed. The gear head preferably has at least one gripping device for releasably holding a workpiece. By means of such a gripping device, the workpieces can be gripped manually or automatically in series production, immersed in the washing container and moved in the manner indicated.

The movement of the workpiece or workpieces must take place at least about an approximately horizontal axis, so that bores and chambers with only one access opening for entry of the blown-in air downwards and for discharging the air with foreign bodies bound to them are directed upwards by buoyancy.

A particularly advantageous embodiment of the invention is characterized in that a separating device, in particular a sieve, is preferably provided on an overflow of the washing container in order to continuously remove the foreign bodies from the circuit of the washing liquid.

In the event that the inlet of the washing liquid of the washing container is arranged below the workpieces, the air blown in can expediently be injected into the inlet. However, it is also possible to arrange a plurality of nozzles into the bottom of the washing container, into which the compressed air is blown.

A particularly advantageous embodiment of the device according to the invention, in which a movement of the workpiece about an at least horizontal axis in In most cases, this is not necessary, characterized in that the inlet at the bottom of the washing container is in the form of a plurality of water nozzles, and that compressed air or another gas is introduced via air nozzles arranged between the water nozzles, in such a way that an even one Water flow with finely divided air bubbles results essentially without swirling from bottom to top past the workpieces arranged in the washing container. In the case of particularly critical workpieces with widely branched bores, in particular with pocket drilling, however, the workpiece will be moved around at least the horizontal axis.

A particularly simple construction of this embodiment is characterized in that the washing container has an intermediate floor, in which the water nozzles are arranged at regular intervals and in which air holes are provided between the water nozzles at uniform, finer intervals, and in that the intermediate space under the intermediate floor connects to one Compressed air source can be connected.

While the method and the device according to the invention can rinse these removed foreign bodies without problems over the overflow of the washing container when removing relatively light foreign bodies such as chips, it can lead to chips due to the machining of steel parts or cast steel because of the greater weight these fall to the bottom of the washing container so that they have to be removed from time to time. To the to avoid operational interruptions caused thereby, a further advantageous embodiment is characterized in that a magnetic separator in the form of a magnetic conveyor belt is provided at the bottom of the washing container, through which the magnetically attracted foreign bodies are conveyed to the outside.

To further improve the cleaning effect, it is also possible to have a vibration generator act on the workpiece immersed in the washing container, which generator either vibrates the workpiece itself or the washing liquid.

In order to make it easy to remove chips or other foreign bodies falling to the floor in the washing container, according to an advantageous embodiment, this consists of an outer container and a basket suspended therein with walls designed as a sieve. This basket can be removed and cleaned at greater intervals after moving the gear head away from the outer container in order to avoid plugging or swirling with foreign bodies.

The invention is explained in more detail below on the basis of exemplary embodiments with reference to the accompanying drawings.

• Fig. 1 eine schematische Schnittdarstellung einer Vorrichtung zur Durchführung des erfindungs­gemäßen Verfahrens;
• Fig. 2 eine Teilansicht des Waschbehälters in abge­wandelter Form;
• Fig. 3 bis 6 schematische Darstellungen eines Werk­stückes im Schnitt in verschiedenen Stellun­gen während des Bewegungsablaufes;
• Fig. 7 eine schematische Schnittdarstellung einer weiteren Vorrichtung zur Durchführung des er­findungsgemäßen Verfahrens;
• Fig. 8 eine Draufsicht auf einen Ausschnitt auf einen Zwischenboden der Vorrichtung nach Fig. 7; und
• Fig. 9 eine schematische Seitendarstellung im Schnitt durch eine weitere Vorrichtung gemäß der vorliegenden Erfindung.

Show it:

• Figure 1 is a schematic sectional view of an apparatus for performing the method according to the invention.
• Figure 2 is a partial view of the washing container in a modified form.
• 3 to 6 are schematic representations of a workpiece in section in different positions during the movement sequence;
• 7 shows a schematic sectional illustration of a further device for carrying out the method according to the invention;
• FIG. 8 shows a plan view of a section of an intermediate floor of the device according to FIG. 7; and
• Fig. 9 is a schematic side view in section through a further device according to the present invention.

The device for washing workpieces, shown schematically in section in FIG. 1, consists of an outer container 1 and a basket 2 suspended in it, which has walls formed as a sieve. The outer container 1 and the basket 2 form a washing container. The washing container 1, 2 is filled with a washing liquid 20 which is fed to the bottom 19 of the outer container 1 via an inlet by means of a circulation pump 12 and is returned to the pump via an outlet 11 in the upper region of the outer container 1. The drain 11 is arranged in the area of an overflow 8 on the basket 2 of the washing container. A separator is in the form of the overflow 8 a sieve 9 is provided in order not to let rinsed foreign bodies into the outlet 11, and thus into the circuit of the washing water.

A gear head 5 is suspended on the outer container 1 by means of a cross member 22 and by means of a holder 21, which (in the present case) has two gripping devices 3 for holding a workpiece 4 each. The gear head 5 is designed such that it exerts a wobbling movement on the workpieces 4, i.e. a multidimensional movement about several axes, of which the horizontal axis 6 and the vertical axis 7 are indicated in FIG. 1. It is important for such a wobble movement or other movement about several axes that each of the workpieces 4 executes such a movement in the washing container that each surface or opening of the workpieces successively one after the other essentially downwards and once essentially upwards shows.

An air line 13 is introduced into the inlet 10 for the washing liquid and compressed air is supplied via a blower 14. This injected compressed air rises in the form of air bubbles in the washing liquid, that is, it passes through the bottom of the basket 2 into the area of the workpieces 4. Since the air or another gas is larger with respect to solids, such as the foreign bodies to be removed Affinity as compared to the washing liquid 20, the air bubbles adhere to the foreign bodies and tear them up due to the buoyancy. They also climb into downward openings in bores and channels or the like in the workpieces. If the workpieces 4 are now moved further by the gear head 5 in such a way that the previously pointing downward opening is directed upward, the air bubbles with the foreign bodies adhering to them rise upward through buoyancy and are thus removed from the bores o. the like torn out and reach the surface of the washing liquid 20. Since the washing liquid 20 is circulated in such a way that suction is carried out in the area of the overflow 8 via the outlet 11, the flushed foreign bodies are removed from the washing container, ie they are retained on the sieve 9 where they can be removed occasionally.

Fig. 2 shows another embodiment of the device according to the invention in partial view. In the bottom 19 of the outer container 1, a plurality of nozzles is arranged, to which compressed air is fed from the blower 14 via the air line 13. By this training rising air bubbles are generated over a larger area in the washing tank, or the like in the downward bores, channels. the workpieces 4 can get into it.

3 to 6, a workpiece 4 is now shown in different positions in order to explain the effect of the method according to the invention. The workpiece 4 has a multiplicity of bores, channels or other depressions 15a, 15b and 15c which are connected to the outer surfaces of the workpiece via openings 16. In these holes or the like 15 there are schematically indicated foreign substances 17 such as chips from a previous machining production process.

In the position shown in FIG. 3, air bubbles rising from below (see description of FIG. 1) can enter the sack lock 15a via the opening 16 and bind the foreign bodies 17. Air bubbles with foreign bodies 17 then collect in the upper region of the blind hole 15a. Likewise, air bubbles can rise through the opening 16 of the through hole 15b, connect to the foreign bodies and immediately leave this through hole via the upper opening 16. A rise of bubbles in the laterally located blind hole 15c will only take place in an imperfect manner; unless this hole is slightly inclined downwards.

If the workpiece 4 is now rotated into the position shown in FIG. 4, which corresponds to a rotation through 180 °, the blind bore 15a is now open at the top, so that the air bubbles with the foreign bodies bound to them can escape upwards through buoyancy. As far as the through hole 15b is concerned, any foreign bodies still hanging on the unevenness of the walls have the opportunity to rise from the through hole in the opposite direction. Practically nothing has changed with regard to the blind bore 15c lying on the side.

If the workpiece now reaches the position shown in FIG. 5, the air bubbles can move into the position shown in FIG. 3 and 4 ascend lateral blind hole 15c, bind foreign bodies and collect in the upper end of blind hole 15c. When the workpiece is moved further into the position according to FIG. 6, the air bubbles with the foreign bodies can leave the blind bore 15c which is now pointing upwards.

The above explanations therefore show that by appropriately moving the workpiece 4 about several axes, but in particular about a horizontal axis, each hole, in particular blind hole or each channel, is positioned one after the other in such a way that air bubbles can get in and then get out again by buoyancy. The affinity of the air bubbles for the foreign bodies, in particular metal chips, is so great that the bores, cavities or the like. of the workpieces 4 in a relatively short time, i.e. after a few revolutions of the gear head, are rinsed free, so that the workpieces can be used without further manual cleaning.

The further device according to the invention shown in FIGS. 7 and 8 has the following differences compared to the embodiments described above:

An inner container 30 with an overflow 8 is arranged in a closed outer container 1. Via an inlet 10, washing liquid 20 is pumped in via pump nozzles 31 in the direction of the arrow by means of a pump 12, and the washing liquid overflowing via the overflow 8 is pumped out again via an outlet 11. The foreign bodies 17 overflowing with the overflow 8 are collected in a sieve 9 and removed from there in a suitable manner. Compressed air 39 is supplied via an air line 13 and passes via air nozzles 33 between the water nozzles 31 into the lower part of the inner container 30.

The water nozzles 31 and the air nozzles 33 are arranged in the lower part of the inner container 30 in the following way: In the lower region of the inner container 30, an intermediate base 34 is drawn in, which creates an intermediate space 32 between itself and the base 19 of the inner container. A large number of water nozzles 31 are arranged in the intermediate floor 34 (see in particular FIG. 8) at regular intervals, and air nozzles 33, which are designed as fine bores in the intermediate floor 34, are provided evenly between them in a finer grid. The water nozzles 31 are structurally in the form of nozzle tubes arranged in the intermediate floor 34, which are connected to the inlet 10.

The air nozzles 33 in the form of fine bores are supplied with compressed air from the air line 13 via the intermediate space 32.

The uniform and alternating arrangement of the water nozzles 31 and the air nozzles 33 results in a relatively uniform water flow with finely distributed air bubbles in the inner container 30 from bottom to top, with hardly any swirling. This uniform water-air flow sweeps past the workpiece 4 and tears up foreign matter such as chips from its surface.

The workpiece 4 is shown in Fig. 7 only schematically hanging on a bracket 21. If there are workpieces that do not have blind holes, it is not necessary to give the workpiece 4 a movement rotating about a horizontal axis (as in the exemplary embodiments described above), but the uniform ascending water-air flow is sufficient, to achieve a sufficient cleaning effect. However, if the workpiece 4 has blind holes or other inaccessible channels, the workpiece is expediently rotated about a horizontal axis, or it is allowed to perform a wobbling movement.

A further improvement in the cleaning effect can be achieved in that (see FIG. 7) a vibration generator 46 is provided, which acts on the workpiece 4 immersed in the washing liquid 20. This vibration generator 46 can either be coupled directly to the workpiece or is arranged at a suitable location in the washing container.

A further embodiment is now shown in FIG. 9, which is particularly suitable for removing steel and iron chips from the washing container. While, for example, aluminum chips are almost entirely removed via the overflow 8 by the rising water-air mixture, it can also be the case with steel or iron chips come that they fall to the bottom of the washing container 40 and must be removed from there from time to time. For this reason, according to this advantageous embodiment according to FIG. 9, a magnetic conveyor belt 42 is provided in the floor area, which is guided over suitably arranged deflection rollers 41 and driven in a corresponding manner. The foreign bodies present on the magnetic conveyor belt 42 are attracted to the magnetic conveyor belt 42 and are guided outwards over the edge of the washing container. A wiping lip 45 wipes off the foreign bodies 17 so that they fall into a collecting container 44.

In the illustration according to FIG. 9, corresponding water nozzles 31 and air nozzles 33 are of course provided above the magnetic conveyor belt 42, as in the exemplary embodiments described above, or corresponding similar parts are arranged according to the embodiments according to FIGS. 1 and 2. However, these parts must be permeable to the falling foreign bodies 17, which in the case of the water nozzles 31 and air nozzles 33 shown in FIG. 7 can be designed in such a way that the air nozzles 33 are also designed in the form of interconnected air tubes with nozzles.

Claims (12)

1. Method for cleaning workpieces from foreign bodies such as chips or the like. by washing with a washing liquid in a washing container while blowing in compressed air or the like. below the workpieces, characterized in that washing liquid (20) is pumped in via an inlet (10, 31) arranged in the lower region of the washing tank (1, 2; 1, 30) and pumped out via an overflow (8) of the washing tank, and in that in the area of the inlet (10, 31) the compressed air or the like. is introduced. 2. Method for cleaning workpieces from foreign objects such as chips or the like. by washing with a washing liquid in a washing container while blowing in compressed air or the like. below the workpieces, in particular according to claim 1,
characterized in that the workpieces (4) in the washing container (1, 2; 1, 30) are moved about an approximately horizontal axis (16) such that bores (15), channels or other depressions present in the workpieces (4) are directed towards the horizontal with their openings (16) one after the other downwards or upwards and the air or the like blown in below the workpieces (4). penetrates into the bores (15), channels or other depressions of the workpieces directed downward in the course of the rotation of the workpieces and thereafter or the like in the course of the further rotation while entraining the chips. flows out again. 3. Device for performing the method according to claim 1 or 2,
characterized by a gear head (5) which is arranged in the washing container (1, 2; 1, 30) and to which the workpieces (4) can be fastened and which for generating movement of the workpieces at least about an approximately horizontal axis (6), in particular in Form a wobble movement is formed. 4. The device according to claim 3,
characterized in that the gear head (5) has at least one gripping device (3) for releasably holding a workpiece (4). 5. The device according to claim 3 or 4,
characterized by an overflow (8) which is provided with a separating device, in particular a sieve (9), for holding back the foreign bodies (17). 6. The device according to one or more of claims 3 to 5,
characterized in that an air nozzle (13) for injecting air is provided within the water inlet (10). 7. The device according to one or more of claims 3 to 5,
characterized by a plurality of air nozzles (18) for blowing air in at the bottom (19) of the washing container (1, 2). 8. Device for performing the method according to claim 1 or 2,
characterized in that the inlet (10, 31) at the bottom of the washing container (1, 30) is in the form of a plurality of water nozzles (31) and in that the compressed air (39) is arranged via air nozzles (33) arranged between the water nozzles (31) or another gas is introduced in such a way that a uniform flow of water with finely divided air bubbles results essentially without swirling from bottom to top past the workpieces (4) arranged in the washing container (1, 30). 9. The device according to claim 8,
characterized in that the washing tank (1, 30) has an intermediate floor (34) in which the water nozzles (31) are arranged at regular intervals and in which air bores (33) are provided between the water nozzles (31) at uniform, finer intervals , and that the intermediate space (32) can be connected to a compressed air source (39) under the intermediate base (34). 10. The device according to one or more of claims 3 to 9,
characterized in that a magnetic separator in the form of a magnetic conveyor belt (41, 42) is provided on the bottom (19) of the washing container (40). 11. The device according to one or more of claims 3 to 9
characterized in that the washing container (1, 2) consists of an outer container (1) and a basket (2) suspended therein with walls designed as a sieve. 12. The device according to one or more of claims 3 to 11,
characterized by a vibration generator (46) arranged inside the washing container (1, 2; 1, 30).

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