EP2983864A1

EP2983864A1 - Method and device for the surface treatment of workpieces

Info

Publication number: EP2983864A1
Application number: EP14719237.1A
Authority: EP
Inventors: Walfried Wolk
Original assignee: Otec Praezisionsfinish GmbH
Current assignee: Otec Praezisionsfinish GmbH
Priority date: 2013-04-09
Filing date: 2014-03-26
Publication date: 2016-02-17
Anticipated expiration: 2034-03-26
Also published as: ES2634901T3; PL2983864T3; US10357866B2; EP2983864B1; WO2014166594A1; KR102218198B1; US20160016277A1; CN105102186A; CN105102186B; JP6344577B2; KR20150140280A; JP2016515476A

Abstract

The invention relates to a method for the surface treatment of workpieces, in which the workpiece is moved relative to a bulk material of grinding or polishing granulated material. In the method the workpiece is rotated about at least one axis in relation to the granulated material, whereby the workpiece is accelerated to various speeds of rotation in relation to the grinding or polishing granulated bulk material. To ensure a consistently high relative speed of rotation of the workpiece in relation to the granulate particles directly on the workpiece surface, the invention provides for the workpiece, or a container holding the bulk grinding or polishing granulate particles, to be accelerated backwards and forwards in periodic cycles of no more than 5 seconds between a first speed of rotation and a second speed of rotation and/or for rotation under continuous acceleration with continuously varying rotational speeds. The invention relates further to a device suitable for performing a method of this kind such as a drag or immersion finishing machine, which comprises a control device that is configured to act on a rotary drive of the workpiece holder on which the workpieces may be clamped or on the container accommodating the bulk granulated material with rotational speed profiles of the type referred to above during operation.

Description

Method and device for

Surface machining of workpieces

The invention relates to a method for the surface treatment of workpieces by the workpiece is moved relative to a bed of a grinding and / or polishing granules, wherein the workpiece is rotated with respect to the bed of the grinding and / or polishing granules about at least one axis wherein the workpiece is accelerated to different rotational speeds with respect to the bed of abrasive and / or polishing granules. The invention further relates to a device suitable for carrying out such a method for the surface treatment of workpieces by moving the workpiece relative to a bed of a

Grinding and / or polishing granules, with at least one workpiece holder for releasably securing a workpiece to be machined and optionally a container for receiving the grinding and / or. Poliergranulates, wherein the workpiece holder and / or the container is associated with at least one rotary drive and the device further comprises a programmatically set up control device which is able to control at least the rotational drive of the workpiece holder and / or the rotational drive of the container.

Such devices for the surface processing of workpieces using a granular grinding and / or polishing medium are known for example in the form of so-called drag and dip finishing machines. Their mode of action is based on dipping the workpiece to be machined in a bed located in a container of the grinding and / or polishing granules and the Werk-

1

CONFIRMATION COPY piece, in particular rotationally and optionally also translationally to move relative to the granules, whereby the surface of the workpiece is ground and / or polished depending on the type of granules. Towing and immersion finishing machines represent a special form of sliding grinding machines, wherein the workpieces to be processed, for example, can be clamped individually on one or more workpiece holders rotatable about their axis by means of a rotary drive. In order to move the workpieces translationally relative to the grinding and / or polishing granules, known drag finishing machines often comprise a generally rotating part substantially in the form of a plate, for example driven by a motor via a suitable gear, to which the work holder is attached directly or, for example via lifting devices, are indirectly determined. This happens in particular eccentrically with respect to the axis of rotation of the rotating part of the drag finishing machine. If this part - the so-called plate - of the towing machine is rotated, the workpiece holders defined here describe a trajectory. The workpieces carried by the workpiece holders are immersed in the working container, which is filled with the bed of the particulate abrasive or polishing granules, often with the addition of liquid processing media, such as water, surfactants, etc. Due to the relative movement of

Workpieces in relation to the granules takes their surface processing in the form of a vibratory finishing. Such drag finishing machines are known for example from DE 102 04 267 Cl, DE 200 05 361 Ul or DE 10 2010 052 222 AI.

DE 10 2011 103 606 A1 and DE 10 2009 021 824 A1 further devices for surface treatment of large format workpieces, in particular in the form of turbines, which comprise a rotationally driven workpiece holder, which dips into a stationary, the granule receiving container. An associated with the workpiece holder movement unit provides for a rotating or alternating movement of the workpiece about its axis or for different movements of the workpiece in the abrasive granules (rotating and oscillating) with varied rotational speed and immersion depth.

As an alternative or in addition to a translational movement of the workpieces clamped on the workpiece holders themselves, the container receiving the processing medium can also be moved relative to the workpieces, which in turn are rotated about their own axis, for example about its own axis and / or along a trajectory , eg in the form of a circular path. If only the container is moved and the workpieces themselves do not perform a translatory movement, then this is also referred to as "dip grinding" or "dip polishing", which thus represents a special form of drag finishing.

Modern for the surface treatment of the workpieces commonly employed apparatus such as the dipping and / or drag finishing machine of the aforementioned type include for effecting an automated operation in the Re ^¬ gel a program-equipped control means which at least the rotary drive of the workpiece holder and optionally also a translational drive the same and / or a (rotary) drive of the container according to various, can be entered into an input device Control speeds, movement speeds and processing times.

DE 10 2011 015 750 A1 describes a further method and a device for the surface treatment of workpieces, which are intended in particular for the gentle machining of very sensitive workpieces, in particular in the form of optical lenses, which have to meet very tight tolerances. The workpiece holders in this case are carried by a programmed controllable manipulator, such as an industrial robot, to pivot a workpiece clamped on the workpiece holder about several different axes during machining, thereby reducing the angle of incidence of the grinding and / or polishing tool moved in the container. Change granules with respect to discrete surface areas of the workpiece and thus to be able to provide the desired grinding and / or polishing effect for the respective surface area of the workpiece. The manipulator is able, as required, to continuously rotate the workpieces clamped on the workpiece holder at constant or adjustable different rotational speeds and / or rotational directions about the axis of the workpiece holder and / or to translate them in the bed from the grinding and / or polishing granules or To immerse workpiece only in the same. The container may in turn comprise a controlled rotary drive to enable it to rotate at the respective desired rotational speed and to change the flow velocity of the granulate relative to the workpiece.

Incidentally, the grinding and / or polishing granules used in generic grinding or polishing processes may in principle, depending on the workpieces to be treated, undergo of the most varied nature and eg of natural origin (eg of organic material, such as walnut or coconut shells, wood, cherry stone etc.), of mineral origin (eg of silicates, oxides etc.) and / or synthetic origin (eg of plastics) be. Moreover, as already indicated, it is possible to carry out the finishing process dry or in the form of wet processing with the addition of a liquid processing medium such as, for example, water, which may be mixed with additives such as surfactants.

However, it has been found that, even in the case of a rotational movement of the workpieces about the axis of the workpiece holder which is superposed by a translatory movement of the workpieces through the grinding and / or polishing granules, which may be both clockwise and anticlockwise, that is to say in different directions of rotation, can occur, at least partially unsatisfactory surface machining of the workpieces can come, which is particularly true for workpieces with relatively complex geometry, such as those with grooves, undercuts or even with more or less large cavities, wells or the like. The reason for this consists primarily in the fact that the granules are taken in the immediate vicinity of the rotated relative to the granulate workpiece from the latter, so that the relative movement of the granules in relation to the workpiece on the workpiece surface is significantly less than the rotational speed of the workpiece itself (or as the rotational speed of the granule bed rotated together with the container). This applies, as already stated, to a particular extent when the workpiece is provided with surface structures, such as grooves, undercuts, etc., or If the workpiece has one or more larger cavities or depressions, in which the granules can store during machining and are taken with the rotating workpiece.

In the prior art, this problem is primarily to be addressed by turning the workpiece with the highest possible rotational speeds, but this requires a high drive engineering effort and limits the maximum speed set. In addition, it has been found that a mere reversal of the direction of rotation can not entirely remedy this problem even when the workpiece is rotated at high rotational speeds both clockwise and anticlockwise. As regards relatively large cavities or depressions of the workpiece, such as in the case of workpieces in the form of bottles or other vessels or a mold cavity having molds, so can also very high rotational speeds only after (too) long processing time to a satisfactory surface processing of such cavities or To lead recesses of the workpiece surrounding In ^¬ nenwandungen.

The DE 20 2009 008 070 Ul describes a for Schleppfi- nishmaschinen provided workpiece holder whose displaceable in rotational workpiece support to which the to bear ^¬ beitenden workpieces can be clamped, at an inclination angle of between 5 ° and 35 ° with respect to the chuck of the workpiece holder self- are arranged, wherein the inclination angle, in particular between said angular range and an angle of 0 (vertical arrangement) can be adjustable. In this way, the storage of granular particles in grooves or undercuts of the Workpiece effectively reduced, since the particles are discharged due to the inclined axis of rotation during operation of such surface structures of the workpiece again. However, there is also the aforementioned problem of forming a velocity gradient, wherein the relative velocity of the granules decreases with respect to the rotated workpiece, the closer a granular particle is to the workpiece.

The invention is therefore the object of a method and apparatus for surface treatment of workpieces of the type mentioned in a simple and cost-effective way to the effect that the problem of entrainment of workpiece granules close to the workpiece and thus caused efficiency losses of the surface treatment can be effectively countered can and in particular a satisfactory surface processing of relatively large cavities or depressions having workpieces in economically acceptable processing time is possible.

In procedural terms, this object is achieved in a method of the type mentioned in that the workpiece and / or a bed of the

Grinding and / or polishing granules receiving container

- accelerated in periodic cycles of at most 5 s between at least a first rotational speed and at least one second rotational speed back and forth; and or

- Rotates under continuous acceleration with continuously different rotational speeds

will or will be. In device technology, the invention provides for solving this problem in a device for the surface treatment of workpieces of the type mentioned further, that the control device

- For reciprocating the rotational drive of the workpiece holder and / or the rotational drive of the container in periodic cycles of at most 5 s between at least a first rotational speed and at least a second rotational speed; and / or - for continuous acceleration of the rotational drive of the workpiece holder and / or the rotational drive of the container with continuously different rotational speeds

is set up during operation.

The inventive design prevents in a very simple and cost-effective manner the formation of a velocity gradient of the granular particles in the immediate vicinity of the rotated workpiece by the latter is accelerated in very short periodic cycles between different rotational speeds back and forth and / or with continuously different rotational speeds with respect to the granules , Consequently, the workpiece or the granulate bed received in the container is in particular continuously accelerated back and forth between one or more first rotational speeds and one or more second rotational speeds, in each case one expediently within the short periodic intervals or cycles maximum rotational speed is reached, in order to then decelerate again (to accelerate negatively), then to accelerate again (positively), etc. In this way a time-varying, in particular high relative ensured speed between the workpiece and the grinding and / or polishing granules directly to the workpiece surface, whereby a significantly increased processing efficiency and concomitant, shorter processing times can be achieved. This is especially true for workpieces with relatively large cavities or depressions, in which the granulate particles of the bed in the case of a more or less constant rotational speed of the workpiece according to the prior art after a relatively short time only be moved together with the rotating workpiece, without It comes to a significant relative movement more, but of course for a surface treatment is absolutely necessary. Any conversion of known towing and Tauchfinishmaschinen to the embodiment of the invention basically requires only a programmatic intervention in the control device to cause this, the rotational drive of the or the workpiece holder (s) or the container during operation in very short periodic cycles to accelerate back and forth between different rotational speeds and / or with continuously different rotational speeds.

By "accelerating" in the sense of the invention, moreover, both a positive acceleration and a negative acceleration or deceleration of the rotating workpiece or of the workpiece holder and / or the rotating container carrying it are addressed. In this context, "cycles" refer to the successive-identical or possibly also different-durations during the surface treatment, in which the workpiece or the granulate deposit received in the container is between at least one first and at least one is moved once and once at a second rotation speed.

In an advantageous embodiment it can be provided that the workpiece and / or the container with the granulate bed located therein is accelerated to and fro at least temporarily or temporarily between at least a first rotational speed of substantially equal to zero and at least a second rotational speed not equal to zero , Accordingly, a rotational speed profile described above is preferably set, in which the first rotational speed is approximately equal to zero, and it is generally sufficient to achieve the effect according to the invention, the workpiece or the granules deposited in the container not to absolute standstill (negative ), but can also the workpiece or the container, for example constantly at a very low (first) rotational speed of, for example, a maximum of about

50 rpm, preferably at most about 10 rpm (negative) and then returned to the desired one, e.g. maximum (second) rotation speed (positive) can be accelerated. As will be explained in more detail below, in both cases, the rotational speed of the workpiece and / or the container with the granulate therein can preferably be substantially sinusoidal (ie both periodically between at least two rotational speeds back and forth and under continuous

Acceleration with always temporally changed rotational speed) run, whereby the amplitude (speed) of such a sine curve approximately constant (eg between a Rotation speed of about zero and the same maximum rotational speed) or may be different, for example, if for the initial roughing very high (or rather low) speeds and for later fine machining on the other hand lower (or higher) speeds are desired (in this case decreases Amplitude of such a sinusoid, for example, with increasing processing time off or to).

In an advantageous embodiment can also be provided that the workpiece and / or the container with the granulate therein herein at least temporarily or temporarily between at least a first rotational speed not equal to zero and at least a second rotational speed with respect to the first rotational speed opposite direction of rotation back and forth is accelerated or become. Such reversal of the direction of rotation during machining, which takes place in continuously periodic cycles, prevents the formation of a velocity gradient of the granulate particles in the vicinity of the workpieces rotated relative to these, in particular also in the case of grooves, depressions or similar surface structures. The same applies to a filled in a relatively large cavity or such recess of the workpiece granule bed when the workpiece is accelerated in the aforementioned manner. The amounts of rotational speeds in or counterclockwise can in turn be either constant or variable over the processing time and the same or different from each other. The maximum rotational speed (s) can basically correspond to the rotational speeds which are usually set and suitable for the respective workpiece, wherein the workpiece and / or the container with the granulate bed located therein in particular at least one (first and / or second) Rotation speed of at least about 200 U / min, in particular of at least about 500 U / min, preferably of at least about 1000 U / min, can be accelerated. Particularly preferred maximum rotational speeds are at least about 1500 rpm or, in particular, at least about 2000 rpm. Corresponding values apply to the amount of the speed difference between at least a first and at least a second rotational speed, between which the workpiece and / or the container is accelerated to and fro.

On the occasion of the rotational movement of the workpiece and / or the container between the at least one first and the at least one second rotational speed back and forth, the periodic cycles should be chosen as short as possible in terms of effective and time-efficient surface processing, wherein it may preferably be provided that the workpiece and / or the container having the granulate bed therein at least temporarily in periodic cycles of at most about 4 seconds, more preferably at most about 3 seconds, preferably at most about 2 seconds, for example at most about 1 second or even at most about 0.5 second the at least one first and the at least one second rotational speed are accelerated back and forth. As already indicated, a particularly advantageous embodiment of the method according to the invention provides that the workpiece and / or a container receiving the filling from the abrasive and / or polishing granules both

- In periodic cycles of at most 5 s between at least a first rotational speed and at least one second rotational speed accelerated back and forth and also

will or will be. In this context, the workpiece and / or the container with the granulate bed located therein is advantageously accelerated over time, at least temporarily or temporarily with a substantially sinusoidal profile of the rotational speed over time, the period or the cycle of the may be substantially sinusoidal course of the rotational speed, in particular at most about 5 s (but may also last longer, as long as a continuous rotation speed change is ensured).

In this case, the workpiece and / or the container with the granulate bed located therein can at least temporarily with a substantially sinusoidal course of the rotational speed over time with approximately constant amplitude (ie with approximately constant distance between the minima or maxima of the rotational speeds ) or with amplitude that varies over time (ie with different distances between the minima or maxima of the rotational speeds) can be accelerated back and forth. If the latter method variant is selected and the workpiece and / or the container with a substantially sinusoidal course of the rotational speed with variable amplitude over time is accelerated back and forth, such as on the occasion of an above-mentioned initial coarse grinding, which gradually into a Finishing passes, preferably the amplitude of the substantially sinusoidal course of the rotational speed over time, at least temporarily, in particular substantially steadily, decrease or increase, so that the minima or maxima of the rotational speeds converge or diverge.

According to an advantageous embodiment may also be provided that at least one cavity or at least one recess of the workpiece with the bed of the grinding and / or polishing granules filled and the workpiece at least about an axis, in particular substantially around the central axis of the cavity or the Deepening,

is at least to grind and / or to polish the wall surrounding the cavity or the recess wall of the workpiece. Of course, preferably speed profiles of the above type can be set. In this way, in particular the inner walls of the workpiece surrounding such cavities and / or depressions, such as, for example, a workpiece, can be shaped a mold, a bottle or any other vessels, etc., in a very effective and time-efficient manner grind and / or polish, wherein the in the depression / in the cavity of several times at different Rotationsge ^¬ speeds accelerated workpiece filled granule bed due to inertia not ( appreciable) of the always differently rotated workpiece is taken. If only the recess or the cavity is to be surface-treated in such a workpiece, it goes without saying that a device suitable for this purpose does not necessarily have to have a container for holding (further) grinding and / or polishing granules. Moreover, it may be useful in such a case, when the hollow workpiece is rotated about the central axis of its cavity or its recess in the manner according to the invention, which in particular can be arranged substantially horizontally during the surface processing in order to take advantage of the gravity of the granular bed do.

If such cavities and / or depressions having workpieces (also) should be surface-treated on the outside and / or provided that workpieces with only re ^¬ relatively small grooves / undercuts or workpieces without such surface contours should be effectively surface-treated in a relatively short time ^¬ Kur, then may alternatively or additionally be provided in an advantageous ^{Ausgestal ¬} tion, of course, that the workpiece immersed in such a known manner in the container given a charge from the grinding and / or polishing granules and in particular the workpiece

- In periodic cycles of at most 5 s between at least a first rotational speed and at least accelerated back and forth at a second rotational speed; and or

becomes. Compared to a rotational movement of the container with such a velocity profile of this alternative (active rotation of the workpiece itself) due to the usual inertia of a particle bed and the consequent delay entrainment with an accelerated container is usually preferred to give, but it can be particularly at Of course, also offer relatively heavy workpieces and consequent high torques during braking / accelerating the same, instead of such a rotational movement of the workpiece itself to provide an active turning of the container with the granules with such Rotationsgeschwin- digkeitsprofil. Moreover, of course, a combination of both alternatives is conceivable, with the workpiece and container should be expediently at least largely rotated in opposite directions. As will be explained in more detail below, it is further conceivable, for example, to accelerate only the workpiece in the manner according to the invention to different rotational speeds and to let the container rest or if necessary to move more or less uniformly to the workpiece in addition to the container or otherwise only to accelerate the container in the manner according to the invention to different rotational speeds and to immerse the workpiece in the granulate bed located in the container and optionally in turn in addition more or less uniformly, eg translationally, to move, etc. Consequently, in particular when the workpiece is accelerated with a rotational speed profile according to the invention, it can be advantageously provided that the container is at least temporarily or temporarily

- stationary (dormant container); and or

- translationally moved back and forth;

- translationally along a trajectory, in particular along a circular path, moves; and or

rotated rotationally about its central axis (uniform or with different rotational speed and / or direction)

becomes. In the latter case, the container is expediently - be it substantially constant or be it with a temporally changed rotational speed - rotated about its central axis to avoid imbalances. The same applies in principle with preference also for the rotated workpiece.

The control device of a device according to the invention for the surface treatment of workpieces is therefore expediently set up for setting at least one, in particular several or preferably all above-described rotational speed profiles of the rotary drive of the workpiece holder and / or the container during operation.

As already mentioned, the invention of course also offers the possibility that the workpiece further - ie in addition to the rotational acceleration of the workpiece itself or in particular of the container - translationally, in particular along a trajectory, relative to the bed of the grinding and / or polishing granules is moved. This can be done, for example, by by the container with the packed bed of the grinding ^¬ and / or polishing granules moved relative to the workpiece, in particular rotated, is such that a continuous flow of the workpiece with the grinding and / or polishing granules in the direction of the relative movement between the latter and the workpiece results, in particular when the workpiece, which in turn is rotated, is immersed eccentrically to the axis of rotation of the container in the granulate bed or even moved translationally. In terms of device technology, it can be expediently provided in this connection that the control device is also set up to control the rotational drive of the container to a rotational speed which is essentially constant in time but preferably variable or else variable in time.

Alternatively or additionally, for example, another, e.g. be provided translationally reciprocating reciprocating motion or vibration drive of the container, which is in operative connection with the control device.

Alternatively or additionally, a translatori ^¬ specific movement of the workpiece in the bed of the grinding and / or polishing granules can also be made relative thereto characterized by the workpiece translate along a track curve, in particular in the form of a circular arc or any other trajectory, in the bed of the grinding and / or polishing granules is moved relative thereto. In this case, the workpiece can be moved in translation at a substantially constant speed relative to the charge from the grinding and / or polishing granules or, of course, at a variable speed become. In terms of device technology, it can be expediently provided in this connection for the work holder and / or the container also to be assigned a translatory motion drive and for the control device to be able to control the translational motion drive of the workpiece holder, in particular along a path curve, such as a circular path or any other desired path other trajectory. Such translational motion drives of the workpiece holder are known inter alia from the cited prior art and may for example comprise a rotating part of a drag finishing machine, the so-called plate, on which one or more workpiece holders are arranged eccentrically; or, for example, they may also include manipulators, such as robots and the like, carrying the workpiece holder (s).

As already mentioned, an advantageous embodiment of the method according to the invention also provides that at least the rotational movements of the workpiece and / or of the container with the granulate bed located therein and optionally the further (n) - translational and / or rotary (s) - Movement (s) of the workpiece and / or the container controlled, in particular programmed to be performed.

Servo motors, which can be preferably provided for rotationally driving the workpiece holder and / or the container of a device according to the invention, have finally proved particularly suitable for the high accelerations according to the invention within short cycles. Depending on the weight and conditional moment of inertia of the workpiece or the container can the respective rotary drive also be associated with a lower or transmission gear.

Further features and advantages of the invention will become apparent from the following description of exemplary embodiments with reference to the drawings. Showing:

Fig. 1 is a schematic perspective view of a

Embodiment of a device according to the invention for the surface treatment of workpieces in the form of a towing or dip finishing machine;

2 shows a schematic perspective exploded view of a further embodiment of a device according to the invention for the surface treatment of workpieces;

3 is a diagram of an embodiment of a during operation of the devices of Figure 1 and / or 2 controllable adjustable Rotationsgeschwindigkeits- profile of a workpiece holder with a workpiece clamped thereto over time. and one of the Fig. 3 corresponding diagram of an embodiment of another advantageous rotational speed profile.

The reproduced in Fig. 1 embodiment of a device for the surface treatment of workpieces in the form of a drag or Tauchfinishmaschine comprises a frame 1, at its upper end a about a vertical axis 2 in the direction of arrow Pi back and forth rotating part 3 in the form of a rotatable support plate is mounted in the manner of a plate. The rotatable part 3 is for this purpose with a flat if fixed to the frame 1, controllable motor drive 4 equipped. On the underside of the rotatable member 3 eccentric to the axis of rotation 2 and in the circumferential direction of the same distance voneinan- consecutively and at the same radial distance from the axis of rotation 2 of the rotatable member 3 arranged lifting devices 5 are fixed, provided in the present embodiment, three such lifting devices 5 are, but of course only two or more than three lifting devices 5 may be provided. The lifting devices 5 each carry a workpiece holder 6, which may be provided with one or more clamping devices 7, for example, in order to releasably clamp workpieces (not shown) to be machined on the occasion of their surface treatment. The drive 4 of the rotatable part 3 can serve in this way as a translational motion drive of the eccentrically arranged on the rotatable part 3 workpiece holder 6, which are moved in the case of rotation of the part 3 along a circular path.

Each lifting device 5 comprises in the present embodiment, for example, along a vertical guide 8 back and forth movable support unit 9, which for example by means of a chain or belt drive can be moved up and down. Furthermore, in the present exemplary embodiment, the lifting devices 5 in the present exemplary embodiment are movable independently of the other lifting devices 5 upwards and downwards independently of one another by means of a motor (not visible in the drawings) also attached to the underside of the rotatable part 3. At the vertically displaceable support unit 9 each one of the workpiece holder 6 is fixed, wherein the workpiece holder 6 by means of a respective controllable rotary drive 10 in Rota- tion can be offset in order to set a, for example by means of the clamping device 7, on the workpiece holder 6 clamped workpiece on the occasion of its surface processing in rotation (arrow P ₄ ).

Below the equipped with the workpiece holders 6 lifting devices 5, a container 11 for receiving a grinding and / or polishing granules (not shown) is arranged, which is rotatable about a vertical axis by means of a rotary movement drive, wherein the axis of rotation of the container 11 here, for example with the The axis of rotation 2 of the rotatable part 3 is aligned, so that the relative movement between the workpieces fixed to the workpiece holders 6 and the granulate bed located in the container 11 is the same. Each lifting means 5 is able to fastened to its supporting unit 9 work holder 6 along the arrow P2 between a obe ^¬ reindeer, arranged above the container 11 position in which ters 6 machined workpieces can be taken from the chuck 7 of the respective Werkstückhal- and this with raw Workpieces can be fitted, and a lower position in which the tensioned on the clamping device 7 of the workpiece holder 6 workpieces 17 dive into the container 11 in order to edit these, verti cal back and forth to relocate.

In addition, the rotatable part 3 is movable about its axis 3 in the direction of the arrow Pi in such a way that it can successively transfer each workpiece holder 6 with a respective workpiece fastened thereto into a loading / unloading position, such a loading / unloading position being Removal position, for example, the right in Fig. 1 workpiece holder 6 occupies, in which he - after he from the Lifting device 5 has been moved to its upper position - is freely accessible from the side.

As can be further seen from Fig. 1, the workpiece holders 6 with their clamping devices 7 can be inclined at a finite angle with respect to the vertical, this angle in the present case being e.g. about 30 °. This has proved advantageous in many cases with regard to uniform and effective surface processing. The angle of inclination of the workpiece holders 6 can be individually adjustable, e.g. the carrying the respective workpiece holder 6 supporting unit 9 of each lifting device 5 to a - here approximately horizontal - axis is pivotable. In this case, it is usually advantageous if the workpiece holders 6 have a tilt direction component arranged counter to the direction of rotation of the container 11 (arrow P3), i. the workpieces fixed to the workpiece holders 6 submerge at a slope counter to the direction of rotation of the container 11 into the granulate bed located therein, so that a surface treatment of the lower end side thereof can also take place.

As further shown in FIG. 1, the container 11 for receiving the grinding and / or polishing granules in the present embodiment on a means

Rollers 12 movable carriage 13 may be arranged to provide a simple and quick replacement of the granules by a container 11 is replaced with another container. The carriage 13 comprises the example arranged on its underside rotation drive (not visible in Fig. 1) of the container 11. In order to ensure an exact alignment of the container 11 with respect to the device carried by the frame 1, both the carriage 13 as Also, the frame 1 be equipped with mutually complementary centering devices 16, which are arranged for example on three of four sides of the carriage 13 and the frame 1 and a lateral insertion of the carriage 13 in the frame 1 for a SelbstZentrierung of the carriage 13 with respect to provide the frame 1, so that the axis of rotation of the container 11 coincides with the axis of rotation 2 of the rotatable member 3. The device further comprises a (not shown in the drawing) programmatically configured control device, which may be, for example, an electronic data processing unit with a processor and which is capable of controlling the rotary drives 10 of the workpiece holder 6 such that the latter during operation in periodic cycles Z of at most 5 s between at least one first rotational speed Ri and at least one second rotational speed R ₂ are accelerated to and fro and / or rotated with continuous different rotational speeds under continuous acceleration, wherein the corresponding desired rotational motion profiles are suitably programmed and also not graphically ^{dargestell ¬} te) input unit of the control device can be entered. In addition, for example, can also be provided that it is able to control the control means of the rotary drive of the Behäl ^¬ ters 11 in such a manner that they latter during operation at periodic cycles Z of at most 5 s between at least a first Rotationsge- speed Ri and At least a second rotational speed R2 accelerates back and forth and / or rotates with continuous acceleration with continuously different rotational speeds, wherein the wished rotation profiles also expediently programmed and can be entered into the input unit of the control device. Exemplary rotational motion profiles are explained below with reference to FIGS. 3 and 4 by way of example. The control device is furthermore capable of controlling the rotational movement drive of the container 11 in such a way as to apply it to one or more desired, more or less constant rotational speeds and / or directions.

In addition, the control device is operatively connected both to the drive 4 of the rotatable part 3 and to the drives of the lifting devices 5, wherein in the input unit of the control device, for example, the desired machining times of the workpieces as well as the loading / unloading position including the residence time of a each workpiece holder 6 can be entered in the insertion / removal position. In this case, the control device can be set up such that it moves the rotatable part 3 at periodic intervals, transferred to each workpiece holder '6 after the preset machining time in the placement / removal position and there over a sufficient for removal / assembly of workpieces, also preset Period holds. In this way, a semi-continuous workpiece assembly or release is achieved. In this connection, the control device furthermore ensures that each lifting device 5 of the respective workpiece holder 6, at the clamping device 7 of which the respective workpiece (s) is to be exchanged, is after, before or during the method the workpiece holder 6 by means of the rotatable part 3 - from the lower working position in the upper loading / unloading position vertically upward verla- Gert, held there at least on the sufficient for removal / placement of workpieces, also preset period, and then - after, before or during the process of the workpiece holder 6 by means of the rotatable member 3 - is again transferred vertically down to the working position.

FIG. 2 shows a further embodiment of a device for the surface treatment of workpieces, identical or equivalent components being provided with the same reference numerals as in FIG. The device according to FIG. 2 in turn comprises a container 11 for receiving a grinding and / or polishing granules

(not shown), which is rotatable about a vertical axis 2 by means of a rotary motion drive. In the present embodiment, the container 8 is arranged on a carriage 13 according to FIG. 1 corresponding carriage 13, on which, for example on its underside, again the rotary drive (in Fig. 2 is not completely visible) of the container 11 is arranged and which one equipped with a cam shaft 17 support plate 18 includes, on which the container 11 rotatably and self-centering can be placed. The apparatus shown in FIG. 2 further comprises a manipulator in the form of a robot, generally designated by the reference numeral 110, which carries the workpiece holder or holders 6 for releasably securing a workpiece to be machined (not shown). The robot 110 is, for example, a multi-axis industrial robot which has a frame 112 on which a carousel 113 is pivotably mounted about a vertical axis. On the carousel 113 sits a console 114 with a horizontal bearing for a rocker 115, at the console 114 facing away from the (upper) end turn a boom 116 is mounted on a horizontal, parallel to the pivot axis of the console 114 arranged axis. The expander 116 is equipped at its end with a three-axis robot hand 117, which carries the workpiece holder 6. While the carousel 113 is driven by a control motor 118 relative to the stationary frame 112, a control motor 119 serves to drive the rocker 115 and a control motor 120 for driving the boom 116. The three-axis robot hand 117 is of three further control motors 121, 122 , 123, which are mounted, for example, on the robot hand 117 facing away from the end of the boom 116. The three-axis robot hand 117 with the workpiece holder 6 can thus pivot the latter under any orientation in three-dimensional space in order to align a workpiece detachably fixed to the workpiece holder 6 in the desired position with respect to the granulate bed located in the container 11 Also to move the workpiece holder 6 translationally in any spatial directions. In addition, the three-axis robot hand 117 can rotate the workpiece holder 6 in particular in the direction of the arrow P ₄ about its longitudinal axis, wherein the rotational movement control is in turn arranged to hold the workpiece holder 6 with a workpiece attached thereto during operation in periodic cycles Z of at most 5 s between at least a first rotational speed Ri and at least one second rotational speed R2 to accelerate back and forth and / or to rotate under continuous acceleration with continuously different rotational speeds (see below with reference to the 3 and 4), wherein the corresponding desired rotational motion profiles can be programmed and entered into an input unit (also not shown in the drawing). The same can again apply to the rotation movement control of the container 11.

In FIGS. 3 and 4, advantageous rotational speed profiles of the workpiece holder 6 (and / or of the container 11), as can be carried out by means of the devices according to FIGS. 1 and 2, are reproduced by way of example. 3 and 4, on the y-axis, rotational speed n (for example, in revolutions [U] per minute) is representative of rotational speed

[min]) against the processing time t (eg in seconds [s]) on the x-axis. As can be seen from FIG. 3, the rotational speed profile of the workpiece holder 6 or of the container 11 clamped there runs substantially sinusoidally or in the form of an undamped oscillation, whereby the workpiece is constantly less stable in periodic cycles Z. (Positive or negative) acceleration between a first rotational speed Ri of about zero and a second rotational speed R ₂ , which may be, for example, about 2000 U / min, is accelerated back and forth. However, the second rotational speed does not necessarily have to be constant, but may also change over the processing time t, ie the amplitude A of the approximately sinusoidal curve may change with increasing processing time (not shown). Likewise, the first rotation speed Ri does not necessarily have to be equal to zero, but in particular can also have a rotational speed which is appreciably lower than the second rotation speed R ₂ , for example between be about 0 and about 100 rpm. The duration of the periodic cycles Z may be, for example, between about 1 s and about 10 s. The rotational speed profile of the workpiece holder 6 or of the container 11 clamped by way of example in FIG. 4 differs from that of FIG. 3 primarily in that the workpiece is continuously non-zero in periodic cycles Z between a first rotational speed Ri and a second rotational speed R ₂ also non-zero, but with opposite direction of rotation, is accelerated back and forth. The curve is also essentially sinusoidal with an inertia-related flattening in the region of the standstill (n = 0) when the direction of rotation of the workpiece is reversed. The rotational movement takes place again under continuous (positive or negative) acceleration. The amounts of the first R _x and / or second rotational speed R ₂ may in turn be about 2000 rpm, for example, but may not be any different from each other in terms of their sign. Again, both rotational speeds Ri, R ₂ do not necessarily have to be constant, but one or both rotational speeds Ri, Ri can also change over the processing time t, ie the "amplitude component" Ai of the first rotational speed Ri up to the zero point (point-by-point standstill of the workpiece in the direction of rotation reversal) and / or the "amplitude component" A2 of the second rotational speed R ₂ to the zero point of the approximately sinusoidal curve can change with increasing processing time (not shown). The period of the periodic cycles Z may be, for example, between about 0.25 s and about 5 s.

Claims

claims

A method of surface machining workpieces by moving the workpiece relative to a bed of abrasive and / or polishing granules, the workpiece being removed from the bed of material relative to the bed

Grinding and / or polishing granules to at least one Ach ^¬ se rotates (P _4), wherein the workpiece is accelerated with respect to the bed of the grinding and / or polishing granules in various rotational speeds (Ri, R2), characterized in that the workpiece and / or a container (11) receiving the charge from the abrasive and / or polishing granules

in periodic cycles (Z) of at most 5 s between at least one first rotational speed

(Ri) and at least a second rotational speed (R ₂ ) reciprocates; and or

is / are rotated under continuous acceleration with continuously different rotational speeds.

A method according to claim 1, characterized in that the workpiece and / or the container (11) with the granulate therein herein at least temporarily between at least a first rotational speed (Ri) of substantially equal to zero and at least one second rotational speed (R2) nonzero and will be accelerated or be.

A method according to claim 1 or 2, characterized in that the workpiece and / or the container (11) with the granulate bed located therein at least temporarily between at least a first rotation speed (Ri) not equal to zero and at least a second rotational speed (R ₂ ) is accelerated back and forth at a rotational direction opposite to the first rotational speed (Ri).

Method according to one of claims 1 to 3, characterized in that the workpiece and / or the container (11) with the granulate therein herein at least temporarily to at least one rotational speed (Ri; R ₂ ) of at least 200 U / min, in particular of at least 500 U / min, preferably of at least 1000 U / min, is accelerated or become.

Method according to one of claims 1 to 4, characterized in that the workpiece and / or the container (11) with the granulate therein herein at least temporarily in periodic cycles (Z) of at most 4 s, in particular of at most 3 s, preferably of at most 2 s, between at least a first rotational speed (Ri) and at least a second rotational speed (R ₂ ) is accelerated back and forth.

Method according to one of claims 1 to 5, characterized in that the workpiece and / or the container (11) with the granulate bed located therein is accelerated to and fro at least temporarily with a substantially sinusoidal course of the rotational speed over the time (t) , wherein the period or the cycle (Z) of the substantially sinusoidal course of the rotational speed is in particular at most 5 s.

7. The method according to claim 6, characterized in that the workpiece and / or the container (11) with the granulate therein herein at least temporarily with a substantially sinusoidal course of the rotational speed over time (t) with approximately constant amplitude (A) out and will be accelerated or be.

8. The method according to claim 6, characterized in that the workpiece and / or the container (11) with the granulate therein herein at least temporarily with a substantially sinusoidal course of the rotational speed over time (t) over time (t) variable Amplitude (A) is accelerated back and forth.

9. The method according to claim 8, characterized in that the amplitude (A) of the substantially sinusoidal course of the rotational speed over time (t) at least temporarily, in particular substantially steadily, decreases or increases.

Method according to one of claims 1 to 9, characterized in that at least one cavity or at least one recess of the workpiece with the bed of the grinding and / or polishing granules filled and the workpiece at least about an axis, in particular substantially around the central axis of the cavity or the depression,

- accelerated in periodic cycles (Z) of at most 5 s between at least a first rotational speed (Ri) and at least a second rotational speed (R ₂ ) back and forth; and or is rotated under continuous acceleration with continuously different rotational speeds to at least grind and / or polish the wall of the workpiece surrounding the cavity or the recess.

11. The method according to any one of claims 1 to 10, characterized in that the workpiece immersed in the container (11) discontinued bed of the grinding and / or polishing granules and the workpiece

(Ri) and at least a second rotational speed (R ₂ ) reciprocates; and or

- Is rotated under continuous acceleration with continuously different rotational speeds.

12. The method according to claim 11, characterized

that the container (11) at least temporarily

- is kept stationary;

- is moved translationally back and forth;

- Translatorisch along a trajectory, in particular along a circular path, is moved; and or

- Rotationally about its central axis (2) is rotated.

13. The method according to claim 11 or 12, characterized in that the container (11) is rotated at least rotationally about its central axis (2).

14. The method according to claim 13, characterized

that the container (11) is provided with a substantially constant rotational speed, which in turn is temporally altered. is rotated about its central axis (2).

Method according to one of claims 1 to 14, characterized in that the workpiece further translationally, in particular along a trajectory, relative to the bed of the grinding and / or polishing granules moves (Pi) is.

Method according to one of claims 1 to 15, characterized in that at least the rotational movements of the workpiece and / or the container (11) with the granulate therein and optionally the further movement (s) of the workpiece and / or the container ( 11) controlled, in particular programmed to be performed.

Device for the surface treatment of workpieces by moving the workpiece relative to a bed of a grinding and / or polishing granules, in particular for performing a method according to one of the preceding claims, with at least one workpiece holder (6) for releasably securing a workpiece to be machined and optionally one Container (11) for receiving the grinding and / or polishing granules, wherein the workpiece holder (6) and / or the container (11) at least one rotary drive (10; 17, 18) is associated and the device further comprises a programmatically established control device, which is able to control at least the rotary drive (10) of the workpiece holder (6) and / or the rotary drive (17, 18) of the container (11), characterized in that the control device

- To back and forth acceleration of the rotary drive (10) of the workpiece holder (6) and / or the rotary drive (17, 18) of the container (11) in periodic cycles (Z) of at most 5 s between at least a first rotational speed (Ri) and at least a second rotational speed (R2 );

and or

- For continuous acceleration of the rotary drive (10) of the workpiece holder (6) and / or the rotary drive (17, 18) of the container (11) with continuously different rotational speeds

is set up during operation.

Apparatus according to claim 17, characterized in that the control device

- For back and forth acceleration of the rotary drive (10) of the workpiece holder (6) and / or the rotary drive (17, 18) of the container (11) in periodic cycles (Z) of at most 5 s between at least a first rotational speed (Ri) and at least a second rotational speed (R2);

and or

is set up during operation with at least one rotational speed profile according to one of claims 2 to 9.

19. The apparatus of claim 17 or 18, characterized in that the control device at least - For reciprocating the rotational drive (10) of the workpiece holder (6) in periodic cycles (Z) of at most 5 s between at least a first rotational speed (Ri) and at least one second rotational speed (R ₂ ); and or

- For continuous acceleration of the rotary drive (10) of the workpiece holder with continuously different rotational speeds

and further for controlling the rotary drive (17, 18) of the container (11) is set to a substantially constant in time or variable rotational speed during operation.

Device according to one of claims 17 to 19, characterized in that the workpiece holder (6) and / or the container (11) is further associated with a translatory motion drive (4) and that the control device further comprises the translational motion drive (4) of the workpiece holder (6 ) and / or the container (11) is able to control, in particular along a trajectory (Pi).

Device according to one of claims 17 to 20, characterized in that for the rotational drive (10) of the workpiece holder (6) and / or the container (11) are provided servo ^{motors ¬} .

Device according to one of claims 17 to 21, characterized in that the rotational drive of the workpiece holder (6) and / or the container (11) is associated with a transmission.