EP1899248A2

EP1899248A2 - Method for singulating stacked, disk-shaped elements, and singulating device

Info

Publication number: EP1899248A2
Application number: EP06753527A
Authority: EP
Inventors: Mathias Buhl
Original assignee: Brain Bernhard
Current assignee: AMB Apparate und Maschinenbau GmbH
Priority date: 2005-05-20
Filing date: 2006-05-09
Publication date: 2008-03-19
Also published as: WO2006122677A2; DE102005045583A1; WO2006122677A3

Abstract

The invention relates to a method for singulating stacked, disk-shaped elements (3, 3', 3'') from a stack (2) as well as a singulating device. Said singulating device (1) comprises a feeding mechanism (4), by means of which a stack (2) of disk-shaped elements (3, 3', 3'') is delivered to an accelerating unit (5). A section of a peripheral edge (9') of a first element (3) of the stack (2) is accelerated by the accelerating unit (5), thus increasing the traveling speed of the first element (3) of the stack (2). The element (3) that has been accelerated on one side at the peripheral edge (9) thereof is placed on a conveying mechanism (32), with the aid of which the deposited element (3) is conveyed away.

Description

Method for separating stacked, disk-shaped elements and separating device

The invention relates to a method for separating stacked, disc-shaped elements, as well as a separating device.

In many production processes, it is necessary to separate the same elements, which are in a stacked form, from one another and to supply them separately for further processing. In this case, the topmost element is usually removed from a stack. In many processes, in particular in those in which the stacked disc-shaped elements are sensitive, a person is used for this purpose, which manually decreases the respective first element of a stack. Under disk-shaped elements are understood, the thickness of which is significantly smaller than their dimensions in length and width. The disk-shaped elements do not have to be round, but may have any peripheral shapes.

It is also known to effect the lifting of the respective first element by means of a vacuum device. In this case, a suction device is placed on the surface of the first element, the gap evacuated, and so lifted the respective first element of the stack.

Both approaches have significant disadvantages. So it is, for example, in the manual separation of

Elements of a stack disadvantageous that the performance of an employee wears off in the course of a working day.

This can lead to the number of isolated

Elements in the course of a working day sinks, or the committee rises. In addition, high current

Personnel costs.

When lifting the respective first elements by means of a suction device, it is disadvantageous that for larger or not quite flat elements for sealing the suction cup relative to the element a considerable effort or a significant suction power is required to ensure safe handling of the elements. In the event that such a system is to be used for light elements of high surface quality, it is disadvantageous that the performance of such a machine far exceeds the requirements and therefore correspondingly high costs can not be justified.

With brittle materials, there is also a significant risk that elements break when overcoming the adhesion forces. The removal of the debris and the cleaning of the plant then bring the production to a standstill.

It is therefore an object of the invention to provide a separating device and a method for separating disc-shaped elements from a stack, which enables automated separation with high reliability and consistency in a simple manner.

The object is achieved by the method according to claim 1 and the separating device according to claim 11.

In the method according to the invention, first of all a stack of disc-shaped elements is fed to an acceleration device. The stack consists of stacked, disk-shaped elements. The respective first element of the stack is lifted off the stack by increasing its conveying speed. To increase the conveying speed, the element is accelerated at a part of its peripheral edge in the direction of the stack axis away from the stack by an accelerating device. The thus lifted from the stack element is deposited on a transport device and then carried away by the transport device. By accelerating the element at a part of its circumferential Edge can be dispensed with a complicated vacuum technology.

For this purpose, the separating device has, in addition to a feed device for feeding the stack, an accelerating device with which the respectively first element of the stack experiences an acceleration force at a part of its peripheral edge. By a transport device, the accelerated element is removed and thus increasingly removed from the rest of the stack. The acceleration at the part of the peripheral edge of the first element takes place in each case for the elements of the stack with a constant force, resulting in a constant separation both in terms of quality and the time interval of the separated elements.

The subclaims relate to advantageous developments of the separating device according to the invention and of the method according to the invention.

In particular, it is advantageous to effect the acceleration by means of a conveying element. In this case, a conveying element moves at a speed which is increased with respect to the axial speed of the peripheral edge of the first element of the stack. Now meets the peripheral edge of the first element on the conveying element of the accelerator, this part of the peripheral edge is taken by the conveyor element and accelerated in the direction of the stack axis away from the stack.

According to a further preferred embodiment of the method or the separating device according to the invention, the acceleration of the part of the peripheral edge of the first element takes place in at least two acceleration stages. This has the advantage that the acceleration forces and the bending moments acting on the element by the unilaterally acting acceleration force are low. The element to be separated is first unilaterally lifted a bit before in the second step, a further acceleration takes place on the same peripheral edge. However, this affects the already solved element, so that effects, such as adhesion, between the individual elements of the stack no longer play a role at this point.

The acceleration of the element at a part of its peripheral edge further has the advantage that a rotational movement of the element to be separated is triggered by the unilateral acceleration. If the stack is fed, for example, with its stacking axis in the horizontal direction, the element to be separated is deposited in the horizontal due to the rotational movement. The rotational movement is initiated solely on the basis of the unilateral acceleration of the element, so that the accelerated lower peripheral edge opposite lying upper peripheral edge of the first element tracked by gravity and the singulated element is stored, for example on a conveyor belt.

Depending on the thickness of the disc-shaped elements to be separated, it is advantageous to make the delivery of the stack to the accelerator clocked. Such timing ensures that the element initially detached from the stack is already far enough away from the stack so as not to collide with it when the next element is separated.

In order to prevent that not only the accelerated at its peripheral edge element is lifted from the stack due to adhesion, but also accidentally the subsequent element of the stack due to adhesion is lifted off the stack with, it is advantageous to provide a braking device with the at least the adjacent element of the first element to be lifted is subjected to a holding force directed counter to the acceleration force. Significant adhesion forces can occur between the individual elements of the stack. These can lead to the force applied to the peripheral edge of the first element not being sufficient to lift off the first element. According to a preferred embodiment, therefore, shortly before the start of the acceleration, a fluid jet is started to be injected or injected into the region of a contact surface between the first element to be lifted and its adjacent element. For this purpose, preferably one or more nozzles arranged around the stack are provided, each of which directs at least one fluid jet onto the stack, wherein the fluid jet strikes the stack at the contact surface between the first element and its adjacent element at least immediately before the acceleration of the peripheral edge of the first element , Such a fluid jet can be directed by one or more nozzles also from different directions on the stack, wherein the rays with a stacking axis can also have a deviating from 90 ° angle.

In order to prevent the surface of the adjacent element from slipping off the edge of the first element opposite the accelerated peripheral edge, a fluid cushion is generated between the already slightly lifted first element and the stack by at least one fluid jet through which the fluid cushion in The space between the first element and the stack is formed on which slides off the first element. In this way, a contact between the peripheral edge of the first element opposite the accelerated peripheral edge and the adjacent element of the stack is prevented or minimized.

A preferred embodiment of the separating device according to the invention and of the method according to the invention is shown in the drawing and is in the following description explained in detail. Show it:

1 shows a perspective view of an inventive dicing device at a first time;

FIG. 2 is a perspective view of the separating device according to the invention at a second time; FIG.

3 shows a perspective view of the separating device according to the invention at a third point in time;

4 is a perspective view of the separating device according to the invention at a fourth time;

5 shows a section of the separating device according to the invention;

6 shows a section of an exemplary embodiment with a braking device;

7 is an enlarged view of the transfer area according to a second embodiment;

Fig. 8 further embodiments of the embodiment of the transfer area and

Fig. 9 is an illustration of an alternative feeding device.

In Fig. 1, a separating device 1 according to the invention is shown in a perspective view. The illustration of FIG. 1 shows the separating device 1 according to the invention at a first time, too from a stack 2 already a first element 3 has been slightly lifted. The stack 2 consists of a plurality of elements 3, 3 ', ..., each having the same dimensions. It can also be used stack with elements having different sizes, the separation can be combined with a sorting process. Such elements 3, 3 ', 3 ", ... can be, for example, silicon wafers for the production of photovoltaic systems. Silicon wafers typically have a thickness of about 50 μm to 300 μm. However, the singulating device 1 according to the invention and the corresponding method for singling are not limited to such thin elements 3, 3 ", 3", ... The singling device is also, for example, for the singling of stacked printed circuit boards or other elements to be singulated used.

In order to lift the respective first element 3 from the stack 2, first the stack 2 is transported by a feeding device 4 in the direction of an acceleration device 5. For this purpose, the feeding device 4 has in the illustrated embodiment a first pair of conveyor belts consisting of a first conveyor belt 6a and a second conveyor belt 6b. The first and second conveyor belts 6a and 6b together form a conveying element of the feeding device 4. The first conveyor belt 6a and the second conveyor belt 6b are guided over a first pair of rollers 7a, 7b and a second pair of rollers 8a, 8b, wherein in FIG. 1 only the roller 8b of the second pair of rollers 8a, 8b can be seen. The drive of the conveyor belts 6a and 6b, for example via a between the rollers 7a, 7b shown, fixedly connected to the rollers 7a, 7b drive axle.

The disk-shaped elements 3 forming the stack 2 have a peripheral edge 9, which in the exemplary embodiment illustrated is identical for all elements 3, 3 ',... Of the stack 2 and these are illustrated in FIG Embodiment rectangular limited. The separation of the elements is also feasible for elements that are limited by deviating from each other in their geometry peripheral edges. With their respective lower peripheral edges 9 'are the elements 3, 3 ¹ , 3' ^{1 of} the stack 2 on the conveyor belts 6a, 6b of the feeder 4 and thus by the feeding device 4 in the in Fig. 1 by an arrow promoted direction.

Due to this feed movement, the first element 3 of the stack 2 in the figure 1 is promoted so far to the right at a certain time that its lower peripheral edge 9 'loses contact with the conveyor belts 6a, 6b. As will be explained in detail with reference to FIG. 5, the conveyor belts 6a, 6b of the feeding device 4 and the further conveyor belts in the illustrated embodiment have different levels for this purpose. In a simpler version, the levels can also be identical. The acceleration of the first element 3 is effected by a further conveying element. The further conveying element consists of a third conveyor belt IIa and a fourth conveyor belt IIb, which cooperate as a third pair of conveyor belts. The third and the fourth conveyor belt IIa, IIb move at the lower peripheral edge 9 'of the first element 3 contacting side with a speed in the direction of arrow, which is greater than the feed rate of the stack 2 and which is greater than the axial speed of the elements 3, 3 ', 3 ^■', ... of the stack 2 in direction of the stacking axis 10. the lower peripheral edge 9 'of the first member 3 is accelerated by the second pair of conveyor belts IIa, IIb in the arrow direction and moves away increasingly adjacent ones of the Element 3 'of the stack 2. The second pair of conveyor belts IIa, IIb forms a first conveying element of the accelerating device 5. The second pair of conveyor belts IIa, IIb is located substantially in axial extension to the first pair of conveyor belts 6a, βb. Due to the higher conveying speed, the lower peripheral edge 9 'of the first element 3 is accelerated relative to the lower peripheral edges of the remaining elements of the stack 2 in a first acceleration stage. In the preferred, illustrated embodiment of Fig. 1 is followed by the second pair of conveyor belts IIa, IIb a third pair of conveyor belts 12a, 12b as a further conveyor element, which again have a relation to the second pair of conveyor belts IIa, IIb increased conveying speed. Due to this second acceleration stage, the lower peripheral edge 9 'of the first element 3 is further accelerated.

The second pair of conveyor belts IIa, IIb and the third pair of conveyor belts 12a, 12b run like the first pair of conveyor belts 6a, 6b via corresponding pairs of rollers 14 to 17, wherein corresponding letter suffixes a, b to the reference numerals denote the respective side membership, wherein a Part of the roles is hidden in the figures. The first pair of rollers 14a, 14b of the second pair of conveyor belts IIa, IIb and the second pair of rollers 8a, 8b of the first pair of conveyor belts 6a, 6b are arranged in pairs on a common axis. In order to be able to realize different conveying speeds of the first pair of conveyor belts 6a, 6b and of the second pair of conveyor belts IIa, IIb, the rollers are in each case rotatably mounted to one another. In a corresponding manner, the second pair of rollers 15a, 15b of the second pair of conveyor belts IIa, IIb and the first pair of rollers 16a, 16b of the third pair of conveyor belts 12a, 12b are also arranged in pairs on a common axis.

By accelerating the lower peripheral edge 9 'of the first element 3, a rotational movement about the part of the peripheral edge 9' of the first element 3 is initiated. Compared to the accelerated lower peripheral edge 9 ' An opposite circumferential edge 9 "remains behind and, following gravity, slides on the surface of the element 3 'adjacent to the first element 3.

As soon as the lower peripheral edge 9 'of the first element 3 is far enough away from the remaining stack 2 by the second pair of conveyor belts IIa, IIb and the third pair of conveyor belts 12a, 12b, the first element 3, now turned horizontally, lies with its original one Stack 2 facing surface flat on the conveyor belts. By the third pair of conveyor belts 12a, 12b, moreover, the already separated element 3 is fed to a transport device 32, which consists of a fourth pair of conveyor belts 13a, 13b. The conveyor belts 13a and 13b are again guided by two pairs of rollers 18a, 18b and 19a, 19b. At the end of the fourth pair of conveyor belts 13a, 13b, the singulated element 3 can be stored, for example in the case of silicon wafers, either individually in a cassette, or fed directly into another processing process. Unlike in the illustrated embodiment, the second acceleration stage can also be designed as a transport device at the same time.

During the feeding of the stack 2 by the feeding device 4, the stack 2 is held on at least two sides of the feeding device 4 by guide elements extending in the axial direction. The guide elements are not shown for better illustration in the figures.

As already explained in the introduction, the separating device 1 shown is particularly suitable for separating silicon wafers. Such silicon wafers are available in different designs. With regard to singling, a distinction must be made here primarily between two types of wafers. For one thing, there are so-called drawn wafers whose surface is slightly wavy is. A distinction must be made between monocrystalline or multicrystalline wafers in which, due to their smooth surface, considerable adhesion forces occur in stacked form. In order to enable the detachment of the respective first element 3 from the stack 2, further measures are therefore necessary or possible in addition to the acceleration of the lower peripheral edges 9 ^{1 of} the respective first element 3.

According to the invention, the detachment of the first element 3 from the stack 2 is brought about by arranging a plurality of fluid nozzles 27a, 27b, 27c laterally in a transfer region from the supply device 4 to the accelerating device 5, with the aid of which a plurality of fluid jets 21a, 21b and 21c are applied to the Stack 2 will be addressed. Just before the acceleration of the lower peripheral edges 9 'begins, the first element 3 with its peripheral edge 9 has passed the fluid steels 21a, 21b and 21c. The fluid is injected through the fluid nozzles 27a, 27b, and 27c into the area of a contact surface between the first member 3 and the adjacent member 3 ", thus causing easy lifting of the adhered wafers.

The fluid nozzles 27a, 27b and 27c are preferably arranged to be movable. The movable arrangement allows either a linear movement in and opposite to the transport direction of the stack 2 or a rotation of the fluid nozzles 27a, 27b, and 27c. In a rotatable arrangement, the angle at which the fluid impinges on the elements 3 to be separated of the stack 2 changes. To improve the separation, the fluid nozzles 27a, 27b and 27c are moved together oscillating, so that a gradual fanning of the elements of the stack 2 takes place. In this case, either the fluid can be continuously supplied by the fluid nozzles 27a, 27b and 27c or clocked, wherein in the case of a pulsed supply of fluid, the fluid flow is preferably for a Movement of the fluid nozzles 27 a, 27 b and 27 c counter to the conveying direction of the stack 2 is exposed.

The fluid used in the simplest case is air. However, higher integration into a manufacturing process is possible by using a fluid tuned to a machining process. In particular, it is conceivable to use a cleaning fluid as the fluid.

The injection or injection of the fluid can also be started before the entry of the stack 2 in the transfer area. Thus, the stack 2 is ideally already loosened during the feeding continuously.

In the figures, a particularly preferred embodiment is shown in which both on both sides of the stack 2 and at the bottom of the stack 2 each have a fluid nozzle 27a, 27b, 27c is provided, each with a sharp beam 21a, 21b, 21c the Lift off the first element 3 effect. The geometry of the beams 21a, 21b, 21c substantially corresponds in each case to a circle segment, the extent being sharply delimited in the direction of the stack axis 10. Good results can also be achieved with a cylindrical jet, which is preferably sharply defined. In the figures it is shown that the beam direction is approximately perpendicular to the stacking axis 10. However, it may also be advantageous to guide the fluid jets 21a, b, c slightly in the direction of the conveying direction in order to promote the lifting of the first element 3 by the fluid jets 21a to 21c.

In FIG. 2, the singulating device 1 according to the invention is shown at a later point in time. While the first element 3 is already almost completely deposited on the third pair of conveyor belts 12a, 12b, the adjacent element 3 ^{1 has} already been accelerated at its lower peripheral edge and initiated its rotational movement. The other element 3 ^{1 1} , however, still has contact with the first pair of conveyor belts 6a, 6b, so that its lower peripheral edge does not experience any accelerating force. For the sake of clarity, the further elements of the stack 2 are no longer shown in FIG.

As already explained, a particularly gentle method of singling results, in which in particular the surface of the respectively adjacent element, in the illustrated example, the surfaces of the adjacent elements 3 ', 3 ^{1 1 is} not damaged by the upper peripheral edge 9 " in that the rotational movement of the first element 3 is carried out with the assistance of a fluid cushion. For this purpose, further fluid nozzles 23 to 26 are provided with which on the stack 2 facing side of the rotating elements 3, 3 ', a fluid cushion is provided. This supports the rotating elements 3, 3 ', so that the respective upper peripheral edge of the rotating elements 3, 3' does not come into contact with the surface of the subsequent element 3 'or 3' ^{1 of} the stack 2.

The individual fluid nozzles 23 to 27 can also be operated with different fluid media. In particular, a mixture of different fluid media may also be used on a part or all of the fluid nozzles 23 to 27. For example, a cleaning liquid may be sprayed as a spray along with air through the fluid nozzles 23 to 27.

The first fluid nozzle 23 of the fluid cushion is already arranged shortly after or in the transfer region from the supply device 4 to the acceleration device 5 in the region of the first pair of conveyor belts IIa, IIb. The injected from the first fluid nozzle 23 for generating the fluid cushion or fluid flows into the forming in the region of the lower peripheral edge 9 'of the first element 3 gap between the first element 3 and the adjacent element 3' or at the time of FIG. 2 between the adjacent element 3 'and the further element 3''. By using different fluid nozzles 23 to 26 and fluid media, the singling device 1 can be easily adjusted to different stacked elements 3, 3 ', 3 ",... In particular, this makes it possible to adjust the separating device 1 in a simple manner to, for example, different wafer thicknesses. In accordance with the increasing attack surface as the rotational movement of the elements 3, 3 ', 3 "progresses, it is also advantageous to adapt fluid jets 28 to 31 generated by the fluid nozzles 23 to 26 with regard to their geometry or their beam intensity. In the illustrated embodiment, in which the acceleration device 5 and the transport device 32 each have a pair of parallel conveyor belts IIa, IIb, 12a, 12b and 13a, b for two acceleration stages and the conveying of the elements 3, 3 ', 3'",. .., the fluid nozzles 23 to 26 are preferably arranged in a space formed between the respective conveyor belt pairs gap.

In FIG. 3, the separating device 1 is shown at a later point in time. Here, the further adjacent element 3 '' has been accelerated at its lower peripheral edge and the first element 3 is already in a horizontal plane on the conveyor belts 13a, 13b of the transport device 32. Here already a device for controlling the correct separation can be integrated. It is conceivable, for example, a weight detection or an optical thickness control. The integration may also involve automatic sorting of the elements or other devices. If the separation is not correct, the element (s) not correctly separated is taken from the further transport and returned to the singulation process. In the adjacent element 3 'whose rotational movement is almost complete. During the acceleration by the accelerating device 5, it must be ensured that there is a sufficient distance between the respective lower peripheral edge 9 'of the successive elements 3, 3', 3 ¹ ',..., In order to prevent overlapping of elements 3, 3 deposited one after the other in conveying ', 3 ¹ ' to prevent. For this purpose, it is possible, for example, in particularly thin elements 3, 3 ¹ , 3 ¹ 'to clock the feeder 4. By a corresponding timing of the feeding device 4 causes the contact of the lower peripheral edge 9 'of the adjacent element 3' and the further adjacent element 3 '' with the conveyor belts IIa, IIb of the accelerator 5 only then takes place when the lower Peripheral edge of the preceding element 3 or 3 'already has a sufficient distance. On the other hand, such a clocked supply device 4 can be dispensed with, for example, if the elements to be separated are comparatively thick elements. Such thicker elements are, for example, stacked printed circuit boards. Due to its own thickness, the contact with the conveyor belts 6a, 6b of the feeding device 4 remains at a correspondingly selected, constant feed speed before an acceleration occurs until the lower peripheral edge 9 'of the preceding first element 3 has already been transported sufficiently far.

4, it is finally shown how three elements 3, 3 'and 3 ¹ ' of the stack 2 are arranged for further processing individually and successively on the fourth pair of conveyor belts 13a, 13b, which form a conveying element of the transport device 32. The presentation of further elements has been omitted, so that once again clearly shows the preferred arrangement of the fluid nozzles 27 and 23-26.

FIG. 5 again shows an enlarged view of the transfer region from the delivery device 4 to the accelerator device 5. It can be seen that the stack 2 with the lower peripheral edges 9 'of the elements 3, 3 ", 3' ¹ etc. rests on the pair of conveyor belts 6a, 6b, wherein in the side view only the second conveyor belt 6b of the feeding device 4 can be seen Peripheral edge 9 'of the individual elements 3, 3 ¹ , 3 ^{1 1 of} the stack 2 on the pair of conveyor belts 6a, 6b results in a first distance d _{x of} the conveyor belt 6b from the stack axis 10. In contrast, a second distance d _{2 of} the conveyor belts IIa, IIb of the second pair conveyors IIa, IIb d opposite the first distance _x increases. An increase of the distance of the second pair of conveyor belts IIa, IIb may be achieved, for example, that the diameter of the rollers 14a, 14b relative to the diameter of the rollers 8a , 8b, of the first pair of conveyor belts 6a, 6b, which are arranged on the same pair of axles 20, is reduced.

FIG. 5 shows a particularly advantageous embodiment in which the second distance d _{2 is increased in} relation to the first distance d _x . Likewise, it is also possible to move the first element 3 in the direction of the accelerating device 5 when the stack 2 is fed, the first pair of conveyor belts IIa, IIb of the accelerating device 5 being opposite the first distance _{dx of} the conveyor belts 6a, 6b of the feeding device 4 having reduced distance d ₂ . In this case, the stack 2 is moved with the first element 3 against the second pair of conveyor belts IIa, IIb, whereupon the lower peripheral edge 9 'of the first element 3 also at a defined time in contact with the faster moving conveyor belts IIa, IIb has.

In addition, the position of the contact surface 22 between the first element 3 and its adjacent element 3 'is once again clearly shown in FIG. 5.

FIG. 6 again shows a section of the separating device according to the invention. In An example of a braking device 33 is shown in the transfer region between the delivery device 4 and the acceleration device 5. A transported through the conveyor belts 6a, 6b of the feeder 4 in the direction of arrow stack 2 reaches it with its first elements, the braking device 33. For the sake of clarity, only the designated with the addition "a" conveyor belts and rollers are shown. The brake device 33 has, on its side facing the stack 2 to be transported, a one-sided elevation 34 arranged in the conveying direction, against which the stack 2 to be transported is conveyed by the feed device 4. Instead of the curved contour shown in FIG. 6 of the stack 2 facing side of the braking device 33 may alternatively z. B. also a wedge-shaped geometry of the braking device 33 can be selected. During transport in the direction of the arrow, the distance of the braking device 33 with respect to the stacking axis 10 decreases. In the conveying direction, the braking device 33 is arranged so that a rear edge 35 is reached by the first element 3 of the stack 2 at a time in which another Contact with the conveyor belts 6a, 6b of the feeder 4 no longer occurs. Instead, the respective first element 3 of the stack 2 slides at a defined time when the trailing edge 35 of the braking device 33 is exceeded and is accelerated at its lower peripheral edge 9 'by the conveyor belt IIa of the accelerating device 5.

It can also be seen in FIG. 6 that, in contrast to the exemplary embodiments of FIGS. 1 to 5, an enlarged transfer region can also be formed, in which the respective axes 20 of the rollers 14a and 20 'of the roller 8a are offset relative to one another in the conveying direction are. As has already been explained in detail with reference to the embodiment of FIG. 5, also in the embodiment of FIG Conveyor pair IIa, IIb arranged with respect to the first distance d _{x of} the first conveyor belt pair 6a, 6b of the stacking axis 10 enlarged second distance d ₂ .

In the figures, two conveyor belts together form a conveying element of the feeding device 4, the accelerating device 5 and the transport device 32. The use of other conveying elements is also possible.

In Fig. 7 is an enlarged view of a transfer area between the feeding device 4 and the acceleration device 5 is shown. As in the previous examples, the level with respect to the stacking axis in the feeding device 4 and in the accelerating device 5 is different. In order to improve the lifting of the respective first element 3 of a stack 2, a toothed wheel 36 is additionally provided. In the exemplary embodiment illustrated in FIG. 7, the toothed wheel 36 is designed as a toothed wheel. However, deviating flank geometries may be required to adapt the toothed wheel 36 to the thickness of the elements 3 to be singulated. The toothed wheel 36 preferably has an outer diameter greater than the diameter of the rollers of the second pair of rollers 8a, 8b plus twice the thickness of the first and second conveyor belts 6a, 6b, respectively. As can be seen in Fig. 7, this has the consequence that movement of the stack 2 in the direction of the arrow before reaching the end of the feeder 4 brings the first element 3 of the stack 2 into contact with the rotating toothed wheel 36. As a result of the toothed wheel 36, the respective first element 3 of the stack 2 is thus grasped at the respectively lower peripheral edge 9 'and lifted off the stack. Due to the slightly larger diameter of the toothed wheel 36 while a lifting movement is performed with the element 3. As already explained, the geometry of the teeth of the toothed wheel 36 is tuned to the thickness of the elements 3 to be separated so that one element 3 is safely transported through two successive teeth of the toothed wheel 36 towards the accelerator 5. The respective lower peripheral edge 9 'is transported by the toothed wheel 36 until the lower peripheral edge 9 ^{1 of} the transported element 3 comes into contact with the third and fourth conveyor belt IIa, IIb. At this time, the third and fourth conveyor belt IIa, IIb takes over the further transport of the lower peripheral edge 9 ', whereby it comes in a manner already described to a storage of successively isolated elements of the stack 2.

In the embodiment shown in the drawing, the toothed wheel 36 preferably rotates at the same angular velocity as the first pair of rollers 14a, 14b of the second pair of conveyor belts IIa, IIb, thereby achieving acceleration of the lower peripheral edge 9 '. Notwithstanding the embodiment shown in FIG. 7, however, the toothed wheel 36 can also have its own drive, whereby in particular the first pair of rollers 14a, 14b of the second pair of conveyor belts IIa, IIb can be rotatably mounted on a separate axis. Even with the use of a toothed wheel 36 for lifting the respective first element of the stack 2, it is possible that the level of the third and fourth conveyor belt IIa, IIb exceeds the level of the first and second conveyor belt 6a, 6b and the resulting height difference by a Lifting the respective first element by means of the toothed wheel 36 is overcome.

In particular, when the elements 3 to be separated are silicon wafers, plastic gears are preferably used as the toothed wheels 36. Another possibility is to use aluminum gears, wherein at least the surfaces of the aluminum elements in contact with the elements 3 to be separated are gears are coated. As the coating of the contact surfaces of the aluminum gears an anodization is preferably used.

In Fig. 8, the transfer area from the feeder 4 to the accelerator 5 is shown again for three alternative embodiments in which the arrangement of the toothed wheels 36, 36a and 36b is different. In the simplest embodiment, which is shown in Fig. 8a), a single toothed wheel 36 is used, which is arranged centrally between the first rollers 14a, 14b of the second pair of conveyor belts IIa, IIb. In order to dispense with a separate drive for the toothed wheel 36, unlike in the previous embodiments, the toothed wheel 36 is disposed on a drive shaft 20 "which is disposed between the rollers 14a, 14b of the first pair of rollers of the second pair of conveyor belts IIa, IIb This drive shaft 20 'is non-rotatably connected to at least one of the two rollers 14a, 14b and thus transmits a drive torque to the toothed wheel 36. The arrangement shown in Fig. 8a) makes it possible to retrofit an additional toothed wheel 36 already in place To integrate systems, since the distance and the course of the first pair of conveyor belts 6a, 6b and the second pair of conveyor belts IIa, IIb remains unchanged.

Another possible arrangement is shown in FIG. 8b). In order to enable secure detection of the respective first element without generation of a tilting moment in the case of a non-central position of the supplied stack 2, in contrast to the exemplary embodiment of FIG. 8a), each of the rollers of the first pair of rollers 14a, 14b of the second pair is conveyor belts IIa, IIb associated with a toothed wheel 36a and 36b. The toothed wheels 36a and 36b can be directly connected to the first pair of rollers 14a and 14b, respectively, so that a drive takes place indirectly via the second pair of conveyor belts IIa, IIb. In this In this case, the common axle 20 may be fixed, with the second pair of rollers 8a, 8b of the first pair of conveyor belts 6a, 6b and the first pair of rollers 14a, 14b being connected to the pair of toothed wheels 36a, 36b independently of each other on the common axis 20 rotate .

In Fig. 8c), a further embodiment is shown, in which the elements to be separated 3 at its respective lower peripheral edge 9 'still further to the outer edge through the toothed wheels 36a, 36b gripped and lifted. The toothed wheels 36a, 36b are in turn connected to the first pair of rollers 14a, 14b of the second pair of conveyor belts IIa, IIb. However, unlike the embodiment shown in Fig. 8b), the toothed wheels 36a, 36b are now sandwiched between the second pair of rollers 8a, 8b of the first pair of conveyor belts 6a, 6b and the first pair of rollers 14a, 14b of the second pair of conveyor belts IIa, IIb arranged. In this way, the conveyor belts of the second pair IIa, IIb continue to be offset to the center.

FIG. 9 shows an alternative delivery device 4 'in a side view. The alternative feeding device 4 'has, instead of the first conveyor belts 6a, 6b, a stack holder 37 with the aid of which a stack 2 is conveyed in the direction of the accelerating device 5. The stack holder 37 is slidably mounted on a running rail 38 and can be moved by means of a drive element 39 in the arrow direction on the running rail 38. The stack holder 37 has a support element 40, on which a contact surface 41 is formed. At the contact surface 41 is the last element of a stack 2, which rests on a support surface 42 of the stack holder 35. The transport of the stack 2 is thus carried out not via the first pair of conveyor belts as in the previous embodiments, but with the help of the stack holder 37th The support element 40 preferably consists of two components arranged parallel to one another, whose end faces together form the contact surface 41. In extension of the contact surface 41 in approximately horizontal direction to the accelerator 5 towards the contact surface 41 is in the support surface 42, which also consists of two parallel components. Due to the fork-shaped arrangement of the support surface 42, the support surface 42 engages far enough in the region of the acceleration device 5 that the last elements of the stack 2 can be detected by the accelerator 5 at its respective lower peripheral edge 9 '. The fork-shaped bearing surface 42 is in this case positioned in the intermediate spaces of the conveyor belts 111, IIb and 12a, 12b of the acceleration device 5.

Opposite the contact surface 41, a retaining nozzle 43 is provided which acts on the respective foremost element 3 of the stack 2 in the direction of the contact surface 41 with a fluid jet. As a result, the individual elements of the stack 2 are held in contact with the contact surface 41 with a force that can be adjusted by the fluid jet and tilting of the elements 3 during movement of the stack holder 37 is prevented. In FIG. 9, the fluid nozzles 27a, 27b, 27c are not shown for reasons of clarity. Instead of the already described movable nozzles, the nozzles may also be fixed, wherein a relative movement between the fluid jet and the stack 2 is generated by an oscillating movement of the stack holder 37. In this case, a pulsed supply of fluid can again take place via the fluid nozzles 27a to 27c. The lateral alignment of the stack 2 on the stack holder 37 is effected by a stop surface 48 which is fixedly mounted on a support 49.

In FIG. 9, a guide element 45 can also be seen, which on both sides of the Acceleration device 5 is arranged and causes with its vertical walls an exact alignment of the individual elements 3 on the conveyor belts of the accelerator 5. The distance between the two walls of Führungselernents 45 decreases in the transport direction. Furthermore, two bearing blocks 46, 47 are shown in the side view, in which the axes or shafts for receiving the rollers of the acceleration device 5 are provided.

The invention is not limited to the illustrated preferred embodiment. Rather, the individual features of the embodiment can be combined with one another in any desired manner.

Claims

claims

1. A method for separating stacked disc-shaped elements (3, 3 ', 3 ^{1 1} ) from a stack (2) with the following method steps:

Feeding a stack (2) of disc-shaped elements (3, 3 ', 3 ^{1 1} ) to an accelerating device (5);

Increasing a conveying speed of a first element (3) of the stack (2) by accelerating the

Element (3) at a part of its peripheral edge (9 ¹ ) in

Direction of a stacking axis (10) through the

Accelerating device (5);

- Laying the element (3) on a transport device (32) and

- Transporting the deposited first element (3).

2. The method according to claim 1, characterized in that the stacking axis (10) is oriented approximately horizontally and the first element (3) at a lower part of its peripheral edge (9 ¹ ) is accelerated.

3. The method according to claim 1 or 2, characterized in that the acceleration by a relative to the axial velocity of the peripheral edge (9) of the element (3) with increased relative speed moving conveying element (IIa, IIb) of the accelerator device (5).

4. The method according to any one of claims 1 to 3, characterized in that an acceleration of the part of the peripheral edge (9 ') of the element (3) is carried out in at least two acceleration stages.

5. The method according to any one of claims 1 to 4, characterized. that the acceleration of the respective first element (3) at a part of its peripheral edge (9 ¹ ) initiates a rotational movement of the first element (9) with which the element (3) is deposited on the transport device (32).

6. The method according to any one of claims 1 to 5, characterized in that the respective first element (3) of the stack (2) by a relative movement of the stack (2) with respect to the acceleration device (5) with a part of its peripheral edge (9 ¹ ) is brought into contact with the accelerating device (5).

7. The method according to claim 6, characterized in that the relative movement of the stack (2) with respect to the accelerator device (5) is clocked.

8. The method according to any one of claims 1 to 7, characterized in that a first element (3) adjacent to the element (3 ¹ ) of the stack (2) is acted upon by a braking device with a holding force.

9. The method according to any one of claims 1 to 8, characterized in that at least before the start of acceleration, at least one fluid jet (27a, 27b, 27c) in a region of a contact surface (22) between the first element (3) and an adjacent element ( 3 ") of the stack (2) is injected or injected.

10. The method according to any one of claims 1 to 9, characterized in that by at least one further fluid jet 28, 29, 30, 31, a fluid cushion for the element to be deposited (3, 3 ') is generated and the element to be deposited (3, 3' ) during its rotational movement through the fluid cushion passed without contact or contact with an adjacent element (3 ¹ , 3 ^{1 1} ).

11. The method according to any one of claims 1 to 10, characterized in that the respective first element (3) by a toothed wheel (36, 36 ', 36' ') is lifted from the stack.

12. Separating device for separating stacked, disk-shaped elements (3, 3 ¹ , 3 ^{1 1} ) from a stack (2) with a feed device (4, 4 ") and an accelerator device (5) for increasing the conveying speed of a first element (3 ) of the stack (2) by accelerating a part of a peripheral edge (9 ¹ ) of the first element (3) and with a transport device (32) for conveying the element (3).

13. Separating device according to claim 12, characterized in that by a conveying element (6a, 6b) or a stack holder (37) of the feeding device (4, 4 ') of the stack (2) with an approximately horizontally oriented stacking axis (10) to the accelerating device (5) is transportable.

14. separating device according to claim 12 or 13, characterized in that the acceleration device (5) as an acceleration element at least one conveying element (IIa, IIb) with respect to the axial velocity of a peripheral edge (9) of the first element (3) increased axial velocity component and in that the conveying element (IIa, IIb) of the accelerating device (5) is arranged essentially in the axial extension of the conveying element (6a, b) of the feeding device (4) or of a bearing surface (42) of the stacking holder (37).

15. Separating device according to claim 14, characterized in that the Förderelernent (IIa, IIb) of the accelerator device (5) relative to the conveying element (6a, 6b) or the support surface (42) of the stack holder (37) of the feeding device (4, 4 ') a greater or lesser distance ( d ₂ ) from a stacking axis (10).

16. Separating device according to one of claims 13 to 15, characterized in that the conveying element (6a, b) of the feeding device (4) and / or the conveying element (IIa, b) of the accelerating device (5) are pairs of conveyor belts.

17. Separating device according to one of claims 12 to 16, characterized in that the separating device (1) has a braking device.

18. Separating device according to one of claims 12 to 17, characterized in that the separating device (1) at least one fluid nozzle (27a, 27b, 27c) for injecting or blowing at least one fluid jet (21a, b, c) in a transfer area of the feeding device (4) to the accelerator device (5).

19. Separating device according to claim 18, characterized in that in a subsequent to the transfer area of the accelerating device (5) at least one further fluid nozzle (23, 24, 25, 26) is arranged, which the first element (3) against gravity with at least one fluid jet (28, 29, 29, 30) acted upon.

20. Separating device according to one of claims 12 to 19, characterized in that in a transfer region from the Zuführungsvor- direction (4) to the accelerating device (5) at least one toothed wheel (36, 36 ', 36 ¹ ') for lifting the respective first element (3) of the stack (2) is arranged.