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Title:
METHOD AND TRANSFER APPLIANCE FOR LOADING AND UNLOADING A WIRE SAW CUTTING MACHINE
Document Type and Number:
WIPO Patent Application WO/2012/031900
Kind Code:
A1
Abstract:
The invention is directed to a method for loading and unloading at least one work piece (1) to and from a machine such as a wire saw cutting machine (20), whereby the workpiece is fixed to a fixture attachment (3, 41), the machine comprising tensions means (47) for fixing the fixture attachment, the top surface of the fixture attachment being provided with a T-shaped groove (46). The work piece (s) is/are suspended in a transfer appliance (35) comprising a loading device (35) and a unloading device (35), the loading device is brought in front of the machine and carried into the machine under the tension means without being supported by a machine part and the fixture attachment with the work piece (s) is clamped to the machine, the loading device carried back outside the machine, whereupon the work piece (s) is/are processed, then the unloading device is brought under the processed work piece (s), the work piece (s) loaded on the unloading device and carried back for being further treated. Preferentially, at least the unloading device is operating without being supported by a machine part. With this loading and unloading method slipstick effects are avoided and much bigger and heavier work pieces can be more easily handled.

Inventors:
WENGER ANDREW (CH)
SCHNYDER MATTHIAS (CH)
Application Number:
PCT/EP2011/064621
Publication Date:
March 15, 2012
Filing Date:
August 25, 2011
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
MEYER BURGER AG (CH)
WENGER ANDREW (CH)
SCHNYDER MATTHIAS (CH)
International Classes:
B23D57/00; B28D5/00
Foreign References:
JP2010149248A2010-07-08
JP2008246643A2008-10-16
JPH10128736A1998-05-19
JPH11188600A1999-07-13
Other References:
None
Attorney, Agent or Firm:
AMMANN PATENT ATTORNEYS LTD. BERNE (P.O.Box 5135, Berne, CH)
Download PDF:
Claims:
Claims

1. Method for loading and unloading at least one work piece (1) to and from a machine such as a wire saw cutting machine (20) , whereby the workpiece is fixed to a fixture attachment (3, 41), the machine comprising attachment means (47) for fixing the fixture attachment, characterised in that the work piece (s) is/are suspended in a loading and unloading assembly (24, 24A) comprising a loading device (35, 35A) and an unloading device (35, 35A) , the loading device is carried into the machine under the attachment means and the fixture attachment with the work piece (s) is clamped to the machine, the loading device carried back outside the machine, whereupon the work piece (s) is/are processed, then the unloading device is brought under the processed work piece (s), the work piece (s) is/are suspended in the unloading device and carried back for being further treated. 2. Method according to claim 1, whereby the loading and unloading assembly (24, 24A) is supporting the work piece continuously as it moves into and out of the machine.

3. Method according to claim 1 or 2, whereby the top surface of the fixture attachment is provided with a T- shaped groove (46), characterised in that the workpiece ( s ) , being fixed to the fixture attachment, is/are clamped to a feed carriage of the machine by introducing the attachment means into the groove in the fixture attachment.

4. Method according to any of claims 1 to 3,

characterised in that the attachment means are tension rods (47), whereby their heads are introduced into the T-shaped grooves in the fixture attachment, then rotated for

successively pressing the fixture attachment to the machine.

5. Method according to any of claims 1 or 4, characterised in that the transfer appliance is handled for all loading and unloading movements by a robot.

6. Transfer appliance for carrying out the method of claims 1 to 5, for loading at least one work piece (1) being fixed to a fixture assembly comprising a fixture attachment (3, 41), the machine comprising attachment means (47) for fixing the fixture attachment, characterised in that the fixture assembly is provided with suspension members (43) and in that the loading and unloading assembly (24, 24A) , comprising a loading device (35, 35A) and an unloading device (35, 35A) , has two supports (37, 68) for receiving the fixture assembly with the work piece (s), whereby parts of the suspension member (43) are supported by the supports (37, 68) .

7. Transfer appliance according to claim 6, characterised in that the suspension members (43) are provided at the lateral sides of a suspension plate (42), or fixture

attachment (41) .

8. Transfer appliance according to claim 6 or 7,

characterised in that it comprises means (44; 63, 64, 65,

66; 69) for positioning the fixture assembly (41) within the loading and unloading device (35, 35A) .

9. Transfer appliance according to any of claims 6 to 8, characterised in that the loading and unloading assembly

(24, 24A) further comprises an outer docking device (25, 25A) , the loading and unloading device (35, 35A) being slidingly held with the outer docking device (25, 25A) , the docking device and the loading and unloading device being the same entity or two differently operating entities.

10. Transfer appliance according to claim 9, characterised in that the loading device (35, 35A) is connected to the docking device (25, 25A) by telescopic guides (32), whereby one part of it (33) is attached to the docking device (25, 25A) and the other part of it (34) is attached to the loading device (35, 35A) .

11. Transfer appliance according to claims 10,

characterised in that the docking device (25, 25A) is provided with an attachment means (31, 60) .

12. Transfer appliance according to any of claims 6 to 11, characterised in that the top surface of the fixture attachment (41) is provided with a T-shaped groove (46) for receiving the attachment means (47) through the plane of the top surface.

13. Transfer appliance according to any of claims 6 to 12, characterised in that the attachment means are tension rods

(47) with heads (47H) that have two opposite sides with a smaller diameter then the remaining part.

14. Transfer appliance according to any of claims 6 to 13, characterised in that the work piece (1) is a silicon or sapphire brick or ingot.

15. Transfer appliance according to any of claims 6 to 14, characterised in that a machine part (20, 21) is provided with positioning means cooperating with the corresponding end of the 3transfer appliance or of the fixture assembly, or with corresponding positioning means thereon.

Description:
Method and Transfer Appliance for Loading and Unloading a Wire Saw Cutting Machine

The present invention pertains to a method and transfer appliance for loading and unloading a work piece fixed to a fixture attachment to a wire saw cutting machine comprising tension rods for fixing the fixture attachment to a machine part, according to the preamble of the independent claims 1 and 6.

In the known prior art, a fixture attachment to which a silicon brick is glued to be machined by a wire saw cutting machine is loaded in that the lateral under surface parts of the T-shaped fixture attachment is received on L-shaped strips and charged while sliding on the L-shaped strip.

This causes some inconveniencies : It is required that the fixture attachment with the relatively heavy work piece must be brought with high accuracy in front of the receiving strips, then there is the danger of a slip-stick effect whilst pushing the fixture into position.

While unloading, the adverse effects are enhanced since the sawing creates an amount of slurry which causes not only an enhanced slip-stick effect, which leads to rocking or even detachment of sawed silicon wafers thus being damaged but also to soiling the environment when it drips off.

Departing from this prior art it is the object of the invention to provide for a method and transfer appliance for loading and unloading a machine, more particular its working chamber, for sawing ingots, which allows to charge bigger and heavier work pieces with more accuracy and ease, without danger to loose cut wafers while avoiding the slip-stick effect and the soiling of the environment. Such a transfer appliance is defined in independent claim 1 and in method claim 13. The invention is explained below by means of drawings of exemplary embodiments which demonstrate also further advantageous features. shows a prior art machine part charged with a fixture attachment with a work piece, shows in an isometric view and schematically a part of a machine with an embodiment of a transfer appliance of the invention, shows in an isometric view and schematically an embodiment of the transfer appliance

according to the invention, shows a section according to the plane IV - IV in Fig. 3, shows a longitudinal section according to the plane V - V in Fig. 3, shows a section according to the plane VI - VI in Fig. 2 in one position of the transfer appliance, Fig. 6A shows the section of Fig. 6 in another position of the transfer appliance,

Fig. 7 shows a section according to the plane VII - VII in Fig. 6 in a first position of the feed carriage, Fig. 8 shows the section of Fig. 7 in another position of the feed carriage during sawing, Fig. 9 shows in details the transfer appliance shown in

Fig. 3,

Fig. 10 shows a section according to the plane X - X in

Fig. 9,

Fig. 11 shows a longitudinal section according to the plane X I - X I in Fig. 9,

Fig. 12 shows a variant of the docking device of the

transfer appliance, and

Fig. 13 shows a variant of the loading device of the

transfer appliance. In Fig. 1 only essential parts of a prior art machine 6 in a schematically manner are shown, for better understanding the invention. The work piece 1, for example a silicon or sapphire brick, is fixed to a transitional part 2, for example glass, which in turn is fixed to a fixture

attachment 3 of a clamping device 4. This clamping device 4 is attached to a machine part, in occurrence a feed carriage 5. The machine 6 comprises sawing or cutting means like saw bands or saw wires 7 which can form a field of bands or wires and which are held between wire guiding rolls 8. The term "brick" means that it has been shaped to make wafers from.

The essentially T-shaped fixture attachment 3 comprises two angled guiding shoulders 9 at both edges of the top surface 10, in which top surface a T-shaped groove 11 has been executed for receiving tension rods 18. An adapter piece 12 is fixed to the feed carriage 5 and comprises corresponding parts, e.g. a flat bottom 13 and two angled guiding

shoulders 14, closed by L-shaped strips 15.

Loading the machine is effectuated by introducing the fixture attachment 3, which is carried by a handling wagon, by the two lower surface parts 16 onto the inner surfaces 17 of strips 15. The sliding of these two parts causes a slip- stick effect, in particular if the parts are not accurately aligned and if the total weight of the fixture attachment and ingot is high. It is evident that the dimensions of the ingot (s) are limited with such a loading method. Moreover, making the ingot too long or too heavy would result in an enhanced slip-stick effect. Furthermore, the tension rods 18 are engaging from the front into the T-shaped groove, increasing the need of accuracy.

When unloading, the above mentioned adverse effects are even more problematic, the inside of the machine not being cleaned and therefore dirty when introducing the work piece. If the slip-stick effect is too high it might cause to loosen sawed wafers that could fall down rendering them useless. Furthermore, when drawing out the fixture

attachment with the cut and soiled wafers the slurry is dripping down, further soiling machine parts and the

environment. Also when cutting is effectuated by means of for example diamond wire and no slurry is used, the fluids used cause the same effect.

For obviating all these drawbacks a transfer appliance according to the Figures 2 - 13 has been elaborated. These Figures show possible embodiments of a transfer appliance within and without a loading assembly. Fig. 2 shows the relevant machine part 20 comprising a support 21, supporting a housing 22 comprising the wire guiding rolls 23, only one visible. The loading and

unloading assembly 24 is attached to the housing 22 of the machine .

In Fig. 3 the loading and unloading assembly 24 is shown in details. Assembly 24 comprises an outer docking device 25 in the form of a basket, the docking device comprising a U- shaped body 26 with two lateral walls 27 and a bottom 28. In this embodiment the two lateral walls are connected at the machine front surface 29 by an attaching bridge 30 with a suspension hook 31 for connecting the device to the machine housing 22, see Fig. 2. The two lateral walls 27 are

provided at its outside with a support 53.

The lateral walls 27 are provided with telescopic guides 32, which are designed analogue to an extension guide for drawers. One part 33 of the telescopic guide is attached to the docking device 25 and the other part 34 of the

telescopic guide is attached to the loading device 35, as can be seen in Fig. 4. As can be seen also in Fig. 4 the inner telescopic guide 34 runs within the outer telescopic guide 33 on ball bearings 52.

Loading assembly 24 contains a transfer appliance which comprises a loading device 35 and a unloading device 35. In this application the two devices are the same and therefore, for simplicity sake, they are named loading device 35. The transfer appliance can comprise two separated devices, also being operated differently for loading and for unloading and having the same two supports, the lateral walls 37.

The loading device 35, comprises a trough 40, for example made of sheet metal or plastics, with a U-shaped body 36 with two lateral walls 37, a bottom 38 and an end front wall 39 being cut out for the telescopic guides 33, see also Figures 9 - 11. The trough has several functions: On the one hand it gathers all the dripping slurry when unloading the sawed wafers and on the other hand it centres and supports the ingots 1 with positioning means 44 to be cut and

attached to a fixture assembly comprising the fixture attachment 41, see Fig. 4 and 10. As is best shown in Fig. 8 and 11, two workpieces 1 are glued to the transitional part 2, which in turn is fixed to a suspension plate 42. The suspension plate 42 comprises positioning bolts 43 on both lateral sides co-operating with a positioning strip 44 on the top surface 45 on both sides of the trough 40. The suspension plate 42 is fixed to the essentially T-shaped fixture attachment 41 possibly

according to the state of the art, having on its upper side a T-shaped groove 46 for receiving the tension rods 47 at the feed carriage 50. To this end the heads 47H of the tension rods 47 are milled at two sides resulting in having there a smaller diameter as the remaining part for being able to be introduced into groove 46.

Upon twisting the tension rods and lifting the fixture attachment with the workpieces, the two lateral angled guiding shoulders 48 of the fixture attachment cooperate with the inner angled guiding shoulders 49 of the feed carriage 50 for an exact positioning. It is also possible to provide the suspension and

positioning parts 43, for example positioning bolts,

directly at the fixture attachment 41. In this way the suspension plate can be omitted. In Fig. 5 it is shown how the two ingots 1, aligned

together, are suspended in the loading support. In this embodiment the docking device 25 is fixed by its suspension hook 31 in an opening 51 in the front wall 29 of housing 22. The advantage of a suspension hook is that the docking device is automatically aligned with the machine. If the basket 25 were attached to a mobile lifting device, that device would have to ensure correct alignment. With an uneven floor that may be dirty this may not be practicable. The hook may engage the machine in a self centering way.

The work cycle is explained hereinafter with regard to Figs. 6 and 6A: The loading device 35 is loaded with two silicon ingots 1 by suspending the ingots glued to the fixture attachment in the loading device which in turn is positioned within the docking device, see Fig. 6. The docking device containing the loading device is carried by a handling apparatus to the front of the opening 51 of the housing 22 of the machine 20 and suspended therein as shown in Figures 2 and 6. This is the situation of Fig. 6.

Then the loading device 35 is pushed forward into the machine, sliding on the telescopic guides, into the position of Fig. 6A. For positioning the loading device within the machine, the rear wall, in Fig. 6 the left wall, is provided with positioning means, f.ex. in the form of wedges, for bringing the loading device into the correct position, whereby the positioning means cooperate either with the corresponding end parts of the loading device or suspension plate 42 or with corresponding means thereon.

Thereupon the feed carriage is descending until the tension rods 47 reach into the groove 46 whereupon the tension rods are rotated by 90° for engaging their heads into the T- shaped groove. During this operation the fixture attachment is held by the transfer appliance. Then the whole fixture attachment with the ingots is clamped to the feed carriage and lifted off the loading device. The transfer appliance is released only when the fixture attachment is securely held by the tension rods.

The loading device is pushed back into the docking device and the sawing can begin, see Fig. 8 where the feed carriage has been lowered and will continue to be lowered until the saw wire 7 almost reaches intermediate part 2.

After the cutting procedure the feed carriage is lifted, the loading device or the separated unloading device is brought under the cut work pieces and the fixture attachment with the worked pieces lowered until the part is suspended in the trough. Thereupon the loading or unloading device is pushed back into the docking device and carried away for being discharged. The otherwise dripping and polluting slurry is safely collected by the trough.

The Figures 9 - 11 show the loading device 35 without the docking basket 25 and comprising the trough 40 with the U- shaped body 36 having the lateral walls 37, the bottom 38 and the end front wall 39. As already disclosed, the trough has suspended the fixture attachment 3 with the work

piece (s) 1.

The loading device 35 according to Figures 9 - 11 is handled by an appropriate roboter or another similarly working handling device, which performs all movements described for the loading and unloading procedure with docking device 25.

In another, still simplified embodiment, the loading device 35 could consist of a U-shaped body 36 only where the fixture attachment with suspension means is suspended therein. One preferred embodiment however, comprises the trough 40 made of sheet metal comprising centring strips.

Figs. 12 and 13 show another embodiment of the loading and unloading assembly 24A with an outer docking device 25Ά and a loading and unloading device 35A. The docking device 25A is designed to be permanently attached to the machine.

Therefore, instead of the suspension hook there is an attachment part 60 comprising screw holes 61 for attachment at the machine. This attachment part 60 can have a not shown hinge for lifting off the docking device when not in use.

Near the bottom 62 of the docking device centering elements 63, 64 are provided that cooperate with corresponding centering elements 65, 66 at the loading device 35A. The centering elements of the docking device comprise two slanted surfaces 63 for the centering in x-direction, and two pins 64 for the centering in the y-direction. The corresponding centering elements at loading device 35A are two pairs of gaps 65, 66 at the under side 67 of the side walls 68, on the front and on the back side. Normally, only one of each pairs of gaps is used. The transfer appliance can be mounted outside the processing chamber and extend into the processing chamber.

The loading device 35A is also U-shaped, whereby the top of the side walls 68 are provided with a polymer guide 69 instead of positioning strip 44. In the embodiment according to Fig. 13 the loading device 35A comprises a removable bottom plate 70 enabling an easier cleaning of it from the slurry then a complete through.

As shown in Fig. 13, the fixture attachment can be the same as in the previous embodiments with transitional part 2 , suspension plate 42, and bolts 43 sliding on the polymer guides 69.

According to the prior art, the brick with the fixture attachment has to be brought into the correct position in front of the machine, necessitating a very good alignment with the attachment means. This is e.g. done with expensive automatic handling means such as robots. Since the inventive carrier is self-aligning inside the docking device, it can be placed into it by a fork lift, a crane and even by hand, the docking device itself also being self aligning relative to the machine. This also reduces the time needed for loading and unloading thus saving costs. It follows from the description that it is possible to easily handle and treat bigger and more work pieces as with the prior art devices. This with higher precision even if the work pieces are not only bigger but also much heavier. The transfer appliance within or without a loading assembly according to the invention allows to use the usual machines and fixture attachments without the need of costly

alterations thereon. It follows further from the description that for obviating all slip-stick effects at least the unloading device should ideally operating without being supported by a machine part. It is of advantage if both the loading and the unloading device are operating without being supported by a machine part.

However, even if there is some support by a machine part, for ex. the tension rods, the telescopic guides 32 already reduce sufficiently the friction between thew fixture attachment and the machine part to prevent the slip-stick effect. The fact to attach permanently the loading device to the machine does not lessen the prevention of the slip-stick effect. In all embodiments and methods of loading and unloading according to the patent he transfer appliance suporting the working piece (s) is continuously supported as it moves into the machine, resp. its processing chamber. There is no transfer from one supporting means to another.

It is further evident that the work pieces are not limited to silicon bricks, any other material to be cut with high precision can be processed with such a device.