EP0767036B1 - Wire saw having a wire management system allowing for wire rollers of very large length - Google Patents

Description

The present invention relates to a sawing device per wire comprising a sawing zone in which a workpiece is pressed against the susceptible wire to be moved in an alternating or continuous motion for sawing the workpiece and a wire management device comprising a supply coil supplying new wire to the sawing area and a take-up reel taking up the wire worn from the sawing area (see eg US-A-3841297).

Known sawing devices most include often a layer of thread likely to move according to a continuous or reciprocating movement pressing against a workpiece to be sliced thus defining an area of sawing. The sawing area consists of a set of cylinders placed in parallel. These cylinders called thread guides, are engraved with grooves defining the interval between the tablecloth wires, i.e. the thickness of the slices to be sawed. The workpiece is fixed on a table support which moves perpendicular to the sheet of son. Travel speed defines the speed of chopped off. The renewal of the wire as well as the control of the tension is done in a part called "management zone of the wire "and located outside the sawing area properly called. The agent that will govern the cutting is either a abrasive fixed on the wire, i.e. a free abrasive brought by sparging. The wire acts only as a conveyor.

The wire used, even if it only acts as a transporter, undergoes some wear which will have to be compensated by a renewal rate which will be defined by the area sawn per unit of time. The current development of wire sawing is driven by the trend of users to move towards sawing large pieces, so large areas and therefore a large consumption of wire. The use of long wires becomes imperative.

Common wire management systems in sawing devices are made by using coils mounted horizontally or vertically on a motorized axis whose speed is managed by a device regulating the thread flow and tension via a electronic control. The wire will therefore pass from a spool of new wire at the sawing area to return after use to a spool of used wire. In much of case, an asymmetrical longitudinal back-and-forth movement is applied, asymmetry being used to adjust the renewal rate. The back and forth movement longitudinal will impose on the reels of new wire and used frequent changes of direction with strong accelerations. If we don't want to increase the engine power beyond reasonable, limitation current of these sawing devices is therefore determined by the weight of the spools of wire which must be accelerated or decelerate and therefore by the length of wire that can be managed this way. Another difficulty stems from the fact that the reel goes from full weight to empty weight during work. This great variation of weight disrupts regulatory systems and makes more difficult, if not impossible, control in general. In addition, if the length is limited, the change of thread must be made more frequently with the consequence greater handling and interruption extended production time.

Wire sawing devices of the above type are already known especially in the components industry electronics, ferrites, quartz and silicas, for obtaining thin slices of materials such as silicon poly- or monocrystalline or new materials such as GaAs, InP, GGG (gadolinium-gallium garnets) or also quartz, synthetic sapphire, and ceramic materials. The high price of these materials makes sawing by more attractive thread compared to other techniques like diamond disc sawing. These devices wire sawing use steel wire with a diameter generally between 0.1 and 0.2 mm, typically 0.18mm. The current length is between 100 and 300 km therefore with a maximum weight of 60 kg, not including the coil support.

The precision of the pieces to be sawed, very important for electronic applications, depends on the management of wire and its consumption. Consumption control will allow the control of the wear of the wire adapted to the requirements technology that allows manufacturing larger diameter work pieces and longer length. This trend requires control of consumption adapted to these new possibilities and this fact requires the use of very long wires conducive to current systems.

The aims of the present invention therefore consist in remedy the limitations of known sawing devices, who can only handle limited lengths of wire, remove the inertia factor of the rotating coils during large accelerations and decelerations, to be returned possible very long lengths of wire and to obtain high sawing precision.

In order to achieve these goals, the device according to the present invention is characterized in that the device wire management includes at least one rotary member of unwinding and / or rewinding mounted so rotating around the periphery of the supply reel and / or of the take-up reel and arranged so as to unwind and / or rewind the thread with a adjustable flow.

By these characteristics, the invention allows the use coils of heavy wire having a large diameter without the use of high power motors being necessary. This will also allow you to work during long periods without human intervention, improving thus productivity and quality. By the use of static coils, or in any case without rapid rotation, and by winding or unwinding the wire by a rotating device around these, inertia is no longer dependent the weight of the wire or that of the spool, but only that of the winding or unwinding device which can be made as light as possible. Wire lengths only become limited by the market availability, and thus 400 kg reels containing up to 2000 km of 0.18 diameter wire are made possible.

The use of non-rotating wire spools allows therefore to produce a wire sawing device having a extended operating autonomy with very large lengths of wire, without the wire control system is affected by the mass of it. This will allow to have a more regular flow, to get bigger speeds while keeping the operational benefits and high cutting precision.

An advantageous embodiment is characterized by the the wire is arranged in the sawing area under form of a sheet of parallel wires, by the fact that the two supply and take-up coils are mounted so not rotatable on a support and that the management device of the wire comprises two rotating members mounted so rotating around the two coils and arranged so as to act as flow and thread tension regulators.

A sawing device for a construction is thus obtained. simple, reliable, fast, precise operation and completely independent of the weight of the two coils of wires and comprising a regulation of the flow and the efficient, uncomplicated thread tension with a price of comes back weak.

Advantageously, said rotary member comprises a winding head rotatably mounted around the periphery of the coil and comprising at least a first return element arranged to guide the wire coming from or ending at the coil in the direction of a second element of reference.

These characteristics allow a very precise and uncomplicated.

The second reference element can favorably be arranged so that the wire is arranged substantially on the axis of rotation of said rotary member coincides with the axis from the spool and arranged to guide the wire in the direction of the sawing area.

This arrangement ensures very favorable wire management and precise.

According to a particularly advantageous variant, the first deflection element includes a first pulley of which a normal to the axis of rotation is substantially perpendicular to the axis of the coil around which it turns and a second pulley whose axis of rotation is mounted rotating around a tree arranged so that the wire ends substantially tangentially to the coil whatever the degree of filling of the latter.

The wire can thus be wound and unwound from start to the end of the spool, very regularly and with an orientation precise.

Advantageously, the rotary member comprises a arm equipped with said winding head and having as axis the axis of the coil.

We obtain by these characteristics a construction simple and low cost.

Alternatively, the rotary member may include a concentric ring to the coil and carrying said head winding driven by a motor rotating on the ring.

According to another variant, the rotary member can comprise a ring concentric with the coil formed by a bearing with two rings, the winding head being fixed on one of the rings driven in rotation by a motor.

These variants make it possible to obtain a very precise and reliable.

Favorably, the bobbin cutting function is achieved by an axial back and forth movement of these by means of a mechanical drive member, electric, hydraulic or pneumatic.

The wire can thus be wound very evenly on the coils. The movement back and forth along the axis of the coil is applied, with an amplitude which is equal at the filling length defined by the distance between the flanges of the coil.

In conclusion, the sawing device will present itself so in the form of two modules, one containing the area sawing consisting of the wire guide cylinders supporting the tablecloth, wires and support table which moves perpendicularly to the sheet of wire, the other containing the wire management, will consist of coil support on which will be installed the supply and take-up coils. These can be animated by a movement of back and forth to perform the slicing operation, at know the successive winding wire against wire. To each of coils of wire is assigned a winding system or unwinding revolving around it. This function can be achieved for example by a centered rotating arm on the axis of the coil having at its ends a device pulleys with various references or by an external rail supporting a carriage with the pulleys.

Other advantages emerge from the characteristics expressed in dependent claims and description setting out the invention below in more detail at using drawings which represent schematically and at As an example, an embodiment and variants.

Figure 1 shows schematically a device conventional sawing, used before the present invention.

Figure 2 is a schematic view of an embodiment of the sawing device according to the present invention.

Figure 3 is a schematic view of a detail of the figure 2.

Figures 4 and 5 are schematic views of two variants.

In the technique used before the present invention illustrated in Figure 1, the new wire 1 comes out of the spool debtor 2 which is driven by a motor 3. A measurement tension 4 corrects a tension arm 5 coupled to a motor 6. The wire then passes through the sawing zone 40, around the wire guides 7 to form the sheet of wires 8. The sawing piece 9 fixed on a support table 10 comes in press against it to be sawn with abrasive 11 from a distributor 12 and driven by the son of the ply 8. The used wire 13 leaves the ply and returns to the take-up reel 14 via the arm of tension 5, tension measurement 4 and the pulley trancanning 15 actuated back and forth sideways by the motor 16. The wire management device 41 therefore comprises coils 2 and 14 mounted to rotate about their axis.

Figure 2 schematically illustrates an embodiment of the present invention. The new wire 1 comes out of the supply coil 2a around which an arm 17 rotates supporting pulleys 18,19,20,21. The arm motor 22 gives the tension to be applied to wire 1, this tension being given by a measurement gauge 4. Wire 1 goes to the area sawing 40 composed of the same elements as in FIG. 1. The worn wire 13 returns to the take-up reel 14a by through the gauge 4 and the rotating arm 17. The supply 2a and take-up 14a coils can be driven back and forth by a drive device 23 for trancanning purposes. The wire management device 41a can be perfectly reversible.

Thus, the coils 2a and 14a are mounted so fixed, not rotatable on any support. The arms 17 with their pulleys 18 to 21 each form a rotary member 42 of unwinding and / or rewinding mounted so rotating around the periphery of the coils and arranged way to unwind and / or rewind the thread with a flow adjustable by the speed of the motors 22. The gauges of measure 4 are connected to the control of motors 22, way that the rotary members 42 act as regulators thread flow and tension.

FIG. 3 represents a possibility of carrying out the wire management device 41a according to the invention. Thread enters by a pulley 18, fixedly oriented and coupled to the tension gauge 4, coming from the sawing zone 40. This passes through a bearing 24 at which is fixed the tension arm 17 driven by the tension motor and of rotation 22 fixed on a support 26. It passes around the pulleys 19 and 20 fixed relative to the arm and having parallel axes of rotation. The output pulley 21 can be rotatable relative to the shaft 25 to keep a fixed orientation to the next wire filling the take-up reel 14. The bearing 24 supports the rotary arm 17 with its pulley system. The coil is driven by a back and forth movement generated by a mechanism 23 which can be electric, hydraulic, pneumatic or other.

The pulleys 20, 21 therefore form a winding head 29 rotatably mounted around the periphery of a coils 2a, 14a. The pulley 21 constitutes a return arranged to guide the wire coming from or ending to the spool in the direction of the pulley 20. The latter guides the wire to the pulleys 19 and 18 which are arranged so that the wire is arranged substantially on the axis of rotation of the bearing 24, coincident with the axis of the coil. From pulley 18, the wire then passes to the sawing zone 40.

The pulley 20 has an axis of rotation such as a normal to this axis is substantially perpendicular to the axis of the coil. As the pulley 21 turns around the shaft 25 the wire terminates substantially tangentially at the coil whatever the degree of filling of the latter.

FIG. 4 represents a variant making it possible to carry out the function using a linear motor 27 in rotation on a concentric ring or circular rail 28 to coil 2a. Linear motor carriage 29b 27 forming the winding head supports the necessary pulleys 20b and 21b. The pulley 18b coupled to the gauge tension 4b, as well as the bearing 24b are fixedly mounted on the support 26b and the pulley 19b rotating relative to the pulley 18b is fixed on the bearing 24b. Pulley 21b is rotating rise on the shaft 25b, while the pulley 20b has a fixed axis of rotation relative to the carriage 29b.

The second variant shown in Figure 5 includes a support 26c and mobile support arm 26d carrying the coil 2a fixed, non-rotating. Thanks to the 23d motor, which can be mechanical, electrical, hydraulic, pneumatic or other, the support arm 26d can be moved vertically to perform the slicing function, corresponding to a transverse back-and-forth movement, axial of the coil so as to wind the wire gradually. A ring concentric with the coil is formed by a ball bearing 30 comprising two rings. The winding head 29c is mounted on the inner ring 32 driven in rotation by the motor 31, for example in function of signals received from the voltage gauge or a other control element.

As previously described the pulleys 18c and 20c have axes of rotation with fixed orientation relative to to the support 26c, respectively to the winding head 29c, while the pulleys 19c and 21c are mounted so rotating relative to the support 26c thanks to the bearing 24c, respectively with respect to the winding head 29c thanks to tree 25c.

According to a third variant, the coils 2a, 14a could be rotatably mounted on their arm 26d support (fig. 5) and rotated for pass the wire at a continuous rate from the spool debtor to the take-up reel. We would then have a first reciprocating sawing movement of the wire obtained thanks to the rotary members 42 with their winding head 29 and a second continuous movement of rewinding the thread on the take-up reel to compensate for wear. The alternative sawing movement can then have a speed greater, for example 20m / sec, than that of the movement continuous, for example 1 to 2m / sec.

Generally, the saw wire forming the web 8 wires consist of spring steel with a diameter between 0.1 and 0.2 mm in order to saw blocks of material hard or more specific compositions, such than silicon, ceramic, composed of elements of groups III-V, GGG, sapphire, etc., in slices 0.1 to 5mm thick about. The abrasive agent is a commercial product and can be diamond, silicon carbide, alumina etc, in form attached to the wire or in free form in sparging.

The sawing device allows by the use of coils 2a, 14a heavy, containing great lengths of wire, streamline the sawing and cutting operation large-sized sawn pieces 9 while obtaining the necessary precision. In addition, the general concept of the machine is simplified, making it possible to obtain for the user a lower investment and a more economical operation.

It is understood that the embodiment and the variants described above have no character limiting and that they can receive any modifications desirable within the framework as defined by the Claims 1. In particular, the sawing device may only have one in the sawing area wire, instead of a sheet of wire. He could also have a single, non-rotating coil either receiver and another wire management device at the other end, for example a monoflasque conical coil. The coil cutting function could also be performed by a back and forth movement transverse of the winding head parallel to the axis coils. Pulleys 18 to 21 could be replaced by any other suitable return and guide device. The orientation of the axis of the coils 2a, 14a could be different, vertical or oblique.

Claims (12)

1. Device for wire sawing comprising a sawing region (40) in which a piece (9) to be sawed bears against the wire (1) adapted to be displaced with reciprocal or continuing movement to saw the piece and a wire management device (41a) comprising a payout spool (2a) supplying new wire to the sawing region (40) and a take-up spool (14a) taking up the used wire from the sawing region, characterized by the fact that the wire management device (41 a) comprises at least one revolving unspooling and/or respooling member (42) mounted to revolve about the periphery of the payout spool (2a) and/or of the take-up spool (14a) and arranged so as to unwind and/or rewind the wire with an adjustable flow rate.
2. Sawing device according to claim 1, characterized by the fact that the wire is arranged in the sawing region (40) in the form of a layer of parallel wires (8), by the fact that the two payout and take-up spools (2a, 14a) are mounted non-rotatably on supports and that the wire management device (41a) comprises two rotatable members (42) mounted so as to revolve about the two spools and arranged so as to act as regulators of flow rate and tension of the wire.
3. Sawing device according to claim 1 or 2, characterized by the fact that said rotatable member (42) comprises a spooling head (29) mounted to revolve about the periphery of the spool and comprising at least one first return element (20, 21) arranged to guide the wire from or to the spool in the direction of a second return element (18, 19).
4. Sawing device according to claim 3, characterized by the fact that the second return element (18, 19) is arranged such that the wire is disposed substantially on the axis of rotation of said rotatable member (42) coinciding with the axis of the spool (2a, 14a) and arranged so as to guide the wire in the direction of the sawing region (40).
5. Sawing device according to claim 3, characterized by the fact that the first return element comprises a first pulley (20) of which a normal to the axis of rotation is substantially perpendicular to the axis of the spool (2a, 14a) about which it revolves and a second pulley (21) whose axis of rotation is mounted to revolve about a shaft (25) arranged such that the wire will end in a substantially tangential manner at the spool (2a, 14a) no matter what the degree of fullness of this latter.
6. Sawing device according to claims 4 and 5, characterized in that the second return element comprises a third pulley (19) mounted to revolve on a support such that its axis of rotation is substantially parallel to the axis of rotation of the first pulley (20) and a fourth pulley (18) arranged so as to guide the wire in the direction of the sawing region (40).
7. Sawing device according to one of claims 3 to 6, characterized by the fact that the rotatable member (42) comprises an arm (17) provided with said winding head (29) and having for its axis of rotation the axis of the spool.
8. Sawing device according to one of claims 3 to 6, characterized by the fact that the rotatable member (42) comprises a ring (28) concentric to the spool and carrying said spooling head (29b) driven by a motor in rotation on the ring.
9. Sawing device according to one of claims 3 to 6, characterized by the fact that the rotatable member (42) comprises a ring concentric to the spool formed by a roller (30) with two rings, the spooling head (29c) being secured on one (32) of the rings driven in rotation by a motor (31).
10. Sawing device according to one of claims 1 to 9, characterized by the fact that the traversing function of the spools (2a, 14a) is carried out by an axial reciprocal movement of these latter by means of a mechanical, electrical, hydraulic or pneumatic drive member (23).
11. Sawing device according to one of claims 1 to 9, characterized by the fact that the traversing function of the spools is effected by axial reciprocating movement of the spooling head (29) parallel to the axis of the spools (2a, 14a).
12. Sawing device according to claim 1, characterized by the fact that the wire control device (41a) is arranged so as to effectuate a first reciprocating movement of the wire saw obtained thanks to the action of said rotatable member (42) and by the fact that the spools are mounted to revolve on supports to effect a second rewinding movement of the used wire on the take-up spool.

Images