EP0767036A1 - Wire saw having a wire management system allowing for wire rollers of very large length - Google Patents

Abstract

The wire sawing device has a sawing zone (40), in which a workpiece (9) contacts the reciprocating or continuously moved wire (1), and a wire management system (41a), which includes a fresh wire feed spool (2a) and a used wire reception spool (14a). The wire management system includes one or more rotating unwinding and/or rewinding devices (42) which move around the periphery of the spool and which unwind and/or rewind the wire at a controllable rate. The wire is in the form of a layer (8) of parallel wires in the sawing zone, the two spools are mounted stationarily on supports and the wire management system comprises two rotating devices acting as wire travel rate and tension regulators. Each rotating device includes a winding head, which is mounted for movement around the spool periphery and which has one or more first return elements for guiding the wire to or from the spool in the direction of a second return element.

Description

The present invention relates to a wire sawing device comprising a sawing zone in which a workpiece to be sawn is in abutment against the wire capable of being moved in an alternating or continuous movement to saw the workpiece and a wire management device comprising a supply reel supplying new wire to the sawing area and a take-up reel taking up the used wire coming from the sawing area.

Known sawing devices most often comprise a sheet of wires capable of moving in a continuous or reciprocating movement pressing against a piece to be sawed in slices, thus defining a sawing zone. The sawing area consists of a set of cylinders placed in parallel. These cylinders, called wire guides, are engraved with grooves defining the interval between the wires of the sheet, that is to say the thickness of the slices to be sawed. The piece to be sawn is fixed on a support table which moves perpendicular to the wire table. The traveling speed defines the cutting speed. The wire renewal as well as the tension control is done in a part called "wire management area" and located outside the sawing area proper. The agent which will govern the cutting is either an abrasive fixed on the wire, or a free abrasive brought by bubbling. The wire acts only as a conveyor.

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

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

Wire sawing devices of the aforementioned type are already known especially in the electronic components, ferrites, quartz and silica industry, for obtaining thin slices of materials such as poly or monocrystalline silicon 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 wire sawing more attractive compared to other techniques such as diamond disc sawing. These wire sawing devices use a steel wire with a diameter generally between 0.1 and 0.2 mm, typically 0.18 mm. The running length is between 100 and 300 km, therefore with a maximum weight of 60 kg, not including the support coil.

The precision of the pieces to be sawed, which is very important for electronic applications, depends on the management of the wire and its consumption. The control of consumption will allow the control of the wear of the wire adapted to the increasing requirements of the technology which authorizes the manufacture of sawn pieces of larger diameter and greater length. This trend requires consumption control adapted to these new possibilities and this fact necessitates the use of very long wires which are not conducive to current systems.

The aims of the present invention therefore consist in overcoming the limitations of known sawing devices, which can only manage limited lengths of wire, in eliminating the inertia factor of the coils in rotation during large accelerations and decelerations, to make it possible very long wire lengths and to obtain high sawing precision.

In order to achieve these goals, the device according to the present invention is characterized in that the thread management device comprises at least one rotary unwinding and / or rewinding member mounted in a rotatable manner around the periphery of this reel and arranged so as to unwind and / or rewind the wire with an adjustable rate.

By these characteristics, the invention allows the use of coils of heavy wire having a large diameter without the use of high power motors being necessary. It will also allow you to work for long periods without human intervention, thereby improving 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 device rotating around them, the inertia is no longer dependent on the weight of the wire or that of the coil, but only that of the winding or unwinding device which can be made as light as possible. Wire lengths only become limited by market availability, and thus 400 kg spools containing up to 2000 km of 0.18 diameter wire are made possible.

The use of non-rotating wire spools therefore makes it possible to produce a wire sawing device having an extended operating autonomy with very long lengths of wire, without the wire control system being affected by the mass thereof. this. This will make it possible to have a more regular flow, to obtain higher speeds while keeping the operational advantages and a high cutting precision.

An advantageous embodiment is characterized in that the wire is arranged in the sawing zone in the form of a sheet of parallel wires, in that the two supply and take-up coils are mounted in a non-rotatable manner on a support and that the wire management device comprises two rotary members rotatably mounted around the two coils and arranged so as to act as flow rate and wire tension regulators.

A sawing device of a simple construction is thus obtained, of a reliable, fast, precise and entirely independent operation of the weight of the two spools of threads and comprising an efficient, uncomplicated regulation of the flow rate and of the tension of the thread, and of a low cost price.

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

These characteristics allow a very precise and uncomplicated construction.

The second deflection element can favorably be arranged so that the wire is disposed substantially on the axis of rotation of said rotary member coincides with the axis of the spool and arranged so as to guide the wire towards the sawing zone.

This arrangement ensures very favorable and precise wire handling.

According to a particularly advantageous variant, the first deflection element comprises a first pulley of which a normal to the axis of rotation is substantially perpendicular to the axis of the coil around which it rotates and a second pulley whose axis of rotation is mounted rotating around a shaft arranged so that the wire terminates substantially tangentially to the coil regardless of the degree of filling of the latter.

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

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

These characteristics give a simple construction and a low cost price.

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

According to another variant, the rotary member may 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 winding.

Advantageously, the function of slitting the coils is achieved by an axial reciprocating movement thereof by means of a mechanical, electrical, hydraulic or pneumatic drive member.

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

In conclusion, the sawing device will therefore be in the form of two modules, one containing the sawing zone composed of the wire guide cylinders supporting the wire ply and the support table which moves perpendicular to the wire ply , the other containing the wire management, will be made up of support of reels on which the delivery and reception coils will be posed. These may be driven back and forth to carry out the slicing operation, namely the successive winding wire against wire. Each of the spools of thread is assigned a winding or unwinding system rotating around it. This function can be achieved for example by a rotating arm centered on the axis of the coil having at its ends a pulley device with various references or by an external rail supporting a carriage with the pulleys.

Other advantages emerge from the characteristics expressed in the dependent claims and from the description setting out the invention below in more detail with the aid of drawings which schematically represent, by way of example, an embodiment and variants.

FIG. 1 schematically represents a conventional sawing device, used before the present invention.

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

FIG. 3 is a schematic view of a detail of FIG. 2.

Figures 4 and 5 are schematic views of two variants.

In the technique used before the present invention illustrated in FIG. 1, the new wire 1 comes out of the supply reel 2 which is driven by a motor 3. A tension measurement 4 corrects a tension arm 5 coupled to a motor 6. The wire then passes into the sawing zone 40, around the wire guides 7 to form the sheet of wires 8. The workpiece 9 fixed on a support table 10 comes to bear against it to be sawn by the abrasive 11 coming from a distributor 12 and driven by the wires of the ply 8. The used wire 13 leaves the ply and returns to the take-up reel 14 via the tension arm 5, the tension measurement 4 and the transfer pulley 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 reel 2a around which an arm 17 supporting pulleys 18,19,20,21 rotates. The motor of the arm 22 gives the tension to be applied to the wire 1, this tension being given by a measuring gauge 4. The wire 1 goes towards the sawing zone 40 composed of the same elements as in FIG. 1. The used wire 13 returns to the take-up reel 14a via the measuring gauge 4 and the rotary arm 17. The feed-back coils 2a and take-up 14a can be driven back and forth generated by a driving device 23 for cross-checking purposes. The wire management device 41a can be perfectly reversible.

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

FIG. 3 represents a possibility of producing the wire management device 41a according to the invention. The wire enters via a pulley 18, fixedly oriented and coupled to the tension gauge 4, coming from the sawing zone 40. The latter passes through a bearing 24 to which is fixed the tension arm 17 driven by the tension and rotation motor 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 maintain a fixed orientation relative to the wire following the filling of the take-up reel 14. The bearing 24 supports the rotary arm 17 with its pulley system. The coil is driven back and forth 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 one of the coils 2a, 14a. The pulley 21 constitutes a deflection member arranged to guide the wire coming from or ending at the spool in the direction of the pulley 20. The latter guides the wire towards the pulleys 19 and 18 which are arranged so that the wire is disposed substantially on the axis of rotation of the bearing 24, coincident with the axis of the coil. From the pulley 18, the wire then passes to the sawing zone 40.

The pulley 20 has an axis of rotation such that a normal to this axis is substantially perpendicular to the axis of the coil. As the pulley 21 rotates around the shaft 25 the wire terminates substantially tangentially to the spool regardless of the degree of filling of the latter.

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

The second variant shown in FIG. 5 comprises a support 26c and mobile support arm 26d carrying the fixed, non-rotating coil 2a. Thanks to the motor 23d, which can be of the mechanical, electrical, hydraulic, pneumatic or other type, the support arm 26d can be moved vertically to perform the slicing function, corresponding to a transverse, axial reciprocating movement of the spool 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 as a function of the signals received from the tension gauge or from another control element.

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

In a third variant, the coils 2a, 14a could be rotatably mounted on their support arm 26d (fig. 5) and driven in rotation to pass the wire at a continuous rate from the supply reel to the take-up reel. There would then be a first reciprocating movement of sawing the wire obtained thanks to the rotary members 42 with their winding head 29 and a second continuous movement of rewinding the wire on the take-up reel to compensate for the wear of the latter. The reciprocating sawing movement may then have a higher speed, for example 20 m / sec, than that of the continuous movement, for example 1 to 2 m / sec.

In general, the saw wire forming the sheet of wires 8 is made of spring steel with a diameter of between 0.1 and 0.2 mm in order to saw blocks of hard materials or more specific compositions, such as silicon, ceramic , composed of elements from groups III-V, GGG, sapphire, etc., in slices of 0.1 to 5mm thick approximately. The abrasive agent is a commercial product and can be diamond, silicon carbide, alumina, etc., in a form fixed to the wire or in free form in bubbling.

The sawing device makes it possible, by the use of heavy coils 2a, 14a, containing long lengths of wire, to rationalize the sawing operation and to cut 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, lower investment and more economical operation.

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

Claims (12)

Wire sawing device comprising a sawing zone (40) in which a workpiece (9) is pressed against the wire (1) capable of being moved in an alternating or continuous movement to saw the workpiece and a device for wire management (41a) comprising a supply reel (2a) supplying new wire to the sawing zone (40) and a receiving coil (14a) taking up the used wire coming from the sawing zone, characterized in that the device for thread management (41a) comprises at least one rotary unwinding and / or rewinding member (42) rotatably mounted around the periphery of this spool (2a, 14a) and arranged so as to unwind and / or rewind the thread with adjustable flow. Sawing device according to claim 1, characterized in that the wire is arranged in the sawing zone (40) in the form of a sheet of parallel wires (8), in that the two supply and take-up coils (2a , 14a) are mounted in a non-rotatable manner on supports and that the wire management device (41a) comprises two rotary members (42) rotatably mounted around the two coils and arranged so as to act as flow and flow regulators thread tension. Sawing device according to claim 1 or 2, characterized in that said rotary member (42) comprises a winding head (29) rotatably mounted around the periphery of the spool and comprising at at least a first return element (20,21) arranged to guide the wire coming from or ending at the spool in the direction of a second return element (18,19). Sawing device according to claim 3, characterized in that the second deflection element (18,19) is arranged so that the wire is arranged substantially on the axis of rotation of said rotary member (42) coincident with the axis of the spool (2a, 14a) and arranged so as to guide the wire in the direction of the sawing zone (40). Sawing device according to claim 3, characterized in that the first deflection 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) around which it rotates and a second pulley (21) whose axis of rotation is mounted rotating around a shaft (25) arranged so that the wire terminates substantially tangentially to the coil (2a, 14a) whatever the degree filling the latter. Sawing device according to claims 4 and 5, characterized in that the second deflection element comprises a third pulley (19) mounted on a support so as to rotate 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 zone (40). Sawing device according to one of claims 3 to 6, characterized in that the rotary member (42) comprises an arm (17) equipped with said winding head (29) and having as axis of rotation the axis of the coil. Sawing device according to one of claims 3 to 6, characterized in that the rotary member (42) comprises a ring (28) concentric with the spool and carrying said winding head (29b) driven by a rotating motor on the ring. Sawing device according to one of claims 3 to 6, characterized in that the rotary member (42) comprises a ring concentric with the spool formed by a bearing (30) with two rings, the winding head (29c) being fixed on one (32) of the rings driven in rotation by a motor (31). Sawing device according to one of claims 1 to 9, characterized in that the function of cutting the coils (2a, 14a) is carried out by an axial reciprocating movement thereof by means of a mechanical, electric, hydraulic or pneumatic drive member (23). Sawing device according to one of Claims 1 to 9, characterized in that the function of cutting the coils is achieved by an axial reciprocating movement of the winding head (29) parallel to the axis of the coils (2a, 14a). Sawing device according to claim 1, characterized in that the wire management device (41a) is arranged so as to carry out a first reciprocating sawing movement of the wire obtained by the action of said rotary member (42) and by the fact that the reels are rotatably mounted on supports to carry out a second rewinding movement of the spent wire on the take-up reel.

Images