JPS63237863A - Wire saw - Google Patents

Abstract

PURPOSE:To increase abrasion resistance at groove section and to reduce fluctuation of groove pitch due to temperature variation by guiding/driving a wire through a tubular roller composed of ceramic or cermet having high hardness with a plurality of grooves being formed in the surface. CONSTITUTION:A head roller 20 is entirely formed from ceramic or cermet into an approximately tubular member, where about 170 grooves for guiding a wire are made in the outer circumference and a fixing through-hole 22 is made therein. The bottom of the groove 21 is curved with curvature of about 0.05mm in order to guide the wire stably, and the grooves are machined highly accurately such that the error of the pitch of groove is within about 3mum. A drive roller 10 is made by coupling a surface member 12 composed of ceramic or cermet having grooves 11 with a core member 14 composed of metal having a fixing through-hole 13. Grooves 11, 12 are machined by means of a diamond wheel.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a wire saw that performs precision machining such as cutting and grooving a workpiece by driving a wire to which an abrasive is attached.

[Conventional technology]

A device called a wire saw was used for introducing and cutting magnetic heads and vibrators, and for precision cutting such as cutting ceramic and silicon wafers. This wire saw has a drive roller 10 and two head rollers 20 rotatably attached to a frame S, and a wire 30 is placed around these three rollers at regular intervals, as shown in FIG. and two head rollers 20.
It was equipped with a spray nozzle (not shown). By driving the wire 30 in the direction of the arrow by a take-up roller (not shown) while rotating the drive roller 10 in a reciprocating manner, the wire row 31 is moved in a reciprocating linear motion, and the workpiece H is pressed against the wire row 31. By interposing an abrasive material between them, cutting and introduction can be performed according to the pitch width of the wire row 31.

The wire 30 was a special piano wire with a diameter of about 0.08 to 0.25 mm, and the abrasive used was a mixture of GC abrasive grains and special cutting oil.

The head roller 20 constituting such a wire saw, as shown in a partially cutaway view in FIG. The surface member 22 was made of a resin such as nylon 66 or UMPB resin. Further, the drive roller 10 was also a combination of a surface member made of resin with grooves formed therein and a core material made of metal.

[Problems with conventional technology]

However, in such a conventional wire saw, since the groove portions of the drive roller 10 and head roller 20 were made of resin, the wire 30 caused severe wear. If the wear increases, the wire 30 will become wedged in the groove 21, increasing the resistance to drive the wire 30, and eventually causing the wire to break. 10. The head roller 20 had to be replaced with a new one, which was not only time-consuming but also expensive.

Further, as described above, the cutting width of the workpiece H is determined by the pitch width of the wires 30 in the wire row 31, but this also depends on the pitch width of the grooves 21 formed on the two helad rollers 20. Therefore, the pitch width of this a21 had to be made with very high precision. However, since resin has a large coefficient of thermal expansion, the pitch width of the groove 21 changes greatly due to temperature changes during groove processing, subsequent annealing, or use, making it difficult to obtain excellent dimensions for high-precision cutting. It was difficult to maintain accuracy.

Furthermore, since the resin has low hardness and is easily deformed, the groove portions are easily deformed during handling of the drive roller 10 and head roller 20, and there is a fear that the dimensional accuracy of the pitch may be deteriorated.

[Means for solving problems]

In view of the above, the present invention has a plurality of grooves on the surface, and the wire is guided by a cylindrical roller made of a highly hard material such as ceramic, cermet, or sapphire, and the wire is polished while being driven. This wire saw is configured to be able to cut a workpiece using a material.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS A drive roller and a head roller that constitute a wire saw according to an embodiment of the present invention will be explained below with reference to the drawings.

The head roller 20 shown in FIG. 1(a) is a generally cylindrical body made entirely of ceramic or cermet such as alumina, zirconia, silicon carbide, silicon nitride, etc., and has grooves 21 on its outer peripheral surface for guiding the wire 30. It is equipped with about 170 pieces, and has a through hole 22 for attachment formed inside. As shown in the enlarged view in FIG. 1(b), the groove 21 has a curved bottom with a radius of curvature of about 0.05 mm to improve the stability of the wire 30, and the pitch P of the groove 21 has an error of within 3 μm. Processed with high precision.

The drive roller 10 shown in FIG. 2 also has a surface member 12 made of ceramic or cermet in which grooves 11 are formed
and a core member 1 made of metal with a through hole 13 for mounting.
It is made by combining 4.

Furthermore, the drive roller 10 shown in FIG. 3 has a surface member 12 made of sapphire single crystal with grooves 11 formed therein and bonded to the outside of a core member 14 made of ceramic or metal with a through hole 13 formed therein for attachment. It is also true.

In the embodiments shown in FIGS. 1 to 3 above, only one of the drive roller 10 and the head roller 20 was shown, but it goes without saying that the embodiments can be applied to both rollers. Further, the grooves 11 and 21 were processed using a diamond wheel.

Table 1 shows a comparison of the properties of various ceramics, cermets, sapphires, and resins. As shown in Table 1, the ceramics, cermets, and sapphires used in the examples of the present invention have higher hardness (higher hardness, thermal expansion coefficient, etc.) than resins. It can be seen that is small.

Therefore, the drive roller 10 and the head roller 2
If the grooves 11 and 21 of 0 are made of these materials, the wear resistance is high and the change in dimensional accuracy due to temperature change is small, so that highly accurate cutting can be performed.

[Margins below C] Table 1 Next, as an example of the present invention, a drive roller 10 and a head roller 20 were prototyped by combining a metal core material and a surface member made of alumina as shown in FIG. incorporated into. As a comparative example, conventional nylon 6
A wire saw using a drive roller 10 and a head roller 20 having grooves formed therein according to No. 6 was prepared, and both were used to cut a magnetic head under the same conditions. As a result of continuous use for 8 hours a day and 21 days a month, the comparative example had to be replaced with a new one after one week, while the inventive example lasted for 6 months. It remained in a usable condition to a certain degree.

In addition, in the head roller 20, the dimensional accuracy of the bift P of the groove 21 is limited to 3 μm, and the conventional one made of nylon 66 exceeds the dimensional accuracy limit with a temperature change of about 0.7°C, so temperature control is required. In contrast, in the case of the embodiment of the present invention made of alumina, even a temperature change of about 7° C. was within the above-mentioned dimensional accuracy limit, so temperature control was easy.

In the above experimental examples, only groove portions formed of alumina were shown, but similar results were obtained with groove portions formed of other ceramics such as zirconia, silicon carbide, silicon nitride, cermet, sapphire, etc. In particular, those in which the groove portion was made of sapphire, silicon carbide, silicon nitride, etc. had much better wear resistance.

In addition, the drive roller 10. It would be more effective if not only the head roller 20 but also the guide roller 40 were made of ceramic, cermet, or the like.

〔Effect of the invention〕

According to the present invention, a plurality of grooves are formed on the surface, and the wire is guided by a cylindrical roller made of a highly hard material such as ceramic, cermet, or sapphire. By configuring the wire saw to cut the workpiece using an abrasive while driving the wire, the grooves have high wear resistance and can be used stably for a long period of time. Because the change in dimensional accuracy of the pitch width is small and there is no deformation during handling, high-precision cutting can be performed without particularly strict temperature control, and the quality of the workpiece can be improved. It is possible to provide a wire saw having the following features.

[Brief explanation of the drawing]

FIG. 1(a) is a partially cutaway side view showing a head roller constituting a wire saw according to an embodiment of the present invention, and FIG. 1(b) is an enlarged view of section A in FIG. 1(a). FIGS. 2 and 3 are partially cutaway side views showing drive rollers constituting wire saws according to other embodiments of the present invention. FIG. 4 is a schematic perspective view showing the main parts of a wire saw, and FIG. 5 is a partially cutaway side view showing a head roller of a conventional wire saw.

Claims (1)

[Claims] A wire saw that uses an abrasive material to cut or groove a workpiece by driving a wire wound around the rollers arranged in a triangular shape with multiple grooves on the surface. A wire saw characterized in that at least the groove portion of the roller is formed from a highly hard material such as ceramic, cermet, or sapphire.