WS-22 High Precision Wire Saw

Application

The WS-22 wire saw has been developed to meet two important requirements: 1) cutting should not introduce deformations or defects, and 2) loss of material should be minimized. These two requirements have been met by the development of an improved cutting technique which utilizes the precision guidance of the wire and uniform application of an abrasive slurry. The WS-22 wire saw is a semi-automatic machine and requires no supervision during its operation. This saw can be used for precision cutting of semiconductors, ferrites, metals, and glasses, as well as many other hard or brittle solids. The WS-22 wire saw enables cutting of very thin slices (down to a thickness of 10 μm) with smooth cut surfaces (when surface roughness does not exceed 1µm). The WS-22 wire saw is particularly recommended for cutting materials where minimization of material and surface loss are important. Using the thinnest available wire (20 μm diameter) and proper abrasive powder ratio, the material loss does not exceed 30 μm. The obtained slices are perfectly parallel thus additional lapping is unnecessary. Cutting at any desired angle is possible due to the rotation of the sample holder. Use of the special accessories (goniometers, orientation devices, etc.) extends the WS-22 wire saw's application in precision cutting of crystallographically oriented crystals.

General Characteristics

A thin tungsten wire, moistened with an oil or glycerin-suspended abrasive slurry, is used for cutting. The slurry is applied continuously to cutting area. The wire moves rapidly back and forth in an oscillatory motion. High cutting accuracy is guaranteed by the following features:

• Sawing wire slides on two wire guide bars in a reciprocating motion
• Wire load on the sample is precisely controlled;
• To prevent wire wear, new wire is fed continuously to the cutting area.

Cutting speed depends mainly on the wire load, sample hardness, and sample shape and materials (for such materials as Ge, InSb, HgTe, and GaS, cutting speed is approximately from 1-3cm^2h. The WS-22 wire saw is equipped with a high precision horizontal sample carriage mechanism of high precision. Displacement of the sample by 30mm with a deviation of less than 0.002mm is possible. Sample holder can rotate around the vertical axis and be fixed in any desired position. The WS-22 wire saw is equipped with an automatic shut-off (AUTO-STOP) which turns off the saw when the cutting wire is torn, the cutting is completed, or the desired cutting depth is achieved. The saw is also equipped with a magnetically driven mixing device which batches the slurry. The mixing and batching procedure is automatically controlled by an electronic system, which enables adjustment of dropping frequency and drop formation time (dependent on the viscosity and density of the slurry).