WS-22B

The WS-22B wire saw has been developed to meet two important requirements: cutting should not introduce deformations or defects, and losses 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 saw is a semi-automatic machine and requires no supervision during its operation. The saw can be used for precision cutting of semiconductors, ferrites, metals, glasses as well as many other hard or brittle solids. The wire saw enables cutting very thin slices (down to thickness of 10 µm) with smooth cut surfaces (surface roughness does not exceed 1µm). The WS-22B saw is particularly recommended for cutting materials where minimization of material losses and surface demands are important. Using the thinnest wire (20 µm diameter) and proper abrasive powder dimensions the material losses do 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. The use of the special accessories (goniometers, orientation devices) extends the WS-22B saw's application to precision cutting of crystallographically oriented crystals.

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

    • The sample is in the swinging motion around the axis perpendicular to the cutting plane;
    • The sawing wire slides on the two guidebars which are in a swinging motion;
    • The wire load on the sample is precisely controlled;
    • To prevent wire wear, new wire is fed continuously to the cutting area.

The cutting speed depends mainly on the wire load, the sample hardness, the sample shape and for such materials as Ge, InSb,HgTe, GaS is approximately from 1 up to 3 cm²/h. The WS22 saw is equipped with a high precision horizontal sample carriage mechanism of high precision. The displacement of the sample by 30 mm with a deviation less than 0.002 mm is possible. The sample holder can rotate around the vertical axis and be fixed in any desired position. The saw is equipped with an automatic switch-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 by means of which the cutting slurry is being batched. The mixing and batching procedure is automatically controlled by an electronic system, which enables the dropping frequency and the time to form a drop (dependent on the viscosity and density of the slurry) to be programmed.