Water jet processing

Three principles of the water jet processing are distinguished (Fig. 5.10). In conventional pure water jet milling, also called hydrodynamic machining, simply pure water jet is used for cutting. The velocity of the water jet reaches 900 m s and nozzle diameters can be as small as 0.1mm. For precision machining dimensional tolerances of 50 pm with a minimum width of grooves and bars of 200 pm are possible. 

In abrasive water jet processing, also called hydroabrasive machining, abrasive particles are added into the water jet. The particles increase the erosive effect of the jet. Normally the abrasive is added by the suction generated by 

The laser enables to separate the workpiece with almost perpendicular side walls compared to the inclined walls that the action of a conventional water jet produces. This is especially interesting for the precision machining of microsystems [211]. Water jet guided laser processing enables to produce cuts of width of 0.05 mm with tolerances of about 0.01 mm. Very thin substrates and also those with a thickness of 3 mm can be cut. 

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In the second step, a papermaking method is also used for the fine fibers, less than 0.1 tex (1 den). This process is usually followed by a high pressure water jet process instead of the third step. In the fourth step, to obtain the required properties in specific appHcations, a polyurethane is selected out of the segmented polyurethanes, which comprises a polymer diol, a diisocyanate, and a chain extender (see Urethane polymers). A DMF—water bath for coagulation is also controlled to create the adequate pore stmcture in combination with fibers. 

TMSA has an additional feature for the realization of various kinds of Cherenkov counters. Because of blocks excellent hydrophobicity, it is possible to cut them by water-jet processing and secondarily to arrange them to the required shape or size of Cherenkov counter. Figure 28.17 shows the samples cut down from standard blocks by water-jet. The properties and hydrophobicity are not depreciating after the cut processing. 

Figure 28.17. TMSA samples cut down from the P-EW s standard TMSA blocks by water-jet processing.

Figure 6.2 Photograph of rubber crumb produced using a water jet process. Reproduced with permission from Smithers Rapra Technology Ltd, Shawbury, UK. 2006, Smithers Rapra Technology Ltd...

Figure 6.3 The BTRC UHP water jetting process for removing rubber from end-of-life large tyres (a) cutting operation and (b) jetting operation. Reproduced with permission of Big Tyre Recycling Corporation, Martelaarslaan, Belgium. 2014, Big Tyre Recycling Corporation...

The use of cryogenic grinding and water jet processes for the manufacture of crumb is not currently included in any PAS, but PAS 107 2007 can be used for these types of processes when manufacturers want their crumb to be considered as having been manufactured according to the Quality Protocol published by WRAP (see Section 6.4.1). The only part of PAS 107 2007 that does not need... 

Blue gas, or blue-water gas, so-called because of the color of the flame upon burning (10), was discovered in 1780 when steam was passed over incandescent carbon (qv), and the blue-water gas process was developed over the period 1859—1875. Successfiil commercial appHcation of the process came about in 1875 with the introduction of the carburetted gas jet. The heating value of the gas was low, ca 10.2 MJ /m (275 Btu/fT), and on occasion oil was added to the gas to enhance the heating value. The new product was given the name carburetted water gas and the technique satisfied part of the original aim by adding luminosity to gas lights (10). 

Fuse-quench Also called the Kjellgren-Sawyer process. A process for extracting beryllium from beryl. The beryl is fused at 1,600°C and then rapidly quenched by pouring through a water jet of high velocity. The glassy product is heated to 900°C to precipitate beryllia from its solid solution in silica, and then extracted with sulfuric acid. Operated by the Brush Beryllium Company, Cleveland, OH. 

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