At present, materials for making nozzles in China include diamond, gem, ceramics, cemented carbide, high-grade stainless steel and high quality carbon steel. The synthetic diamond has the highest hardness and wear resistance, but the high pressure chemical stability is poor, the cost is very high, and the ordinary machine can not be processed at all. The special machining only can be processed by laser and ultrasonic, but it will make the high temperature change (carbonization when the diamond is 1400 C) in the process of processing, so the diamond is not easy to be used. And Ruby (that is, artificial corundum)
Other materials have unparalleled hardness (Mohs 9), wear resistance and high temperature resistance.
(can still work normally in 1200 ~ C) and chemical stability (even boil the no damage to the aqua regia), in the industry figure 4
The process area of gem nozzle is widely applied.
The following is a brief introduction to the processing technology of gemstone nozzle. Industrial ruby is a single crystal of alumina. Its shape is half pear shaped. The processing flow is shown in Figure 4. First, the cutting is made. A mixture of epoxy resin and polyamide (mass ratio 1: 115) was used.
The jewel stick in the glass (with sticky shellac film) slicing, cutting, cutting off the grains in the machine. For larger blank size, polycrystalline gem is used to reduce cost, but its hardness is slightly lower than that of single crystal gemstone. Then the small holes are processed.
There are three ways to process gem nozzles, namely grinding, ultrasonic machining and laser processing. Grinding is a primitive method, which is inefficient and difficult to guarantee.
Although the ultrasonic machining is suitable for the processing of brittle and hard materials, because of the limitation of the size of the horn and the size of the ultrasonic head, the size of the processing is limited, and the wear of the ultrasonic head tool is serious, it is not ideal for the processing of the water jet jewel nozzle, and the laser processing efficiency is high, the workpiece is easy to be clamped, and the minimum aperture can be down to <0104mm, tolerances. Up to 0102mm. Therefore, fast laser drilling is generally used.