Industrial ruby is a single crystal of alumina, its shape is half pear shape, first of all, it is cut by water. The gemstone is glued to the glass with the mixture of epoxy resin and PPTA (mass ratio 1:1.5) (shellac is used for gluing), and sliced, sliced and broken on the water cutting machine. For billets with large profile size, polycrystalline gemstones are often used to reduce the cost, but their hardness is slightly lower than that of single crystal gemstones.
         Then the holes are machined. At present, there are three ways to process the small holes of the gem nozzle, that is, grinding, ultrasonic processing and laser processing. Grinding method is an original method with very low efficiency and difficult to guarantee the quality. Although ultrasonic machining is suitable for the processing of brittle and hard materials, it is not ideal for the processing of water jet gem nozzle because of the objective limitations of the size of horn and ultrasonic head, the limited machining aperture, and the serious wear of ultrasonic head tools; The surface water cutting laser processing efficiency is high, the workpiece clamping is convenient and simple, the surface and the minimum aperture can be as small as 0. Onm, and the tolerance can reach 0. 02xnm. Therefore, the rapid laser drilling machine is generally used.
         Finally, reaming and post-processing are carried out. Because the holes made by laser are not smooth enough and there is a scorch layer on the surface and the wall of the holes, it is necessary to carry out coarse and fine reaming on the reamer. The outer circle processing of nozzle is carried out on the inner base outer circle grinding, the processing of contraction angle can be carried out on the flat grinding machine with the electroplated diamond cone grinding rod cone grinding needle, the chamfering outer edge is carried out on the micro bowl electroplated diamond grinding wheel, and the finished product is finished after the pure tin plate is polished with WS agate powder water agent (i.e. fine grinding).

(1) The nozzle is the core component of the high-pressure water jet equipment. When the pressure is fixed, the larger the diameter of the nozzle, the greater the impact force of the jet, but the increase of the diameter of the nozzle will lead to the increase of the damaged surface, and lose the advantage of the high-pressure water jet. Because the diameter of the surface water jet nozzle is generally small, from several millimeters to tens of microns. The conical nozzle has the characteristics of jet concentration, small diffusion angle and no backflow, which can be used for all kinds of jet cutting.
(2) There are four main factors that affect the jet impact pressure: jet pressure P, jet flow Q, the transverse velocity of the nozzle and the jet distance h from the nozzle to the water cutting material. When designing the nozzle, it is necessary to balance all aspects of the factors and reasonably determine all parameters.
(3) The nozzle material needs further research. At present, a kind of "composite carbon" nozzle named Roctec has been developed in the United States. Its density is similar to that of cemented carbide, but its service life is 40-80 times longer than that of cemented carbide. It is imperative to develop new materials such as composite carbon in our country, and to strengthen the technological research of nozzle processing.