To improve the roughness of its surface and the out of roundness of the ball. Grinding is precision machining. The grinding of a sphere is different from that of a flat plate and a cylinder. It is particularly required to have a uniform degree of processing. The high labor intensity of manual processing requires high technology, low work efficiency, difficult quality control, and easy to scrap. According to the above processing characteristics, the ball grinding is realized by mechanical equipment. It is more in line with its work characteristics. The movement track of the ball grinding equipment for advanced hard seal pneumatic ball valve is more consistent with the geometric shape of the ball. The structure is compact, reasonable, scientific, and simple to operate. Use the concentric inner hole of the sphere to cover the sphere on the inner expansion sleeve of the elastic center of the main shaft. Rotate with the spindle at low speed to improve its machining accuracy. The lapping tool rotates on the spherical surface at an angle of 25 degrees by adjusting the pressure of the spring. Grind the shaft sleeve and rotate the rocker arm on the main shaft. The lapping tool can be made of ordinary cast iron or brass. Material sources are extensive. The ratio of the outer diameter of the lapping tool to the diameter of the sphere should be 6/10, and the ratio of the outer diameter of the lapping tool to the inner diameter should be 5/9. The speed of the lapping tool is too fast to avoid frequency vibration and overheating, which will affect the accuracy. The ball shall be carefully checked before grinding, and there shall be no bruises, defects and other defects near the sealing belt. The difference in geometric shape of large-sized spheres will be larger during surface hardening treatment, so it is recommended to use coarser grinding emery for grinding. The upper limit of grinding pressure can be selected. Due to the change of sand particles in the grinding process, lubricating fluid should be added in time to improve work efficiency. The key point of the first grinding is to correct the geometric tolerance. Be careful and patient.

Design request for pneumatic butterfly valve
Model building request
(1) In order to reduce the model, prevent too many model features, improve the operating speed of the computer, and try to reduce some unnecessary features (such as rounding, chamfering, etc.) when establishing the three-dimensional model of stainless steel pneumatic butterfly valve joint.
(2) It is required to establish the coordinate system of the inlet and outlet ends at the joints. Because it is required to use it in the pipeline design and wiring, there is also a reference point introduced to ensure that the connected pipe joints are straight. If this coordinate system is not established, it will bring inconvenience to the design of the pipeline.
When establishing the coordinate system at the inlet and outlet ends, the guidelines shall be followed:
The direction of the z-axis determines the direction of the wiring. At the outlet end of the pipe joint, the z-axis direction always points to the outer edge of the pipe joint, and the pipeline entry or exit is parallel to the z-axis of the pipe joint.
The coordinate system at the entrance end shall be subject to the practical device junction surface and on the centerline, so that when the designer assembles (the designer shall try to use the coordinate system device when assembling, and can use the ordinary device when it needs to turn a certain angle.) (3) Hide some unnecessary reference features (such as datum plane, axis and coordinate system).
(4) Set up a reference point, place it on the axis, and request that the spacing between the point and the outlet end face be taken as one time of the outer diameter of the pipe joint.