The precision cylindrical grinding machine is different […]
The precision cylindrical grinding machine is different from the cylindrical grinding. During internal grinding, the diameter of the grinding wheel is limited by the aperture of the workpiece. It is usually small, so the grinding wheel wears quickly and needs to be repaired and replaced frequently. The grinding wheel used in internal grinding is softer than the grinding wheel used in precision external grinding machines. This is due to the larger contact area between the grinding wheel and the workpiece during internal grinding. In addition, the diameter of the grinding wheel shaft is relatively small, the overhang length is large, and the rigidity is poor, so the grinding depth cannot be large, which reduces the consumption rate.
The outer circle of the workpiece is generally ground on a precision cylindrical grinder or cylindrical grinder. The cylindrical grinding of precision cylindrical grinder generally has three methods: longitudinal grinding, horizontal grinding and deep grinding.
(1) Precision cylindrical grinding machine longitudinal grinding method. When the longitudinal grinding method grinds the outer circle, the high-speed rotation of the grinding wheel is the main movement no. While the workpiece is in circular feed motion, it also moves longitudinally with the task table to complete the workpiece along the workpiece. Axial feed fa. At the end of each single stroke or each reciprocating stroke, the grinding wheel performs periodic lateral movement to complete the feed fr along the radial direction of the workpiece, thereby gradually grinding away all the remaining grinding allowance in the radial direction of the workpiece. After grinding to size, stop the smooth grinding process without lateral feed until the spark disappears. Because the longitudinal grinding method has less radial feed per time fr, small grinding force, and good heat dissipation conditions, it has greatly improved the grinding accuracy and appearance quality of the workpiece, which can meet the higher processing quality requirements, but the grinding efficiency is relatively high. low. The longitudinal grinding method is suitable for grinding larger workpieces, and is a common method for single-piece and small-batch production.
(2) The horizontal grinding method of precision cylindrical grinding machine. When the horizontal grinding method is used to grind the outer circle, the width of the grinding wheel is larger than the grinding width of the workpiece, and the workpiece does not need to make longitudinal (workpiece axial) feed motion, and the grinding wheel moves at a slow speed. Continuously or intermittently along the transverse feed movement, complete the radial feed fr of the workpiece until the grinding reaches the size requirement. Its characteristics are: the cutting ability of the grinding wheel is fully developed, the grinding efficiency is high, and it is also suitable for forming grinding. However, the large contact area between the grinding wheel and the workpiece during the grinding process increases the grinding force and the workpiece is prone to deformation and burns. In addition, the shape error of the grinding wheel indirectly affects the geometric shape accuracy of the workpiece, the grinding accuracy is low, and the surface roughness value is large. Therefore, it is necessary to use a grinding machine with high power and good rigidity, and at the same time, it is necessary to provide sufficient cutting fluid to achieve the purpose of cooling. Using the horizontal grinding method, the rigidity of the process system is required to be good, and the workpiece should be short rather than long. This kind of grinding method is usually used for the fine grinding process of the short stepped shaft journal.
(3) Precision cylindrical grinding machine deep grinding method, deep grinding method is a relatively advanced method, the consumption rate is high, the grinding allowance is generally 0.1-0.35mm. In this way, the entire margin can be ground in one pass. When grinding, the feed rate is small, the normal longitudinal feed rate is 1-2mm/r, which is about 15% of the "longitudinal grinding method", and the processing time is about 30-75% of the longitudinal grinding method.