Improvement of Grinding Technology of CNC Roll Grinder
The CNC roll grinder is an important supporting equipment for sheet rolling production, and its grinding accuracy and grinding efficiency directly affect the rolling quality and production efficiency of the sheet. Its grinding mechanism has the characteristics of general large-scale cylindrical grinders, but it is much more complicated than the movement of cylindrical grinders. In addition to the relative rotary motion of the grinding wheel and the workpiece, it also requires relative longitudinal motion of the grinding wheel and the workpiece. In order to meet the process requirements for shape control, the roll surface busbar needs to be processed into various special high-power curves (such as CVC curves) according to different process requirements. This requires a certain radial relative displacement when the grinding wheel and the workpiece of the CNC roll grinding machine move relatively longitudinally. Therefore, the requirements for the transmission mechanism of the CNC roll grinder are very high, and the requirements for the working accuracy of the machine tool are also high. At the same time, good grinding process parameters, grinding wheel and coolant are also important guarantees for roll grinding accuracy and surface quality.
(1) Improve the accuracy of the guide rail
According to the precision requirements of the bed V-type guide rail, the bed plane guide rail, the pallet seat V-type guide rail, and the pallet seat plane guide rail, the guide rail is scraped and ground to improve its contact accuracy.
(2) Through the adjustment of the pre-tightening force and axial clearance of the ball screw, the transmission accuracy of the screw is improved. For CNC grinding machines, ball screws are generally used for transmission. Therefore, the transmission accuracy of the ball screw has a great influence on the machining accuracy.
(3) Improve the accuracy of the grinding wheel spindle bearing
For the dynamic pressure bearing, repair and scrape the bearing bush to make the contact point reach 12~14 points/25mm×25mm, so as to ensure that the gap between the grinding wheel spindle and the bearing bush is adjusted to 0.0025~0.005 mm. For hydrostatic bearings, check whether the pressure in the oil chambers of the front and rear bearings is normal, and ensure that the clearance reaches 0.0025~0.005mm. Measured with a dial indicator, the radial runout of the grinding wheel spindle is 0.001~0.002mm.
(4) Improve roll grinder accuracy through the balance of the grinding wheel. Static balance: After the flange is installed on the grinding wheel, the grinding wheel is installed on the grinding wheel spindle. After the diamond pen is trimmed, the grinding wheel is removed and placed on the balance frame for static balance. The method is to adjust the three adjustment blocks in the circumferential direction of the flange, so that the grinding wheel can stop on the balance frame at four 90° positions of the circumference. Through good static balance, the influence of unbalanced grinding wheel on machining accuracy is reduced. Dynamic balancing can also be performed if conditions permit: after the grinding wheel is installed on the grinding wheel spindle, a dynamic balancing device is installed on the flange, so that the offset of the center of gravity of the grinding wheel is less than or equal to 0.2μm.
(5) Reasonable selection of guide rail lubricating oil to improve the lubrication of the guide rail and avoid the phenomenon of crawling.
(6) By using the live center, the calorific value is reduced and the machining accuracy is improved.