How to Improve the Precision of Bearing Centerless Grinder
Grinding principle of centerless grinding machine: Centerless grinding method is composed of three organizations: grinding wheel, adjusting wheel, and workpiece holder. During this process, the grinding wheel is used to perform grinding operations. The adjusting wheel controls the rotation of the workpiece, and causes the workpiece to generate feed speed. As for the workpiece holder, which supports the workpiece during grinding, there can be several cooperative methods for these three types of machines, but the principle of stopping grinding is the same.
The MG1020 centerless grinder is a very profitable machine tool due to its high accuracy, efficiency, and stability. However, due to its high price, few people ask about it. A new 1020 costs more than 130000 yuan, but an old 1020 only costs about 50000 to 60000 yuan. If you are smart enough, let me teach you to treat an old machine tool as if it were new, with the same accuracy and stability:
Check whether the outer diameter of the grinding wheel shaft is 75MM. If it is smaller than 5 wires, it is recommended to replace the shaft and make a 75MM plus 10 wire pig iron grinding rod to grind the bearing bush until all of them are in contact. During installation, make an inner hole of 75 plus 2 wires. A concentric sleeve with an outer diameter of 110 minus 2 wires is used to adjust the concentricity of the machine tool's main shaft and the machine tool's housing. It is also necessary to ensure that the lateral clearance of the main shaft is not greater than 0.01 mm, and the grinding wheel shaft can be easily changed by hand.
Since the MG1020 uses a hydraulic self smoothing guide rail, it is necessary to completely disassemble and clean the hydraulic system and adjust the pressure from the beginning. For details of the pressure, please refer to the manual. Make a mark at the junction of each component, and then disassemble the machine tool subsystem. 1. Grinding wheel system. 2. Grinding wheel dressing system. 3. Guide wheel system. 4. Guide wheel dressing system. 5. Hydraulic system. 6. Smooth system. Please place the accessories and bolts of each component in categories to avoid confusion or loss.
Check that the dresser and the oil cylinder are disengaged, and pull the dresser with your hand to ensure it is smooth and free of weight. Shake it with your hand to the left and right without gaps, and do not scrape it. Handle the shaft and bearing bush of the guide wheel in the same way as the grinding wheel, and then adjust the guide shaft of the machine tool with a concentric sleeve to ensure that the lateral clearance of the shaft is within 0.002MM and there is no axial transmission. There must be no abnormal noise after driving
Centerless grinding machines are a type of grinding machines that do not require the use of the axis of the workpiece for grinding. "It is composed of three mechanisms: a grinding wheel, an adjustment wheel, and a workpiece holder. The grinding wheel actually performs the grinding task. The adjustment wheel controls the rotation of the workpiece and causes the workpiece to have a feed speed. As for the workpiece holder, which supports the workpiece during grinding, there can be several ways to cooperate with these three mechanisms, except for stopping grinding, which is the same in principle.". Centerless grinding machines can automatically trim and compensate. The guide wheel feed guide rail is a dual V-shaped needle roller guide wheel fed by a servo motor that can compensate for grinding wheel dressing. The machine tool is equipped with an automatic loading and unloading mechanism, which can perform automatic circular grinding. The development of centerless grinding machines has gone through the process of completely relying on system suppliers to initially having general development capabilities. However, the application of CNC systems is still in the stage of improving the performance of mechanical transmission chains, replacing mechanical handwheels, and simple processing cycles. Compared with advanced levels, centerless grinding machines still have many gaps, and there is a lot to improve in terms of machine tool accuracy, automation functions, processing efficiency, and reliability of centerless grinding machines Breakthrough issues need to be resolved. Summarize the various structures and use processes of various products currently produced, analyze their advantages and disadvantages, explore what automatic functions the product should achieve, and have a plan for its gradual development to facilitate learning and work; Attaching importance to the development of CNC software, centerless grinders have the conditions to introduce technology or learn from overseas, to keep up with the development trend. In terms of hardware, combined with market needs, centerless grinders will apply new technologies and new functions one by one in product manufacturing, in order to narrow the gap with advanced levels. In the centerless grinding machine industry, to promote industrial progress. The formulation of new standards and the revision of old standards lag far behind the development of the industry. Due to changes in government agencies, industry standards have not been addressed. Given the very backward standards, it seems impractical for mindless grinders to propose creating international brands. To create an international brand of centerless grinding machines, domestic standardization work must take the lead. To further establish contacts with international standardization organizations and establish cooperative relationships based on communication, thereby improving the international competitiveness of China's product standards, creating an international brand has the foundation.
The general operating method is to come back three laps during the feed and then enter three laps to remove errors caused by gaps. If it is still inaccurate, we need to perform other operations. Have a brief understanding of how to handle this matter. 1. Check to see if the screw brake handwheel is locked. If you are not sure about it, the two pins of the brake handwheel tap against the screw rod have fallen off. Grasp the screw brake handwheel tap and check for reinstallation. If the feed of the lower slider is not accurate, check whether the left or right side of the object rack has touched the falling workpiece. This problem sometimes occurs and needs to be checked. 2. For centerless grinding machine types, because the tool is fed from the lower right corner, check whether the set screw of the feed handwheel and the anti retraction screw on the feed screw are loose or the gap is too large. Rolling back and forth feels like the gap between the handwheels is too large, or if the handwheel is too tight when rotating. 3. Slightly adjusting the offset or looseness of the feed housing downward will cause the sliding conflict to cause excessive clearance between the helical gear and the adjustment screw. Or tightening the nut will make the rotation inflexible. Generally, loose nuts can also lead to inaccurate feed. 4. Both the handwheel fine adjustment and the screw rod differential disc drive screws have fixed screws, and it is also necessary to ensure that there are no looseness, fine adjustment screws, and the edge bearing of the screws to ensure that there is no wear or excessive clearance. For slightly worn parts, they can be properly tightened, and severely worn parts need to be replaced in a timely manner. Matching high-quality parts as much as possible can improve the feed accuracy of the grinding machine and reduce the maintenance rate of the machine.
A grinding machine that uses a centerless grinding method to grind the rotating surface of a workpiece is commonly referred to as a centerless cylindrical grinding machine. On a centerless cylindrical grinding machine, the workpiece is not centered and supported by the center, but is placed between the grinding wheel and the guide wheel and supported by the tray and guide wheel. The grinding wheel is generally installed at the end of the spindle, and the grinding wheel with a width greater than 250mm is installed in the middle of the spindle. The width of the grinding wheel can reach 900mm. The grinding wheel rotates at a high speed for grinding, and the guide wheel rotates at a slower speed in the same direction, thereby driving the workpiece to rotate for circular feed. During grinding, axial feed is achieved by adjusting the slight inclination of the guide wheel shaft, which is suitable for grinding elongated cylindrical workpiece, short shaft without central hole, and sleeve type workpiece. In the process of plunge grinding, radial feed is achieved through the movement of a guide wheel frame or grinding wheel frame. It is suitable for grinding workpieces with shoulders or bosses, as well as cones, spheres, or other workpieces with curved curves. Centerless grinding machines have high productivity and are easy to automate with the addition of various handling devices. Most of them are used for mass production and can be operated by unskilled workers. The grinding accuracy of centerless grinding machines is generally 2 microns for roundness and 4 microns for dimensional accuracy. High precision centerless grinding machines can reach 0.5 microns and 2 microns respectively. In addition, there are centerless internal grinding machines and centerless thread grinding machines. Centerless grinder can automatically trim and compensate. The guide wheel feed guide rail is a dual V-shaped needle roller guide wheel supplied by a servo motor and can be mutually compensated by grinding wheel trimming. The machine tool is equipped with an automatic loading and unloading mechanism for automatic circular grinding.