Centerless Grinding Technology of NSK Bearing Ring
Writer: Eric Bearing Limited
1. High-speed grinding technology
General production efficiency can be increased by 30%-60%, and the durability of the grinding wheel can be increased by about 0.71 times. High-speed grinding can achieve the two major goals pursued by modern manufacturing technology to improve product quality and labor efficiency. Practice has proved: If the grinding speed is increased from 35m/ to 5060m/h. The parameter value of the surface roughness of the workpiece is reduced by about 50%. An important measure to realize high-speed grinding is to increase the power of the grinding wheel drive (transmission) system and improve the rigidity of the machine tool. Among them, the high-speed spindle unit is the most critical component of the high-speed grinder. In high-speed grinding, the grinding wheel should not only have sufficient strength, but also need to ensure good grinding performance in order to obtain a high grinding effect.
2. CBN grinding wheel grinding technology
The grinding wheel manufactured by it is called CBN grinding wheel, and the cubic boron nitride abrasive is referred to as CBN abrasive. It mainly has the following characteristics:
(1) High hardness, high thermal conductivity, good thermal stability, and can withstand high temperatures of 1300-1500°C.
(2) High durability, low wear, and the grinding ratio can reach 4000:10000. Grinding ratio refers to the ratio of the amount of workpiece material removed during the grinding process to the amount of grinding wheel wear.
The ordinary corundum grinding wheel is only 50-80°C. The use of CBN for ring grinding is a new processing technology. The application prospect is very broad, but the following technologies need to be studied and resolved: CBN grinding wheel manufacturing technology, dressing technology, special NSK Bearing grinder and grinding coolant etc. The use of CBN grinding wheels to grind NSK bearing rings has already been developed abroad and used in production, because CBN grinding wheels have good processing characteristics. And called it "a great revolution in production and processing technology" Since 1982, CBN grinding wheels have been widely used in Japan and have grown rapidly.
3. Automatic dynamic balance technology for external surface grinding wheel
Because the grinding wheel is large and heterogeneous, it can grind the outer surface. The center of gravity of the grinding wheel system always deviates from the center of the spindle. High-speed rotation will definitely cause vibration of the grinding wheel system and the entire machine tool, which directly affects the service life of the machine tool.
After starting the machine, the most balanced position is quickly approached directly, and a mechanical or other automatic dynamic balancing device is directly installed on the grinding wheel of the machine tool. This technological breakthrough has promoted the development of grinding technology, and at the same time can greatly extend the life of grinding wheels, dressing diamonds and spindle bearings, reduce machine tool vibration, and temporarily maintain the original accuracy of the machine tool. If you are looking for NSK 51104 , ERIC BEARING LTD can supply , click here , we will contact you shortly .
4. Technology to quickly eliminate the idle stroke of inner surface grinding
The level of the inner surface grinder is symbolic. This is mainly because the grinding aperture limits the size of the grinding wheel and the corresponding system mechanism set parameters, in all NSK bearing grinding processing equipment. The rigidity of the process system is fundamentally restricted, and at the same time the machining accuracy is high. All of these require me to enter an in-depth study of the internal and external grinding process. In addition to maximizing the cutting ability of the machine tool and the grinding wheel, reducing the auxiliary grinding time is the key to improving the grinding efficiency, because the grinding is empty. It accounts for about 10% of the entire grinding time.
5. CNC technology and AC servo technology
The servo amplifier can be connected to form the servo system, the AC servo motor and the positioning module of the PLC programmable controller. The servo motor itself has an optical rotary encoder, and the output signal is fed back to the servo amplifier to form a semi-closed loop control system. High speed (3000rpm and low speed operation can guarantee the positioning accuracy, the servo system can complete fast jump, fast trend, trimming compensation, rough and fine grinding, which greatly simplifies the feed mechanism of the machine tool and greatly improves the performance reliability.
6. AC frequency conversion speed regulation technology
The ratio of the linear velocity between the beginning and the end is about 3:2. At present, the linear velocity of the grinding wheel in grinding gradually decreases with the consumption of the grinding wheel. In the field of grinding wheel grinding, high linear speed grinding has been adopted. In order to improve the grinding efficiency and ensure the consistency of grinding quality, the programmable controller calculation function is used to calculate the radius of the grinding wheel after each dressing of the grinding wheel, and then calculate the constant line of the grinding wheel. The input frequency of the speed inverter is transmitted to the AC inverter to ensure that the linear speed of the grinding wheel remains unchanged.