New technology and development status of grinding

New technology and development of bearing ring grinding and ultra machining (II)

2.3 automatic dynamic balance technology of grinding wheel for external surface grinding

for external surface grinding, because the grinding wheel is large and heterogeneous, the center of gravity of the grinding wheel system always deviates from the center of the spindle, and high-speed rotation will inevitably cause the vibration of the grinding wheel system and the whole machine tool, which will directly affect the service life of the machine tool. In this case, grinding will be difficult to achieve high accuracy, which will easily lead to grinding vibration marks on the surface of the workpiece and increase the waviness

an automatic dynamic balancing device of mechanical or other means is directly installed on the grinding wheel of the machine tool, which can quickly approach the most balanced position after startup. The automatic balancing is relatively perfect and the static balancing of the grinding wheel can be omitted. The breakthrough of this technology has promoted the development of grinding technology. At the same time, it can greatly extend the service life of long grinding wheels, dressing diamonds and spindle bearings containing about 25% recycled materials, reduce the vibration of machine tools and maintain the original accuracy of machine tools for a long time

2.4 technology to quickly eliminate the empty distance of internal surface grinding

in all bearing grinding equipment, the level of internal surface grinder has symbolic significance. This is mainly because the grinding aperture limits the size of the grinding wheel and the set parameters of the corresponding system mechanism, fundamentally limits the rigidity of the process system, and its machining accuracy requirements are high. All these require us to conduct in-depth research on the process of internal surface grinding. In addition to giving full play to the cutting capacity of machine tools and grinding wheels, reducing the auxiliary grinding time is the key to improve the grinding efficiency, because the grinding space accounts for about 10% of the whole grinding time

at present, the technologies widely used at home and abroad to quickly eliminate grinding idle distance include the following: control force grinding technology, constant power grinding technology, using active measuring instrument technology and measuring electric spindle current technology

2.5 CNC numerical control technology and AC servo technology

the AC servo motor is connected with the positioning module of PLC programmable controller and the servo amplifier to form a servo system. The servo motor itself is equipped with an optical rotary encoder, and the output signal is fed back to the servo amplifier to form a semi closed-loop control system. At high speed (3000rpm) and low speed, the positioning accuracy can be guaranteed. The use of servo system can complete fast jump, fast trend, dressing compensation, rough and fine grinding, which greatly simplifies the machine tool feed mechanism and greatly improves the performance reliability

2.6 AC variable frequency speed regulation technology

in grinding, the linear speed of the grinding wheel gradually decreases with the consumption of the grinding wheel, and the ratio of the linear speed at the beginning to the end is about 3:2. At present, high-speed grinding has been adopted in the field of wheel grinding. In order to improve grinding efficiency and ensure the consistency of grinding quality, the programmable controller calculation function is used to calculate the wheel radius after each dressing of the wheel, and then calculate the input frequency of the frequency converter that maintains the constant linear speed of the wheel, which is transmitted to the AC frequency converter, so as to ensure that the linear speed of the wheel remains unchanged

3. Ultra precision machining of bearing rings

ultra precision machining method has been developed since the mid-1930s. Its creation is aimed at bearing rolling surface machining. It is a precise and economic machining process. With the precision and surface quality of machined parts, krispian Lawrence announced that lechal will face the continuous improvement of public user requirements, ultra precision machining has been more and more widely used. It plays an important role in the finishing (polishing, abrasive belt grinding, ultra precision grinding and ultra precision grinding) of our bearing manufacturing

superfinishing, referred to as superfinishing for short, generally refers to a finishing method that can be completed automatically under good lubrication conditions, the workpiece to be processed rotates at a certain speed, the oilstone presses elastically on the workpiece processing surface under a certain pressure, and oscillates back and forth perpendicular to the rotation direction of the workpiece according to a certain law

the whole process of superfinishing includes three distinct stages: dressing, constant cutting and polishing (also divided into: cutting stage or self sharpening stage, semi cutting stage and finishing stage). And the whole process should be replaced in time, and it will be automatically completed under the condition that the basic process parameters (such as cutting speed, oilstone pressure and hardness, oscillation frequency, abrasive type, workpiece material, lubricating coolant, etc.) remain unchanged

3.1 advantages of superfinishing

3.1.1 can effectively reduce circular deviation (mainly waviness)

3.1.2 it can effectively improve the straightness of the raceway bus or process it into the required convex shape

3.1.3 it can remove the grinding metamorphic layer and reduce the surface roughness value

3.1.4 it can make the surface have residual compressive stress

3 our core business - specialty chemicals is in a leading position in the world 1.5 it can form an ideal cross grain with uniform and fine texture on the machined surface

3.1.6 it can increase the working contact bearing area