The strategic goal for the development of the bearing industry is to move from a major bearing producer in the world to a powerful bearing country in the world. Through continuous efforts and development in the bearing industry in recent years, the manufacturing level of China's'Class 0 bearings' has improved quite quickly, and the manufacturing level of some bearing manufacturers It is almost equivalent to the manufacturing level of well-known foreign companies. For example, the vibration value of ball bearings increased from the Z1 group to the Z2 group in the early 1990s, and then increased to the Z3 and Z4 groups after 1995. The ball bearing users were common in the late 1990s. The vibration value of the approved low-noise Jin bearing has exceeded the Z4 group, up to the present silent bearing (no abnormal noise bearing). High-end products require high-end component assembly, and high-end components require high-end technology and equipment. In order to achieve the goal of mass production of silent ball bearings, ball bearing manufacturers work hard on bearing processing and assembly and choose high-end CNC assembly. In the past, some bearing manufacturers relied on imported CNC equipment. Due to the high price of the equipment, high cost of production, long maintenance cycle, shortage of repair parts, poor personnel skills, and lagging after-sales service, bearing manufacturers were unable to mass produce high-end products. In recent years, with the continuous improvement of the domestic CNC machine tool manufacturing level, since 2000, the silent bearing produced by Zhejiang Wanbang Industrial Co., Ltd. has been produced with domestic CNC equipment and connected to it. After three years of operation, the product The quality has gone up a big step, meeting the requirements of ball bearing users for the continuous improvement of bearing accuracy. At the same time, we have also mastered some basic knowledge in the application of CNC grinders. The basic composition and working principle of a bearing CNC grinder

The universal bearing grinder we use is currently mainly used in the grinding of ball bearings 'two grooves and one holeThe inner wheel groove and the outer soft groove are single because of the processing. Single-axis single servo drive is adopted. The structure is simple and the operation is convenient. The numerical control system (CNC) is controlled by numerical control program, input/output equipment, computer numerical control device, and programmable control. It is composed of PLC, spindle frequency conversion drive device, feed drive (AC servo) device and active detection device.

High precision: In order to ensure the accuracy of bearing grinding, in addition to the geometric accuracy and good structural characteristics of the machine tool body, it can be achieved by reducing the error of the CNC system and adopting certain compensation techniques. Must have high-precision position measurement and a high-performance CNC system with a pulse equivalent of 0.1μm.

High-speed and high-efficiency machining: Bearing production is mass production, and increasing productivity is also the main feature of CNC machine tools. Therefore, the frequency conversion spindle speed is generally selected as 60000r/min. When the machining diameter is less than 20mm, the spindle speed can also be selected as 75000. With r/min spindle, the numerical control system automatically allocates the feed speed and feed rate of the four stages of fast trend, rough grinding, fine grinding and smooth grinding according to the machining allowance, automatically eliminates the idle stroke, shortens the processing cycle, and improves the processing efficiency.

High reliability is a key indicator of CNC machine tools, and MTBF Mean Time Between Failures (MTBF Mean Time Between Failures) is used for assessment, and the average guarantee must be more than 40,000H.

Intelligent use of adaptive control technology to detect the signal of the spindle current change from the bearing grinding process to automatically adjust the grinding parameters such as the feed amount and feed speed of the CNC system to improve the grinding process State to achieve the best grinding effect. At the same time, the numerical control system should have a self-diagnostic function, and the faulty parts can be found and eliminated in time during operation.

Open-loop servo system: For example, when the bore grinder 3MZ144 grinds ordinary bearing grooves, there is no position measurement. The input data is distributed by the numerical control system to output command pulses, and the command pulses control the operation of the stepping motor , The command is issued and no feedback is returned. This control method is only suitable for processing ordinary precision products. The Union of Bearing Engineers is the best! (Bearing people pay close attention to WeChat)

Closed-loop servo system: For example, when the bore grinder 3 M K205D is grinding the bore diameter, the bore diameter control dimension tolerance range of bearing P4 is within 0-4μm, with automatic detection device During the grinding process, the signal is fed back to the numerical control system at any time according to the change of the machining size of the ring. This control method is suitable for processing high-precision products

Semi-closed-loop servo system such as groove grinder 3MK135D3MK147D processing groove The control size tolerance range is relatively wide, within 0-30μm. Because the worktable is not fully included in the control loop, the transmission error of the screw and guide rail cannot be compensated. This control method is suitable for processing products with a smaller size tolerance range.

Factors affecting the machining capacity and quality of CNC bearing grinding machines 1. Working conditions affect the machining capacity of CNC grinding machines.

1) Because our company is located in the most coastal area, the ambient temperature The temperature difference is large. In summer, the indoor temperature can reach above 40℃, and the working temperature in the case will generally reach above 60℃. At this time, the control of the CNC system is unstable, causing soft faults such as drift. The machine was paralyzed.

2) Due to the limitation of the cooling circulating water conditions of the bearing CNC grinder, the humidity in the case is very high. The most common fault is that the servo motor is short-circuited and damaged, which causes the drive to be damaged. If the machine is shut down, it should be powered on, so as not to shut down for a long time and cause short-circuit and damage to the components on the circuit board of the CNC system.