Camshaft grinding female misunderstanding é…— Discussion Long Xiaobing, Gong Xiaotong (Institute of Metal Materials, College of Materials Science and Engineering, Hunan University, Changsha 410082, China) The model plate relies on the principle of grinding. In order to improve the manufacturing precision of the prototype model, a new method such as 'automatic reciprocity' and "program compensation" was proposed.
1 Introduction Camshafts are a wide range of mechanical parts and are key components of the engine. With the rapid development of the automobile industry, energy conservation and bad insurance benefits have become the focus of attention, and the manufacturing precision of the camshaft of the key parts of the engine is becoming higher and higher. For example, the accuracy requirement of the original camshaft of the Jiefang brand camshaft is ±0.1mrn, and the improved camshaft of the Jiefang brand car is reduced to ±0.05mm. The accuracy of the camshaft of the currently introduced automobile engine is ±0.03, and its geometric precision is improved several times. In the existing domestic camshaft grinding machines, the camshaft parts are generally profiled by a model, and the accuracy of the camshaft is directly affected by the manufacturing precision of the model.
At present, the production of domestic camshafts is generally controlled by the MXBS8312 series of microcomputer-controlled high-speed powerful camshaft grinding machines. The control of the grinding precision of the model-like wheel gallery is the key technology to ensure the high quality of the camshaft. For many years, the author has been engaged in the assembly and commissioning of the MXBS8312 series of microcomputer-controlled high-speed powerful camshaft grinding machines, and personally experienced the defects of the entire grinding machine from the hardened surface. It provides a good processing method for the polishing of complex curved workpieces with difficult materials.
Chen Yuquan. Study on Electrochemical Grinding Process of SnSb Alloy Chen Yuquan, Wang Shijian, Erbin University of Technology. Electrolytic-non-woven polishing and polishing research. Harbin Science and Technology Department installed the final assembly, including mechanical, hydraulic, electrical, control assembly and commissioning, as well as grinding the entire process of grinding the template, familiar with the mechanical structure and mechanism of the entire grinding machine parts, hydraulic principle, electrical control principle , including programmable controller (Programmab1eContro11 from the Hao single-chip microcomputer programming and modification, especially in the MXBS8312 series microcomputer control high-speed powerful camshaft grinding machine model sample contour grinding accuracy has some experience. This article is a brief introduction On the basis of the grinding principle, the methods and measures for improving the accuracy of the profile grinding of the model are proposed.
2Inversely, the grinding principle MXBS8312 series mechanical camshaft grinding machine cam model is manufactured. It is often used in the opposite method and the grinding principle. That is, the grinding wheel is replaced by the diameter of the grinding wheel on the camshaft grinding machine. The diameter of the opposite guide wheel, the mold roller is replaced with the same diameter as the roller, the grinding wheel is rotated against the model spindle to drive against the grinding wheel, with the help of the standard mother Cao Guohui. The mold cavity conforms to the research of finishing process m. Electric Machining and Mould, 2001, (5). (Editor enlightenment), male difficult graduate student, research direction is afraid of mechanical manufacturing and automation.
Chen Yuquan, Ph.D., the cam grinding cam model, allows the machine to grind out the qualified workpiece after a single cam model. In order to ensure that the camshaft profile 3 affects the accuracy of the profile grinding accuracy, there are many factors affecting the grinding accuracy of the model. There are five aspects summarized: 1) Machine tool accuracy. It is the main reason that affects the precision of the grinding of the model;) grinding wheel and coolant. Grinding wheel with good cutting performance Cooling and lubricating The coolant has a good influence on the grinding effect;) The grinding process parameters. Such as the mold spindle speed rough grinding, fine grinding, light grinding feed amount, feed speed, no spark delay, grinding wheel correction status; 4) machine structure. High-rigidity wheel frame spindle bearing, high-rigidity wheel frame feed system, high-rigidity cradle, tailstock, high-precision slewing head frame and anti-back grinding head (spindle) are factors that can not be ignored in improving the grinding accuracy of the model. 5) Manufacturing precision of the female cam itself. Obviously it will directly affect the grinding accuracy of the model. In short, many factors affecting the accuracy of the grinding of the model are more complicated than those of other workpieces.
4 Ways and measures to improve the grinding accuracy of the model plate The preparation of the head frame spindle rotation accuracy is carefully prepared. If it is found that the radial runout of the main shaft is strict, there is foreign matter such as iron filings falling from the oil head hole of the headstock main bearing housing into the bearing main shaft and the bearing bush is pulled by the iron filings. The metallized sandpaper polishing spindle shaft for the main shaft must be removed. After the neck and the bush are cleaned, the rotation accuracy of the headstock can be restored.
Check against the grinding head. Since the original grinding wheel flange is not equipped with a locking steel ball, it is directly used with a tapered retaining screw. In this assembly, the locking of the flange is unreliable or cannot be locked. It is necessary to increase the size of the steel ball. , use the flat head to stop the screw, and the spindle's warp direction must be verified after the grinding head is installed. 1 or less. The rotation precision of the headstock mainframe and the rotation precision of the grinding head spindle have a great influence on the grinding precision of the model, which directly affects the surface roughness, waviness, contour lift error and base circle runout of the model.
Improve system stiffness. MXBS8312 series microcomputer control high-speed powerful camshaft grinding machine grinding wheel frame feed guide rail adopts unequal area oil chamber static pressure unloading guide rail. Its unloading pressure is usually adjusted according to the design. 1.15MPai, but when it comes to grinding, it will be found that when the mother cam is turned from the base circle to the cam apex on the guide wheel, the wheel frame will retreat to 0.00.0.04rnm. Otherwise, the wheel frame will advance by 0.00.0.04. The lift of the model plate is low. When grinding, the unloading pressure is generally only adjusted at 005 MPa, so that the error of the oil film rigidity ib will be less than 0.005 mm. 4.2 Eliminating the vibration source to improve the vibration resistance of the machine tool. Self-excited vibrations have a negative effect on the grinding effect. The grinding of the waviness by the pattern is mainly caused by vibration.
Forced vibration is mainly caused by the unbalance of the rotating parts. Where there is a forced vibration source, there must be a vibration isolating pad, so that the vibration is not directly transmitted to the machine and attenuated. For example, the head frame motor and the opposite motor must be on the fastening screws. Putting on a thick rubber mat reduces the natural frequency of the machine tool and improves the anti-vibration performance of the machine tool. The machine tool is not prone to self-excited vibration under the influence of external vibration (forced vibration). In addition, the machine tool is equipped with two kinds of anti-belt belts, one is a hard rubber belt, and the other is a soft hemp belt. The latter is much smaller than the vibration caused by the former. When grinding, try to use soft hemp tape.
The new anti-grinding method is automatically reversed to the traditional anti-grinding process. The manual wheel-wheel handwheel feeds, and each piece of the model is ground to the gauge value, leaving the finishing allowance. In the case of fine grinding, manual feeding is still performed, and the rotation of the spindle of the head frame by the motor is also changed to the manual handing precision when it is rough grinding. To this end, the author proposes a new anti-grinding process, an 'automatic reciprocal', instead of the traditional 'manual reciprocal' grinding process. The new automatic anti-grinding method fully exploits the potential of the MXBS8312 series of microcomputer-controlled high-speed and powerful camshaft grinding machines. It is divided into the rough grinding and fine grinding programs (also can be combined) on the numerical control microcomputer. The grinding process of the grinding process is automatically reversed as shown in the figure.
Advantages of automatic anti-grinding method After rough grinding, the sea plate retains a fine grinding allowance (with a deviation of ±0.02 or less), which can reduce the number of grinding wheels during fine grinding, and can strictly guarantee the diameter of the grinding wheel and the guide wheel. The diameters are close to each other: Grinding parameters can be arbitrarily increased to improve the precision of the prototype model as needed.
Modification and automatic control, and automatically rely on the grinding method to change the head spindle manually to automatic, and high and low self-shifting, to ensure the head spindle smooth rotation and speed requirements, to avoid the head frame caused by operator fatigue caused by uneven hand The spindle flutters to produce a distinct 'ripple' on the profile surface of the master model; the automatic grinding method keeps the same cutting conditions of each model sample. After grinding, the model sample has high dimensional accuracy and the base circle diameter deviation is only ±0.01 ( The general processing product requirements are ±0.05 or ±0.1mm. The automatic anti-grinding process is of great significance for improving the profile grinding accuracy and reducing the roughness of the model and ensuring the deviation of the grinding size.
Remedy for manual grinding against the defects of the grinding method - The program compensates for the manual grinding method mentioned above. The generation of corrugation during refining is inevitable. Once the corrugation is generated, it must be re-finished, which will inevitably result in the model of the piece. The diameter of the base circle is small, and the diameter of the base circle of the worn model is too large and the size deviation often exceeds the allowable value. This has to re-grind the model of the larger diameter. For a motorcycle camshaft model with only two cams, the problem is not big, just re-grind one. However, if the size of the camshaft of the car with 12 cams is small, if it is the last one, then it is necessary to re-grind up to 11 pieces, which shows the difficulty of working. In fact, in case of the deviation of the diameter deviation of the base circle of the model, there is no need to re-grind, as long as the machining program in the numerical control microcomputer is modified, the user processing program in the microcomputer solidified chip is transferred to the user storage area for corresponding Modifications to achieve size compensation, the problem is solved. For example, when I was in the after-sales service of a camshaft factory in Shandong, I found that the diameter of the base diameter of the 160-type camshaft model was different, which caused the deviation of the diameter of the cam base circle of the workpiece (the technical drawing requirement was ±0.1mm). Using the above program compensation method, the solution is solved from the machining program in the numerical control microcomputer, so that the automatic size compensation problem of the machining program can be satisfactorily solved, and the workpiece dimensional deviation is only ±0.02 mm (mainly caused by the wear of the grinding wheel and the clamping error of the center frame).
5 Summary) Familiar with the machine tool performance, according to the existing manufacturing precision and process level of the machine tool, it is very important to carefully prepare for the anti-reliance. After the automatic grinding of the model is achieved, the grinding accuracy is mainly determined by the performance of the machine.
Automatic grinding against grinding, grinding parameters are easy to master, accurate feeding can achieve 0.5/step micro-feeding, no fire delay, less grinding, less residual, high profile accuracy, base diameter diameter deviation can be controlled at ±0.01 Within.
By means of the automatic counterback of the model and the program compensation of the deviation of the base circle size, the complicated and technically strong mold manufacturing work is simple and easy, which reduces the technical requirements for the workers and greatly reduces the labor intensity of the operator. ) 'Automatic reciprocity' and "procedure compensation", proved to be successful through practice, it should become a new function of our company's series MXBS8312 microcomputer control high-speed powerful camshaft grinding machine. (Editing enlightenment) 5 introduction Xiaoman, master's degree engineer.
Taiwan launches polycrystalline diamond and boron nitride tool grinding machine According to overseas media reports, Taiwan's Yuanshan Machinery Co., Ltd., which is famous for manufacturing high-precision tools and drill grinders, has launched a new type of polycrystalline diamond and boron nitride tool grinding machine. The machine can be set, polished and inspected once, greatly reducing the wear time and effectively increasing the work efficiency.
The high-precision FC-500D grinding machine introduced by Yuanshan Machinery Co., Ltd. is made of high-strength cast iron. The machine body can withstand high-pressure load and maintain stability. The wheel head slide is made by Schneiderberg 9 in Switzerland. The slide rail is suitable for gravity and precision grinding. The grinding wheel spindle adopts the inclined ball bearing assembly to rotate smoothly and quietly. In addition, this mechanism is equipped with the specially designed CCD high-precision photographic device of Yuanshan Machinery Co., Ltd., which is easy to move in the grinding process. The accuracy can be detected at the same time without stopping the machine, and the camera magnification can be arbitrarily adjusted from 15*20 times. With the precision instrument detection, different arcs can be used, and the arc as small as 0.05 legs can be clearly measured from the camera. It is a precise and convenient tool grinding machine.
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