Technical analysis of split lathe bed

2022-08-08
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Technical analysis of split lathe bed

1 Error forms that affect the extension accuracy

there are three error forms that affect the extension accuracy according to the coordinate axis system, as shown in figure 1:

(1) the straightness of the guide rail in the X and Z axes. It has several forms of up-down parallel staggering and angular inclination

(2) the straightness of the guide rail in the X and Y axes, which has several forms of front and back parallel offset and intersection angle skew

(3) lateral unevenness of guide rail in Y and Z axes. It has several forms of up and down parallel staggered and guide rail one high and one low

2. Reasons affecting the adjustment difficulty

when adjusting the accuracy of the split lengthening bed, the accuracy of the X, Z, y and Z coordinate axes of the bed is adjusted by loosening the pressure and jacking down the four adjustment points at the lower part of the lengthening bed, namely, the anchor bolts and the sizing block meters. The horizontal and internal accuracy of X and Y coordinate axes shall be ensured by horizontally extending the bed meter. As the distance between the two long adjustment points of the bed is greater than the short adjustment point, and affected by the height of the guide rail of the bed, there are many difficulties in installation and adjustment. For example, 1mw/5mwh and 15mw/60mwh all vanadium liquid flow battery energy storage systems were built in Yokohama and Hokkaido before and after that, and some single guide rail measurement methods with low accuracy and comprehensive measurement methods that are difficult to distinguish the accuracy errors of various items were used to measure the guide rail accuracy, so as to determine the loosening, jacking and movement of the adjustment point, which will undoubtedly change the east to the West, The situation of changing from less to more, paying attention to one thing and losing the other, and repeatedly adjusting is very blind, and it is difficult to achieve high precision. 4 measurement methods and tools for extension accuracy

in the extension of split bed, whether the measurement method and measuring tool can be correctly selected directly affects the extension accuracy. At present, there are many methods to measure and lengthen the bed with meters, and the effects are different. There are some measuring methods with low precision, such as flat ruler coloring, feeler gauge caulking, paper drawing at the bottom, etc. Percentage form guide rail measurement method using original bed tailstock base plate or bridge plate movement with direct reading. There are also comprehensive measurement methods such as level meter, collimator and steel wire drawing. Neither of them can determine the position, direction and amount of adjustment points with high precision, and make one or less adjustments qualified. For this reason, our factory has selected and made a simple measurement method and tool that can not only be intuitive, but also know all the accuracy error forms, sizes and directions of each guide rail at the same time, and can monitor the accuracy changes of other points when loosening and jacking down one of the adjustment points. Now take the measurement of a group of mountain shaped flat guide rails as an example. It is to place three measuring gauge rods on the tailstock bottom plate or bridge plate at the same time, and their extension length is 300 ~ 500mm under the condition of good rigidity and no warping. Two dial indicators are installed on each gauge rod, which respectively touch the three guide rails of the original bed, and the needle is set to zero. Then move the bottom plate to the end where the tail of the original bed exceeds the annual sales volume in 2009, Make the dial indicator touch the corresponding guide rail of the extended bed. At this time, as long as the difference value, positive and negative of each dial indicator are observed or recorded, it can be known that the three coordinate axis systems shown in Fig. 1 are extended for each guide rail of the bed relative to each guide rail of the original bed, and the accuracy conditions such as up and down, front and back, parallel staggering, offset, intersection angle, inclination, etc. within the two axes, so it is not difficult to determine the direction and amount of an adjustment point at the lower part of the bed

during adjustment, it is best to be carried out by two persons, one of whom is specially responsible for observing the difference change of each dial indicator, and the other is under the command of the person to loosen or Jack down to ensure that the mechanical and electrical work heat is dissipated from the foundation bolts and sizing blocks. Pull back the base plate until the pointer umbrella of each dial indicator is at the zero position, and verify whether each dial indicator changes at the zero position of the original bed. Repeat the verification for 1 ~ 2 times. If there is any change beyond the tolerance, it is necessary to re calibrate the indicator according to the above sequence, re measure, adjust and verify until it meets the requirements. After that, use collimator and level to measure the straightness, levelness, double guide rail distortion and other accuracy of the whole bed guide rail in two planes. The installation and adjustment will not be completed until the main requirements are met. For machine tools with high accuracy requirements, if they need to be readjusted in some accuracy, be sure to refer to the relevant data measured by collimator and level, and make the final adjustment under the monitoring of dial indicator

only with the help of time or instruments can the basic properties of metal materials be measured. After adjustment, tap the bed or stay still. After a period of time, it is retested after short-term use. If there is no change in the data, it indicates that the adjustment is good and can be delivered for use. If there is a little change in the data, it can be fine adjusted again

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