Research And Application On A Measurement System Of Straightness And Parallelism Of Guideway

With the advancement and development of modern precision measurement technology,we have also put forward higher requirement for the measurement accuracy of various geometric parameters of the machine tool.As the most basic item in the field of metrology and inspection,the straightness and parallelism of guideway are important factors that affect the precision of machine tools and are also the inspection items for the accuracy detection and promotion of machine tools.The methods of the straightness and parallelism of guideway are mainly classified into laser measurement methods and non-laser measurement methods.Laser measurement methods usually require expensive optical instruments such as laser interferometers and laser collimators,as well as various accessories for optical components,thereby greatly increasing the measurement costs.Non-laser measurement methods generally need a higher straightness physical reference,such as a flat rule.This method usually involves a complex measurement process and low measurement accuracy.Therefore,it is of great significance to propose a small,low-cost measurement system that can achieve the measurement of the straightness and parallelism errors of guideway accurately.This paper develops a compact,low-cost and precise measurement system for straightness and parallelism of guideway combining the usage of dual-axis optoelectronic level and pentagonal prisms based on the principle of laser collimation and self-collimation.According to the structure of the common laser collimation system,the design and construction of the measurement system is completed.Then a reasonable program control strategy is developed based on the labview graphical programming software.The whole control program is divided into data acquisition and filtering module,graphic display and data storage module,straightness data processing module and parallelism data processing module using modular programming idea.Finally,with the actual straightness and parallelism measurement flow,the friendly human-computer interaction interface is designed.We achieve the controlling of the entire measurement system and realize the functions of data acquisition,data processing,data saving and graphic display.In order to verify the accuracy and stability of the proposed measurement system,calibration experiment,stability experiment and comparison experiment are performed using laser interferometer and photoelectron autocollimator.The experimental results show that the calibration residual of the measurement system is less than ±0.8?m.The comparison residual is less than ± 2?m,which is compared with the straightness measurement result with the method of level.And the result of stability experiment shows that the drift of the measurement system in 10 seconds and 30 minutes are 0.13?m and 1.8?m.So,it proves that the measurement system has a reliable stability.Finally,the adjustment device for measuring the straightness and parallelism of two guideways is introduced in detail.An adjustment method for making the measurement light parallel to the motion axis by using the triangle similarity method is proposed.The straightness and parallelism errors of the guideway and linear stage straightness are measured by this system.The experimental results show that the straightness and parallelism of the guideway have been effectively improved after measurement and adjustment.Therefore,the measurement system can be used for actual measurement of the straightness and parallelism of guideway,and it also has important guiding significance to the adjustment of the straightness and parallelism of the guideway and the improvement of the linear stage accuracy of machine tools.