| With the implementation of the "Made in China 2025" grand plan,the micro-nano measurement technology and fine processing technology in advanced manufacturing technology have also ushered in rapid development.The demand is increasing,and the requirements for their manufacturing accuracy are also increasing.For example,the deviation of the geometric parameters of the injection hole of the diesel engine nozzle has a significant impact on its working efficiency,fuel consumption and pollutant emissions.The working performance of various micro-gears,threads,chips,lenses,pin arrays and other precision components is also closely related to their manufacturing accuracy.High-precision dimensional parameters require high-precision detection technology and means to match,so the micro-nano coordinate measuring machine used for the measurement of precision components and the probe system serving as a scanning or triggering function in the micro-nano coordinate measuring machine have become the research hotspot.In the field of micro-nano measurement,it is more difficult to measure the inner dimension of the large aspect ratio than the measurement of the outer dimension,mainly reflected in the challenges brought by the narrow measurement space and the measurement depth requirements.Therefore,this paper focuses on the problems of low measurement accuracy,small measurable depth-to-width ratio,and complicated measurement chain in micro-nano internal size measurement.The corresponding measurement is built around the tuning fork fiber integrated three-dimensional resonance probe independently developed by the laboratory.The system and the micro-hole of the needle valve body of the diesel engine injection nozzle with design indicators are selected for measurement to verify the practicability of the resonant probe.The main tasks completed are as follows:1.Construction of the experimental system: Based on the quartz tuning-fork resonant probe system,combined with a high-precision large-stroke three-dimensional nano positioning table,a micro-scale measurement system is built,which makes the system feasible and effective for nano-level accurate measurement in three dimensions.2.Measurement and control software development: Combined with the specific measurement requirements of the experiment,the measurement system control software is written based on MFC using C++ language.The main functions include the test verification of the probe performance and the three-dimensional automatic shape of themicro-cone shape of the fuel injection nozzle measurement,etc.3.Probe performance verification: Based on the constructed experimental device,the measurement performance of the quartz tuning-fork resonance probe is tested to verify that the probe has sub-nanometer resolution and good repeatability.4.Aiming at the problem that the probe can't extend to the bottom of the micro hole to complete the measurement of the micro hole's overall three-dimensional shape caused by the deviation of the axis of the injection hole from the vertical direction,the coarse adjustment fixture of the angle and attitude of the injection nozzle and the precision two-dimensional angle turntable are designed and selected,and the angle and attitude of the injection hole are adjusted by combining the experimental data.So that the axis of the probe can be vertically upward,and the ball can reach the bottom of the micro hole.5.Three-dimensional topography measurement of fuel injection hole: Using a quartz tuning-fork resonant probe with proven performance,the micro-cone of the injector with angle and posture adjustment is tested including the diameter of the inner hole and the solution of the taper angle parameters.Combined with the measuring characteristics of the probe,the depth of the micro-hole is also measured.The experimental results show that the quartz tuning-fork probe based on the principle of resonant trigger measurement can achieve high-precision micro-hole measurement with large aspect ratio. |
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