Research On Smart Cutting Tool System Based On Cutting Force Signal

As the basic industry of the country’s economic development,the machinery manufacturing industry has a high strategic position.In recent years,some countries such as Europe and the United States have token restrictive measures on China continuously,and the China’s chip technology has been strangled caused the phenomenon that no chips available for the suppressed companies.In the final analysis,China’s manufacturing industry is not strong enough,so the transformation from “Made in China” to “Intelligent manufacturing in China” and “Created in China” in the “Made in China 2025”development plan needs to be accelerated.Intelligent manufacturing is the development direction of the machinery manufacturing industry in the future,and the process of intelligent manufacturing depends on the development of intelligent equipment.Cutting is the material processing method which most widely used.The affection of intelligent equipment can not only reduce processing costs,but also improve processing efficiency.Cutting status monitoring has become a research hotspot in intelligent cutting processing.Cutting force signal is used in cutting status monitoring and processing quality prediction universally,and it is significant to obtain the cutting force signal accurately.This paper has carried out the research of smart force measurement tool holder for turning processing.After analyzing the present research situation of cutting force measurement in machining at home and abroad,it is found that there are some difficulties in the measurement technology of resistance strain cutting force signal,which have low stiffness of elastic structure and temperature error affecting measurement accuracy.After the force analysis of the standard size turning tool holder and the static stress analysis of the cantilever beam model,it is found that the strain produced on the surface of the tool holder can be used as the physical signal sensed by the resistance strain sensor.The tool holder modeling and simulation have obtained the force sensing area suitable for the universal size of strain gages,and after the strain measurement experiment,the measurement effect of the metal strain gage and the semiconductor strain gage on the strain of the force sensing area is compared,and it is found that the measurement capability of the semiconductor strain gage is much higher than that of metal strain gauge.Therefore,semiconductor strain gauges are used to design the sensing system.In the process of designing the sensing system,the temperature error caused by the resistance temperature coefficient and sensitivity temperature coefficient of the semiconductor strain gauge is analyzed under the influence of temperature,therefore,the series-parallel resistance method and BP neural network are used to compensate the temperature error.To obtain the static and dynamic performance and cutting application performance of the smart force measurement tool holder,static calibration test,dynamic calibration test and applied cutting comparison test were designed,respectively.The static sensitivity of the main cutting force is 1.14×10-2 m V/N by the step-by-step loading and unloading method,and the first-order natural frequency of the smart force measurement tool holder assembled on the lathe is 6.0823 k Hz by the attenuation vibration method.The dynamic calibration tests the results show that the average relative error of the BP neural network prediction results is 1.48%,which has a good temperature compensation effect.At the same time,a cutting test of the application performance of the smart force measurement tool holder is carried out,which verifies that the signal of the smart force measurement tool holder measures the main cutting force in the turning process is reliable.At the same time,a verification test for the application of smart cutting tools was carried out.The measurement performance experiment verified the reliability of the smart cutting tool in measuring the main cutting force signal in the turning process.The proposed method of using the average cutting force threshold method to monitor the cutting state can clearly distinguish different tools at different stages of wear,which proved the purpose of monitoring the cutting state is achieved.