In die casting,the real-time measurement of the stress of the tie-bar helps ensure product quality and protect the machine itself.However,the traditional magnetic-attached strain gauge is installed in the mold and product operating area,which hinders the loading and unloading of the mold and the collection of die castings.In this paper,a method for real-time measurement of stress using ultrasonic technology is proposed.The stress variation of the tie-bar is analyzed,and a mathematical model between ultrasonic signal and stress based on acoustoelastic theory is established.Verification experiments show that the proposed method agrees with the strain gauge,and the maximum of the difference square is only 1.5678(MPa)2.Furthermore,single-factor experiments are conducted.A higher ultrasonic frequency produces a better measurement accuracy,and the mean of difference squares at 2.5 and 5 MHz are 2.3234 and 0.6733(MPa)2,respectively.Measurement accuracy is insensitive to probe location and tonnage of the die-casting machine.Moreover,the ultrasonic measurement method can be used to monitor clamping health status and inspect the dynamic pulling force of the tie-bar.This approach has the advantages of high precision,high repeatability,easy installation,and noninterference,which helps guide the production in die casting.

Chaojie ZHUO;Peng ZHAO;Kaipeng JI;Jun XIE;Sheng YE;Peng CHENG;Jianzhong FU

The State Key Laboratory of Fluid Power and Mechatronic Systems,College of Mechanical Engineering,Zhejiang University,Hangzhou 310027,China;The Key Laboratory of 3D Printing Process and Equipment of Zhejiang Province,College of Mechanical Engineering,Zhejiang University,Hangzhou 310027,China;Ningbo Haitian Die-Casting Equipment Co.,Ltd.,Ningbo 315821,China

机械工程前沿

[1]Chaojie ZHUO;Peng ZHAO;Kaipeng JI;Jun XIE;Sheng YE;Peng CHENG;Jianzhong FU-.Ultrasonic measurement of tie-bar stress for die-casting machine)[J].机械工程前沿,2022(01):182-195

acoustoelastic,noninterference

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