The Research Of Monofilament Orientation Degree Measuring Instrument

This project is in cooperation with Jilin Textile Industry Design and Research Institute to study a measuring instrument for measuring the degree of orientation of filamentous polymer.With the filamentous polymer materials(hereinafter referred to as monofilament)the quality requirements are getting higher and higher,the nature of the detection has gradually attracted the attention of scientists.The degree of orientation in the parameters to a certain extent,can characterize the strength of monofilament,hardness and other aspects of the nature.The degree of orientation refers to the polymer material in the process of manufacturing by the external force,the polymer chain along the direction of the force to a certain degree of orderly arrangement,the arrangement of the degree of neatness is the degree of orientation.In view of the market-oriented degree of measurement equipment is expensive and complex operation,Jilin Textile Industry Design and Research Institute only by experienced technical staff to determine the size of the degree of assessment based on experience.But the results are often a lot of inaccuracies,for which the need to design a convenient and practical,reasonable price of monofilament degree of degree measuring instrument.The traditional method of measuring degree of orientation is optical birefringence method,infrared dichroism method,X-ray diffraction method and sound velocity method.Comparison of the advantages and disadvantages of various methods,the design of the use of sound velocity method to measure the degree of orientation of monofilaments.The velocity of the monofilament is measured by measuring the velocity of the monofilament by measuring the propagation velocity Cx of the sound vibration signal in the monofilament.The value of the degree of orientation F is calculated by the formula F=1-(CuCx)2,where Cu is the non-oriented velocity of sound,Cx is the velocity of the sample to be measured.In this design,according to the principle of correlation,calculate the sensor in different locations of the receiving time difference,known sensor movement distance,you can calculate the sound vibration signal in the monochromatic sound velocity.In this paper,the design process of monofilament orientation degree measurement is described.Firstly,the background and common methods of the topic selection are briefly introduced.Then,the speed of the project is selected to improve the degree of orientation of the project.Therefore,the principle of sound velocity measurement and the whole system framework.This paper introduces the implementation scheme of the project from the hardware part and the software part,and demonstrates the principle and realization of the circuit of each part of the hardware.The microcontrollers STM32 module,the power conversion module,the excitation module,Receive processing module and other parts.Software aspects of the project for the first time the introduction of cross-correlation algorithm for measuring the degree of monofilament orientation,and describes its calculation formula and algorithm applications,as well as the various parts of the software to achieve the flow chart.The realization of the degree of orientation measurement is as follows: Monofilament sample is fixed in the degree of orientation measurement device,when the receiving sensor and the transmission sensor close to the computer through the serial control STM32 microcontroller to generate excitation pulse,amplified after acting on the piezoelectric ceramic sensor The sound vibration signal is generated and the sound wave signal is converted into an electrical signal by the receiving side piezoelectric ceramic sensor after the monofilament sample in the measuring device is propagated,and then the filter circuit,the amplifier and the level converter are transmitted to the I / O port,this signal is acquired by STM32 internal AD and stored.And then move the receiving sensor so that the receiving sensor is located at a distance from the transmitting sensor,repeat the above steps,and the AD collects the signal 2 and stores it.The two signals are calculated by cross correlation algorithm to obtain the time difference,and calculate the speed of sound and degree of orientation.The measurement accuracy of this equipment is better than ± 1%.The device is simple in principle,convenient and practical,low cost,and has high stability,reliability and other characteristics,can be used for monofilament,fiber and other high polymer filament material orientation degree of measurement,has broad application prospects.