Nondestructive Tablet Hardness Testing By A New Laser Ultrasonic Method

Hardness is an important mechanical properties of materials, which indicated that surface resistance to local plastic deformation and destruction capabilities. In recent years, as people continue to in-depth study and application of hardness testing in many areas have made gratifying progress, developed more than some dozens methods have their own hardness of detection and can adapt to different applications. This paper focuses on the hardness of the recent detection of a variety of methods, including the traditional measuring method, pulsed eddy current method, Pap-noise method, micro-hardness method, ultrasonic hardness method, and compared with the ultrasound indentation hardness tester hardness tester of the advantages and inadequate. This paper presents a new tablet hardness testing method: laser ultrasonic testing method. By comparison, validation of the method to a large extent to overcome the existing approach can not be non-destructive and on-line rapid detection of problems. And through the river grass coral pharmaceutical tablet production conducted experiments again verify the feasibility of the proposed method in this paper. Finally, according to the characteristics of this new approach, and the situation with regard to traditional Chinese medicine solid preparations and looking forward to a laser ultrasonic detection method and type of tablet hardness testing methods in industrial production growth prospects.In this paper, tablet hardness of laser-ultrasonic detection of the main research contents includes the following:(1) surface acoustic wave data analysis, based on surface acoustic wave in tablet take some time to spread the basic idea of changing the reception from the (He-Ne laser detection point), by measuring the thickness of about 2.5mm tablets the upper surface of the sample received the vertical displacement of surface acoustic wave, the speed of surface waves on behalf of the entering tone formula calculated results show that: Using the experimental measured data and theoretical data basically consistent.(2) The surface acoustic wave velocity and the relationship between the hardness, in order to clear understanding of tablet hardness and ultrasonic velocity of the relationship between the use of laser irradiation to the tablet, and through the determination of a reflective surface acoustic wave velocity, and the right experimental data analysis to arrive at the tablet hardness and the relationship between the SAW velocity curves. The experimental results showed that with the increase in tablet hardness, the reflected SAW speed will be reduced.(3) In measuring the value of treatment, when the design of laser ultrasonic hardness tester, the first storage area in the hardness tester surface acoustic wave velocity is stored in advance with the tablet hardness values correspond to the data. When you need to measure tablet hardness values, as long as the value of measuring the speed of surface wave aloud, and then use ARM-CPU in the store to find a matching hardness value, so that to achieve the purpose of measuring tablet hardness. The measuring system with YD-1-type tablet hardness tester comparison done. The results showed that the hardness measurements and YD-1 model is the difference between 0.01 ~ 0.02kg, to meet the measurement accuracy requirements.