The Studying And Manufacturing Of Automatic Micro-liquid Sampling Equipment

The porous plate injectors have a wide range of applications in pharmaceutical analysis, biochemical analysis and chromatographic analysis. Its accuracy and reliability directly affects the analysis results of the reagent sample, and its sample adding speed and efficiency has a direct impact on the development of periodic reagent. Its application increase the reagent sample’s utilization, save a large amount of reagent and reduce the workload of staff’s, which also can decrease errors of manual work and reduce the repetition and intensity of the manual operation. After looking up the domestic and international document literature, I analyze the history and the present situation of the porous plate injector at home and abroad. The development of porous plate injector in foreign research started thirty years earlier than the domestic, and its precision and speed are better than domestic products, but its price is high.According to the application in pharmaceutical industry and the user’s requirements for efficiency and error, through a variety of sample analysis, syringes which are choosed as a sample; through calculation and selection of the stepping motor, ball screw, synchronous belt, the whole structure of the injector is determined; through analysising the source and nature of the sample errors,which generated during the motion, the solutions are proposed; MCU STM32chip is choosed as the control chip, and the exponential curve’s acceleration and deceleration control strategy is used to control stepper motor. Finally, testing the accuracy of sample, the test results show that the error of the injector is less than1%, to meet user’s requirements.