Research On A Method For Automatic Inspecting Foreign Particles In Injections

The foreign particles are probably interfused into the injections in the processing progress. Research shows that the foreign particles can cause health problems to human body. So the injections must be inspected before they left the factory. Most of domestic pharmaceutical factory uses traditional manual inspection method to inspect ampoules for foreign particles. The traditional manual inspection method, with heavy labor intensity and low productivity, is subjective. So the research and development on automatic machine for inspecting foreign particle in the injections is very important and possesses broad application prospects. An automatic inspection method based on light-blocking theory for foreign particles detected in injections is proposed.Firstly the main inspection methods in particle measurement filed and the research situation of automatic inspection machine for inspecting foreign particle in the injections are introduced. The principle of light scattering theory is described in details including basic concept of light scattering and Mie scattering theory. Numerical calculation and simulation of light scattering for different size parameter and complex refractive index are accomplished with Matlab. The extinction efficiency and scattering efficiency is calculated and the scattering pattern is simulated for 3μm particles or larger. The principle of inspection method based on light-blocking theory is analyzed and described in details.The hardware of inspection system based on light-blocking method is designed including optical system, rotating platform, low noise pre-amplifier circuit, high resolution and precision analog-digital conversion and data acquisition. The graphic user's interface is programmed by using the multithread technology. Different filtering method is researched in order to analyze the data properly. Compared with the conventional manual inspection method, the experimental results show the new method a satisfied conformance rate of 96.30% in the case of static offline detection. In order to improve the inspection effect, a method of dual-light-path is proposed to avoid the foreign particles miss inspection in case of the track testing time is too short or the testing area is too small.