Vision system inspects test strips

A five camera vision system has been deployed at a major pharmaceuticals company to inspect medical test strips. The test strips are manufactured in high volume on sheets of a polyester-based material using a roll-to-roll screen printing process that builds up the components of the strips sequentially layer-by-layer.

High-speed inspection

Once the capability of a manually fed proof-of principle-system had been verified, the pharmaceuticals manufacturer commissioned the development of two high-speed machines to automatically feed the sheets of strips sequentially into the vision inspection system from a stack.

Although the machines used the same camera configuration, to match their speed, the image processing tasks were split between two PCs - one runs software to process the images of the three registration targets and the dot matrix code, while another processes the images of the reagent pads and the surrounding electrodes. In the high speed machines, the linear motors were controlled by a separate hardware PLC.

The PC processing the image data from the two outer cameras also runs Optimal Industrial Automation’s own proprietary SynTI® software which collates the results from all the image analysis software tasks and performs a statistical analysis on the data which is displayed on an HMI. In doing so, it enables the plant operators to examine the specific nature of any misalignments that occur so the reel-to-reel manufacturing process can be fine tuned.