Assembly in Action: Vision Sensor Ensures Correct Dispensing
The chemical assay strips are sealed in a fixed position during the meter assembly process. The only variable that could affect blood-to-strip contact is the width and position of the chemistry stripping. This is applied to a foot-long, inch-wide laminate card that is diced into 100 individual chemistry strips. "Basically, we are drawing a line with liquid running the length of the laminate using a precision pump dispenser," explains Joel Blatt, director of research and development. "The laminate is hand-placed onto a table, which moves under the dispenser’s pen tip sitting on a micro-meter stage. If the micrometer is slightly off or the thickness of the laminate varies, the striping may not fall within our set tolerances."
To ensure the width and position of the striping, the company uses an In-Sight 2000 vision sensor from Cognex (Natick, MA). The inspections were previously done manually. An operator would place the laminate under a reticle and perform the measurements. While the required measurement accuracy could be achieved with this approach, the process was slow and became a production bottleneck. "With the sensor, we realized we could get the same accuracy in less time than it was taking under the eyepiece," says Blatt.