Blood Testing Strips

The machines used by diabetics to test their blood sugar levels contain a disposable strip, which is replaced after each test. It is essential that the composition of these strips is correct otherwise the test result will be incorrect. This in turn can very have serious consequences.

The material is produced as sheets (shown in the image to the right), which are then cut up into individual strips once the manufacturing process is complete.

Envisage added a vision system to the machine that applies the key component to the strips.
The challenge in thsi application was that the applied enzyme was effectively invisible and it was only by the use of a structred lighting approach thta the detection bacame possible.

The system inspects the active area of each strip to check that sufficient material has been applied and that it is correctly located. These checks are fully configurable by the operators.

Strips that are identified as being unsatisfactory are identified on a visual representation of the sheet that forms part of the system's user interface. These strips are then "struck through" using a permanent marker, so they can be identified and removed once the sheet is cut into individual strips.

The system also has the capacity to record statistics by both sheet and batch, to enable any trends within the manufacturing process to be identified and tracked.

In this case a stepper motor was incorporated to drive a moveable bridge to which five cameras were fixed.
The vision system was designed to ensure that a full card could be inspected in the same time as the next card was prepared by the enzyme application machine in order not to cause bottle necks in the production process.