One of our customers had requested if tapered slots were achievable and if so to provide samples filter tubes for testing. There would be three sets of sample filter tubes, each set having a different slot geometry. The geometries consist of straight, positive tapered, and negative tapered slots. The negative and positive taper were to have an angle from 5 to 10 degrees. Our research team developed experiments to achieve the positive and negative taper slots. After each experiment, the tube would get cut axially so that the slots could be inspected. Once sufficient results were achieved, samples were produced and sent to the customer for testing. These tests determine the specifications of their future filter tube orders.