Foam Resilience Tester also known as ball rebound resiliennce tester determines the resilience of flexible cellular polyurethane. The machine provides results of foam rebound performance. After the load ball has its impact on it. The procedure starts with dropping a steel ball vertically on to a test piece. And then measure the rebound height to express as a percentage of the height dropped. When in operation, the Foam Resilience Tester drops a steel ball vertically on to a test piece and the rebound height is measured and expressed as a percentage of the height dropped.
Foam Resilience Tester Apparatus
The Foam Resilience Tester is constructed of a transparent rigid polycarbonate tube with a 44.5mm internal diameter, which is held in a vertical position. A 16 ±0.2mm diameter steel ball weighing 16.5 ±0.5g is held in place before the test, at the top of the tube, by an electro magnet. When released, the ball free falls, with out rotating, centrally down the tube.
The height of the tube allows a drop of 500mm above the surface of the test specimen. There is a scale engraved on the edge of the tube of 1% increments. At every 5% increment there is a complete circle while at every increment between there is a 120° arc.
Test Sample Preperation
The test specimens shall have parallel top and bottom surfaces. Test pieces should be cut down, or plied together, to get an end result of 100mm x 100mm x 50 ± 2mm. For moulded test pieces, the top skin shall be removed.
Ball Rebound Resilience Test Procedure
a) Ensure the apparatus is set up on a flat level surface. Use the spirit level to check.
b) Place the test specimen, of specified dimensions, under the vertical rebound tube. If samples of non-standard thickness are to be used, the height of the tube assembly can be adjusted using the adjustment screws.
c) Place the ball in place under the magnet
d) Press the Ball Release button to DROP. Note the rebound height by visually comparing rebound to the marked percentage incremental lines. If the ball touches the side of the rebound tube, the test should be rejected.
e) Determine the mean of three tests, carrying out each test in a different location on the same test sample.
Test results
The mean of three rebound values gives a accurate caculation Recording the test results includes reporting the mean of the three specimen mean values as the ball rebound resilience value of the sample in percent. The test result also requires to note if the measuremenet were made at different specimen locations or on different specimens.