Firmness Retention and Surface Deformation Test Procedure
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Firmness Retention and Surface Deformation Test Procedure

 Knowing the testing steps of Connell testing machine will help us to evaluate and judge the hardness and surface deformation of the mattress.
 1.Prepare the sample and place it on a rigid flat surface as described in the standard.
 2.Raise the ram head to the top of the stroke and rotate the eccentric.
 3.Lower the ram head and the shaft until a test load of 1025 N (230 lbf) is reached. Return ram head to the initial “up” position, then lower it again until 22 N (5 lbf) is reached.
 4.Adjust static scale to zero. Lower the ram head until 1025 N (230 lbf) is reached. Record the static reading for the test load.
 5.Raise the ram head and rotate the eccentric once more and adjust the stroke scale to the final static scale reading obtained in the previous step.
 6.Rotate the eccentric at the top of the stroke and reset the ram head and shaft so that displacement is at zero.
 7.Run the test for 200 cycles at 100 ± 5 strokes/min.
 8.Stop the machine with the eccentric at the top of the stroke and lower the ram head until 1025 N (230 lbf) is reached. Return ram head to the initial “up” position, then lower it again until 22 N (5 lbf) is reached.
 9.Reset the static scale to zero.
10.Lower the ram head and record the load, obtaining readings for each 12.7 mm (0.5 in) increment until 1025 N (230 lb) is reached. Record the static scale or deflection reading for the test load at each increment.
11.Reset the ram head and shaft so that there is zero deflection.
12.Run the test for at least 6000 cycles at 100 ± 5 strokes/min.
13.Stop the machine with the eccentric at the top of the stroke and lower the ram head until 1025 N (230 lbf) is reached. Return ram head to the initial “up” position, then lower it again until 22 N (5 lbf) is reached. Record the deflection data and call this reading the “additional dimple”.
14.Repeat steps 9-13. This time instead of 6000 cycles, run the test for a total of 12,000 cycles.
15.Repeat steps 9-13 at 25,000, 50,000, 75,000, and 100,000 cumulative cycles.
16.At the end of tests, plot the load deflection curves at each cycle.

Article From http://www.bangtest-china.net            Author Bang Instrument co.,ltd
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