We did not know the type of rubber used in the original foot. This was not a problem as we used Simulation Premium and the Nonlinear material models to determine a relative stiffness. By physically testing the original foot under a 2.5 lb. vertical load we measured a 0.1 in. displacement. Using Simulation and varying the material properties we found that a Shore Value of 70, gave a 0.095 in.corresponding vertical displacement. Feeling confident in the design the next step was to test for vibrational characteristics.
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The turntable operates at 33 1/3, and 45 RPM. This equates to 0.556, and 0.75 Hz respectively. SOLIDWORKS Simulation Professional made it possible to test the resonant frequency of the design. The analysis results predicted the lowest resonant frequency at 16.32 Hz. This is well above the induced vibration due to the turning motor and drive mechanism, and lower than the 20,000-20 Hz most receivers output.
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Next we turned to the Stratasys Polyjet line of printers that delivered an amazing print. The Polyjet printed a 70 Shore value model that behaved just like we expected. Not only did the print physically work, it looked great too.
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