cymex 5.0 was available to download from the developer's website when we last checked. We cannot confirm if there is a free download of this software available. The program lies within Education Tools, more precisely Science Tools. This free tool was originally created by wittenstein. We recommend checking the downloaded files with any free antivirus. The most popular version among the software users is 5.0.
From the developer:
This sizing solution enables you to size and design your entire drive train (application + transformation + gearhead + motor) faster, easier and more reliably than ever before.
It lets you customize motion and load profiles, use Master-Slave function to adjust stiffness and backlash, size a complete project in a fraction of the time, and generate drawings and CADS on request.
You may want to check out more software, such as Trachtenberg Speed Math, wxMaxima or ChemDBsoft Lite Demo, which might be similar to cymex.