CAM Jam Challenges
What Are CAM Jam Challenges?
CAM Jam Challenges, or CJCs as I hope to start calling them for ease, are structured exercises that members can complete at their own pace. These challenges are rated by a Complexity Level and, more importantly, once completed you can validate the accuracy of your own work!
The intention is to release new sets of challenges each month and then discuss and review in our monthly CAM Jam sessions so that we can all learn collectively as well as individually.
How Do I Check My Completed Challenges?
Each challenge is based around an engineering style drawing that includes specific dimensions and material density. Given that mass and volume details can be calculated from this information it is easy to compare the expected value(s) listed in the SELF CHECK block of the drawing against your design.
I'm Pretty New To FreeCAD, How Do I Find Volume and Mass Information?
The first step is to ensure that the density value in your materials library matches that listed on the challenge sheet. For current challenges density values should be as follows:
| Material | Density |
|---|---|
| ABS | 1020 kg/m3 |
| American Cherry | 570 kg/m3 |
| Carbon Steel | 7800 kg/m3 |
| 6061 Aluminum | 2700 kg/m3 |
The key point is the the density, the material name and other parameters really don't matter. You can modify existing materials to match the given density, create new ones, or likely the easiest method is to copy the materials into your library.
The second step is to install an Addon called CenterOfMass. With the material set, select a body in FreeCAD and this utility will provide the necessary Mass and Volume numbers to check against. NOTE: Watch your units in Preferences at the top of the page! If it defaults to kg/m3 for instance but you need g/cm3 your numbers will look way off!
