Flywheel CAMTags: design, innovate, think, and mechanical
Task: CAM and cut our flywheel model
Today we CAM'd the flywheel model and cut it out on the CNC. This was our first CNC project this year in the new house, so we spent a lot of time setting everything up. We first drilled all the holes and screwed the plate down, then proceeded with the pattern contour. We discovered issues with our CAM G-code settings: The CNC started cutting material too high above the plate, and before each operation it would raise the spindle all the way to the top and hit the emergency stop switch. We checked the G-code export settings and found that the safe retract height was set to the home position of the machine, not the clearance height we set. This was probably a default fusion setting that we didn't fix on the new computer. We fixed the stock height, the height of the material that the machine starts cutting out of, which was set to have an offset from the model. In the future we will be sure to make our models the exact thickness of the aluminum and use no stock offset.
After solving these issues we continued the pattern contour with no problems, but realized that it would have been a better use of time to cut the outside contour first. The pattern contour is very time-consuming, and if something goes wrong afterwards we will have wasted all that time. We learned our lesson when the cutting surface slipped during the outside contour, and we ended up with a line in the flywheel. This will affect the balance and how well the flywheel spins, but can be compensated with different sized screws. This could have been easily avoided if someone had checked to see if the screws were tight, but we learned to check in the future.
Ultimately this project got us comfortable again on the CNC. We broke a few bits trying to get the speeds right and rediscovered things that we need to pay attention to, like what bits to use, model stock, G-code presets, and making sure the cutting surface is actually tightened down. We will be able to more efficiently machine the rest of the launcher now that have experience with cutting speeds and settings that work. Next we will work on finishing the launcher, cutting motor mounting plates and the main structure of the launcher assembly.