I’ve got one of the C3D VFD Spindles in my SO4 and I’m starting to get occasional whine when running jobs. Gut says that the bearings might be shot, but thought I’d run it by the collective brain trust first. Can’t say how many hours are on it as I bought it from someone on the forums here. I’ve got some video of it running sounding normal, whine present, and a off-state manual spin. I honestly can’t remember what the spindle sounded like doing a manual spin with my fingers. I also don’t feel any movement in the spindle itself, but that’s just by feel, I don’t have a dial indicator reading.
The C3D spindle on our SO4 Pro at work, my HDM, and my SO5 Pro with C3D spindle all have that exact same sound that comes and goes. It has lessened over time as the grease in the bearings distributes more evenly, but is still often present. I’ve sent videos to @Luke and he confirmed it is not a problem. We even run a spindle warm-up macro before running the machines for the day.
The HDM Getting Started guide says:
“Operating the Chiller
The chiller must be turned on when operating the spindle. Operating the spindle without the chiller could cause fire and/or catastrophic damage to the spindle, VFD, or machine. Always leave the chiller on for an additional 5–10 minutes after turning off the spindle to allow the it to completely cool. Never run the chiller when the coolant tank is empty. Ensure there is plenty of clear space on all sides of the chiller to allow for adequate air circulation.” Shapeoko_HDM_Getting_Started_Guide_12_17_2021_v1_final_web.pdf (1.5 MB)
Probably recommended to work against thermal lag, (IMO) for the mass of the spindle probably unnecessary, but it isn’t my product to support ;-). This is why a car’s engine fan will continue to run for a few minutes after turning off, otherwise the engine can get hotter than when it was running.