I store my CNC machine upright due to space limitations. That means the weight of the gantry, about 15 kg, is supported by the two y-axis lead screws, which are 8 mm ballscrews. That means there is roughly a 7.5 kg weight supported by each ballscrew nut. I am worried that this may in the long term damage the ballscrew because it is parked in this upright position for potentially many days or even months before it is used again. Is a 7.5kg constant load over months at one location a problem for a ballscrew?
I wouldn't think so - the risk would be the gantry moving, turning the leadscrews and the motors - generating back emf which could damage your stepper drivers. Either park your gantry at the end of it's travel which will be down while stored or make something that will fix to the spoilboard or C-beams that the gantry can rest against. Alex.
The gantry doesn't move at least not visibly. The two NEMA23 steppers provide enough holding torque to support the weight of the gantry. I don't have the specs for my ballscrews, but looking at similar ballscrews online it appears the static axial load rating of 8 mm ballscrews is typically above 1000N. That means there should be enough safety margin even if I assume the entire 150N of the gantry is supported by one ballscrew.
Lucky that steel has excellent creep resistance.. our plastic wheels on the other hand will get a flat spot. Don't get me started on back emf! Cheers