what are the disadvantages of a one-plate gantry?
Posted: Mon Mar 21, 2016 5:47 am
Hi, I've located a shop in the US that will laser-cut small runs of steel at a reasonable price, and I'd like to start customizing my Liteplacer. Big thanks to Juha for being willing to make the DXF's available. Aside: they can only cut 1.0mm steel, not 1.5mm -- but for the low-force plates in the gantry (not like the X/Y motor plates, for example) this shouldn't be a problem, right?
One of the more major changes I want to try is moving to a HiWin linear bearing for the Z-axis, and perhaps a double-head setup (as many previous designs display you can get a second head "for free" if you don't need both to be "down" at the same time).
The current Liteplacer design uses a pair of makerslides for the X-axis, and a pair of steel plates (one on each side of the makerslides) for the gantry. One reason for this is that it provides a secure, well-centered place to mount the very powerful and long-stroke threaded-rod stepper for the Z-axis.
Assuming that it was not necessary to mount the Z-stepper this way, is there a big reason not to eliminate the back steel plate and one of the X-axis makerslides? This would result in the gantry riding on a single makerslide using four V-wheels the same way the (current) Z-axis makerslide rides. I figure if it works for the Z-axis it should work for the X-axis too, no? This would also let me lay a much larger dragchain along the X-axis; right now I'm constrained by it having to fit in the small hole between the makerslides and the bottom face of the Z-stepper. I also wouldn't have nearly so much weight hanging off the front gantry, pulling it away from the makerslides.
My plan is to then mount a HiWin rail on the remaining front plate and use a much weaker, much shorter-stroke drive for the Z-axis, maybe even a simple hobby servo or one of those ubiquitous DVD-drive-head steppers. I'm already limited to about 30mm of Z-travel due to a mistake I made in one of my other customizations (long story), so I know I can live with a much shorter Z-travel.
One of the more major changes I want to try is moving to a HiWin linear bearing for the Z-axis, and perhaps a double-head setup (as many previous designs display you can get a second head "for free" if you don't need both to be "down" at the same time).
The current Liteplacer design uses a pair of makerslides for the X-axis, and a pair of steel plates (one on each side of the makerslides) for the gantry. One reason for this is that it provides a secure, well-centered place to mount the very powerful and long-stroke threaded-rod stepper for the Z-axis.
Assuming that it was not necessary to mount the Z-stepper this way, is there a big reason not to eliminate the back steel plate and one of the X-axis makerslides? This would result in the gantry riding on a single makerslide using four V-wheels the same way the (current) Z-axis makerslide rides. I figure if it works for the Z-axis it should work for the X-axis too, no? This would also let me lay a much larger dragchain along the X-axis; right now I'm constrained by it having to fit in the small hole between the makerslides and the bottom face of the Z-stepper. I also wouldn't have nearly so much weight hanging off the front gantry, pulling it away from the makerslides.
My plan is to then mount a HiWin rail on the remaining front plate and use a much weaker, much shorter-stroke drive for the Z-axis, maybe even a simple hobby servo or one of those ubiquitous DVD-drive-head steppers. I'm already limited to about 30mm of Z-travel due to a mistake I made in one of my other customizations (long story), so I know I can live with a much shorter Z-travel.
