Bench-top or welded frame

[Doddy]

This is done by Getting rid of the Z axis altogether and raise/lower the whole Y axis. This way the only deflection is from the tool stickout and any deflection in the gantry beam and supporting frame.
Build the support frame and Gantry beam strong enough and then the only deflection can come from tool it's self regardless of clearence and material thickness.
Because your lifting the Gantry beam which spindle runs along fixed to solid back plate you remove the Z axis from the equation altogether so then can have very high clearence and still have low deflection because there isn't a Z axis to deflect only the length of tool sticking out the spindle.

This is going off-thread, but you have got me thinking. Particularly as I've committed to buy a Chinese pack of rails and screws, delivered in the next week or so (as much to get me motivated to get off my arse and do something). I'm not a fan of spending a weekend playing with F360, but, and considering this is a fragment of a design (until I get the bits and validate the generic CAD models I've been using are broadly appropriate), is this the sort of thing that you're talking about, and is this a viable starting point for a design.



Basic design centred around the 400/700/1000 lengths sold cheaply. Steel box for the end cheeks (okay, only one in the images, but you can imagine the mirrored cheek), as well as the gantry. 100x50x4 mild steel box section. Spindle mount on 15mm aluminium tool plate. Some poetic license at this time with the mounting of the rail direct to the box section - but I don't think I need to model the epoxy at this time. Clearly I'd need to slave the Z-Axis drives and source a second 400mm screw but this isn't the end of the world.

I don't want to waste more time in F360 on this design if it's a non-starter, so would appreciate your view if this addresses some of the rigidity issues.