To be clear, the 20x20 is used for the cross bars to hold the print head, but the outer frame uses 40x40. I have not done the calculation yet to look at the amount of deflection of the various different parts, but keep in mind that each 20x20 rail is only holding half the weight of the head. Ultimately, I was merely looking at the parts available on OpenBuilds and trying to figure out how I couldby tlewis3348 - Mechanics
Sorry. I guess I was unclear. There's no DIY large printer designs. I suppose this is an unrealistic expectation.by tlewis3348 - Mechanics
I'm currently using OpenBuilds' V-Slot 20x20 Linear Rail (link) in my design. Since it's aluminum, I'd think it'd be relatively light, but maybe not? My expectation is that the rails are plenty stiff enough, but the mechanism connecting them to the structure may have too much slop in it. In other words, I think the weakest link right now is the mechanism connecting parts together, not the rails tby tlewis3348 - Mechanics
Well, I'll be the first to admit that I have very little knowledge about the advantages and disadvantages of different designs apart from what I read on the internet (which can obviously be unreliable), but every place I've looked at that described the advantages and disadvantages of various different mechanisms always mentions difficulties related to belt tension in connection with the CoreXY. Iby tlewis3348 - Mechanics
Oh! Thanks for pointing me to Ultimaker. That helps me know that I'm not completely insane. I think the biggest struggle for me is knowing the effects of size as things are scaled up. For example, just yesterday, I discovered Rat Rig and found the design logic behind their bed design to be intriguing. But I'm still working out how the size factor changes things. In any case, it's clear that simpby tlewis3348 - Mechanics
I'm a mechanical engineer and have been investigating the possibility of building a self-designed 3D printer capable of handling build volumes of 1 cubic meter (or more, depending on what the main limiting factors are). After researching motion systems, obviously CoreXY came up as a popular choice. Two the downsides of the CoreXY design regularly mentioned however is (1) the fact that the belts aby tlewis3348 - Mechanics