Hey people. About to start collecting parts for a full sheep lowrider 2. Is there any benefit to having the 3 cut parts out of aluminium rather than wood? Has anyone done this? And what thickness did you go?
Thanks John
OR… I don’t suppose 3D printed parts would be strong enough?
I think I’ve seen one or two made in metal. I would think quarter inch aluminum would be plenty strong and stiff enough.
Thanks Barry. Is there any possibility of cutting small aluminium pieces on a lowrider, or is it purely for wood?
MDF is really the best for this on my opinion. I have Baltic Birch and they are not as rigid as MDF. I tried some stainless, and for it’s weight it was still more flexible. Aluminum would take some thickness to get it right. I designed it with wood in mind. The first version will work with anything, not so much the second one. If you redesigned the Y plate a bit it could help but…
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Thanks Ryan,
MDF it is then. I was thinking that maybe I could do some aluminium with it if I get the plates done in aluminium. Is there any chance of doing a little aluminium with the lowrider 2?
If steel can be done with the MPCNC then I see no reason why the Lowrider couldn’t do aluminum. The sweet spot will probably be harder to get, given the size of the machine, but I’m pretty sure it should work.
Yeah, we’ll see how it turns out. Thanks
Did you end up doing MDF plate(s)? Wondering if you ever ventured in doing them in aluminum?
I’ve done some playing with ultralight mdf… 3/4” ultralight would be the same weight as 1/2” regular mdf. Might make a nice upgrade without changing the weight if everything fits.
Jake I just stuck with MDF. I don’t have plans to change it in the near future but you never know later on.
I’ve hand cut mine in ply for an initial proof of concept.
Will then be looking at getting the lowrider to cut about 8mm aluminium for the plates. Will post results once done.
So then are you mainly referring to the y plates here? I’m looking to possibly make just the 611 plate from aluminum in the future, or even gauged steel plate…
As a heads up, the modulus of elasticity for MDF is pretty linearly tied with density. Using an ultralight MDF would require the full 3/4" more than likely to retain the same rigidity.
What’s the verdict on Aluminum then? I too was wondering if that would be an option; it might sound odd, but I have better access to cutting the flat parts in aluminum than MDF! 1/4" for the 611 plate and 0.5 for the Y plates.
Are you sure? The few discussions I found online as well as the lumber yard contradict this. The 3/4” ultralight in my shop seems more rigid than my 1/2” mdf although I haven’t done any tests on it.
If you can get aluminum parts for a good price, that is awesome! End result, probably not very different, and a little heavier.
I am not real close to a good lumber yard anymore, I need to get my hands on ultralight and try it out.
I imagine it depends on the application. Thinking of printing the part, with different thicknesses and the same amount of plastic. If a bolt was being pulled parallel to the surface, the thicker material would have a bigger lever arm to hold it in place. I am not a mechanical engineer though…
See attachment.
E1 = modulus of elasticity along the place (weight of Z-axis bearing down on XY gantry in our case), E3 = modulus of elasticity perpendicular to the plane (the main thing we’re concerned about, lateral forces from X-axis milling), M = moisture content.
Source
Pretty sure, but not 100%. MDF in generally definitely does change modulus of elasticity linearly with density. I suppose it’s possible that ultralight somehow gets around this by using some special property of radiata pine, but I doubt it. Radiata pine and black spruce (the wood used in the experiment above) have about the same weight and modulus of elasticity, so I have to assume that it’s reduced weight comes from a reduced wood mass. The pressing action in the manufacturing process would likely largely keep the longer fibers in the ultralight oriented along the board rather than across its thickness. This would probably yield some rigidity in E1 since the height perpendicular to the force is the main factor in deflection, but I believe E3 is the real concern in our application. I’d love to be wrong though.
I’m not really sure what the graphs are from but if they are for same thicknesses and different densities I could see that but I’m wondering if the difference in thickness is adding some structural rigidity. I guess I could do some tests next time I have some cutoffs.