alex_b submitted a new resource: Ultra-Rigid G10 X-Gantry Plate for C-Beam - 1/4" thick gantry plate with 12 wheels and a wider base. Read more about this resource...
do you have a picture of this mounted on the C-Beam? I am trying to wrap my head around it and it just went poof
This picture should help. there is supposed to be eccentrics on all the inner wheels. (unlike in this picture.) The mounts onto the X axis just like the normal C-Beam plate. Hope this helps!
I understand it a little better now because I just put my gantry plate on my C-Beam together and see how it works. The mini V's go on the inside of the C-Beam on either side of the lead screw providing outward pressure. Do you think there is an advantage to that over using a second plate on the back side with additional wheels so you could turn the C-Beam around and protect it from chips?
With the inner and outer wheels applying both inward and outward pressure, the contact area against the beam effectively doubles for the same size of plate. If you used 2 standard plates on the front and back, that would have a similar effect I would guess. As for protecting against chips, I have been surprised at how little debris actually makes its way into the C-Beam cavity on the X. I usually use a dust shoe so I guess if you don't have one, chips could be an issue.
lol...I haven't gotten far enough to even consider a dust shoe but see how that would keep the chips down. I am going to be making one and am going to need to make this near the top of the list! I am also going to enclose the entire machine because it will be in my wood shop and that gets dusty QUICK
where did you get your G10 from? Cool setup, i would think you would need eccentrics on both sets of interior wheels?
Thanks! G10 for this project came from McMaster-Carr, link for it is below. A few different color options besides black. McMaster-Carr And yes, eccentrics are on both interior sides of the plate, otherwise the tolerances are too tough to align perfectly for proper preload against the C-Beam.
I like rigid stuff, and dislike vibrations,resonanes Always shows up when dont whant it. My machine have so hevy Z axis in solid alu,, and i can say i never gona build in solid alu again so mutch drilling and tapping bolt holes..... Mutch better to build with alu profiles , the side plates is okk to do in solid alu but next time i will take the easyer way it can be as rigid as s solid, and ther is other materials to use with alu i have seen komposit material that is light and stiff as h--l. I like the hardend steel axel that u can fit on the alu profilr and u groove steel Wheel . But this seems just as rigid aas that, like it a lot!
Thanks @Christopher Björkqvist ! I like G10 a lot, same tensile strength as carbon steel and a quarter of the weight!
Have you got any specific information sources on the flexural and torsional rigidities, resonance characteristics, etc of G10? I understand it's a pressure-formed epoxy fiberglass, which seems like it should be doable in the home shop depending on the actual pressure requirements- and even if not, it's fairly readily available commercially. Seems like it would be ideal for projects where rigidity is important, but mass is reduced in favour of speed and acceleration- anything without a spindle, really, but I'm particularly thinking large format, gantry-mounted-tube laser cutters and things like that.
Rob, found this pdf attached.. as for the stiffness (Young's Modulus) the paper says G10 is about 19 GPa, best i found was 24 GPa. (here) lots of other property data in there By comparison carbon steel is about 200 GPa, and 6061 is about 70 GPa. I've cut some with my CNC before, used a carbide burr, and took it slow. Cheers
This is also known as Garolite. A member here used to offer OX plate kits a few years back. I bought a set, but sold them. It's very rigid, flat, and temperature stable. One should take health precautions cutting it.
Hmm. I guess you'd need three times the cross-sectional area/total volume (of a 2D prismatic shape) to match the absolute values of an equivalent aluminum plate, then? If its density is substantially below a third of that of aluminum, that's a pretty good deal. If it's even somewhat similar to aluminum, it seems to me like its structural heterogeneity makes it a fairly inconvenient material. From what I'm seeing, it's about 1.8g/cm3 to aluminum's 2.7g/cm3. Which looks good if you're swapping out like-for-like, but not if you're re-speccing the part to maintain structural consistency. It would actually be heavier to achieve the same stiffness, and not in every dimension like aluminum. Unless I'm missing something, it's very much pre-coffee-o'clock here.
Very different stress strain curves. G10 is brittle aluminum is ductile. The grade aluminum makes a difference too. You can place the same amount of stress on them yet have very different deflection values. One has to compare the strain of each at a given stress to get a better idea of how "stiff" each is. I'm sure you'll find that aluminum has a greater region of elasticity (a property which can be a good or bad thing) prior to permanent deformation and the g10 mostly skips plasticity for failure. I haven't compared the two, but let me know if you find similar stress/strain charts for both(the g10 will probably have a few because of its structure). I bet the scales are different for strain. Joe
I would like to see your "END" plates on the Gantry C-Beam and how they fit on the Y axis. Thanks, pat