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Discussion in 'CNC Mills/Routers' started by Adam Filipowicz, Apr 30, 2017.
CNC Based on CBeam, with No custom Plates, and Z GANTRY
Adam Filipowicz published a new build:
Read more about this build...
Looking forward to hearing some feedback on this idea.
Current photo is a quick rough to get the idea out of my head
doesnt include wheels and many other small parts.
once I flesh this out I will redo a proper cad drawing.
I like that so far this is all Openbuilds parts. No custom Plates
What I dont like is 5 Steppers
No need for all those corner brackets. Just bolt into T nuts through the plate that then connects to the threaded rod.
You might consider moving the X-axis to the back side of the vertical risers. This will center the mass of the router better over the Y-axis wheels.
As Rick said, with the spindle/router out on a limb like that, you are putting a lot of stress onto the wrong side of the gantry.
Thanks for the feedback!
here is an updated version
If you're dropping back to single gantry plates on the Z-axis (which should more than sufficient), you might consider using the C-Beam™ Gantry Plate - Double Wide plates instead, connecting the X beam to the upper half of the plates (leaving the lower half operating in what is functionally dead space along the sides of the Y axis). This will give you another 45mm to work with in both the X and Z directions and make the frame a bit stiffer due to the increased vertical spread of the wheels. I would also suggest the 8 wheel configuration on these plates for additional rigidity.
XL gantry plate can do 6 outer and 4 inner mini wheels correct?
Double gantry 8 mini inner
I would have though XL would be stiffer.
No, the XL plate doesn't accept inner wheels. So the difference here is the leverage provided by the roughly 145mm vertical spread of the double gantry wheels versus the 100mm vertical spread of the wheels on the XL plate. This will help with both the racking of the frame and resisting the torsional load induced on the X axis by the spindle. (It doesn't help the X axis itself, merely the way the force is transmitted into the Z axis.)
Good to know! Thanks!
Revised again switched to Double Wide Gantry plates for Z and Y
again,. please ignore some of the obvious errors in the rendering. (, random wheels, screws, acme being too short lol)
I was just thinking about something like this today too! Then I said no since it would be another axis that could become shifted.
But your z travel is going to very poor if you used the bottom on the double c beam plate.
I like the idea of this... Julius, your suggestion of mounting the plate directly to the C-Beam using T-nuts (and then getting rid of the cast corners) is also something I had noticed... Do you know if the head of a low profile screw will fit in the gap between the plate and the C-Beam with the threaded rod, or would it be necessary to countersink the screws?
Adam, if you don't want to run 5 steppers it may be possible to increase the height of the base and then have the Y and/or Z axes driven from underneath using the standoff plates and some GT-3 belt pulleys... It would work in wood, etc, in the same way as the Ox, but I don't know how well it would handle working in aluminum if that was a target material for you.
I am very new to this and have never done a project building anything. I would like to build a small CNC machine for some wood work and perhaps at some point use for cutting Alu (making plates like needed for this machine). For first project, I don't want to spend too much money and was thinking to limit spend $500-$750, including electronics. I see several options for 4 motors with independent drives and power supply around $200-$250. That leaves me about $500 for the build part. Is that possible with some decent capabilities?
Was thinking to make something with X=400 mm, Y=600 mm+, and Z=150-200 mm. Looked at Sphinx kit and by the time I add the cost of available parts, it becomes to expensive. Other ready kits in the price range seems to be too limited in capabilities and potential to improve in the future.
Will appreciate any thoughts and suggestions.
I like the idea of moving the x-axis up and down. This moves the spindle close to the x-axis reducing the torque on it and there is less torsion. Also the mass on the x-axis is small reducing oscillation. I'm tempted to switch my build to your setup.
My goal is also a build without custom parts. My setup needs only 4 steppers. I keep the x-axis short to gain on stiffness. I'd like to be able to cut alu.
Here is the current state:
Well that spoiled what was beginning to be an interesting thread ! .................. what was all that about Laurmees !?
I quite like the design, a good idea I haven't seen yet. Surely the stresses involved would come down to the type of material being machined.
In the last image PatrickB I would put the Z axis uprights on the outside of the Y beams and stiffen the gantry, would give you a wider cutting bed.
I might do something similar as I need that extra cut depth.
If you have FreeCad questions it is best to ask them in the CAD section of the forum or because it is not a program not used by many here, it may be even better to ask on a FreeCad forum.
Recommend a functioning CAD project