Hey guys, fantastic forum !
My story is below - but to cut to the chase,
Has anyone seen T-slot mounts for a 16mm precision rod with floating and fixed Bearing? ( Ie, 40mmx2 holes one side, and then the mount holes for a flange bearing on the 90 face?
I am mounting the bearing on the outside of a long Y axis 80x160 extrusion, and don't intend on having an end plate hanging off the machine to mount motors or flange bearings to.
I was thinking - getting a heavy duty 40 series sized piece of 90 angle, that would bolt straight up to the side of the 80/160, and then drill the holes in it for the flange type bearing?
That would allow me to slide / manoeuvre the T-slot 90angle to get a really nice bearing fit. and also requires less stringent designing of the frame size and end plates with overhangs - as I can slide the bearing to where I need it?
Anyone have any thoughts on this?
Secondly - On the Z axis, If I'm mounting that to a square plate that's on the X axis, then the preferred way to mount is put the bearing blocks on the square so the rail can overhang the square block ( and allow more travel ) ?
Thirdly: Is there any guide regarding travel distance - or can anyone guess what my Z axis working range would be on aluminium using a 200mm spacing on the Y axis bearing carts and also 200mm between the rails? or does this also depend a lot on the workpiece to gantry distance? ( the effective pivot distance ) ?
Thirdly - if I want my X axis gantry spaced so the precision nut was a flange mount on the outside of the gantry side plate, does it need to be designed so that the precision screw threaded portion terminates, exactly where the flange bearing would seat?
If this is correct - I will probably re-visit my other idea of using a T-slot 90 mount, again so I can accurately position the bearing blocks so they work and are straight , vice designint he machine for the screw, or getting a custom screw length cut for an exact design?
Read on for my story
I have spent the last year toiling with a turd of a hobby CNC/3dPrinter that cannot do either well, and refuses to finish most jobs - specially the large 3D print jobs
Things this hobby CNC tought me:
1. Leadscrews with brass bushings suck balls and after 5 uses, the brass bushing is worn so much that there is now 1mm of slop in the axis that cannot ever be removed, unless bushing replaced = 2 hour job.
2. The setups with 4 contact V rollers on aluminium extrusion are an absolute pain in the bum to align correctly, and as they wear and deposit bits of themselves onto the extrusion profile, torque required increases eventually causing a jam.
3. Above wear can be minimized by cleaning all 8 rollers per axis and 16 roller rails in between every use = 1 hour job.
4. If you replace the brass bushings with nylon bushings, they are tighter to begin with, the torque required to turn the screw increases a lot, and in the end, they wear as well
5. Connecting a parallel port or USB to a computer, requires that the entire setup ( including the PC ) be all grounded together, or expect electric shocks. ( So we changed to Ethernet which electrically isolates the PC from the CNC )
6. It's never too big, and 840 x 600 x 140 was not a big enough area
I have the ****s so much, that I refuse to put another roll of PLA on the thing to come back 14 hours later and find it 3/4 finished with evidence of some new kind of jam/mis-alignment / filament bind/electrical malfunction or other issue.
So I'm building my own designed 1500 x 1000 x 400ish machine using T Slot extrusion. The key components are:
Framing :
80 x 160mm T-slot 40 series Y axis framing, and 80x80 T slot 40 series cross and end bracing for the X axis (sitting flush with the bottom of the 80x160)
2 x 80 x 80 T slot tubes, vertical above one another, spaced in the middle by 80mm to form the gantry structure, with aluminium end plate to connect the 2 tubes, and the Y axis bearing block, and precision screw
Sliding Rails:
2 x 20mm hiWIN linear rails placed on top of the Y axis frame, with 2 bearing blocks per rail, spaced 300mm end to end.
( Gantry side aluminium plate will either sit vertical above bearings, or pass down outside of bearing block and have 90 angle mount, and pass outside Y axis frame, down the side to where the Ballscrew is mounted
2 x 20mm rails for the X axis, to be mounted in the top and bottom most T slot, on the 2 80x80 tubes in the gantry ( rails will therefore be 200mm vertically apart for rigidity )
2 x 20mm rails for the Z axis, mounted on aluminium plate, details TBD, but bearing spacing will be probably around 200 end to end.
Ballscrews:
Y axis 1610 x 2 for rapid movement, and 3d printing at 140-150mm/sec , and 10mm/sec aluminium
X axis 1610 x 1
Z axis 1605 x 1
All using either BFBK, or the Flange mount.
Electonics:
Nema 23 motors, Uccnc, Eth400 controller, Undecided on the breakout board or stepper drivers yet.
This is my first post, so I'm hope I'm in the ballpark - any ideas or concepts that would be better I am open to !
Nick
Similar Threads:
I'd want something more rigid.Thanks, what did you think of my plan to use angle brackets in the t slot to mount ballscrews?
Do you have any CAD drawings of exactly how you planned on doing it, as I'm having a hard time visualizing it.
Gerry
UCCNC 2017 Screenset
[URL]http://www.thecncwoodworker.com/2017.html[/URL]
Mach3 2010 Screenset
[URL]http://www.thecncwoodworker.com/2010.html[/URL]
JointCAM - CNC Dovetails & Box Joints
[URL]http://www.g-forcecnc.com/jointcam.html[/URL]
(Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)
Also - Anyone know where I can get ahold of 80x80 and 80x160 extrusion not for commercial use?
Was going to use Misumi but since this is a back yard job, no way to order.
Another couple pics.
Trying to slim the design of the z axis linear motion setup. But my rail height + bearing cart is less than thickness of ballscrewnut, or balls crew nut housing. Have guys cut out recesses in the mounting plates to allow balls crew to fit, or generally add spacers so there is enough room, and mount bearings on end plates?
Ordered: All of the electronics, linear drives, power and frame ( except gantry sides )
Time to get busy !
Yeah - thanks anyways ( It says all over their website for commercial use only )
Update:
Ordered -
2 x 1.8 meters ( 80 x 160 )
2 x 1.1 meters ( 80 x 80 )
5 x .92 meters ( 80 x 80 )
170 T-nuts and bolts Total $290 USD
Lots of drilling and tapping yesterday,
And I had an accident and slid a bearing cart off the linear rail - then 10 bearings fell out..took ages to pack them back in there, but much easier than repacking ballscrews !
Slides well, next to attach the Y axis ballscrews, and machine the Z axis plate
Nick