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Suggested Design Changes

PostPosted: Thu Dec 19, 2013 3:10 pm
by Cozmicray
X-Y ubis mount arm

Flip bolt and hex indent to bring bolt head to front
for ease to tighten / lossen bolts

Split hotend side of arm vertically to allow bolts to squeeze hotend and
threads clamping hub screw.

:)

Re: Suggested Design Changes

PostPosted: Thu Dec 19, 2013 9:52 pm
by Nicholas Seward
Good idea on flipping the traps. I am not sure about the split. Are you having trouble with the fit? The screws should not really need a nut and will thread on the side of the ubis PEEK insulator.

Re: Suggested Design Changes

PostPosted: Sat Dec 21, 2013 7:05 pm
by Cozmicray
Wider Z axis pulley
or
smaller distance between inner shoulders of Z-axis bracket

Prevent line from slipping into slot and riding on bolt

:?:

Re: Suggested Design Changes

PostPosted: Sat Dec 21, 2013 11:04 pm
by Nicholas Seward
Can you take a picture. I don't follow.

Re: Suggested Design Changes

PostPosted: Sun Dec 22, 2013 2:19 am
by Cozmicray
Reduce gap pulley to pulley holder
Wider pulley that goes over bearing?

Z-Pulley_gap_s.jpg
Z-Pulley gap
Z-Pulley_gap_s.jpg (74.49 KiB) Viewed 75369 times


:?:

Re: Suggested Design Changes

PostPosted: Sun Dec 22, 2013 2:23 am
by Nicholas Seward
I am glad you included a picture. I was thinking about something else all together. I can work something out. That does get annoying to fix all the time.

Re: Suggested Design Changes

PostPosted: Sun Dec 22, 2013 6:47 pm
by Cozmicray
Suggested
WALLY --No arc -- Z-Axis

Design of different Z axis that eliminates arc pure Z movement
it can be driven by pulley system or lead screw
C channels could be slipped in slots in backboard for tracks
uses 608 bearings that would be used in standard arms

WALLY_Z_j.jpeg
Suggested Wally no arc Z-bed
WALLY_Z_j.jpeg (129.16 KiB) Viewed 75355 times


Seems much simpler than standard Wally lift
and maybe only
4 printed parts
8 bearings 4 eccentric spacers
fasteners

may not be RepRap kosher?


:D

Re: Suggested Design Changes

PostPosted: Sun Dec 22, 2013 7:23 pm
by Nicholas Seward
I like it. There is no reason you cant have the bearings roll right on the backboard. You will have to experiment. I am stuck with the arc for 20 beta units.

Re: Suggested Design Changes

PostPosted: Sun Dec 22, 2013 8:22 pm
by see3d
Cozmicray wrote:Design of different Z axis that eliminates arc...
C channels could be slipped in slots in backboard for tracks
uses 608 bearings that would be used in standard arms
:D


This has merit. Aluminum C channels might be good enough for a slow Z axis. I would not want to see it run directly on the wood without a harder and more uniform surface. Steel "Keyway" square stock is cheap, straight, and strong. I would want to see a tie bar at the top of the backboard to keep it rigid.

Actually, since gravity load is cantilevered, only one bearing at top back and one at bottom front are needed on each side. No eccentric needed. However, it needs to be stabilized in sideways direction. One bearing on the left side top, and one on the right side bottom would capture it in all 3 axis, if the string was biased to the right side, so the load was cantilevered to the side also.

It really only needs 3 bearings front to back to define a plane, but might be better with all 4, just in case of twist from parts.

WALLY_Z2_j.png
6 bearings
WALLY_Z2_j.png (18.56 KiB) Viewed 75347 times

Re: Suggested Design Changes

PostPosted: Sun Dec 22, 2013 11:32 pm
by Cozmicray
This has merit. Aluminum C channels might be good enough for a slow Z axis. I would not want to see it run directly on the wood without a harder and more uniform surface. Steel "Keyway" square stock is cheap, straight, and strong. I would want to see a tie bar at the top of the backboard to keep it rigid.


This z axis runs at a mm per fortnight or mm/sec
We don't have a roller coaster here, a CNC machine with 1000 ftlbs or a turbine shaft
and we don't have tons on table we got grams!
If the 608 sat there for a year --- it may put a .001 dent in wood/aluminum

If you can't get a nice straight 10" aluminum C channel time to check out!
Actually birch ply pretty straight, but may sqoosh if bearing sat there for a while

I'll look for some carbide square rail stock and lap it on reference granite (hee - Hee)
but that may hurt the 608 race?

Aluminum Makerslides capable of some real precision and speed

Agree tie bars top and bottom forgot to draw top one

:roll: