Dual Drive Setup (with driveshaft)

discussion of design changes / improvements / suggestions

What would your dual drive preference be?

Drive Shaft
30
41%
Dual Motor
41
56%
Something Else
2
3%
Nothing
0
No votes
 
Total votes: 73

lasershark1
Posts: 143
Joined: Sun Apr 22, 2012 1:52 am

Re: Dual Drive Setup (with driveshaft)

Post by lasershark1 » Mon Apr 23, 2012 8:25 pm

I don't have my Shapeoko yet - I'm on the Inventables list, but I've been devouring information lately and buying the electronics I need. I also run a sign shop (Who likes Zombies? We all love Zombies! Help pay for my Shapeoko parts by buying some Zombie decals: http://www.lasersharkdesign.com/shop ) and am hoping to expand the size of mine to help me do signs in wood that I cannot currently do with my laser (due to the table size of my laser, and the fact that it's hard to 3D with a laser - imperfections in the wood/focus issues lead to not really being able to effectively 3D carve it). Given a 1200mm makerslide I can do an almost 4' by 4' sheet of wood in there. (I'll likely go 4' on the X axis and 2.5 to 3' on the Y).

That being said, I've been brainstorming ideas to extend the Y axis myself. The dual motor drive sounds nice, and so does the shaft, but I've got to ask... why are we keeping the Y axis motor attached to the X axis gantry? Instead of having a belt 'strip' that the motor crawls along, what about putting the Y axis motor at the rear (or front) of the Shapeoko, using a drive shaft to the other side, and then running a loop of belt around the pulleys, down the length of the Y axis, around a pulley on the other side, and attaching both ends to the X axis gantry?

Thats how my CNC laser runs... the motor isnt ON the X axis, it's in the housing. I mocked up an image real quick just now (and it's turned sideways... no idea why I did it that way) of how it could look.

It solves the issue of the shaft being in the way of anything, gets one more set of wires out of the way/stationary (as the wires to that motor arent moving about), reduces load as it gets the motor (and drive shaft) off the X gantry...

Is there any good reason this would NOT work? Not much more expense, other than doubling the belt length needed. One motor, one drive shaft, out of the way...
Attachments
example.jpg
Mock up of what I'm talking about.
example.jpg (46.12 KiB) Viewed 3538 times

RedOko
Posts: 43
Joined: Mon Apr 09, 2012 5:49 pm
Location: TX

Re: Dual Drive Setup (with driveshaft)

Post by RedOko » Mon Apr 23, 2012 8:32 pm

Lasershark1,

That is exactly what I'm planning to do!!!!

the other change will be to mount the X-axis to one of plates too so that the gantry will only be carrying the spindle. Will need longer belts but this will remove the backlash as well since you can put a spring load on the idler wheel on the other end.
Luis
aka "RedOko"

Max Metz
Posts: 240
Joined: Sun May 20, 2012 11:55 am

Re: Dual Drive Setup (with driveshaft)

Post by Max Metz » Sun May 20, 2012 1:31 pm

Only having just ordered the full kit, perhaps my vote is a tad premature, though the shaft idea seems very elegant.

I imagine the shaft will be light tube for rigidity like that of an auto-mobile.

The shaft also leaves the front of the machine free for a 4th axis, doesn't interfere with other future options like dual horizontal slider rails with the spindle running between them on dual carriages for wider builds or heavier spindles.

The shaft concept also reduces the number of drivers should this little gem ever get to 5 axis (perhaps one rotational tumbler on the x or y and another limited perpendicular rotational axis on the z-axis - the last limited one tilting the spindle).

Best regards. :D

nogthree
Posts: 62
Joined: Mon Apr 09, 2012 8:48 pm
Location: Brisbane, Australia
Contact:

Re: Dual Drive Setup (with driveshaft)

Post by nogthree » Mon May 21, 2012 6:50 am

Hey Edward - was there ever a released BOM for this? Needing to collect pending my makerslide order :)
- Brendan Halliday.
ShapeOko Wiki Userpage

edwardrford
Posts: 1250
Joined: Mon Apr 09, 2012 5:40 pm
Location: Dixon, IL
Contact:

Re: Dual Drive Setup (with driveshaft)

Post by edwardrford » Wed May 23, 2012 4:51 pm

I'm not sure if this is up anywhere or not: Attached is the exploded view PDF (and some renders) which has part numbers and quantities. I have yet to prove this design, but am fairly confident it will work as planned.

When I went to hook everything together I had a problem getting the 5mm rod through the chosen bearing. I probably should have either stuck the rod in the freezer or heated up the bearing to give the extra clearance needed for assembly...

Also, if you are going to order the pololu hubs, be sure to get the screws with them! Otherwise you'll have to find some very tiny #4x40 screws.

Keep us updated!

-Edward
Attachments
dual_drive_gantry_driveshaft.zip
(705.89 KiB) Downloaded 572 times
Shapeoko 1 #0 - a couple of upgrades.
Shapeoko 2 #0 - a couple of upgrades.
Shapeoko 3 #2 - Stock

AtomSoft
Posts: 589
Joined: Mon Apr 09, 2012 9:15 pm
Location: Brooklyn NY
Contact:

Re: Dual Drive Setup (with driveshaft)

Post by AtomSoft » Sat May 26, 2012 6:48 pm

Edward i know this is your hard work but can i ask for 2 favors....

1) What software are you using to model that?
2) can you please share that simple model? Im not a pro and would like to show you how i would do mines but am afraid to start from scratch.
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alpha
Posts: 174
Joined: Thu Apr 12, 2012 2:49 pm

Re: Dual Drive Setup (with driveshaft)

Post by alpha » Fri Jun 22, 2012 1:08 am

My SparkFun stepper shaft is not very long, how do I connect the drive shaft - this is the part I don't get? Because I already have the GrblShild I favor the drive shaft system... I have a lot of backlash, see this thread: http://www.shapeoko.com/forum/viewtopic.php?f=10&t=347 and I'm looking for any ways to improve this... maybe this backlash is only present with a pen? Maybe a spinning Dremel creates so much rotational force that is always keeps it off to one side?

AtomSoft
Posts: 589
Joined: Mon Apr 09, 2012 9:15 pm
Location: Brooklyn NY
Contact:

Re: Dual Drive Setup (with driveshaft)

Post by AtomSoft » Fri Jun 22, 2012 1:23 am

Backlash is due to the Eccentric spacer.. i think :)
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zimmer62
Posts: 81
Joined: Fri Jun 22, 2012 4:51 pm
Location: Lansing, MI

Re: Dual Drive Setup (with driveshaft)

Post by zimmer62 » Fri Jun 29, 2012 6:33 pm

I'm going with dual motors, because when I decide to expand my machine to a larger size, all I have to do is replace the makerslide with a longer length and a new belt that's longer.

rustythebear
Posts: 18
Joined: Thu Jun 28, 2012 3:02 pm

Re: Dual Drive Setup (with driveshaft)

Post by rustythebear » Fri Jun 29, 2012 7:40 pm

If I scale up this machine, I think I am going to switch to acme lead screws for all axes.

Putting Y screw in the center for equalizing single motor drive.

I am definetley adding a 4th axis lathe.

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