My design - shapeoko - 1m*1m - openrail

discussion of design changes / improvements / suggestions

My design - shapeoko - 1m*1m - openrail

Postby Misant » Thu Aug 09, 2012 8:13 pm

After having added a 3D-printer to my hobby kit, i am in need of a milling machine, but i found the standard ShapeOko a little bit small. That together with restrictions for packages being shipped from the US to EU, and Makerslide is difficult to get and only comes in 1 size, and shipping on Open Rail is cheaper as it is lighter, i came to a size of 1meter * 1 meter.
This size is also easy to work with. I get the aluminum extrusion from Misumi cut to size and the Openrail comes in a 1m length. So i can just bolt the main part of the frame together.
I also redesigned the motor mount plates to use Nema23 together with other changes to them.
The area that it can mill comes out at a maximum of 85cm*85cm*10cm, but i am sticking to 80cm*80cm*10cm to have some extra room. In the images, the green area is 85cm*85cm*10cm and the red area is the maximum horizontal range of the front of the gantry. Grey square is a wooden plate of 100cm*95cm*2cm that functions as the bottom of the machine. As you can see, the gantry can move the milling tool over the edge for easy access.

Things to add in the design:
- Home and Limit switches
- Belt and Tensioning
- Brackets to assemble frame
- Attachment for bottom to frame
- Attachment for frame to workarea

cnc-openrail-1000-1000-main.png
Main view of milling machine.
cnc-openrail-1000-1000-main.png (204.6 KiB) Viewed 10147 times

cnc-openrail-1000-1000-closeup1.png
Zoomed in.
cnc-openrail-1000-1000-closeup1.png (173.99 KiB) Viewed 10147 times

cnc-openrail-1000-1000-closeup2.png
Zoomed in.
cnc-openrail-1000-1000-closeup2.png (246.08 KiB) Viewed 10147 times
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Re: My design - shapeoko - 1m*1m - openrail

Postby baz » Thu Aug 09, 2012 8:37 pm

Hi, this design looks good. Before you take the plunge with Open Rail, please check out my thread on MakerSlide Europe viewtopic.php?f=7&t=556&p=4571#p4571. We are planning on launching an Ulule (Kickstarter's European cousin) campaign in the coming weeks, and your support would be greatly appreciated. Also, you are venturing in to uncharted territory, hopefully it will be successful and worthwhile, but the current ShapeOko design has gone through many hours of testing and modification by many builders and its current version is arguably the best configuration. I wish you all the best, and hope your build goes well and you see good results. Please post pictures and your findings, it will greatly help the community and help influence other peoples build decisions.

Many Thanks

Regards

Baz

Edit: you may also be interested in this viewtopic.php?f=11&t=363
ShapeOko #676, eShapeOko #11, Hardened MakerSlide, OpenRail, Steel v's, Misumi Extrusion, Kress 800
MakerSlide Europe Store
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Re: My design - shapeoko - 1m*1m - openrail

Postby cvoinescu » Thu Aug 09, 2012 9:18 pm

My feeling is that the wheels on the X and Y carriages are much too close together. The moment of the force of the wheels against they rail is very small, so when the plate tends to twist, there's a lot of strain on two diagonally opposite wheels. Imagine a heavy spindle; it tends to twist the X rail (pull the top forward, push the bottom backward). That is resisted by the wheels on the Y plates (top front and bottom back), but 1 kg of spindle puts 2-3 kg of force on the top front wheels on the Y plates. That's a guess based on about 47 mm wheel spacing (so an arm of 23.5 mm for the normal force in the wheel) and a spindle centered, optimistically, 7 cm in front of the center line of the wheel box. Cutting forces will affect both the Y and the X.

The ShapeOko motor plates are wider for a reason. They resist these forces quite effectively.

Other than that, I think your design is fine (although it is a bit of a stretch to call it a ShapeOko, IMHO).
Proud owner of ShapeOko #709, eShapeOko #0, and of store.amberspyglass.co.uk
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Re: My design - shapeoko - 1m*1m - openrail

Postby northbear » Thu Aug 09, 2012 9:42 pm

Misant,

Interesting design. Thanks for showing it! I like the lowered gantry so that both X and Y extrusions are the same height above the work piece. I also like the drive idlers and motor mount and v-guides on the same bolt! I only was looking at doing the motor and idler (viewtopic.php?f=11&t=538)

Couple of questions

Are you concerned that the v-guides will be too close together? Take a look at this - http://www.youtube.com/watch?v=pmPVlNh5 ... ature=plcp Different material, but narrower spacing.

Is that 20x60 extrusion profile?
Is your plan to have two y axis motors?
My buildlog is here
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Re: My design - shapeoko - 1m*1m - openrail

Postby northbear » Thu Aug 09, 2012 9:47 pm

cvoinescu wrote: (although it is a bit of a stretch to call it a ShapeOko, IMHO).


I should probably start a separate thread, but I was wondering what makes a ShapeOko a "ShapeOko". What qualities give it its "ShapeOko-ness"

**Edit** new thread on this topic started here -- viewtopic.php?f=7&t=621
My buildlog is here
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Re: My design - shapeoko - 1m*1m - openrail

Postby Misant » Fri Aug 10, 2012 10:44 am

I know that i am venturing in unknown territory with the open rail and modified motormounts, but that is also the fun in designing and building, trying new things. I am aware that this might cause problems. and i already joined the kickstarter for open rail, so wont be investing in the Makerslide Ulule-fundraiser.

I was debating what to call it, but as it is started out as a shapeoko i drew up in sketchup, so for now i stuck with shapeoko (and i couldnt come up with a good name).

The X-axis uses 2 motors and the extrusion is 20x60 and wanted to make the motormounts out of dibond for the first build.
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Re: My design - shapeoko - 1m*1m - openrail

Postby Digitalmagic » Fri Aug 10, 2012 1:42 pm

Have got extra Makerslide (1000mm) and pledged on OpenRail, too, with same perspective.

Apparently, your gantry rail is like a 20mm x 40mm (double 20) mitsumi T-slot with 4 OpenRail, right?
Even if 4 OpenRails would add rigidity, I would use a 40mm x 40mm here,
'coz deflection/displacement for a 20x40 1000mm rail is in the 2mm-ish when applying a 25lbs at one extremity.

You strengthened the frame, by using 20x60, but you could explore L-shaped 40mm x 40mm (20x40 angled with 20x20), perhaps.

Perhaps you did not choose belt/pulley yet, it is a good idea to compare MXL and GT2, apparently you would wish more length, more strength and precision! :D
s/o #650 - Wish my digits are ... magic!
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Re: My design - shapeoko - 1m*1m - openrail

Postby Misant » Fri Aug 10, 2012 8:51 pm

The gantry is 40x60 and i have selected GT2 as pulley/belt.
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Re: My design - shapeoko - 1m*1m - openrail

Postby Digitalmagic » Fri Aug 10, 2012 9:15 pm

Misant wrote:The gantry is 40x60 and i have selected GT2 as pulley/belt.

Which pitch and belt size?
Which idler do you plan to use?
s/o #650 - Wish my digits are ... magic!
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Re: My design - shapeoko - 1m*1m - openrail

Postby Misant » Sat Aug 11, 2012 9:28 am

As per this artice http://mendelmax.com/tikiwiki/tiki-index.php?page=Choosing+Belts+and+Pulleys i have choosen
this pulley: https://sdp-si.com/eStore/PartDetail.asp?Opener=Group&PartID=8545&GroupID=347 (with 6.xx mm bore) 40 teeth
and a 2mm pitch, 6mm belt.
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