Hackaday alumni [Will O’Brien] sent in a few projects he’s been working on lately while he’s in the process of upgrading his workspace. He’s building a 1200 x 1200 mm CNC router based on the Shapeoko router, and it sure looks like he’s having fun doing it.
The Shapeoko router is based on the Makerslide open source linear bearing system. This system uses common aluminum extrusions as the frame of a very simple, very inexpensive CNC router. The Makerslide system is designed to be expandable; if you want a larger axis, just bolt in a longer piece of aluminum extrusion. We haven’t seen many Makerslide builds take advantage of this fact, a shame as the stock Shapeoko only has a build area of 200 mm square.
[Will] is expanding this build area to 1200 mm square, but of course this means beefing up some parts of the build. He’s already moved up to very hefty 250 oz/in Nema 23 stepper motors (up from the Nema 17s for a standard Shapeoko), as well as beefing up the motor mount a great deal.
[Will] also sourced a few lengths of cable drag chain (yes, that’s what it’s called) to keep all the wires for his huge CNC routers out of the path of a moving gantry and spinning motors. It looks like he’s got a very nice build shaping up, and we can’t wait to see it in action.
For what it is worth, the “cable drag chain” stuff can be had for next to nothing.
http://www.cnczone.com/forums/diy-cnc_router_table_machines/114054-dirt_cheap_cable_carrier_flesh.html
Warning: The last link about cable drag chain tries to run a Java applet of unknown provenance.
Just because the rails are longer, why would the steppers need to be beefed up? I mean, you don’t need a larger locomotive to take a train further down a track (just more fuel or fueling locations).
Well, on second thought, if the router head has to drag along the larger cable drag chain and beefier wires to compensate for the increased length…
Super beefy motors, indeed, do not seem to be strictly necessary. Improbable Construct, who built the first 1meter^2+ Shapeoko , only used (fairly high torque) Nema 17’s and his setup works extremely well.
Your second thought is heading on the right track. Although it is not the cables but the guide rails that are the bulk of the increased load. So your train analogy breaks down when one axis carries another, because trains don’t carry other trains on their tracks, on themselves like CNC machines do. Plus when you scale a CNC machine up unless you’re very patient most people want faster rapid moves. Then the time it takes to traverse the length an axis stays the same.
All of that adds up to just one thing, bigger motors.
Looks like he took some inspiration from my build :P
http://www.shapeoko.com/forum/viewtopic.php?f=5&t=505
There’s a whole forum surrounding the ShapeOko and plenty of people have been scaling up.
http://www.shapeoko.com/forum/
Pity it uses a proprietary, localised and hence expensive linear bearing…
@garym53, please point me at a cheaper alternative. MS isn’t nearly as easy to get outside the US as it ‘should’ be, but I’ve yet to find an alternative.
Skate bearings FTW!
Alumni -> Plural
Alumnus -> Singular
You can also use “alum” informally.
On topic: I don’t have a Shapeoko, or anything made of MS, but I love the CNC builds. Keep ’em coming!
You could possibly use open rail if you are looking for an alternative to the makerslide. There are people working on bringing makerslide to the EU. You can find more info on the shapeoko forum
Certainly not breaking any new ground with this design are they? I’m not even sure how this ended up on HaD. It looks like it costs a lot to build to me.
For what its worth, I just finished building my 4′x4′ MakerSlide CNC router with 260 oz/in NEMA 23′s, but only used a single MakerSlide on the Y axis. After playing with it for a week, I was noticing quite a bit of “bounce” in the Y axis when the router touched down (enough to shake the whole table on some pieces). I decided to disassemble the Y axis to double it up, similar to this large Shapeoko router. At the same time, I doubled up the Z axis, as there was some flexing there as well. It seems much sturdier now. Hooking the motors back up next week for a test.
How dd the beefed up machine work? Did the bounce disappear?