Living-room project... CNC !

ben_mtl · Post by **ben_mtl** » Thu Nov 29, 2012 5:57 am

Z-axis looks promising... just have to check with my machine shop if they can improve the edge surface quality, the bearing runs OK on it but it could be smoother...

twizzstyle · Post by **twizzstyle** » Thu Nov 29, 2012 8:01 am

That's a pretty sweet design!

Do the bearings have side-to-side adjustment, or springs or something? Would really suck if you got slop there and couldn't adjust it (the equivalent of a gib strip)

ben_mtl · Post by **ben_mtl** » Thu Nov 29, 2012 8:07 am

the 2 bearings on one side are mounted on eccentric bushings, allowing for some adjustment.
I'm fine tuning the other parts of the machine since I received all my electonics and a few mechanical components... Can't wait to have them cut ! I'm super excited !

Jekul · Post by **Jekul** » Thu Nov 29, 2012 8:12 am

I'm having renewed interesting in doing a project like this myself. Are you keeping a detailed log for part pricing, lead time, tolerance, all that good stuff? It can be a pain in the a$$ but if you ever do it again it make the process 2x as easy.

ben_mtl · Post by **ben_mtl** » Thu Nov 29, 2012 8:23 am

yes I do keep track of what I spend and I have drawings of the parts I have custom made... This Z-Axis assembly was mainly a mock-up to validate the concept (I knew it would work in theory but having real parts made with good precision was the challenge)

twizzstyle · Post by **twizzstyle** » Thu Nov 29, 2012 9:29 am

ben_mtl wrote:the 2 bearings on one side are mounted on eccentric bushings, allowing for some adjustment.
I'm fine tuning the other parts of the machine since I received all my electonics and a few mechanical components... Can't wait to have them cut ! I'm super excited !

So awesome Ben! I'm having flashbacks to last spring when I was building my machine. Super exciting stuff!

Jekul · Post by **Jekul** » Mon Dec 03, 2012 10:25 am

Looks like you went from lead-screw design to rack and pinion? Any reason you went that way instead of beefing up the acme screw, or using a belt drive?

ben_mtl · Post by **ben_mtl** » Mon Dec 03, 2012 2:55 pm

My X-Axis is 7feet long, above 4feet a lead screw would start to whip. Only way to avoid it would have been to use a larger lead-screw -> super expensive. Rotating nut / fixed lead screw could have worked but it meant more custom parts...
Belt drive was an option but there are some "cheap" plug-and-play options for rack and pinion (CNCROUTERPARTS.COM) so I went with the latter... Some say belt have some "spring" too... not sure about this one though..

Jekul · Post by **Jekul** » Tue Dec 04, 2012 5:30 pm

Any luck finding a 7ft + long press break with good edge quality?

ben_mtl · Post by **ben_mtl** » Wed Dec 05, 2012 5:52 am

Well, I don't know yet... the edge quality comes from the laser cut and 10ft+ laser cutting machines are pretty common. for the bend I guess I'll have to wait till I get the parts in hand (still waiting for the quote... the usual pleasure of being a "small" customer : nobody gives shit about you and you're the last to be answered).
for the long X rails (92") I provided a more profesionnal drawing with tolerances so if it doesn't work (= doesn't match the tolerances) it's their problem and they start again

knightsofnii · Post by **knightsofnii** » Wed Dec 05, 2012 11:30 am

now you got me thinking about getting the entire 4x8 setup from cncrouterparts!!!

Jibber · Post by **Jibber** » Wed Dec 05, 2012 12:01 pm

knightsofnii wrote:now you got me thinking about getting the entire 4x8 setup from cncrouterparts!!!

Thats the best you can get for the money. To save shipping I sourced my x/y-axis alu/steel locally (and in metric) but I use most parts from cncrouterparts.

Cheers, Christoph

ben_mtl · Post by **ben_mtl** » Thu Dec 06, 2012 7:05 am

yeah cncrouterparts is pretty nice, I saw yesterday they sell a kit for the "platform CNC" I took as a reference, not the laser cut parts and only a 4'x3' cutting surface but all that stuff from the same supplier is pretty damn good... and Ahren from CNCrouterparts is very nice and helpful guy.

knightsofnii · Post by **knightsofnii** » Thu Dec 06, 2012 12:28 pm

he's quoting me everything for a 2' x 8' system right now, but if it's not much saving i may just go 4x8, but some other options just presented themselves as well

ben_mtl · Post by **ben_mtl** » Thu Dec 06, 2012 1:02 pm

Well, his system is pretty basic (not in a wrong way), going from 4X8 to 2x8 might just save you a few bucks on extrusion/steel/rack... the most expensive parts are all the electronics, the carriages, the R&P system (minus the racks) and the router, which you will need, whatever the size you go with... at that point size doesn't really matters.
Only noticeable difference in price would be to go from NEMA23 steppers to NEMA34 as the electronics are much more expensive. Even if you go with NEMA23 for now the genius of the CRCcouterparts system is it's not much work to go to NEMA34 afterwards (but it's $$$)

Sitll waiting to know when I'll get my new parts... at leat they're ordered and that's the only thing missing before I can assemble everything... today I tested the electronics, eveything works fine !

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Living-room project... CNC !