Just a quick idea I have about linear rail (I don’t really know if it’s a good one…I put a picture drawn in less than 2 minutes). I already spoke about that before, but tonight I made some new researches.
Just to sum up some of the different systems:
– I don’t speak about SBRxx or Hiwin rails, the best ones but tooooo expensive…
– V-slot are now famous, but it’s not really cheap (and not perfect: delrin wheels on anodised aluminium is nice, but not the best).
– V-groove wheels on steel rails, most famous system in the homemade CNC world ( https://www.youtube.com/watch?v=JSO3OpMyUvU ): very cheap, but wear on the steel and not so easy to make.
– new motedis system ‘easy rider’ ( https://www.youtube.com/watch?v=qvG8j2rkCL4 ). Not very famous, but it’s around the same price than V-Slot but with stronger material (less wear).
– MPCNC system (super cheap but wear and some flex).
If I try to keep all the best of that list, I can imagine something like the picture (I use 8mm rod and SG20, but it can be 10mm rod with SG25):
-Cheap strong U-groove rollers like Motedis Easy Rider ( http://www.aliexpress.com/item/SG-series-of-high-precision-roller-bearings-for-screw-bolts-SG10-SG15-SG20-SG25-SG66/2027853188.html?spm=2114.01010208.3.1.vB4KX6&ws_ab_test=searchweb201556_0,searchweb201602_5_10057_10056_10055_10037_10049_10033_10059_10032_10058_10017_10060_10061_10062_10063_412,searchweb201603_8&btsid=c501c6a2-e5bc-43a3-8bb2-91ec315ac091 )
Sorry for the long link, search ‘SG20’ on AE. Lot cheaper than the motedis ones.
-cheap 8mm smooth rod. A standard, easy to find.
-PLA printed pieces to maintain the rods (Motedis uses a small aluminium profile for that, but bigger PLA pieces can be good enough, MPCNC is the proof than plastic can be strong. http://www.makeitfrom.com/compare/6061-AlMg1SiCu-3.3214-H20-A96061-Aluminum/Polylactic-Acid-PLA-Polylactide )
I know that I already spoke about the RAW CNC (=motedis easy rider style, https://www.youtube.com/watch?v=BE-8hqIeYnQ ) and the U-Groove CNC (with glue : https://www.youtube.com/watch?v=lD0YNi2ucPk ), but I didn’t find the cheap SG20 before, and I just would like to share that. Smooth rod are everywhere, really cheap and have a hard surface. SG20 have 2 row of bearings, hard surface, works like ‘v-wheels’ and they’re cheap.
In fact, I’m too lazy to work and test that idea :=) . I’m actually printing the upgraded parts of the MPCNC, and normally it will be enough to make a better MPCNC (I will make it smaller in all directions, to be sure I can mill more precisely than actually). To thank Ryan, I share what I find, in case of…