04/06 Update
Motors and driver chips arrived in a package with some stuff for other projects today. Can`t find much information about the motors online and they have some marks on the body but they should work great. I`ll breadboard a circuit up to test the motors later.
I drew up a base and gantry in sketchup. Both are made of 15mm MDF. I went through a few different versions of the Y and Z axis trying to waste less space and make it more resistant to inaccuracies in my cutting. Originally the Y was 2 steel bars with adjustion blocks but I couldnt find anything suitable for rails at my hardware shop. Currently it looks like this but could change at the drop of a hat.
This was my first attempt at the Z axis carriages. Turned out pretty good and rolls as smooth as butter on aluminium.
There will be a new blog post when I actually start building the base.
04/05 Update
Slides and bearings arrived! Its actually all recycled stuff but I could never tell from the condition its in. The slides are high quality super solid draw slides with ball bearings. Fully extended and not even a fraction of a mm slop - Im a happy chappy :D Of course they only extend 200mm but its enough for my purposes.
I only got 10 ball bearings this time because I wasnt sure if they would be too small. I think they will *just* do so I`ll have to get a bunch more. At the back is one with an m5 bolt through.
So the weather is getting warmer here and I`m finally finding the motivation to get out from under my cosy and warm kotatsu to do some building when I notice the parts website I usually use has some big stepping motors for cheap. What else does some do with steppers but build a CNC machine of course! This will be my first but I`ve been checking out peoples home made machines for years always dreaming of one.
The ultimate goal is to have the machine cut foam, plastics, wood and aluminium and eventually add a 4th rotational axis so I can engrave pens and cups etc. The bed will be small, maybe a travel of 300x200mm x/y and the z axis about 200mm, that way I don`t have to worry too much about sag and I can send it home in a crate when I move back to Australia in november.
Ideally it will be a moving gantry style so if I want to do longer stuff I can just have it hang over the sides. The bed will be made of MDF and the frame made of 20mm square aluminium tube. I have some used slides in the mail for the gantry to sit on and a bunch of bearings to make a Y rail with. I`m still thinking about the Z axis. I want to get my hands on these slides before I do too much planning.
For now it will all be driven by hardware store threaded rod and some nuts pushed apart with a springto get rid of backlash. The motors should have oodles of torque that they can deal with it. If the rest of the machine turns out OK I can upgrade to acme or ball screws in the future.
I`ll cook up the electronics myself too (anything to keep the cost down) and drive it with an atmega32
This is what I`ve ordered and am waiting for..
2x 300mm linear slides
10x 13mm bearings
..and what I`ve still got to get..
3x 10kg/cm Unipolar steppers
3x SLA7026M integrated 3A driver
Optoisolators
current sense resistors
Photos will be coming when the parts arrive.
Has anyone here built a CNC? What else do you guys think I need? besides cables/connectors/limit switches etc.