"A CNC what..?", was what my wife said when I told her about some hair-brain idea to build my first machine. Closely followed by "how much!!$#?" and several other expletives.
Well, it's really not that long ago since I saw my first video of a homebuilt CNC in action. That fateful day set everything in motion I suppose. The mind started churning and the flame of desire for one of these computerized marvels went from a small pilot light to a roaring inferno the more I read and researched.
So the decision was cast, a machine had to be built, but it had to be done on a fairly tight budget. I looked at a few homebuilt designs that were out there and I was all ready to go with something similar to a Rockcliff design using these fancy linear bearings I've read so much about. (Cough), that was until I got the quote for the bearings
My CNC dreams came crashing down in a big heap. The cost for the bearings and screws would have cost me close to 2 gorillas and that was before considering motors, controllers and all the other bits which make up one of these monsters. Quite simply, it was just way too much for my first CNC rig.
Unfortunately in the land of Oz, we don't have the multitude of vendors and suppliers which a lot of you guys can source your components from. So I shelved the whole idea for a while but the concept never left my mind.
Here in Australia we have a hardware store called Bunnings - its pretty much all there is anymore, but anyhow.. I find myself going there - a lot. Whilst there I ended up with the dream to build a machine using materials which I could source locally (mainly from Bunnings). A design started to take shape in my head and eventually I got to a stage where I had to start putting things together in the computer.
I know what you're thinking here.. he should have just gone with one of the many designs that are out there. Yes, you're right, but somehow I never seem to do things the easy way. I also set myself a few goals; these were:
1) I wanted a machine which was large, sturdy and scalable
2) The machine would need to be a flying gantry type so I wouldn't be constrained by height
3) The whole thing had to come in at around a $1000 aussie smackaroos
4) Most, if not all components had to be sourced locally.
In the spirit of my design goal number 4, I wanted to get my motors and controllers from an Australian supplier. I can't begin to explain the frustration in trying to get the right information and bits at the right price. In the end, I've gone with a plug & play 4-axis system from Xylotex using 425oz. motors. The fact that the AU$ was trading strongly against the greenback and fact that the xylotex system was ready to go straight out of the box had me sold. Have to say I can't regret going down that path. For under AU$700 I had all the electronics and motors, leaving me with around 300 or more to spend at Bunnings on build materials - happy days
So after much sweat, cursing and tears, I'm happy to say that I've finally finished the design on the computer and can start the build process now.
I'm sure I'll stuff up a hundred (maybe 101).. times along the way, but I'm starting to enjoy this little project. I'll post pics and stories along the way, but for now, here's a couple of drawings out of the puter.
If by any chance, you stumble across my sorry tale, look at my design and go "Ach du lieber Gott! What's he doing it like that for.. " and so on and so forth.. then please feel free to comment, contribute or make suggestions at will. I'll take all manner of comments on board and hopefully I'll come out the other end of this whole process with a machine that does .. well .. uhm.. something.
Here's the main design.
The main construction is MDF and in critical areas, clad and reinforced with aluminium. The rails are alloy as well with slides that are designed using standard ball bearings and a mechanism to allow for adjustment against alloy inconsistency, build errors and to to pre-load the bearings.