Hey all,
Well i finally got some time to sit down take a little break and start to get a fair idea of the collossus idea of the cnc machine i'm looking at building. This post is a way to finalise most of the design and much like rod and others mainly just to get me off my butt and do something other than research and price hunting.
Some background for the new build: I decided a little while back i wanted to do some things a little bigger than my current machine. Then ideas got bigger and bigger and ive realised that im better off going for it. So after getting the go ahead by 'she who controls the money' im really looking forward to it. I have a small deadline (not critical but it would be nice) of about 5-6 weeks max because there are a few offers on jobs i'd like to do and get into but i need the size first. Alot of the build will be funded by the good old tax man and the rest by the sale of the rails ive collected over time(will give everyone a heads up first) and maybe my old machine. I should go pretty close now i have a quote from rods supplier.
The design: As usual, i scouted the internet for many ideas, downloading many pictures of machines and designed many half complete ideas in solidworks(mainly cause im really bad at making up my mind), i settled on a simple setup design done by Greolt. It has a really nice solid design/balance for what i would like. I have drawn up a simple draft which is not yet 100% complete(attached). For the machine there were a few things i need it to do. These are basic profiling, 3d relief machining which i do a fair bit of, lithos, aluminum(not as often but i'd really like to have the option), foam(simple but it will be used to make some kite boards and surfboards as well as some prototype stuff for a local company) and fine engraving as this is also one of the jobs i am doing. The design will be using lsk25 rails for the main 2m axis, lsk20 rails for the 1.4m gantry axis, spring/gas strut engaged R&P on the axis too. Z Axis will be either an actuator or made using some rails sitting in the cupboard and finally the 4th axis which i will photograph when done which shouldn't be long now. All this means i will need 5 drivers(most likely keling 5056), some beefy motors and these will interface with a smoothstepper usb board.
Some questions: Firstly will this design do what i want. I had my doubt on the R&P until greg showed me how good it is at 3d and ensures me there is very little backlash if any. I have attached a picture of the stainless steel engraving of a chevy badge which i did and will need to continue to do. It is 70mm wide by 65mm high. This is my main concern as its extremely accurate and mainly because later these will be done by diamond drag spring tooling. Either way i guess if it doesn't work i can always change to dual lead/ballscrews.
Anyway, i think this is a bit of a read for you guys so i will have to stop boring you all to death and will start a new post as soon as i think of more questions or add more detail. Look forward to hearing peoples comments and ideas for improving the design etc.
Daniel
P.S Sorry for the second picture of the engraving. Camera didnt seem to work very well with the SS, also the engraving isn't the best because i broke the tip the AP Workshop 30 degree bit. Also some of the vectors have been changed since they had doubled up so it was machining 2 lines in 1 space.