Hello all,
an introduction..
I have decided to post a build log on CNCzone so that others may see what I am typing about in the forums.
There is a gallery under my name, synthetiklone, with some 10 pictures of the major equipment and parts I have so far. It looks like I can post another 10, & thats the limit. I will post progress reports with pics here if I can, and probably keep the gallery for major updates.
I am an electronics engineer from Wellington, New Zealand - land of the long white cloud, at the bottom of the planet, where all things CNC seem to be rare as hens teeth, or just as costly! eg, local SKF quote was NZ$3600 (US$6000+-) for 2x 200mm long rods with 4 pillow blocks and a 200mm long ball-screw!
This CNC project began with a 3D foam cutting machine, but as I have acquired parts and materials for building a more advanced machine, and after extensive information gathering on the net, especially here on the CNCzone, the CNC bug has bit me! The foam cutter is still going to happen, but most efforts are going towards the 5-axis beast.
The 5-axis machine is to be as mechanically robust as I can build. I happened to come across some good parts from a 2-ton large laser image scanning machine. It provided 40mm thick (!) solid gantry rails, and 40mm thick leadscrews. I couldn't even dream of obtaining buying/importing these for a good price here in NZ (see pictures). I would have liked to cover a 1200x2400 sheet, but again, here in NZ parts are price prohibitive for the home constructor.
So the design is a 1500mm X 1200mm X 700mm table/frame with 860mm X 700mm X 200mm toolspace/workspace.
The x-axis leadscrew will end up going across the top of the whole assembly, rather than the conventional underneath the table approach. I will try it on one side first, but may have problems with "torque-twist" on the y-axis gantry.
There are two reasons the main x-axis leadscrew is placed above the gantry; I need the working space..
This machine incorporates a rotary axis as well - running along the longer length of the x-axis, and the rotary servo becoming the y-axis servo.
The rotary servo pulls in on the flywheel with a solenoid, disengaging the higher speed motor which can be used for conventional lathe CNC work. The job placed here has to be rotated 360 degrees. So if you can imagine it to be possible to carve any details all around an 860mm long section of a 400mm diameter round piece of wood all in one go! It would be possible to carve sections of a totem pole for example, but whether it ever is used for this, who knows, but I can think of numerous applications becoming possible. I'm sure you can think of some too. The rotary end bearings I have can easily accomodate this. See picture.
The other reason for the space required under the z-axis is that I have a friend who has developed a 4th & 5th (a&b) axis servo drive unit for the router. This will be the last addition to the machine, as at the moment, I will be very pleased just to have it run as a 3-axis!
Another thing you will notice (seen in gallery pictures) is that the y-axis rails are horizontal to each other rather than vertical. I see this as an advantage where stability is concerned, however, it limits me on the uppermost rest position of the router, which may have to hang underneath the gantry frame. It wont fit between the y-axis rails! I also have four 20-25mm solid rails about 440mm long from an old scrapped IBM printer, I was thinking of using an all four corner configuration for the z-axis, again for stability, but haven't decided yet, as have also been offered some 20mm, 200mm long THK linear bearings, which I may use (depending on price! ) So Z-axis still to be decided, worse case scenario for me is to flip the gantry up, redesign the bearing mounts, and go for the conventional vertical gantry rails, if I dont have the room between them with the current design.
I am at the stage of building the framework to hold it all together, it is to be made from 40mm square section pre-primed steel, 4mm thickness (I was going to use 3mm, but I'd rather over-engineer now, than be caught out later with flexing problems. The design of the frame is a dilemma in itself, as I have to forward think (and draft drawings) of different possibilities. I don't own a welder, or mill, so am paying someone to do all the metalwork, and bearing milling, and engineering. I don't want to have to pay to do the same job more than once if I can design it properly the first time. Although I probably will
I was going to design my own servo controller w/ quadrature PID feedback, but won't have the time for this, and the Gecko 320's are my first choice, with the possibility of utilising the G-rex in future, although the G-rex option looks like a complicated procedure at first glance through the documents provided, I'm sure it is a simple setup (?) with lots of benefits.
Which brings me to the software side.. err.. I haven't even looked into this as yet, and hopefully will pick it up when I have a working machine to play with.
I know virtually nothing about the software, but am impressed by whats available (Mastercam for US$15,000!??) I have a friend who has laser cutting/engraving machines, and it is hoped that some things will be similar design/software wise, and will work well together, as there is some things a laser beam just cannot do
pictures are here: http://www.cnczone.com/gallery/showg...0/ppuser/36476
Any advice or information on anything regarding thy project is warmly welcomed.
Well, it's getting late here...
Thank you kindly
and CNCleep well!
Tony