Just started building a very primitive CNC router (or is it a miller - what is the difference?)
looking to se what others have done, pick brains and get ideas
may be able to contribute some gcode software a bit doen the line
anyway - hello!
Hi Mike and welcome to the site. Lots of info here. Routers usually have the workpiece fixed and the cutting tool moves in at least one of X or Y... mills usually have a stationary cutting tool and the workpiece moves in both X and Y.... Mills are generally of more massive/solid construction and can generate higher cutting forces...
I always thought they were similar, must have missed that subtlety!
In that case I'm looking at building a very small mill
moving xy table
z gantry fixed (well apart from going up and down!)
initial aim is pcb milling
For milling PCBs is a moving table neccarily the best idea? You want high acceleration and feedrate. Moving the table will require a greater force than to move the spindle, assuming the table is heavier, which limits your acceleration (F=ma).
Originally Posted by mmcp42
You'll need to work it out properly, but it might be something to think about...
I thought that etched was the way to go.
I have seen a thread about hacking a printer to print directly.
As far as moving tables go that could be done but takes a lot more floor space than a moving gantry.
It would be more expensive and more difficult maybe that's why you don't too many of them done.
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All depends. For a small machine with limited cutting forces (and PCB milling meets that requirement) a moving table made from, say, acrylic could work quite well and might well be a lot lighter than a spindle/gantry arrangement. The main impact on acceleration is leadscrew inertia, so keeping the screws small and short and limiting travel would be advisable. Few 'milled prototype' PCBs are going to be larger than 160 x 100mm I'd guess..
Originally Posted by Jonathan
indeed I am aiming for small PCBs
My start point is an old scanner with a small stepper motor
If I can achieve an A5 workspace I'll be pleased
Prototype is already moving XY 200mm by 70 mm (8" by 2.75" in old money)
I have a Dremel that I plan to use as the spindle
Z stage is built, but awaiting motor coupling