1 x Rosewill 2x Serial and 1x Parallel Port PCI card RC-303 $12
4 x easydriver stepper motor drivers $15/per

Total $72.

Solder drivers to old parallel cable, and run with linuxcnc

The easydrivers could be made diy even cheaper.

Any thoughts?

There are perepherial LPT boards to drive 3,4 or 5 CNC stepper motors. And their cost starting from $40. You could find all the information in CNC forums where Mach 3 software used. But the problem - it requires the real LPT port. Most of PCI boards that provide Parallel Port actually provide only printer functionality and not works as fully functional LPT port.
Also it is good idea to go with USB solution and there are USB boards to work with CNC software.

About CNC software:
CNC is going its own direction. And I beleive it is better to not mix CNC with 3D printer because if looking into details there are differncies in the problems people solving there and here. Basically CNC guys could not care if their software behave wrong with 3D printer and opposite any change in CNC software to improve 3D printing could effect CNC and we will need developers who deal with both areas to check that nothing broken. This will unlikely happen.

In my opinion mass production is the best way to make HW cheap. So if all 3D printers will use even complex but the same HW it will be produced in bulks and will become very cheap.

If you go that route you'll also need a temperature controller (2 if you want a heated bed).
The original H1 from SeeMeCNC used Mach as a driver (some people used EMC2) using a separate temperature controller, it can certainly be done.
It's nothing like as convenient as any of the arduino based solutions and you buy the low end boards for similar cost.

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My blog [3dprinterhell.blogspot.com]

To this day, I will never understand why 3Dp and CNC are so different. The technologies are identical. 3DP needs an extra drive extruder motor, and thermistor, and CNC doesnt.

But the similarities are staggering - computer control of gcode. One big output - reprap needs a big heater, and CNC needs a big router head. A fan and nozzle heater add a little more. But why is the directions of these two fields so completely different, with EMC, this bizzarely outdated linux technology based on parallel ports.

The parallel port makes the computer serve in real time (as the SDramps + arduino replacement) and has direct control over independent stepper motor drivers. IT all seems really longwinded to me given modern technology (like USB controlled?). They skipped over USB, and then went straight to ethernet lately.

It turns out a big difference between the technologies is the need to have a computer far from the CNC machine. Therefore USB doesnt work. So you'd think there would be more reason to have the print data in an SD card and transfer it that way?

Okay, so one more thing, CNC motors are big. And 3DP motors fail big time at delivering anywhere near 2 Amps. CNC needs more like 2-5. I think, but Ijest, and digress. IT all seems like a silo mentality.

And I wouldn't say a ramps+stepstick replacement at $72 cheap... I think its more like, a 10% discount compared to sanguinolo and ramps?

Edited 1 time(s). Last edit at 07/17/2013 11:19PM by Simba.

There is a lot more electrical noise in CNC machine, mostly because of the motor spindle.
They must have a reliable ESTOP, and they can't be set up in such a way that an uncommanded move could occur on power up , so they generally require a charge pump.
When big CNC machines so something you don't expect the results can be quite dramatic.
Real time jogging is important, multiple coordinate systems are important, tool offsets etc etc etc.
None of those are generally an issue on a printer.

But yes fundamentally they are very similar.
The big difference is in the host software, adding CNC to a Mill in some ways makes it harder to do simple machining operations, so the software tries to make that easier, EMC does it by supporting parameterized GCode, Mach3 does it with Wizards that generate GCode.

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My blog [3dprinterhell.blogspot.com]