What my project needs is an inexpensive set up that can deliver at least 4x print speed of FDM, operating for a minimum of 6 hours per day in a relatively small work area. Pirvan's suggestion should do the trick, and probably will save me the headache and time, since so many things can go wrong with custom mods. I really like those printrbot kits!

FWIW, I have a Printrbot Simple Maker Edition, nad I really likeit.  It's samll, compact, relatively quiet and produces pretty nice prints.

The only thing it doesn't have by default is a heated bed.  Yes, you can buy the Simple Metal with the heated bed for double the money, but you can also make your own heated bed for less than $30.

If you plan on printing PLA only, a heated bed is not an issue, but it's a necessity for ABS.

http://www.ebay.com/itm/Prewired-Heatbe … &rt=nc

Anyway, god luck in you endeavors.

What my project needs is an inexpensive set up that can deliver at least 4x print speed of FDM, operating for a minimum of 6 hours per day in a relatively small work area. Pirvan's suggestion should do the trick, and probably will save me the headache and time, since so many things can go wrong with custom mods. I really like those printrbot kits!

For now, I'll keep researching for any additional help and will update this thread if I decide to go with the mod.

Thanks for your help!

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Something like the Photoshopped image is in theory possible, but the problem is you'll be left with very little operating room per head.  You can't really use a multi-nozzle head like the Kraken because the nozzles are too close to each other, so you'd have to decide what the largest piece is going to be and space the nozzles apart by that dimension.  What you're left with (if anything) is your X movement.  Y is not a concern in this design.

You could also try a dual X gantry, for a 2x2 configuration.  This would give you more room, but not that much.

Then there's the logistics behind the whole thing.  Like weight, load on the stepper, calibration, etc.  Z calibration in particular will be problematic, as the odds of all the nozzles being at the same height are pretty slim, so you'll have to devise a method to adjust the height of each nozzle individually.

Me personally, if I had something to do like what you're going for, I would probably buy a few small, inexpensive 3D printers and have them do their thing.  For example you can buy the PrintrBot Simple, and get the job done.  Each has a 4"x4'x4" print volume which should be more than enough for your needs.

FYI, going to a "traditional" dual print head, won't allow you to do what your trying to do, however, it will increase your print speed, because you can get the printer to print with both nozzles simultaneously.

I'd simply like to have 4 extruder stepper motors tied in in parallel, all on the same output port of the stepper driver. I'd also like to tie in each of extruder's sensors and the heating elements in a similar fashion, but I'm worried about the differential in temperature due to uneven air flow distribution at each of the 4 extruders sensors.

1) I know it's probably going to cook my stepper drivers, so is liquid cooling appropriate for this set up?

2) Would the X&Y stepper motors handle the increase in friction/load?

3) Is it worth the investment or is it better to have just 4 separate SD3s running together?