Itty Bitty Double FLEX Extruder

[clough42]

Dang, and I just finished printing and dry fitting the itty bitty dual. I guess the obvious questions to decide whether to redo it or not while waiting for motors are: How much am I going to print flexible material and how much x-axis travel is lost? Only I can answer the first part. Can you make sure I'm not off the deep end in my analysis of the second part?

My machine currently homes with the endstop as far right as it will go and the nozzle directly over the edge of the glass. It travels roughly 238mm (10" model) before the carriage hits the left z axis parts, but there is another 10-12mm of glass that is not used. Switching to dual extruders without doing anything else, the left nozzle will home at x=10 (itty bitty dual) or x~=13.5 (itty bitty flex) and the right nozzle will be the same distance off the glass in free air (-10 or -13). At the far left position the left nozzle may actually use the currently dead glass, but the right nozzle will max around 228mm (itty bitty) or 225mm (flex). So in either case the left nozzle will have basically the same travel I have now, but the right nozzle will limited.

If I can redesign the endstop I may be able to move the left nozzle back to the edge of the glass at home and so would get actually more x travel than I have now (hopefully the full advertised 250mm), but the right nozzle will still be limited to max x=228/225mm. Can't say that I care much about the 3mm loss on the secondary nozzle for itty bitty double vs itty bitty flex, but will have to keep in mind that only the left nozzle can reach >225mm.

Does that sound right?

All of this assumes, of course, that the nozzles are centered on the carriage and that nothing else (motors, etc) interferes with the frame.

The nozzles are centered. If you only consider the bed area reachable by both nozzles, which is all you can use for two-material prints, you just lose the spacing width over a single extruder. So with dual, you lose 20mm, and with the flex you lose 27mm--half on each side. If you can physically increase the travel, you may be able to recapture some of the lost space by moving into areas that would have put the single nozzle off the glass.

For a single material print, you typically only lose half the spacing distance, because you can print out to the edge of the glass on one side. In your case, since you have extra glass on the left, if you print with the left nozzle, you may not lose anything.

[jasay]

The nozzles are centered. If you only consider the bed area reachable by both nozzles, which is all you can use for two-material prints, you just lose the spacing width over a single extruder. So with dual, you lose 20mm, and with the flex you lose 27mm--half on each side. If you can physically increase the travel, you may be able to recapture some of the lost space by moving into areas that would have put the single nozzle off the glass.

For a single material print, you typically only lose half the spacing distance, because you can print out to the edge of the glass on one side. In your case, since you have extra glass on the left, if you print with the left nozzle, you may not lose anything.

Alright. I think that's what my long spiel was getting at but much clearer and more succinct. Thanks.

BTW, are any of the parts (idlers & pulleys probably, carriage sides & servo arm [hexagon] maybe) shared with IBDE?

[clough42]

Alright. I think that's what my long spiel was getting at but much clearer and more succinct. Thanks.

BTW, are any of the parts (idlers & pulleys probably, carriage sides & servo arm [hexagon] maybe) shared with IBDE?

Yes. The large pulleys and the spacers are the same. If you're using hexagon hot ends, the servo probe arm and the print cooling fan shroud are also the same. And of course the hardware is all the same. Depending on how much you cut up the insulator, you might be able to use it. If not, I have spares available.

[jasay]

Yeah. Got all assembled and found out the hard way that the carriage sides were different, doh (too stupid/lazy to just look at the stls). Managed to print the sides with the carriage just cantilevered out there. Will have to redo calibration now that the shelf is properly supported, but so far so good. Thanks again. Will get some better pictures once I get around to sleeving the wires.
IMG_20150411_133801-M.jpg

Edit: will probably also look at your start code for some wipe hints after the long ABL process.