Pause and Color Change?

[PannDemic]

If you are printing from the SD card, is it possible to do a manual pause and color change?

I tried to use the pause from the SD menu, but when I restarted the machine crashed into the part, trying to resume a full mm down into the part it seemed. Is there a different way?

[mhackney]

I do color changes on the fly but you don't get the precision as you would if replacing the entire filament. For some prints it makes little difference.

Can we assume you are using a stock Rostock MAX with a RAMBo board?

[IMBoring25]

You may have to upgrade to the 0.92 firmware branch. I just tested this on my v2, but it's now on 0.92.2, and they do have something about fixing a pause bug in the changelog.

My Duet-driven Mendel was doing goofy things after a pause as well. I discovered they stopped happening if I put an M400 (wait for current moves to finish) before and after the pause command (only one may be necessary, but I don't imagine it hurts anything to have both). The code that seemed to work (though I didn't measure the positions of the effector to make sure they were as-commanded) on my v2 was M400 then M25 then M400. Then, the LCD will say Ready. If you go into the SD Card Menu on the LCD there will at that point be an option for Continue Print.

[RichWP]

Hello,

I understand that your asking about a 'manual' pause and change, but if your not aware - Cura 15.x.x has a plugin called 'Pause at height' that (obviously) pauses at a predetermined z height, and parks the head away from the print so you can change filament, clear the nozzle, etc. then resume where you left off. I've used it with gcode on an sdcard a number of times, and it has worked really well for me.

Full disclosure - I don't actually own a delta printer (I'm using this forum to help with my purchase decision), so I'm not sure if there is any gotcha-ya's with a non-Cartesian printer.

Hope this helps in some way,

Rich.

[PannDemic]

Yea, I am on a Stock Rambo board, and I am on version 0.92.

I am trying to find a way to have a pause error happen and measure the height offset. Maybe I'll design a model with 1mm steps and see how far into a step the hot end is coming down by.

Mhackney, how do you change color on the fly? Do you just feed a new piece in and have it push the old filament thru?

[mhackney]

Basically that is how I do it but you need to take retracts into account. I'll often time entry when there are few retracts.

[PannDemic]

Even through the bowden tube? I have not tried this, I assumed it would bind and jam in the bowden tube.

I have some items that would work well for this technique, I will have to get it a go and see how it does.

[mhackney]

Yes. Try it.

[Turpinator]

surely you must still have to pause it, at least for a moment and cut the previous color, otherwise there will be no pressure on the filament in the tube and thus wont extrude (besides any stringing)?

[IMBoring25]

It requires smooth action through the extruder drive and you'll have to manually put some pushing force on the new filament until it's gone far enough down that retraction won't unload the new filament past the hobbed gear.

[mhackney]

surely you must still have to pause it, at least for a moment and cut the previous color, otherwise there will be no pressure on the filament in the tube and thus wont extrude (besides any stringing)?

Nope:

1) prepare new filament: clip end square across and mount on filament holder
2) clip existing filament 6" above extruder square across (I use a pair of sharp wire cutters for both 1 and 2)
3) optional, slow down the print speed so you have more time
4) wait as old filament nears the top of the extruder. As it gets close, 1/2" or so, hold new filament end against old filament end. Do not push, just keep them aligned and touching.
5) follow the old filament into the extruder with the new. If you left a gap, simply depress the pressure arm and push the new filament up against the old
6) if optional step 3 was performed, optionally increase print speed

The new filament will have no problem pushing the old back. You won't get retracts until the old filament is cleared out, which is why this may not work on all models. I posted this in Oct using this technique:
[img]http://forum.seemecnc.com/download/file ... =13686&t=1[/img]

[mhackney]

As an option, you can actually melt the end of the new filament and stick it to the old. This takes more skill but works quite well. In this case, retracts work just fine. The trick is to not overmelt the filament. You just want it soft enough to be tacky. When I do this, I typically leave 12" rather than 6".

[Turpinator]

Ahh. But you still need to measure out the filament where you want the color change to happen, and be there... watching.

As for the melting, ive considered it, Tried it with a lighter once to use up the end of a roll but no dice. I did also see a little jig people had made up with cutouts to help round the filament and keep it nice.

Speaking of multicolor through a single strand, I did see a box/thing/something that cut and spliced 4 different colored filaments together, on the fly to be fed into an extruder. That was pretty neat. Ill see if I can find it later.

[Xenocrates]

Ahh. But you still need to measure out the filament where you want the color change to happen, and be there... watching.

As for the melting, ive considered it, Tried it with a lighter once to use up the end of a roll but no dice. I did also see a little jig people had made up with cutouts to help round the filament and keep it nice.

Speaking of multicolor through a single strand, I did see a box/thing/something that cut and spliced 4 different colored filaments together, on the fly to be fed into an extruder. That was pretty neat. Ill see if I can find it later.

That box is likely the mosaic mfg palette

[Turpinator]

That box is likely the mosaic mfg palette

Yup. that is probably most likely it.