Kraken thread

[enggmaug]

I did not try much 2 color printing with my Kraken.

I am actually printing with one nozzle at a time.

But I have been printing a 2 colors street cone, that looked well, apart from the fact the nozzles were not exactly aligned (maybe 0.5mm off).

BUT, a street cone, is only switching from one color to another: no slice has 2 colors, so it may be easier.

I guess I'll give further tries when my baby son grows up and leaves me more time for myself.

[JFettig]

Just got done installing my Chimera. I'd like to switch to the Kraken soon, but I'm not going to bother unless and until I figure out this mess:

blobs.jpg

Has anyone EVER got a 2-color print out of a Chimera, or a 2+ color print out of a Kraken, that didn't look like unmitigated trash? I said it before, so apologies for repeating myself, but I have NEVER seen a photo of a 2+ color Kraken print that didn't look like it belonged in the sewer. I'm starting to wonder whether anyone has ever been able to print something decent-looking with one of these, other than only using one nozzle at a time.

It does work fine on small parts as long as you set up everything correctly. It does not work very well on a delta printer because they are not exactly a precision machine, your effector tilts as you go left right and forward and backward, for no apparent reason except that they are not a precision built machine and they would need to be for it to work properly. That is why people are going with a cyclops or diamond, multiple filaments in, one out.

When I had mine set up I printed a bunch of small objects just fine. When switching I did a slow long retract(ABS) on the unused one and it never leaked, didn't even need a prime tower.

[mhackney]

I gave up too, I was able to print in 4 colors but it was no where close to reliable. That is not a fault of Kraken, it's a number of factors:

1) multi nozzle printing requires PERFECT calibration. This is very difficult to attain. The Cartesian guys seem to have more success. The reason is that it is very easy for one of the nozzles to snag and drag a layer
2) you must have near perfect extrusion
3) you must absolutely NAIL getting a perfect first layer. This is much harder to do when you have multiple nozzles dragging around over the part.
4) most slicers really don't provide the tools needed to do multi color printing

I am becoming a fan of switching hotends like Cyclops and Diamond. They address 1-3 above. Slicers are an even bigger challenge for them though as they do not give the control needed for switching from one color to another. At some point they might but that's pretty far off (>year at least). I'm talking about advance switching controls like burying the color change in the infill of a part, etc but even the simple priming towers and skirts are primitive. But I have been able to RELIABLY print some pretty sophisticated 2 color parts like this:

[IMBoring25]

I've done some multi-nozzle multi-extrusion on my Mendel. I've gone very aggressive with the standby temperature delta, 50C, and turned on ooze control. It's still rather hit-and-miss whether it winds up depositing a ginirmous blob on the part at some point. Long term plans include a purge canister to use during tool changes but I don't want to take the X axis apart for that right now.

[626Pilot]

I have found some success with ABS and HIPS. Both are low-ooze and don't get hung up on the heat break during long retracts/primes. The nozzles do drag a little bit of plastic around - little flecks stuck to the side - so it is a little messy, but perhaps workable. I also tried PETG, and it didn't get hung up on priming, but it oozed too much.

These are my settings so far.

Before the print, I push some filament through both nozzles, then retract both by 10mm. This prevents the initial prime on both tools from leaving huge globs. The on-tool prime is 1.5mm shorter than the preceding retract in order to avoid globs as well.

Material:

Code: Select all

Prime=4, Suck=4, Wipe=10, vP=15, vS=15

Printer G-code -> Select New Ext & Warm:

Code: Select all

; Select new extruder
T<EXT+n>

; Warm it up (non-blocking)
M104 S<TEMP>

; Warm it up (blocking)
;M109 S<TEMP>

; Prime filament
G92 E0
G1 E8.5 F150
G92 E0

Printer G-code -> Cool & Retire Old Ext:

Code: Select all

; Deselect the (same) extruder (usually to cool)
M104 S<TEMP>

; You may want to retract some filament here
;G92 E0
;G1 F500 E-2.5
;G92 E0

; Retract filament
G92 E0
G1 E-10 F150
G92 E0