My multi-color/-material printers

[spegelius]

Yes the gears spin freely, actually there's some slop because the soluble interface layer as 0.4mm thick on both sides, bottom and top. I would've gone with tighter tolerances, but since this is just a demonstration piece, I tink I can live with it .
It says Palette because the model is made by Mosaic Manufacturing. Apparently PVA/PLA splicing does work if they got this printed.

[spegelius]

And another shot at getting the PVA printing properly. Actually looking pretty good so far, only one failed filament swap and even that was easily corrected by the MMU by using the filament cutter so pretty neat compared to the manual labor I had to put in for the previous prints. Took a couple of tries to get some settings dialed in, but this latest run has been going very well.
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The changes I've made so far:
- swapped the E3Dv6 heatbreak to Trianglelabs bi-metal part I bought as it looked interesting. I did polish it with Dremel, drill bit, steel wool and toothpaste. Not sure if this matters much, although I've heard that this should reduce heatcreep so maybe?
- applied some Boron Nitrate paste the hotend heatsink and heatbreak. Also should reduce heatcreep
- swapped the hotend PTFE tube from Prusa's special 1.85mm id tube to Capricorn tube. The Prusa tube was malformed, most likely while I cleared the infernal clog that happenend during the first PVA experiments (had to ram a hex key in with quite a lot of force...). It seems that the clog happened because this PVA is actually ~1.85mm in diameter, should have measured that in the beginning. So if I use the spare Prusa PTFE tube I got with the MMU, I can't print this PVA. Luckily the Capricorn seems to work nicely and it should be ~1.9mm id.
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On sw side, following changes were made for the PVA filament profile:
- max flow rate restricted to 1.5mm^3/s, which is around 20mm/s head speed, seems to help getting better support structures
- z-hop 0.6mm -> 0.1mm
- retraction 1.2mm
- printing temp 222 C, way over the manufacturers max, but seems to be required to get the PVA to bond to PLA properly. Wonder if this because the PVA is quite old...
- enlarged the support area, wastes material but for now it seems to make the PVA structure more stable
- support interface gap to zero in xy-direction, it has been 0 on z-direction

Looking good so far, I'm happy if I get the PVA used and don't have to throw it in trash.

[spegelius]

The print finished and I'll call it a success although there some problems along the way. This time the tool changes seem to work almost flawlessly, although twice the MMU failed the new filament feed and had to tell it to try again. The latter time was really interesting because the MMU seemed quite confused about the filament position and wouldn't feed it it to the hotend. In the end the problem might've been a strand if filament in the selector that caused some sensor errors or something... But no jamming in the hotend, which was the major issue previously.

Most of the issue were actually caused by the spool containers I use; the PVA container seems to have something restricting the filament and this caused a partially missed support layer, which I luckily noticed and was able to fix by using a soldering iron to smoothe the PVA lumps before it messed up the rest of the print. The PLA container worked ok until the last few layers and totally jammed for reasons unknown. Might be the refill spool I'm using got stuck, need to investigate... Luckily I was able to manually reprint the last layers, although I guesstimated the last printed layer bit wrong and the reprint was bit too low. Oh well, not a big issue, I can post process that.

Now the parts and failures are soaking in water to get rid of the PVA I worked so hard to get in there...

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[spegelius]

A while ago I experimented with custom supports that I modeled myself for this model: https://www.thingiverse.com/thing:1870525. I didn't try printing it until now. The first version is not maybe the most optimal, but I wanted to see how it would work. In this version the model is rotate 45 degrees on X axis, which makes the areas requiring supports quite small as they are just the corners of the rectangles. But this probably affects the overall print quality. But I got it printed yesterday after few retries due to too flimsy supports and curling caused by inadequate cooling.
The MMU seems to be working fine indeed, although the PVA does have the odd change of stringing during filament change, which usually causes some problems so it is a good idea to monitor the print.

I also had to implement support for no sparse layers in filaswitch because PVA on top of sparse infill layer was a total mess. So basically now it doesn't print the sparse infill layers which means that the tower height won't be the same as the model (unless the model has a tool change for every layer). This in turn means that the tower position needs to be far enough from the model to make sure that there won't be a collision with the model when the print head is lowered to the tower. It also saves some filament, making it almost like a purge bucket when only the tower brim and raft is 'wasted' compared to bucket.

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[spegelius]

So Tronxy crapped it's bed surface. The surface is a detachable plate with a Buildtak like surface. Not sure what material the plate is, but it is quite rigid, maybe somekind of fiberglass? Anyways, the buildtak-clone surface has been getting worse, with small dents and holes and finally it started cracking and peeling of the plate. It finally gave away when I needed to print some larger pieces witth PETG and heated the bed to 80C; the glue between the plate and the surface just gave up and the surface detached from the plate, causing a warped print as I didn't notice the peeling off.
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So as I needed to get the prints done and Tronxy is the only printer with big enough build area curently, I just cleaned the crappy glue from the plate, sanded it a bit and tried printing directly to it. And it works like a charm with some gluestick, at least with PETG. The parts pop off guite easily after cooling. And the print bottom has nicer finish than with the original Tronxy surface that was always leaving some black stuff on the bottom.

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[spegelius]

IMG_20210313_155317.jpgIMG_20210313_155929.jpgcopperhead_3.jpg

So I got me a Slice Engineering Copperhead a while ago from the Kickstarter campaign (https://www.sliceengineering.com/pro...rhead%E2%84%A2) and finally got around to installing it to my Tronxy X5S. I got the groovemount variant of Copperhead, which is almost a direct swap for E3Dv6, although I had to do miner modifications to my E3D Tronxy mount (https://www.thingiverse.com/thing:3312783).

I also needed to design a part cooling fan setup since the previous part was designed for E3Dv6. The mount allows swapping the fan ducts so I can revise the design, current one isn't optimal because it's one side only (https://www.thingiverse.com/thing:4793026). I printed the mount and duct with GreenTEC Pro which claims to withstand temps up to 160C.

The thermistor is the 450C version, not sure if I ever need such high temps. Configuring Duet was easy once I found the proper values for config.

Initial test with PLA were stringy and after some tuning couldn't get rid of it. Tried tuning retraction and temperatures to no avail. Might be because of the oncluded 0.4mm vanadium nozzle. Luckily the hotend supports de facto E3D nozzles so I can swap in basic brass nozzle. PETG with 0.6mm brass nozzle produced quite nice results so I'll test PLA next.

Haven't done any multi-material printing with the new hotend yet. Interested to see how the bimetallic heatbreak affects the tip formation, would think that the sharper temperature difference would help with stringing.

[curious aardvark]

impressed with the escher-like model.
But not convinced that the mmu is worth all the hassle if you have to rebuild the printer to accomodate it.

And yes, I know you and autowiz like rebuilding machines. But some of us like to take cost into account.

The more I see of the mmu, the more I'd like to see someone running a mosaic palette as a comparison.

I really need to play with the soluble filament I have.
Pretty much the main thing holdign me back is that I haven't built a top loading filament feeder for the klic-n-print yet. So changing filament is a real pita.
And with the soluble stuff - it has to goback into dry storage after usage and I'm used to leaving filament on the back of the knp for months at a time :-)

[spegelius]

Yeah multi-color and -material printing is a bit of hassle no matter what setup you are using. The Prusa ecosystem is the most complete setup AFAIK since it brings the HW and SW together and the HW is full package. Still it's nowhere near an easy thing to work with, especially when things go wrong. Also I still need to get used to PrusaSlicer, so far I've only used KISSlicer and my own filament change post prosessing script, because it's more configurable regards the filament change procedure.

Ultimakers apparently have dual extrusion capability and I suppose their ecosystem is a full package also, but I don't have any experience about those machines. Downsides: only 2 materials and the price. Would love to try one, though I would probably miss the tinkering part .

What soluble material do you have? There seems to be some options nowadays and also support materials that aren't soluble, but still easy to remove. I've only tested PVA and BVOH, both solubles. BVOH is the better one so far, although I bought a new roll of PVA, hopefully it works better than the old crap I've been testing lately...

Hope you don't have too many soluble layers, gonna be a PITA to swap filaments manually every couple of layers

BTW when MMU is working, it seems to work quite stable. This is PLA benchy print with 5 different colors and PLA brands. Couple of feeding issues right at the beginning of the print, but those were due to white filament breaking in pieces for some reason and I needed to remove the broken parts. After that no interruptions. But the amount of purge... and print time near 20h with all the filament changes, MMU is quite slow on that regard. And finally the color bleed with this one is quite bad, even more purge would be needed to get the colors clean.

[curious aardvark]

the knp is a replicator pro clone - so dual exrtruder.
But the spools are stored at the back of the printer and it uses a lot of oomph to pull the filament all the way up and over the case - which stretched flexibkles, as you can imagine.
Even with the dual extrusion, it's a pain.

Now the jlic-n-orint was made with a solid steel case - and I don't want to drill any holes lol
So My filament holder is a lot more problematic that any I;ve made for the other machines.
I'm getting there.

The soluble filament I have is this stuff: https://3d-print-works.com/products/...lament-1-75-mm

[spegelius]

Ah ok, dual extruders. I've never tried that kind of setup myself, although I had an idea about adding another E3Dv6 to the Tronxy and then using 4x splitters for both of those, totalling 8x materials. Would have to write some SW for that combo though, because none of the slicers understand that kind of frankenstein setup . Maybe someday...

One problem with dual extruders and especially with solubles is the handling of the hotend not in use. PVA and BVOH don't like to sit in a heated nozzle for a long time, apparently they start to go bad and maybe jam so that needs to be handled, I guess cooling down the unused hotend will do the trick.

Interested to hear how that Vanish works.