Advice printing Fiber filled Polycarbonate on Taz6

**Been printing American made Fiberglass filled PC and Carbon filled PC for a few weeks now. ** The repeated issue, no matter which type of material (carbon or glass), a wad of material collects on the point of the nozzle, then gathers more material until the wad is pressed upward toward the hex of the nozzle over 15 minutes, then gathers around the hex and upward until after around 30 minutes, the weight and changing shape of the wad causes it to fall onto the print. This is the only material I’ve ever printed that has this issue (I’ve printed almost everything else).

I suspect that PC is attracted to heat, and so it catches to the nozzle in tiny amounts as the nozzle moves over previous print, and melts towards the heat…towards the nozzle. My only solution so far has been picking wads off the nozzle with a tool at 15-30 minute intervals. You can see all the pieces laying about the bed, picked from the print over a couple hours.

I’m printing at 290c with bed at 110c - 120c.
0.5mm Hard Steel Nozzle, Lines are set for 0.4mm high and 0.6 wide.
I’ve ranged speeds from 30mms to 60mms, and prefer 45mms for most sections of the print.
No cooling fan on the nozzle, set at zero.
I’ve found the best flow rate to be at 80% for both Fiberglass and Carbon filled, even though they each have different mix ratios.
I have a flame retardant-high-heat resistant clear (slight yellow tint) plastic sheet hood over the entire printer to create a heat chamber.
I’ve printed around 1kg now, and haven’t found a solution to the wading material on the nozzle, other than picking it off every so often while printing.

These are production components for canoes and kayaks. Extremely rigid, durable components are being completed in very nice finish. This is a fantastic machine! Fiber filled polycarbonate is far more appropriate for this application than fiber filled Nylon…I’ve tried kilos of NylonX.

I’m wondering if printing at higher nozzle temps such as 335c, might reduce the wading.
Wondering is printing on a much hotter bed, such as 150c, might work. I realize that these temps are beyond the capability and design of my machine, but I wonder if that is the absolute solution.

Your experience? Ideas?

We’re interested in just plain polycarbonate- did you start off with a non-reinforced version with good luck?

I’ve never printed straight up Polycarbonate yet without fibers in it…only with fibers.
Started off with Owens Corning XSTRAND GF30-PC, you are looking at my first project above. I printed multiple prototypes in fiberglass and carbon fiber while working on settings to avoid the wading on the nozzle. I tried 3DXTECH CarbonX PC+CF that printed exactly the same as the Owens Corning material. I really liked the finished parts from these two above materials. They were both SUPER STIFF, both SUPER HIGH DEFECTION, both SUPER HARD, both reflex FAST when I can place enough power on the parts to cause detectable deflection. VERY LITTLE WARP/SHRINKAGE during or after print. FABULOUS material for my purposes, except for wading on nozzle during print…I have to babysit and tend to it far too much. I think the 30% Fiberglass PC from Owens Corning is slightly stiffer, and more reflexive and sands better and is harder, probably because the carbon 3DXTECH PC has a lower Fiber percentage…I ‘think’ it was 10%, not sure without looking it up. Just enough difference so that I can tell by handling the two finished parts. Both are made in the USA.

I tried Priline CF/PC, which I “suspect” is hardly PC at all if any (easy to print, sands in clumps, flexible, spongy, wrong temps, holds a post print bend, low deflection rate, stinks a lot while printing). I’ll end up using Priline for printing first prototypes (junk) to test size and shape before functional prototypes…there’s no other use for it in my operations and opinion. Made in China.

Please, report back to me your Polycarbonate experience and working settings…Please.
This Lulzbot TAZ6 is quite a versatile machine with all the different heads. I’ve got a head that prints 1.75mm filament, that was aftermarket made in the USA.

I wonder, I get that buildup around the nozzle when the filament I am using isn’t dried out that much. I haven’t printed with polycarbonate yet as I don’t have a tool head that can go above 290C (if you know of any that don’t involve too much building/programming I would love to get one).

Hey Jude

It’s good to get in touch for folks doing actual end use parts. We are a NASA experiment payload developer that our hardware goes up to the Space Station for scientific investigations into how to make better materials ultimately.

Polycarbonate is an acceptable flight material, depending on the formulation specifics, and we are interested in 3D printing it directly for aerospace usage with our Taz Pro system. We’re concerned with getting the heat out of the interior of a plastic tray, but we will work that out case by case depending on the power used.

We’re making a modular experiment processing tray arrangement per the attached photo. The trays are a five piece assembly with a bottom electronics bay under a mid plate upon which the experiment apparatus is mounted. Then a lid piece goes on top, that for observations will be a laser or CNC cut polycarbonate sheet:

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Oh, forgot to mention the photo is just PLA as a fit check assembly. We’re printing the two pieces needed to assembly the LuzBot tent so that we can build with the polycarb material. We’ll hopefully have more to share later next week.

Scotty in the Engine Room…

RE: modifying a Lulzbot to reach above 290c on the nozzle…
I had come across something somewhere months ago concerning modifying the nozzle temp up above 300c…can’t remember if it was here or on another forum, but the gist was; Too many things to modify, both hardware and software on the machine and in Cura.

If I’m right about PC flowing towards heat, then a hotter block and nozzle will draw up more material. But I haven’t got another machine that goes to 335c to find out.

RE: Scotty in the Engine Room…
Please, send any advice you come up with…I need to make this material work. Thank you.

The three materials I listed above will print very nicely without covering the machine to contain radiant heat around the print. I do believe that there was a slight improvement in inter-laminate welding with the cover in place…Harder to pull a print line/bead off/away from the part.

If it was an E3D nozzle / heat block, I’d suggest using one of their silicone socks. Short of making your own mold, I’m not sure how to fashion one for the stock (Hexagon?) nozzle / heat block. I do see there are now some available for the CR-10 which has a different shaped heater block.

You could always purchase a hi-temp silicone tube at an auto store or Home Depot and spread it on manually. It will be ugly but may be functional and serve your purpose.

I always thought this article was interesting and may be useful to you and your needs:

In that article is a link to the full article, and in that article is a link to the pdf that actually is the full article :cowboy_hat_face:

Oh, this is very interesting…Thanks for that NASA story on the Lulzbot site…

Firmware Changes were made to several files of the firmware (Marlin) so that the new modified printer would function properly.The maximum allowable hot end temperature was changed in “configuration.h” from 300°C to 500°C to reflect the new high temperature configuration. A new temperature table was added to“thermistortables.h” to allow the controller to interpret the readings from the 500°C thermistor. Two machine commands were added to “marlin_main.cpp”in the form of M codes (M740 and M741) to turn the IR heating lamps on and off when required. The process was written with a 0.5 s delay between the actuation of each relay as a safety measure to prevent the circuit from becoming overloaded. The new pins for operating the relays were added to “pins.h”and defined in “marlin_main.cpp”

Got our tent installed yesterday but are waiting on the PC spools to arrive. Looking forward to how well it will build our parts, and will post when we’ve tried it…

As far as the filament sticking is concerned, you might try an E3D Nozzle X. They claim a polyphobic coating to reduce build up. You could also try using Slice engineering’s PTFE paint.

Thanks for the lead to repellent paint. I’m already running a NozzleX and haven’t had this issue with any other material (printed it all). I suspect that PC requires a little more heat to flow away from the nozzle. I get no wading on the first layer, only on the second layer and beyond. Will try the paint.

I have to back step on a comment I made in the previous exchange. I do get wading on the nozzle during the initial layer, so I think the collection is coming directly from the nozzle opening, rather than coming back off of the print. I’m going to try a different nozzle. Go from a NozzleX to something else.

If you print PC and have any tips, please reply.

If it is a first layer problem, maybe decreasing the first layer squish would help. You might be dragging plastic back off the first layer. Increasing the first layer thickness might also help. I have generally found having a nice thick first layer is helpful. I usually run the first layer at 80% of the nozzle diameter.

Thanks for that idea. I’m collecting PC when applying the first layer, 2nd, 3rd and all the way through the last extrusion on the last layer. .5mm nozzle, layers at .4mm height. Flow has been set between 75-90%…best setting for XStrand was 80%, best setting for CarbonX was 80-85%.
I had been laying .6mm width…I will try .4mm width, narrower than the nozzle opening.

The heat block is regulated at 290c. If I insulate it, it will still regulate at 290c…Using less electricity to achieve and maintain 290c.

It has ‘brand’ new thermister and heater.

If anyone has experience with PolyCarbonate, and especially Fiber filled PC. Please, chime in.

Been printing a part with .4mm width and .4mm height. I’m getting just as much wading. The part is still printing as I write.

If anyone has resolved such a problem with PolyCarbonate, and especially Fiber filled PC. Please, chime in.

I’ve changed the nozzle from coated hardened steel Nozzle X (been using NozzleX from beginning) to a regular hardened steel nozzle, and there’s no difference in the collection of PC around the nozzle. It collects just as much, just as quickly as did the NozzleX.

A demonstration of my hunch:

Here above is a picture of a few inches of the gray Fiberglass filled Polycarbonate extruding. Note how it doesn’t flow downward, but seems to move towards the hot nozzle and block, then loop away, then the loop moves towards the nozzle & block again, touches here and there.

Here below

is a picture of a few inches of white PLA extruding. Note how it flows out like a faucet, straight down from the nozzle.

My “hunch” is; Polycarbonate is attracted to heat that is greater than its own temperature. As the extruded material cools outside the nozzle, it cools fastest from the outside of the bead. One side of the bead may be cooler than another side, so the core of the bead moves towards the hotter side causing a bend or loop. One edge of the loop gets close to the nozzle, heating it back up and intensifying the internal heat differential and magnifying the warping loop until it touches the hot nozzle. Then causing other loops to do the same, and influencing multiple loops, many then reaching the hot surface of the nozzle and block. THIS IS JUST MY HUNCH. It might be a working explanation. My production problem is explained in detail at the top/beginning of this thread.

If anyone has resolved such a problem with Polycarbonate, and especially Fiber Filled PC, Please chime in. Note; I have been using the Nozzle X with the same results.

Looks like too much cooling to me. It doesn’t look like it’s sticking to your nozzle, just warping as it cools. If so, I would worry less about this and more about what it looks like when actually printing.