MK3 Polycarbonate Print Help  

Re: MK3 Polycarbonate Print Help

You sure you had the fan on? This print certainly doesn't look like it.

Re: MK3 Polycarbonate Print Help

Agreed that looks like the fan wasn't running at all, or so slow it made no difference.

Re: MK3 Polycarbonate Print Help

Here are my Print Settings, and Filament ini files that I have been using for printing fan ducts in Polymaker PC-Max. I've had great bridging and fine details with these settings.

Unzip before use.

BTW: Enclosing and preheating the printer is helpful because of the high bed temperature required. I would at least not have the printer in a cold room.

Print Settings

Filament

Re: MK3 Polycarbonate Print Help

I love this forum, I'll double check that the fan is working and try that config that was just posted. Thanks guys.

Re: MK3 Polycarbonate Print Help

I feel silly. The Sli3cer default PC Max Profile disables the fan all together.

I used the profile posted here and results came out great. Thanks!

Re: MK3 Polycarbonate Print Help

Glad it helped. With a polycarb fan duct, you're a step beyond what the usual ABS can withstand.

Re: MK3 Polycarbonate Print Help

I feel silly. The Sli3cer default PC Max Profile disables the fan all together.

Yes, when I was first experimenting with eSun PC that was the first obstacle I came up against. I have no idea why the fan is disabled for PC profiles. You need it, as we have discovered. 😉

RE: MK3 Polycarbonate Print Help

The above polycarbonate settings are bit dated. Since then I have improved settings and technique so I can reliably print in polycarbonate.

1. ALWAYS dry polycarbonate at 158F (70C) for at least 10 hours, preferably 20 hours before use. Even fresh, factory sealed spools have arrived wet. Wet polycarb (epecially Priline) prints very stringy, with poor overhangs, and "pop" defects in extrusion. Dry it if you wish good success.

2. A coat of Elmers Ultra glue stick spread on the build plate helps. Run stick over bed then wet spray on some water to dissolve it as you spread it around to form continuous layer. Dry at 100C for 5 minutes before printing. I use a DIY phenolic plate, but Prusa's smooth PEI + glue works fine.

3. An enclosure helps.

4. Use a brim. Even within an enclosure, parts may pull up from print bed slightly without a brim

5. If brim is detaching from print object, your Live-Z is too high.

Here are the settings I use to print entire extruder assemblies...

RE: MK3 Polycarbonate Print Help

@guy-k2

Thanks! Gonna give this a try.  But, why are there three different folders and different profiles? Looks like they're specific to something?

RE: MK3 Polycarbonate Print Help

I found PC overhangs were challenging to put it mildly, bridging was, well, I could probably win the UK lottery before bridging works properly.

But then again I was using RigidInk PC (No longer available) which requires printing temperatures of around 295 Dec C + !!!.

Shame about Rigid Ink, expensive, but damn good filament, although some were simply not worth the extra cost, but their PC, probably the highest temperature rated PC going.

RE: MK3 Polycarbonate Print Help

An enclosure is absolutely not optional. It's absolutely not optional. I'm repeating myself for people who find this via google - you absolutely cannot print PC without an enclosure. This is the 3D printing community, so I'll say it one more time: PC requires an enclosure. It is completely moronic to keep your bed at 147C and your nozzle at 320C and not have an enclosure. You absolutely do not want human beings around something that hot, moving around of its own accord, without something between the humans and the printer. You absolutely cannot half-ass this sort of thing. Do not take half measures with PC. If you can't heat your nozzle to 320C, don't print PC. Plain as that. When you move to printing polycarbonate, it is no longer amateur hour. Again, because this is the 3D printing community, I need to be explicit: If you touch the nozzle or the bed, it will hurt you. It's not a cute little PLA or ABS burn. It will cook your flesh and scar you, probably for life.

PC in general is a difficult filament. It has very desirable properties, so I find it worth it to print in PC, but it can be quite difficult to dial it in properly. It's very stringy. One thing I suggest is switching to something you know to be PC - it's highly irritating to me to find that most manufacturers list their extrusion temp as "260C" for PC, which I believe is a ploy to convince people they can print it, as that's conveniently just about as hot as their printer can get. So unless you have a reason to use a PC-ABS blend, use PC. PC also responds well to more heat. Seriously, use more power. Nozzle at 320C, bed at 147C. Lots of glue on the bed, and keep your filament dry. I get great adhesion and no warping with glue on glass. I do not need a brim when I do that.

Preheat the enclosure. I set the bed to 100C, put a glass (like a cup) on the bed, then put the spool of PC on top of the cup. Then I forget about it for a few hours - that's longer than necessary, but it dries out the PC nicely. Come back, get the spool out real quick, pop it into the extruder, and get to it. This works because you do have an enclosure, right?

Do not stare at the print from above the bed after it is done printing. I have had PC prints detach during cooldown and go flying upwards. I mean, do it if you want to, I can't stop you.

On overhangs and bridging - I do not know why, but PC bridges well with a fat nozzle. I can get good bridging out of my PC when I use a 0.8mm-1mm nozzle. Use the fan only for very small layers - I will avoid this if at all possible by just printing a purge tower. It will still string like crazy. Set travel speed very high.

Be reasonable about your expectations with PC. It is not a filament meant for great works of art. It is best for functional parts of relatively simple designs.

That's my advice from someone who's been printing PC for a few weeks now.