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Polycarbonate Bed Adhesion: Is there an ultimate solution?

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Hi there,

I have am UM2+ with an I2K and TinkerGnome firmware. I am playing with polycarbonate filament. Not Polymaker, not PC-ABS, the plain old classic polycarb. :) This means I am struggling with bed adhesion and warping.

I've done searching in the forum and looked on reprap.org, but I would like to know:

Does anyone have a "one true ultimate super duper solution" to polycarbonate bed adhesion and warping? Or even something that mostly works?

Should I just go with Buildtak or Wolfbite, or is there something better/cheaper/easier?

I am currently hovering around the settings of 300 C head, 120 C bed, ABS juice and brim, Cura 2.x Normal profile, but I am still not getting things to work completely. So, any settings suggestions are welcome also.

Basically I am looking to solve PC once and for all on the UM2(+). I am even willing to write up the results so everyone can benefit.

Any thoughts/insights would be much appreciated. Thanks so much! :)

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I hope someone else knows more than me but I can tell you one thing for sure - enclosing the printer (even just the front) will help quite a bit. Just throw a big box on top, cover the front with clear plastic and let the bed sit at 100C (or hotter) for 20 minutes to get all the air up to around 40C before starting the print. Having the air at 40C instead of 20C cuts the shrinkage almost in half.

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Hi gr5,

Thanks for the feedback. :)

I do already have an acrylic front plate, and I have been recently working on top covers.

I found a couple cardboard boxes that fit very well (one from my new Siglent function generator and one from Amazon). :) They definitely help with ABS, so I assume they will with PC too.

I also just (yesterday) found a plastic box (for storing papers) that fits really exceptionally well too, and is more sealed, so I am going to play with that.

I did not think about preheating and letting it sit for a bit, though. That is a great idea!

So, thanks very much! :)

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Wolfbite MEGA has actually worked well for me but only with Polymaker's PC-Max.

What exactly is "plain old classic polycarb"?


:) Hi @Artiz,

I don't exactly know. I bought some unbranded polycarbonate on a weird white spool when I first got my printer and before PC-Max or any of these other branded ones existed. I do not know where it comes from or who made it, so I call it generic. The place where I bought it does not even carry it anymore.

Later, PC-ABS, PC-Max and ... there is another PC-something, were created. I assume they have been more specially formulated for easier 3D printing, since they have lower temperature requirements, etc.

So, if the new ones are easier to print and behave differently, then success with them might not reflect perfect results on the generic stuff I have.

Now, I could just get a new spool and go with that, but I still want to see if I can make the old stuff work reliably. :) I am kind of thinking that if I can make that work, then the newer brands should be a piece of cake!

Wolfbite MEGA is on my list to try too. But I have some other potential solutions to try first. I guess I am kind of doing a comparative survey of every method I come across to see what works best.

(That said, currently I am addicted to Minecrack, again, so I am not actually progressing on this project. I will swing back to it eventually though.) :D

Anyway, thanks for sharing your experiences! I hope this helps explain what I meant.

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So, if the new ones are easier to print and behave differently, then success with them might not reflect perfect results on the generic stuff I have.

I get the feeling that messing around with your 'generic' stuff without a point of reference may just be a bit of a waste of time and even perhaps money... then again why not of course.

The other polycarb you couldn't remember is PC-Plus by the way and I really didn't like that stuff... far too brittle and almost impossible to get a decent print out of it.

The polycarbonate enigma is an interesting one though and I do actually think that Polymaker have finally cracked it with PC-Max... I did get a small amount of warping below but nothing serious... the strength really is something special...






Edited by Guest

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I know this is an old thread but I'm thinking about making polycarbonate slurry with Cyclopentanone as an adhesion method as I have an enclosed build chamber but am getting the same problem as you, I'm going to try heating the chamber to 50C (the most my stepper motors can handle) first though because it's cheaper and easier. It's about 40 dollars AUD, 30 USD for 30ml of Cyclopentanone. So really expensive but if you really needed to print something in polycarbonate and you really couldn't tolerate any warping I suspect this would be a definite solution.

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Bed adhesion : glue stick from kit, and a wet paper towel to spread it.

Support: Raft is mandatory.

Bed temp: 107 C (from Cura Polycarbonate profile)

I have printed without door. If you have it is better.

Also in Cura 2.5 is a button to preheat the bed before start printing.

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**STOP: Printing PC usually requires modifications to the printer. At the ambient temperatures needed for PC printing, the plastic printer parts inside the enclosure need to be printed out from annealed PC or at the very least annealed PLA. Do not even think about keeping any electronics inside of the heated enclosure. Do NOT run steppers above 60C ambient without cooling. To actively cool the steppers use local Peltier coolers or water cooling blocks from the PC scene. Before reprinting your printer parts, anneal sample parts to confirm their heat resistance and necessary scaling. No good results can be had without putting good work into it all - it doesn't have to be expensive, but must understand every step of the process and verify each as you go. Any LED strips used inside the enclosure must be ran at 25% duty cycle for thermal derating reasons. Verify performance of any adhesives used to attach anything inside the enclosure - anything stick-on will likely fall off. Use mechanical means of attachment (screws, clips, etc.)**

Bed adhesion is *not* the problem - only a *symptom*. It's OK to print PC on acetone cleaned glass, on PEI, painter's tape, etc. The problem is the internal stresses within the print, as it cools to an inadequate ambient temperature. PC print environment requirements, in my experience, are as follows:

- parts <1x1in - 115C first/140C subsequent bed, room ambient temp,

- parts <0.5in thick - 115C first/140C subsequent bed, 50C ambient,

- all parts - 115C bed & ambient, but anything in the 100-140C range should work with same bed and ambient temps. Bonus: parts come out annealed if you slowly cool down the enclosure and bed after the print.

For the first two scenarios, in a 12V system the bed will slowly warm up to 140C after the first layer is finished, that's normal and not an issue.

I print PC between 285C and 300C, depending on extrusion width (the wider the hotter).

In ambient above 100C there is absolutely no issue with bed adhesion. I've printed PC on corrugated cardboard that way.

Without additional heating, using only the bed as the source of heat, the enclosure is unlikely to go above 60C unless it is quite small. Apply one or more of the following workarounds then for larger prints to succeed. But those only make sense for particular prints that are close to succeeding and fail late in the print only!

- Use white Hobbyking PC. Heat dissipation is controlled by color in the long infrared range, not visible color of course. But it turns out - at least for Hobbyking PC - that the white filament is also quite "white" in the micrometer infrared region. It will radiate heat away slower than the black filament. Again, the colors you can see with your eyes in the visible spectrum play no role whatsoever, it just happens that with Hobbyking PC filament in particular the visibly white one is also long-infrared-white. Other PC filaments may behave like that too - experiment to assess their performance.

- Use very low infill (10-20%). It drives lower aggregate cooling stresses and may not have enough oomph to pull the print off the bed.

- Use very high infill (75-100%) to thermally couple the print to the bed. The bed will then act to maintain sufficient print temperature to prevent warping. Center the print on the thermistor under the bed, and aim for high bed temperatures up to 150C.

- Use adhesion improvement techniques, such as ABS slurry (PC binds well to ABS), PVA slurry, glue stick, etc.

For proper PC prints at any size, without fuss, it's essential to monitor  and actively control the enclosure temperature, and to have a separate enclosure heater, and to aim above 100C. Do not bother with trying to work around this issue by playing with bed adhesion: it's a war you will always lose, even if you happen to win a battle or two.

Source: printed ~10kg of Hobbyking PC on a modified Prusa MK2S with a custom enclosure, including a 15x15x15cm test brick with 140C enclosure and 300C extruder.

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