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Experience with PC Blend & heat  

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matene
(@matene)
New Member
Experience with PC Blend & heat

Hello there,

lately I've done a few test objects with PC Blend to figure out it's usability and a workflow for printing it and ran into a few issues I wanted to share.

  1. Heatbed temp. Prusa recommends the heatbed should run max at 110°C, although the limit is 120°C (reference). PC Blend expects 115°C according to the slicer profile which would always be above the recommendation. Also my heatbed has trouble keeping anything above 110°C and I had instances of stopped prints because of thermal runaway. I don't use an enclosure (yet) but am wondering if isolating the underside of the heatbed would help keep up the high temperatures - and save energy?
  2. Warping. I've had some amazing results with smaller to medium objects (6x6cm or smaller) but anything bigger resulted in more or less warping despite trying out all the recommendations. So I figure this is due to the missing enclosure (or too low heatbed temp - that is around 110°C), though I tried putting up some walls around the printer out of cardbord and the temp stabilized and the warping improved a bit.
  3. Crashes. When printing larger PC objects I had crashes on every second layer or so. The printer continued after the crashes, but still. No such problems with PLA or PETG. So it must be related to the high temperatures. Some searching around the net suggests that high stepper motor temps might return wrong info to einsy. So I measured the stepper temps throughout a 7hr PC Blend print without enclosure and with just the cardboard to stop drafts. The peak temps on the outside of the steppers for X/Y/Z were 41/49/42°C. Does anyone else encounter these probably heat-related crashes?
  4. Enclosure & heat. Still not sure, if I want one 😀 Yes, I can put the PSU and maybe even the EINSY outside the enclosure, but the steppers remain inside at 50°C or more - they don't like such temps as far as I know and am I supposed to disable crash detection inside the enclosure?

Thanks in advance for your feedback

Posted : 16/03/2022 8:51 am
Thejiral
(@thejiral)
Reputable Member
RE:

It is absolutely no problem to print PC-Blend at 110°C bed temperature, at least when using specialized adhesives. I always use Magigoo PC on a smooth bed (there are competitor products specifically for PC out there but that's what I have experience with) bed adhesion of PC is very good with it. With a brim and adhesive, there is no need for higher temperatures and it won't help against warping. As long as you can ensure bed adhesion, lower bed temperatures actually help against (post lifting) warping. 

I do use an enclosure and print effectively at 55°C chamber temperature or above (on the Voron, the Mk3s has probably ~45°C chamber temp). That does help considerably against warping. Generally I would recommend an enclosure. But I have heard it is not strictly necessary. If you don't have an enclosure make sure that there is as little as possible air movement around the printer, use a big brim and most importantly include a skirt in the slicer that is as high as your object, to keep the warm air in around your printed object. 

I have never had any crashes either on my Mk3s or my Voron 0.1 and both of them are in an enclosure, and therefore stepper motors are probably hotter than yours. I am not sure what your issue is there. Crash dedection of the Mk3s can be triggered by too much friction in your x or y axis. Is it always triggered on only one of these two axis? If you have part detachment from the bed on the corners that can also cause crash conditions, especially as PC is especially robust and doesn't give easily way for the extruder head.

In my Mk3s enclosure I have the PSU outside, I think that is strongly recommended (and also fairly easy to do). I left the Einsy (and the MMU) board in the enclosure however and that already for a year or so and to date had no failure or issue with it. Crash detection is on in the enclosure and the only time I had problems with it was when there was excessive friction on the Y-axis.

PS: The largest object, with fairly dense print settings, I have done with PC-Blend was 10 cm squared (the prusament clamp) but in the Voron at +55°C chamber temperature. I had a bit of warping but hardly visible by the bare eye and no functional issue at all. I would not go much beyond that size with dense and rugged prints. 

This post was modified 5 months ago 2 times by Thejiral

Mk3s MMU2s, Voron 0.1

Posted : 17/03/2022 8:11 am
Thejiral
(@thejiral)
Reputable Member
RE:

PS: If you do print with a Prusa MK3s 115°C bed temperature is perfectly feasible if you have an enclosure. In case you want to try out such a high bed temperature.

Without an enclosure the heat losses might become critically high though, especially in a cold room. A cold room should be avoided however anyway, if you don't have an enclosure, as it will make your warping problems worse. 

This post was modified 5 months ago by Thejiral

Mk3s MMU2s, Voron 0.1

Posted : 17/03/2022 11:43 am
jsw
 jsw
(@jsw)
Famed Member
RE: Experience with PC Blend & heat

I've done a number of PC Blend prints on the MK3S very successfully.

At first I used the glue stick, but tried Layerneer with PC Blend and became comfortable with it.

No issues heating the bed.  (Are all bed heater connector screws tight?)

Posted : 17/03/2022 6:13 pm
burtronix
(@burtronix)
Estimable Member
RE: Experience with PC Blend & heat

Try selecting Draft Shield in the skirt settings. It's low effort & uses just a tiny bit of filament. I haven't done it with PC, but it's been quite effective at reducing or eliminating warp with other filaments.

Whatever you find to do with your hands, do with all your might!

Posted : 17/03/2022 6:20 pm
fuchsr
(@fuchsr)
Famed Member
RE: Experience with PC Blend & heat

I've done a fair bit of printing with PC Blend but mostly smaller objects. With an  enclosure and a draft shield warping was modest and not significant enough to affect function. My Dragon mounts for the Mini and all my Mk3S fan shrouds are printed with OC Blend, for example. 

I turned crash detection off a long time ago and never looked back. In my hands, it caused more problems than it solved. 

Posted : 17/03/2022 6:22 pm
matene
(@matene)
New Member
Topic starter answered:
RE: Experience with PC Blend & heat

Thanks for the feedback!

Looks like I'll be trying the smooth bed with Magigoo PC, a full height draft shield and wind protection next.

If that helps I'll go ahead and work on an enclosure - found a blog post where someone moved the PSU and the Einsy out of the enclosure and stuck heatsinks on the steppers. I kinda like that idea 🙂

Posted : 19/03/2022 10:58 am
Thejiral liked
Tommy_W
(@tommy_w)
Active Member
RE: Experience with PC Blend & heat

I´ve done several kg´s of PC Blend lately and my best tips are magigoo pc and an absolute draft free enviroment. I do print in an partially open enclosure, so my chamber temperature never gets over 40C, but the print is well protected against drafts. In my experience, draft-free is more important than chamber temperature. First layer is of course also critical. And finally, be aware of your design, sharp corners seems to be very difficult without a substansial brim. Using the satin sheet only for my PC prints.

Posted : 28/03/2022 3:11 pm
fuchsr liked
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