PC Blend - trying to print extruder  

RE: PC Blend - trying to print extruder

Posted by: @lucas-g-2

I have ordered new Prusa Mk3S+ and would like to use PC Blend material for extruder parts. I am trying to print this parts on both sheets with glue in enclosure.

Temperature in the enclosure is between 37-38°C. 

No matter what I try it will lift off and bend.

How can I improve quality of this print? Will it be possible to install this part when warped a bit?

Have someone printed extruder part using PC Blend? It is rather expensive filament so I would like to get my parts right ant stop experimenting.

For now I don't see Prusament PC Blend as viable option for printing.

 20201213_141145.jpg

"Pure polycarbonate is not suitable for 3D printing because of its bad surface adhesion and significant thermal expansion. Prints tend to deform and crack. For this reason, various additives are usually added to improve printability".

And probably these additives are responsible for the fact that my extruder parts of the MK3 cracked after a few months and finally crumbled.

Small parts can generally be printed better than larger ones.

try following:

- add a brim, raft

- add a draftshield

- add mouse ears

- printfan off

- print slower

- enclosure min. 40deg C.

- use glue like maggigo or similar

- first layer closer to the print bed

- decrease infill

- higher bedtemp, lower nozzletemp

- reduce extrusion multiplier

good luck!

RE: PC Blend - trying to print extruder

I've printed extruder parts in Polymaker PCMax which is their PC blend no problem. Haven't tried Prusa's version. Iirc I run close to nylon speeds and a bit higher temp maybe 270 and bed at 100 with glue stick. PCMax prints beautifully with little to no warp and holds dimensions well. PC blends get a little soft when printing at 300+ so I've reprinted all extruder parts in pure PC. It's tricky but it can be done. My only way to success there is a highly customized raft in Cura to get it to stick and minimize warping as well as a modified hot end and firmware.

RE: PC Blend - trying to print extruder

The first print I did with PC Blend was a replacement fan shroud, as the original had started to droop.  (In fact, this was my excuse to try the PC Blend.)  The admonitions were along the line that the PC Blend would stick too well, and to be sure to use a release agent, and a Kores glue stick was included for just that purpose.  I also used the already-damaged side of a smooth sheet, so I would not be out much if the print stuck too much.

This was before I had the enclosure, so I used the draft shield option, as I was doing with many ABS prints.  I printed both the original and a remixed version, so I could make the choice when I had the machine apart for this and a couple other minor tweaks.

As expected, the print and the accompanying draft shield stuck very well.  You can see the footprint of the removed shield in the residue of the glue stick below.

My only suggestion might be to try a draft shield even though you are using an enclosure.  If the cause of the warping/releasing is thermal contraction, this may help.

So far, all of my PC Blend prints have been relatively small.  The largest I've made was a bracket to hold an aluminum heat sink for a voltage regulator which was about 2 1/2 inches long.  It printed as expected, and the only change I made for that one was to use the Layerneer instead of the glue stick for the release agent.

RE: PC Blend - trying to print extruder

Thank you all for a lot of valuable information.

I have tried all of your suggestions before I even posted except one. Haven't use draft shield as I thought it would not be necessary after I have put the printer in the enclosure. Yesterday I have tried to print ABS part and came out flawlessly. 

I may try another PC brand as @natehansen66 have mentioned.

What is the difference between standard glue stick and Layerneer? Is it the fancy name for the same product? Is it easy to clean off of the PEI sheet afterwards?

RE: PC Blend - trying to print extruder

I have printed all of the parts for a complete hot end in PC Blend and I don't have an enclosure.  I tried with a draft shield but found that a brim worked better, so try a good size brim (6-8mm), and no more than 20% infill (you don't need it as the parts in PC Blend are strong enough).  If you are still having issues try setting the bed temp to max.  I did get a bit of warping on the edges, but the parts went together ok.  The glue stick is used as a release agent so that you can get it off the plate.

RE: PC Blend - trying to print extruder

Posted by: @lucas-g-2

What is the difference between standard glue stick and Layerneer? Is it the fancy name for the same product? Is it easy to clean off of the PEI sheet afterwards?

It's the Layerneer Bed Weld.  It's a liquid and gives a much thinner coat on the build plate than the glue stick.  I've found that it's very helpful both as an adhesion agent for tricky PLA prints with a small footprint or small supports and as a release agent.  I'll also use it on larger prints and dab a bit where the corners of large flat prints will be.  That is extremely effective against warping.

I've also used it as a release agent for ABS and PETg and now PC Blend.

It was originally made for improving adhesion on glass plates, but it works very well on PEI as well, both smooth and textured.

It comes off fairly easily with IPA, although denatured alcohol seems to cut it better.  One of the other users here said he leaves it on for multiple prints and I've started doing that too, but occasionally 'buffing' it a bit with an IPA soaked paper towel.

A bottle goes a very long way.  I've been using the same bottle for several months now and it still has quite a bit in it.  It's available on Amazon.

RE: PC Blend - trying to print extruder

@jsw

Big fan of it. Glue stick builds up very quickly. Layerneer is a very thin layer, and comes off easily with a wipe of IPA. I often build large models that have a propensity to warp at the corners. Layerneer works beautifully. and I don't need to bother with printing and removing brims.

RE: PC Blend - trying to print extruder

I could not find Layerneer  easily so I have tried with Dimafix and the results are stellar. Models sticks nicely to the sheet and the peel after the sheet cools down. Thank for the tips.