High temperature resistant material for MK3S upgrade?  

RE: High temperature resistant material for MK3S upgrade?

I printed mine with Nylon with CF.  

RE: High temperature resistant material for MK3S upgrade?

Something I've thought of, but haven't gotten around to trying yet, is using ProtoPasta's HT-PLA and then annealing it. Once annealed it is supposed to be really heat resistant. But it is also known that it does shrink a little bit requiring printing slightly larger. And, the shrinkage is different in the z vs. the x and y, so for complicated geometries it may warp. Supposedly ProtoPasta's latest HT-PLA doesn't shrink much (compared to regular PLA and earlier formulations of HT-PLA), but I don't know if it would cause issues.

So, if you are up to experimenting, there is another material to experiment with.

RE: High temperature resistant material for MK3S upgrade?

I have several parts printed with ProtoPasta's HT-PLA.  It is not PETG or Nylon with CF, but it does work.  

RE: High temperature resistant material for MK3S upgrade?

Another +1 for Nylon +CF.  Here is a pic of a part using eSun ePA-CF.  Love this stuff but you have make sure it is dry when printing.

RE: High temperature resistant material for MK3S upgrade?

Thank you. It seems PA-CF is the way to go. And yes, that stuff loves to suck up moisture way to much. I keep my roll permanently in a Polybox.

RE: High temperature resistant material for MK3S upgrade?

Posted by: @sembazuru

Something I've thought of, but haven't gotten around to trying yet, is using ProtoPasta's HT-PLA and then annealing it. Once annealed it is supposed to be really heat resistant. But it is also known that it does shrink a little bit requiring printing slightly larger. And, the shrinkage is different in the z vs. the x and y, so for complicated geometries it may warp. Supposedly ProtoPasta's latest HT-PLA doesn't shrink much (compared to regular PLA and earlier formulations of HT-PLA), but I don't know if it would cause issues.

So, if you are up to experimenting, there is another material to experiment with.

Could you Anneal the parts with the extruder heatsink, in place, to maintain the space for the heatsink? 

regards Joan

RE: High temperature resistant material for MK3S upgrade?

BTW, now that I have a couple of Nylon/PA-CF users here, what are your temperature settings?

I started to print the MK3S parts with the same settings as I've always used for PA-CF, which is 280 deg C. I know this is the high end of the recommended temperature range, but it worked for me.

However it's been a while since I last used PA-CF, and several changes has been made since then. The printer is upgraded to 3.8.0, the slicer to 2.1.0, and I got at powder coated plate. Now when I tried to print PA-CF, it clogged the nozzle while putting down the first layer. I tried all the tricks I could think of: Lowering the speed, raising Z calibration, switching to my smooth sticker plate. Nothing helped.

Then as a last desperate attempt, i lowered the nozzle temperature from 280 to 265 deg C, and now it works perfectly. I can understand clogging with temperatures set too low, but the other way around???

So what temperature do you use for PA-CF?

RE: High temperature resistant material for MK3S upgrade?

I use the following setting:

Printing temperature: 260-280 C

Fan Speed: 50-60%

To be honest, I have to adjust a little between different brands.  

RE: High temperature resistant material for MK3S upgrade?

MK3s/MMU2s Here with eSun ePA-CF using:

Extruder: 255 / 260

Bed: 85 / 90

Fan: 30 - 60%

This is what eSun suggest:

• Print temperature range: 240~260℃
• Print Base temperature: 80℃
• Print Speed：30-60 mm/s;
• Move Speed：90-150mm/s

RE: High temperature resistant material for MK3S upgrade?

Thanks again.

I need to experiment some more with my settings. My PA-CF prints at 265℃ doesn't have as strong layer adhesions as previous prints I've made back when 280℃ worked for me. That could be a problem for the two "eyes" that hold the Bondtech idler.

I think I'll print most of the upgrade in PETG, and only change the parts closest to the heat block and heatbed to PA-CF.

RE: High temperature resistant material for MK3S upgrade?

Could it be that you are using a 0.4mm nozzle?.

Just a theory, but CF fibres don't melt or dissolve in the filament but are infused in it and are carried through your nozzle by it, the hotter the filament, the runnier it is so the fibres could move through the filament easily , squeezing the filament in the nozzle, could in theory cause fibres to seperate from the  filament and migrate to the edge where they may clump together causing a blockage. With a 0.6mm nozzle you probably would not notice, a 0.4mm maybe, a 0.25mm, apparently don't even try.

RE: High temperature resistant material for MK3S upgrade?

I use 0.4 mm with out an issue. 

RE: High temperature resistant material for MK3S upgrade?

Hi Charles, I suspect you also keep your temperatures within manufacturers tolerances leaving the filament viscous enough to carry the fibres through with it.

I know it's not the same but this is why I say it is a theory and thought it may or may not be a reason, but sounds plausible and we can discuss it's merit or insignificance. 😀 🙄 

There there was an instance at one of the food plants I used to visit where they were filling jam and the temperature was too high, the jam liquified too much and ran out leaving the fruit in the tapered filling nozzle, which kept blocking, It was only after the nth time clearing the blockage that someone noticed the temperature was set too high. Once set correctly, the jam was viscous enough to carry the fruit through dispersed in the jam enough so as not to cause blockages. I've also had something similar with yoghurt, but in this case they used steam to sterilise the pipework just before filling and pumped fruit pieces yoghurt straight into pipework still over 100 Deg C - This did not liquify!, but I digress.

Anyone got any thoughts on wether too hot filament may leave fibres in a nozzle?.

RE: High temperature resistant material for MK3S upgrade?

@chocki

Yes I do keep the temp in range.  

RE: High temperature resistant material for MK3S upgrade?

Posted by: @chocki

Could it be that you are using a 0.4mm nozzle?.

Indeed I do, but that has never troubled me before.

I have been reading some more on the forum, and I believe my problem is due to the Prusa specific heatbreak and retractions. All my print attempts at 280℃ started well. It printed the primer line, the skirt and started on the actual part. It always clogged up when printing small areas with frequent retractions. I just measured one of the filemant ends that I pulled from a clog. It show signs of being melted too far back. The very end of the clog measures 1.95 mm in diameter, and then it changes to 2.16 mm. That sounds very much like the heatbreak diameter change from 2.2 to 2.0 mm that I've read about.

Perhaps I should change to a standard E3D heatbreak at the same time I do the MK3S upgrade. I don't plan on getting a MMU2, so a standard heatbreak should serve me just as well (or better).

RE: High temperature resistant material for MK3S upgrade?

Posted by: @ejberg

Posted by: @chocki

Could it be that you are using a 0.4mm nozzle?.

Indeed I do, but that has never troubled me before.

I have been reading some more on the forum, and I believe my problem is due to the Prusa specific heatbreak and retractions. All my print attempts at 280℃ started well. It printed the primer line, the skirt and started on the actual part. It always clogged up when printing small areas with frequent retractions. I just measured one of the filemant ends that I pulled from a clog. It show signs of being melted too far back. The very end of the clog measures 1.95 mm in diameter, and then it changes to 2.16 mm. That sounds very much like the heatbreak diameter change from 2.2 to 2.0 mm that I've read about.

Perhaps I should change to a standard E3D heatbreak at the same time I do the MK3S upgrade. I don't plan on getting a MMU2, so a standard heatbreak should serve me just as well (or better).

Are you sure your PTFE  tubing IS all the way in?

RE: High temperature resistant material for MK3S upgrade?

I remember reading that Tim had blockages with non fibre included filament, and he too was printing with lots of short retractions, so maybe it could be the step in the heatbreak that is to blame, plus the extra temperature which could be enough to soften the filament behind the narrowest part and be causing blockages due to the continued ramming of the filament back and forth making it increase in diameter.

One more question, do you have a direct extruder, no 3.5 reduction like skelestruder, it's just that at typical extrusion speeds for the direct drive, it is not in the best range for best torque.

RE: High temperature resistant material for MK3S upgrade?

Posted by: @charles-h13

Are you sure your PTFE  tubing IS all the way in?

Yes, unless it has worked itself back up over time.

Posted by: @chocki

One more question, do you have a direct extruder, no 3.5 reduction like skelestruder, it's just that at typical extrusion speeds for the direct drive, it is not in the best range for best torque.

It is a direct extruder. My printer is a mostly stock MK3. No modifications other than official Prusa improvements (angled part cooling fan, etc) and an Olsson ruby nozzle.

RE: High temperature resistant material for MK3S upgrade?

Have you tried another nozzle?, the more I read about the olsson ruby, the more I'm inclined to stay away.

If you only have a brass nozzle, it will wear away, but at least it would rule the ruby out as being the problem if it clogs as well.