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.8MM temp tower help please!  

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skeletor
(@skeletor)
Active Member
.8MM temp tower help please!

I am trying to print a temperature tower with a .8MM nozzle.  The temp towers I have found seem to be for a .4MM nozzle. The perimeters for an .8MM nozzle are very different from .4MM and it is a real challenge. When I look at the tower in the slicer with a setting for a .8MM it's is a total mess due to my larger nozzle. If I increase the scale to 200% it looks a lot better in the slicer but not perfect. Am I on the right track increasing the scale? I am printing Armadillo and it's not going well.

Once I get the temperature tower dialed in I am thinking about a print speed tower because Armadillo is proving difficult to use. I would think after finding the correct temperature the correct speed should come second. Is this second idea of a speed tower silly or valid. Thanks for your help!

Thanks again!

Posted : 05/02/2020 2:40 am
bobstro
(@bobstro)
Illustrious Member
RE: .8MM temp tower help please!

Hmm. A temp tower is not a good application for a larger nozzle. The whole idea behind the temp tower is to gauge how well the filament can handle printing bridges at different temperatures. A 0.4mm nozzle is ideal because it will show the impact of heat on thin bridge extrusions as the temps are changed. With a 0.8mm nozzle, you're printing very heavy bridge strands that tend to sag no matter what you do. Bridging can be very tricky with such a nozzle in fact. Attempting to bridge with a larger nozzle is more a test of your settings and patience than the filament. I suggest using a smaller nozzle for temp tests to identify the characteristics of the filament (which won't change significantly with different nozzles), then swap to the larger nozzle.

Speed testing with the larger nozzle makes sense. While you're changing the nozzle (and presumably extrusion widths and/or layer heights), you didn't mention changing anything on the hotend. That means you're still up against the limitations of the E3D V6 hotend. That hotend is advertised as having a throughput of 15mm^3/s, though many find 11.5mm^3/s more realistic. That throughput (entered as Maximum volumetric speed (MVS) in PrusaSlicer print and filament settings) is calculated as Layer Height X Extrusion Width X Speed. This means as any one dimension is increased the others need to be decreased to avoid overrunning the hotend's ability to process filament. The square-cube law applies. Go too fast and you're likely to encounter extruder skips and jams.

With more viscous filaments, your MVS is likely even lower. Using an optimistic 8mm^3/s (same as PETG) for your Armadillo, you'll be limited to ~13mm/s using 0.64mm layer heights with 0.96mm extrusion widths. Even at 0.32mm layer heights and 0.96mm widths, you want to stay below ~26mm/s. (The good news is that PrusaSlicer does all this for you if you enter the correct MVS value, so there's no need to change print speed settings.)  More notes here. I haven't worked with Armadillo, so don't know what MVS to expect, but it's fairly easy to test for yourself.

Those are my experiences at any rate. Good luck with it. I've been looking at Armadillo, so please report back with results.

My notes and disclaimers on 3D printing

and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan

Posted : 05/02/2020 3:54 pm
skeletor
(@skeletor)
Active Member
Topic starter answered:
RE: .8MM temp tower help please!

Thanks for your help! A lot of this is over my head but I will get to work on it and let you know. Your comments about the larger nozzle and bridging makes perfect sense. Thanks again!

Posted : 06/02/2020 3:08 am
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