MK3 - Are you printing with 100% speed?  

Re: MK3 - Are you printing with 100% speed?

I normaly use 100% on every print.
But the 100% is just the speed you adjustet in your slicer settings.
So the real printspeed (100%) often differs from print to print, or material to material.

Re: MK3 - Are you printing with 100% speed?

[...] Which printing speeds do you use and when?
Slowing down a print using the front panel knob is a good troubleshooting step. Slowing down can fix a myriad of problems and usually improves quality. That said, there's no need to slow down every print unless you've got your slicer settings way out of whack. I'd suggest doing some test prints and figuring out what speeds work well with different materials.

My front panel is set to 100% speed unless I'm troubleshooting something. I do back down the Prusa preset speeds in the slicer software, particularly the aggressive 200mm/s infill speeds. The key is to avoid overwhelming the E3D V6 hotend with more filament than it can process. Using a 0.20mm layer height with 0.40mm nozzle, your maximum speeds should be closer to 80mm/s. Keep Extrusion Width X Layer Height X Speed < 11.5mm^3/s and you'll generally be safe using PLA. Keep it below 8 mm^3/s for PETG and more viscous materials.

Slic3rPE has settings for these limits so you don't have to tweak individual speeds. Look into the Max volumetric speed options.

Re: MK3 - Are you printing with 100% speed?

I slow down for prints with a lot of support or fancy prints. but after the first few layers I go 100% then 200% or 300% depaneding on what im printing. but the first few layers I have no problem going super slow if it means my print will not fail.

Re: MK3 - Are you printing with 100% speed?

What is 100% speed? Everybody has own speed settings in the slicer.

Re: MK3 - Are you printing with 100% speed?

What is 100% speed? Everybody has own speed settings in the slicer.

It is on the the printer, not in the slicer. If you rotate the knob, you will see the 100% value changing to another. This change slicer values proportionnaly.

Re: MK3 - Are you printing with 100% speed?

[...] Which printing speeds do you use and when?
Slowing down a print using the front panel knob is a good troubleshooting step. Slowing down can fix a myriad of problems and usually improves quality. That said, there's no need to slow down every print unless you've got your slicer settings way out of whack. I'd suggest doing some test prints and figuring out what speeds work well with different materials.

My front panel is set to 100% speed unless I'm troubleshooting something. I do back down the Prusa preset speeds in the slicer software, particularly the aggressive 200mm/s infill speeds. The key is to avoid overwhelming the E3D V6 hotend with more filament than it can process. Using a 0.20mm layer height with 0.40mm nozzle, your maximum speeds should be closer to 80mm/s. Keep Extrusion Width X Layer Height X Speed < 11.5mm^3/s and you'll generally be safe using PLA. Keep it below 8 mm^3/s for PETG and more viscous materials.

Slic3rPE has settings for these limits so you don't have to tweak individual speeds. Look into the Max volumetric speed options.

Woah! That is shifting the paradigm Im used to...
If I understood you right, what I could derive from your reply is - if I print only with 0.2mm layer height, I would make life of my hotend easier by switching to a bigger nozzle (0.8mm) so that faster speed is not giving it a hard time and is not causing issues. Correct or wrong?

Re: MK3 - Are you printing with 100% speed?

Woah! That's is shiftin the paradigm Im used to...
If I understood you right, what I could derive from your reply is - if I print only with 0.2mm layer height, I would make life of my hotend easier by switching to a bigger nozzle (0.8mm) so that faster speed is not giving it a hard time and is not causing issues. Correct or wrong?

Not really.

The limitation is how quickly the filament will warm up and soften enough to be extruded. Switching to a larger nozzle will reduce back-pressure somewhat, but it also requires a thicker line width and hence more material for a given length of line.

How fast you can heat filament is limited by the extruder temperature and the geometry (mainly length) of the melt zone.

Re: MK3 - Are you printing with 100% speed?

[...] If I understood you right, what I could derive from your reply is - if I print only with 0.2mm layer height, I would make life of my hotend easier by switching to a bigger nozzle (0.8mm) so that faster speed is not giving it a hard time and is not causing issues. Correct or wrong?
Yes, in the sense that a larger nozzle might print more quickly. If you like your paradigm shifted, you might like this... Let me see if I can't channel the Dude here...

Speed is an illusion, man! That's all just about how fast you move from point A to point B. What makes the difference in actual print times is the amount of plastic laid down as you make that move. That's measured in cubic mm per sec (mm^3/s). The more plastic you lay down, the sooner the print finishes. The E3D V6 hotend used on the Prusa printers can process (heat and move) approximately 11.5mm^3/s. (It's advertised as 15mm^3/s, but reality puts it lower. Bummer.) Heat increases throughput slightly, at the cost of other issues. Thus your upper limit of filament shoved through the hotend should not exceed 11.5mm^3/s. If you do exceed this limit, you get extruder clicks and skips, and very possibly jams as filament is not fully melted before you attempt to shove it through that tiny nozzle opening. This can contribute to extruder motor and feed heat.

The volumetric rate is calculated as Layer Height X Extrusion Width X Speed. Working backwards, we can calculate our maximum speed as 11.5/(Layer Height X Extrusion Width) = speed. This means that our maximum linear speed goes down as we use a larger nozzle. But get this, man... You rarely print at your maximum speed anyhow. Those "speed" settings are for linear speeds moving from one point to another. The amount of time it takes to get up to those speeds is determined by acceleration and jerk settings. The Prusa hardware has a maximum speed of something like 200mm/s. There's also a throttle in the form of max volumetric speeds on your filament settings (see Advanced). On smaller prints, you may never approach your set speeds.

I suggest firing up Slic3rPE, slicing your typical models and saving the gcode file. Then spend some time in preview mode. Spend time with the speed and volumetric flow rate view settings. See just how often you hit maximum speeds on your typical prints. Notice that speeds will always be limited by the lower of the max volumetric speed set for the filament or the printer. Try the same with different filaments and nozzle sizes. You'll see that spinning that front knob up to higher speeds doesn't really do anything after a certain point. If you're not using Slic3rPE, you may be able to set speed settings that are far too high for the hardware's capacity. You can go slower, but you can only go so fast! It's pretty far out.

What you can do though, is lay down more plastic on those same moves. A wider nozzle may let you use wide enough extrusion widths to avoid printing so many perimeters. To give some examples:

So while our 0.60mm nozzle should be limited to slower linear speeds that are less than half those of the 0.25mm nozzle, it can lay down more than twice as much plastic in wider perimeters. If that eliminates the need for an entire perimeter layer, your prints can finish up much faster. You can also use thicker layer heights, which will further improve speeds (at the expense of finish quality).

To your point about giving your hotend a hard time: The Prusa preset for PLA has the max volumetric speed (under Advanced) set to 15mm^3/s. Prusa's preset for PETG is 8mm^3/s. The E3D V6 limit is generally considered around 11.5mm^3/s. Read through many of the posts on extruder problems and you'll see many in which PLA is a problem, but PETG works well. Think about it!

There's no one panacea for problems, but "slowing down" linear speeds does back off on the volumetric rate, so can be a tremendous benefit if you're having problems. Better would be to fix your slicer settings, but dialing back speeds on the front panel is a definite help. Unfortunately, if you've sliced with really aggressive speeds (e.g. 170mm/s+ for infill), you may have to dial the front knob way back to help. In slicers like Slic3rPE and KISSlicer that allow using max volumetric speeds, that's the easiest setting to change. In other slicers, you have to reverse-engineer the speeds to use based on your extrusion width and layer height.

A larger nozzle really ties the printer together.

If you really want to go down the rabbit hole, consider how this impacts prints when you use software that can use adaptive layer heights such as Cura and KISSlicer. Layers between 0.05 and 0.48mm could be used in the same print. It's pretty trippy, man. Far out stuff.

I've put all my notes on this here if you'd like to check out more.

Re: MK3 - Are you printing with 100% speed?

Bob, this is the most well thought + well written + well explained reply I got on a forum in my entire life (counting from 56 Kbps modems era).
I'll take time to think through what you said and will also go through your Project Notebook. I truly appreciate your desire to help and share knowledge. Thank you!

Re: MK3 - Are you printing with 100% speed?

bobstro said all.

Stock settings should be tuned, they hit max. extrusion on infills, dont know why they set such values and 200 mm/s is crazy to wear the machine and have problems on part.
I also found that auto speeds or rely on max extrusion rate under filament or advanced tab is not good, that is not accurate to me, it end to print more volume than the defined one, so always better to set everything manual on speed tab and based on math.
Also don't use hotend limit at max, give it a margin like 1 or 2mm^3/s less

If you want boost your 0.4mm without change nozzle setup a 0.3mm layer height with 0.7mm to 0.8mm extrusion width will do magic at print time. It will reduce in about half. And as bonus you print slower, which mean better detail

I print always at 30mm^3/s (with few exceptions like small details) with 0.6mm nozzle, 0.45 layer height and 1.2mm extrusions, only 1 perimeter, but i'm with volcano. This print 9h parts into 1.5h with good quality

Re: MK3 - Are you printing with 100% speed?

Bob, this is the most well thought + well written + well explained reply I got on a forum in my entire life (counting from 56 Kbps modems era).
I'll take time to think through what you said and will also go through your Project Notebook. I truly appreciate your desire to help and share knowledge. Thank you!
I'm not sure why I got in the Big Lebowski mode, but it was fun to write. Thank you! Any edits or corrections much appreciated. I'll add this one to my notebook.

Re: MK3 - Are you printing with 100% speed?

If the max volumetric speed for a V6 is considered around 11,5mm3/s for PLA, why is it set at 15mm3/s in Sli3er?

Re: MK3 - Are you printing with 100% speed?

If the max volumetric speed for a V6 is considered around 11,5mm3/s for PLA, why is it set at 15mm3/s in Sli3er?
IIRC, the official maximum spec for the V6 is 15mm^3/s with any material. Searching around and reading first-hand experiences indicate that once installed in a typical printer, it's more like 11.5mm^3/s. I have no idea why Prusa stuck with 15mm^3/s for PLA. They've used lower values for other materials. Colorfabb XT-CF20 is 1mm^3/s. With the right materials at the right temps under the right conditions, 15mm^3/s might be doable. Keep in mind, Prusa is setting up the filament profiles to be independent of the printer profiles. So it may be simply that PLA can be printed at that volume. As Prusa expands their lineup, perhaps newer models will handle higher rates. In any case, if you're having problems, cutting back is a good troubleshooting step.

It's also worth remembering that filament manufacturers themselves typically identify a max printing speed. Some materials have problems at higher rates. Just going faster can cause problems with a number of pieces of the puzzle.

Re: MK3 - Are you printing with 100% speed?

bobstro, do you plan to post some slic3r profiles in your notebook in the nearest feature?

Re: MK3 - Are you printing with 100% speed?

If you want boost your 0.4mm without change nozzle setup a 0.3mm layer height with 0.7mm to 0.8mm extrusion width will do magic at print time.

hmm... I'm confused.
Are you suggesting to print with stock prusa hotend and 0.4mm nozzle with 0.3mm layer height and 0.7mm extrusion width? 😯

According to my understanding maximum possible layer height is about half of nozzle diameter...

Re: MK3 - Are you printing with 100% speed?

hmm... I'm confused.
Are you suggesting to print with stock prusa hotend and 0.4mm nozzle with 0.3mm layer height and 0.7mm extrusion width? 😯

Yes, try it, you will be amazed 🙂 But dont forget to tune speeds too.
The 0.4mm nozzle have a lower diameter of 1mm so you can squish filament up to 1mm, to be safe give a margin of -0.3mm and you end with 0.7mm max. extrusion width that you can use, so from 0.4mm to 0.7mm is safe.

According to my understanding maximum possible layer height is about half of nozzle diameter...

Not half, half height is the recommended first layer, the max. is 80% of nozzle size 0,8*0,4 = 0,32mm.
So you set first layer to 0.2mm and others to 0.3mm, but nothing wrong if you set both at 0.3mm

Re: MK3 - Are you printing with 100% speed?

Thank you! i'll try and post my impressions 🙂

But dont forget to tune speeds too.

you mean limiting max volumetric speed as per bobstro guide?

Re: MK3 - Are you printing with 100% speed?

you mean limiting max volumetric speed as per bobstro guide?

Yes, set speed according your needs, never go more than 10mm^3/s and don't trust autospeeds or volumetric cap . set all speeds manualy based on math: layer height x extrusion width x speed.
So for 0.3 layer and 0.7 extrusion width i recommend 45mm/s everywhere and 50mm/s for infill, keep stock value for gap and small perimeters.
You can boost your speed by set infill at 0.5mm and print it faster, at a cost of weaker infill but anyway it is already stronger than the stock value.
You can also leave first and top layer width stock to have a better looking part at surfaces, myself i like the thick line better, you can play with the values at your own

My values for reference, i'm with 0.6mm nozzle!

At 1.2mm i print only with 1 perimeter it's stronger than print 3 perimeters with the stock nozzle stock settings.

Re: MK3 - Are you printing with 100% speed?

bobstro, do you plan to post some slic3r profiles in your notebook in the nearest feature?
In progress as we speak... er, write. I'm on vacation so without my Mk3 (I wasn't allowed to pack it for some reason) so I'm getting some writing done. I'm putting together a page on configuring Slic3rPE. It's changing by the minute as I figure out features of the documentation system.