Mk3 + 0.8mm nozzle  

Re: Mk3 + 0.8mm nozzle

The Mk3 will work happily with a 0.8mm nozzle; but you have to consider the maximum melt volume of the extruder (just over 10mm^3/sec) when calculating your print speed.

Example: 0.8mm extrusion width, 0.6mm layer height = about 20mm/s print speed (with slightly increased temps).

Peter

Re: Mk3 + 0.8mm nozzle

The Mk3 will work happily with a 0.8mm nozzle; but you have to consider the maximum melt volume of the extruder (just over 10mm^3/sec) when calculating your print speed.

Example: 0.8mm extrusion width, 0.6mm layer height = about 20mm/s print speed (with slightly increased temps).

Peter

Thank you!
I guess about printer settings and some speed settings will remain the same as 0.2mm fast profile, since they are already bump to max mk3 capabilities. is that right? eg speeds are the same as 0.4mm and 0.6mm nozzle

About Advanced -> extrusion width -> Can i set everything to 0.8mm? or double values from 0.4mm nozzle settings? For example 0.6mm nozzle have a default of 0.65mm, and 0.7mm infill

Re: Mk3 + 0.8mm nozzle

Yeah, there are a variety of limitations which come with the hardware and firmware.

As for extruding, generally extrusion width should be from 1 to 1.25 times the nozzle diameter and layer height a maximum of 80% nozzle diameter.

Personally, I only extrude at the same value as nozzle diameter and allow the slicer to adjust thinner for crowning paths and the like. (Please note that I do not use Slic3r.)

Peter

Re: Mk3 + 0.8mm nozzle

A few people here have mounted a volcano hotend to a MK2/3. I also considered it, for the same reasons. But swapping the hotend seems too cumbersome, so the better way would be to have a second printer. However, I have limited space and don't want to accumulate too much stuff.
For me, the game changer was the silent mode of the MK3. I can run it over night so if the print takes 15 hours - no problem. I start the print in the evening and when I come home from work next day, it's finished.
I also considered a CR10 or whatever for a volcano setup, but frankly the MK3 already requires too much fiddling and tinkering to work properly, I don't want to add another (unproven) setup on top of that. I guess it depends on what you want - if you enjoy 3D printer tinkering, this would be fine.

Now the ultimate machine I could think of would be one with toolchanger. I'd have four heads: one 0.4mm ruby for most stuff, a 0.25 mm for fine detail, a 0.4 mm for support (PVA/BVOH) and a 0.6-0.8 mm with volcano. But as Prusa just announced the MMU 2, I doubt we'll see a toolchanger design anytime soon.

- Martin

Re: Mk3 + 0.8mm nozzle

A few people here have mounted a volcano hotend to a MK2/3. I also considered it, for the same reasons. But swapping the hotend seems too cumbersome, so the better way would be to have a second printer. However, I have limited space and don't want to accumulate too much stuff.
For me, the game changer was the silent mode of the MK3. I can run it over night so if the print takes 15 hours - no problem. I start the print in the evening and when I come home from work next day, it's finished.
I also considered a CR10 or whatever for a volcano setup, but frankly the MK3 already requires too much fiddling and tinkering to work properly, I don't want to add another (unproven) setup on top of that. I guess it depends on what you want - if you enjoy 3D printer tinkering, this would be fine.

Now the ultimate machine I could think of would be one with toolchanger. I'd have four heads: one 0.4mm ruby for most stuff, a 0.25 mm for fine detail, a 0.4 mm for support (PVA/BVOH) and a 0.6-0.8 mm with volcano. But as Prusa just announced the MMU 2, I doubt we'll see a toolchanger design anytime soon.

- Martin

Yes, i may buy a new printer and install volcano, but not a mk3, something with big print area to make advantage of it. Buy mk3 to print with volcano at my view is not a good option because it have good capabilities for good detail and small area.
toolchanger is very nice but i don't expect that for the mk3, maybe for mk4 in a long term future. e3d also show the new volcano, i will wait for it.

CR10 is a proven machine, it work right out of the box, cr10s even better but there some good mods, like every printer can be tuned, the only draw back is the ABS printing, a new ac bed may be required for keep the temperature. Hope they release a even better CR with better heatbed, 24V and some other good stuff. But for the price is more than ok. I only dislike the bowden extruder which cause problems with fast printings

Re: Mk3 + 0.8mm nozzle

... maximum melt volume of the extruder (just over 10mm^3/sec) when calculating your print speed.


there are a variety of limitations which come with the hardware and firmware.
As for extruding, generally extrusion width should be from 1 to 1.25 times the nozzle diameter and layer height a maximum of 80% nozzle diameter.

Uh ... is there a list of these "metes and bounds" someplace?

Minimums and maximums and "this times that had better be less than thus or you'll be soreeee" kind of things??

Re: Mk3 + 0.8mm nozzle

Uh ... is there a list of these "metes and bounds" someplace?

When I got into 3D printing, I did quite a lot of research. Reading forum posts, querying things which just didn't sound right and asking the right people and, most importantly, keeping documentation for future reference.

Example: E3D quoted maximum print speeds for the V6 and suggested that was twice the maximum of the Lite6 (at that time in use on the Mk1). But print speed is not the only factor to take into account, so I persuaded them to test melt volume, which they did and supplied me with the result.

Peter

Re: Mk3 + 0.8mm nozzle

Uh ... is there a list of these "metes and bounds" someplace?

No. Read through the forum... all information is there, if you search long enough. On the other hand, there are only few hard limits (like melt volume). Most are rules of thumb for decent results, like maximum layer height/extrusion width/speed for a given nozzle size. You can usually push those depending on your priorities (speed, mechanical stability, quality). The extrusion volume limit is a hard one though, you'll find that out soon enough if you try to increase speed.

- Martin

Re: Mk3 + 0.8mm nozzle

Uh ... is there a list of these "metes and bounds" someplace?

I would go even further and suggest to google certain things. There are many nice places, not only the forum, where you can find very useful information for your questions.
I think the reason why PR don't provide those kind of hard limitations is the kind of the Prusa project. It's not a closed sourced printer with branded filament. Like a regular HP or Xerox laser printer. It's more an evolving, always ongoing project with high community effort. I'm looking for the current "MK3 extrusion issue" and I like how it goes. People are changing heads, settings, firmwares... comparing the results ... trying to improve the print quality.
Means you're able to change so many things on this printer. Many limitations you can see right now, can be bend or bypassed. Rule of thumb settings are provided by PR, everything else is up to you.

Re: Mk3 + 0.8mm nozzle

Uh ... is there a list of these "metes and bounds" someplace?
Sadly no. At the same time, looking at stuff like that as "LAWS" is a bad idea. They are general rules, that can be bent and broken for your needs.

A great example of a general rule.
"Print our PLA at 170-200c"
As I print at 225c.

Rules are meant to be broken. (It just may yield a poor result)

the Laws, are firm numbers, that truly can't be broken, without 100% causing issues.

eg:
Rule: don't eat too many taco's or your gonna end up sick.
Why a rule: The taco's are so damn good. It's worth getting sick.

Law: Don't eat Water Hemlock. Ever.
Why a law: Cause you gonna die if you do.

Re: Mk3 + 0.8mm nozzle

Also i like to ask why prusa don't include a higher layer height with the 0.6mm nozzle? Thier max preset is 0.2mm layer height. I have generated two gcodes from the same stl, one with 0.6mm nozzle and 0.20 layer height and other with 0.4mm nozzle and 0.3mm layer height, the print time with 0.4mm nozzle and 0.3mm layer height is much faster, so the only difference will be the extrusions width, more rigid, but the point of faster prints with lower detail is missing

Re: Mk3 + 0.8mm nozzle

Also i like to ask why prusa don't include a higher layer height with the 0.6mm nozzle? Thier max preset is 0.2mm layer height. I have generated two gcodes from the same stl, one with 0.6mm nozzle and 0.20 layer height and other with 0.4mm nozzle and 0.3mm layer height, the print time with 0.4mm nozzle and 0.3mm layer height is much faster, so the only difference will be the extrusions width, more rigid, but the point of faster prints with lower detail is missing

Whatever you think is missing, feel free to find best values for your purpose and share it.

Right now I don't really understand what you're trying to achieve. You're comparing apples with bananas.

Re: Mk3 + 0.8mm nozzle

... you have to consider the maximum melt volume of the extruder (just over 10mm^3/sec) when calculating your print speed.

It appears that the S3D profile for the MK3 posted by Jo Průša on 1/3/2018 significantly exceeded this maximum melt volume. When the Auto-Configure for PLA and Fast 0.2mm are selected, the Extrusion Width is 0.45mm, Layer Height is 0.20mm, and Print Speed is 12000 mm/min = 200 mm/sec.

If I have this correct (and I'm using a simplified formula for cross-sectional area of the extruded material):

Melt Volume = Print Speed x Extrusion Width x Layer Height
= 200 x 0.45 x 0.2
= 18 mm^3 / sec

I'm guessing that this was a quick-and-dirty profile produced to "get something out there" for the community, and all the "metes and bounds" of the hardware may not have been considered.

Am I missing something?

Re: Mk3 + 0.8mm nozzle

Am I missing something?

Yes, quite a lot. You can search for "acceleration" and "jerk" to see how that affects print speed. You can also research about 8-bit MCUs and the limits they place on speed.

Then you can start to understand that not all is what it seems to be and also that no one person knows everything!

This is a relatively new technology and everyone makes mistakes (e.g. the hot end on the Mk1).

FWIW, I have the Mk3 and when printing a large model at fast speed, it is only very marginally quicker then my Mk2 (+MMU) printing the same model at fairly regular speed.

Peter

Re: Mk3 + 0.8mm nozzle

So let's say I go blazing away with a print at 200 mm/sec when the max advisable based on Max Melt Volume and my Extrusion Width and Layer Height is 125 mm/sec ...

On a practical level, would I see the Live extruder temperature drop? Would the cool filament that is attempting to move too vast through the extruder and being insufficiently heated start to drag down the temperature readout?

Re: Mk3 + 0.8mm nozzle

So let's say I go blazing away with a print at 200 mm/sec when the max advisable based on Max Melt Volume and my Extrusion Width and Layer Height is 125 mm/sec ...

On a practical level, would I see the Live extruder temperature drop? Would the cool filament that is attempting to move too vast through the extruder and being insufficiently heated start to drag down the temperature readout?

I doubt it. The thermistor measures the temperature where it is located and not where the filament is being melted.

Under this circumstance, you would probably get extruder skipping and porosity in the print or wavy perimeters. But as mentioned previously, it is highly unlikely that you will actually be printing at 200mm/s and if you are, it would be only for a small fraction of a second.

Peter

Re: Mk3 + 0.8mm nozzle

Math:
http://manual.slic3r.org/advanced/flow-math

Limit with PLA is 11 mm^3/s,; you can push it a bit by rising the temperature, but not much. Try it! Your extruder will skip, leaving nasty holes (and I have the feeling it gives you an increased jam risk).

Normally flow limit is only reached during infill, because you want the first and outer layers slow to get a nice surface.

Re: Mk3 + 0.8mm nozzle

Limit with PLA is 11 mm^3/s,

11.6, to be precise (and according to E3D), but I set the max at 10, simply because PLA filametns do vary.

Peter

Re: Mk3 + 0.8mm nozzle

Limit with PLA is 11 mm^3/s,

11.6, to be precise (and according to E3D), but I set the max at 10, simply because PLA filametns do vary.

Peter

copper block, copper/nickel nozzle and titanium heatbreak should help at least a little, right?