Does mmu2 work with e3d volcano?  

Re: Does mmu2 work with e3d volcano?

Question, does ramming need to purge all molten plastic? I don’t think it does.

Absolutely not. If fact, it can't as the filament being rammed will also become fluid in the melt zone.

What you need is just enough ramming to enable the tip to be retracted without a string.

Personally, I ram at 10 to 12 mm^3/s for between 13 and 18 mm^3 depending on filament and that will usually work. I see no point in "creeping up" the ramming speed; you just need to get straight in and straight out.

Peter

Re: Does mmu2 work with e3d volcano?

Question, does ramming need to purge all molten plastic? I don’t think it does.

Absolutely not. If fact, it can't as the filament being rammed will also become fluid in the melt zone.

Exactly. That’s why I wanted to make sure that wasn’t an expectation.

What you need is just enough ramming to enable the tip to be retracted without a string.

Personally, I ram at 10 to 12 mm^3/s for between 13 and 18 mm^3 depending on filament and that will usually work. I see no point in "creeping up" the ramming speed; you just need to get straight in and straight out.

Peter

Ok, good. So Volcano should be workable, just need to get a good ramming profile. Sounds like you advocate a flat, fast ram. What duration are you using?

Re: Does mmu2 work with e3d volcano?

Sounds like you advocate a flat, fast ram. What duration are you using?

I advocate whatever works. You probably know I don't use Slic3r 😉

Peter

Re: Does mmu2 work with e3d volcano?

Sounds like you advocate a flat, fast ram. What duration are you using?

I advocate whatever works. You probably know I don't use Slic3r 😉

Peter

Sure, but I’m wondering what strategy KISS uses. I can try to emulate that if it’s working.

Re: Does mmu2 work with e3d volcano?

Sure, but I’m wondering what strategy KISS uses. I can try to emulate that if it’s working.

I have max volumetric set to 12 mm^3/s for PLA. The purging is carried out at 90% of that (I think, from memory) and with the extruder heater turned off. I have set a purge volume of 18 mm^3 (for the Gustav print) but anything from 13 to 18 seems to work most of the time. More purge = longer tip plug and less chance of string.

There are 2 really important things; first is the initial load speed (19mm/s) and the second seems to be printer dependant, but needs to be set as hagh as the hardware can manage and that's the initial retract speed. F4800 (60 mm/s) is borderline but can work for some, F6000 (100 mm/s) does work if the hardware can manage it and F5400 (80 mm/s) works if the printer can't manage the higher speed. BUT this needs tweaking for individual printers, so start at F6000 and work down.

The latest Gustav is F5400.

Peter

Re: Does mmu2 work with e3d volcano?

I have tried many profiles and some look good most of the time where there is minimal tail on the tip, not enough to cause problem. But randomly one unload will still have a large string. Sometimes that causes immediate problem or just adds to build up over time and later the print fails. So I'm not sure volcano is ever going to work with MMU. I will have to put on my v6 again, but not sure my thermistor will survive another transplant.

Re: Does mmu2 work with e3d volcano?

Thinks...

The Volcano will need a lot more ramming at much higher speeds.

What is the max volumetric melt rate with this arrangement? And how much longer is it than the V6?

The amount of ramming will need to be about 75% of the melt zone and at 90% of max volumetric. The problem is whether the Mk3 hardware can manage that!

The unload would also need to be recalculated.

Peter

Re: Does mmu2 work with e3d volcano?

Thinks...

The Volcano will need a lot more ramming at much higher speeds.

What is the max volumetric melt rate with this arrangement? And how much longer is it than the V6?

The amount of ramming will need to be about 75% of the melt zone and at 90% of max volumetric. The problem is whether the Mk3 hardware can manage that!

The unload would also need to be recalculated.

Peter

Ok, making progress. Here are settings I am using for volcano which give acceptable tips and minimal strings (but not zero):

For ramming, need to purge over 40 mm^3.

need to lower cooling section and keep short. I am actually using 18mm and 5mm now.

The ramming and cooling changes were critical for improving reliability of filament changes.

Re: Does mmu2 work with e3d volcano?

Just one comment on that. The "unloading speed at start" is way over the firmware maximum which I think is in the order of 120 mm/s and even that speed may be too high for the hardware to operate at. You may find that too high a value will cause stringing as the extruder motor can miss steps if it can't keep up.

Peter

Re: Does mmu2 work with e3d volcano?

Anyone reading this thread, I was never able to get a successful print with ramming.

But I have success now and actually turned off ramming! See https://www.thingiverse.com/thing:3255317