Large diameter nozzle?

Mostly Printed CNC - MPCNC Hardware Development
#1

I’ve seen some large diameter E3D Volcano nozzles being used and wondered if anybody who has used them had thoughts to share, or if they are available for the MK8. If they aren’t available for the MK8, I’d like to turn some on the lathe and see what happens. Maybe send a few freebies out for testing :wink:

I’m thinking somewhere between .6mm and 1.2mm, although 1.2mm seems a bit much for the MK8. I’ll turn them from 6mm or 8mm brass hex stock and plan on threading them M6. I guess stainless nozzles can happen later if these work out. Since I don’t have any experience using a stainless nozzle, I don’t know if they are even worth the cost and effort of researching which alloy to use. I’ll probably order the stock and tool steel that I will need on Saturday anyway.

Thoughts on design? I’d like to experiment a bit and see if there isn’t a way we might do nozzles differently. Like inside bore taper angle at the tip, or edge shaping of the hole on the outside of the nozzle.

#2

The volcano turns the heat block to transfer more heat faster to the filament, or have a larger heat zone.

Not sure how well 1.75mm will work extruding at 1.2mm, you probably have to got to 2.85, not really sure. Can’t wait to see your experiments. The larger extruders would be nice on some of these bigger machines.

There are a few volcanoes being used in the forums.

#3

I know that some of the older J-heads had a one piece heater block/ nozzle, but that seems like a nightmare to machine in bulk. I’ve also been wondering if the heat blocks are aluminum because of cost and ease of manufacturing, or because of aluminum’s thermal properties. I have a bunch of brass bar, hex and rod stock laying around…

Is it all about the size of the heat zone? What about maintaining the same nozzle to heat block arrangement but making the nozzle out of wider stock and bringing the top face of it into more contact with the heat block? Might have to use higher temps, but who knows. This sort of question is the reason I’ve wanted to build this new machine.

Anyway, thanks!

#4

1.75 mm filament works pretty well with 1.2mm nozzle, no problem.

I’m not sure to understand what you want to do in this thread? Is it different than what I’ve used on my printer?
Except for the fact I use a bowden setup, I don’t see where the difference is.

Also, if you plan on printing with a 1.2mm nozzle, you might want to consider watercooling for nozzle’s cold part. Made a big difference in terms of reliability on my printer so far.

#5

I think on the MK8 you’ll have a heating issue. Just from me messing around with my machine if I double my feed rate from 4 to 8mm/s it will skip and grind the filament. I guess you could always print really slow. Maybe around half speed.

#6

You can print pretty fast, the easiest way is simply to set a higher temperature. Hence the need for watercooling in some cases.
The resistance is actually pretty low when you push a 1.75mm wire in a 1.2mm nozzle, its much more smooth than pushing the same wire through a 0.4mm nozzle.
Also, you can use bigger motors/controllers for the extruder if necessary, or even use a demultiplication gearing system to increase a little the output speed, which would paradoxally increase the overall torque at a given output speed by lowering the motor RPM . Many solutions available there.

And even if you do reduce the speed of your print head, it still prints a lot faster with a 1.2mm nozzle than a 0.4, number of layers divided by 3 and 3 times the width per path… In my experience, it is generally 4 times faster overall.

I’ve used the 1.2mm nozzle on my MPCNC for a few months now, on a E3DV6 hotend and I don’t really want to go back to anything smaller any more. At least when small details don’t matter.

An other thing: you will need a a beefier way to cool down the part, either more fans or more powerful ones. Layers stays hot much longer due to the volume of plastic extruded, good results will largely depend on that especially on small parts. I realized the importance of thas last week while printing without cooling, now I’m waiting for some high powered 40mm fans to replace the weak ones I used before.

#7

I was thinking of making the nozzles for the MK8, that’s what my goal was. Making a water/ liquid cooled MK8 wouldn’t bee too difficult, but with the number of modifications that would need to be done, I might as well design a whole new hot end. I have printed up to 125mm/s with a .35mm nozzle and achieved what I considered very good results by raising the hot end temp to compensate for the shorter time the filament spends in the hot zone. After my current print finishes tonight, I’ll try and do a high temp/ high speed print and take pictures. I think the higher temperature idea is worth investigating before the water cooling.