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.75mm Nozzle and print speed

Posted: Sun Nov 10, 2019 3:49 pm
by airscapes
So I picked up a hot end with .75mm nozzle form a forum user who has sold his M2. After installing, cleaning (esun cleaning filament) and setting offset for a .5mm layer at .8 Extursion width I figured I would be able to print fast with a larger nozzle. My model is a simple flat plate 135x168x4mm
This was setup to print 2 shells/tops/bottoms and 20% infill. I tried to run it at 80mmS which is what I would do with a .35 Nozzle on a simples model like this. But I had issues with the perimeter not sticking and being way inside the infill area at corners and under extrusion in the infill I slowed things down to 50mmS and all is well..
So the question is, with a larger nozzle, what are the factors preventing the same speeds. I Assume but have not tested, print temp needs to be higher as a huge amount of plastic in comparison is being extruded at high speed and maybe there is insufficient time for it to melt? Another factor I would guess is mass of the plastic thread being much higher prevents accuracy in turns, even with rounded corners? Anything else I am not thinking of?

Just wondering if anyone has seen similar and found the needed change to compensate. I was using PLA+ which I hate.. when I get time I would like to try this with ABS..
Thanks,
Doug

Re: .75mm Nozzle and print speed

Posted: Mon Nov 11, 2019 8:48 pm
by Phil
It is not so much Print Speeds as heating capacity. It takes a certain amount of power to melt a flow of plastic, and the filament heaters have a limit; try to put plastic through the extruder any faster, and it just will not work. You likely have excess heat available at common print speeds, but that is quickly overrun with a bigger nozzle. A .75mm nozzle has about 4.6 times the area of a .35mm nozzle, so it may quickly exceed the power of the heater.

Re: .75mm Nozzle and print speed

Posted: Mon Nov 11, 2019 9:36 pm
by airscapes
That is my assumption as well..

Re: .75mm Nozzle and print speed

Posted: Wed Nov 13, 2019 9:44 pm
by willnewton
Makers Muse on youtube in his cr10v2 review video posted just a day ago tried a 1mm nozzle.

He discusses having to slow down the print speed because the hot end heater can’t keep up.

One of my old printers (mpcnc) had a similar issue and I switched to a Volcano hot end which helped, but you still have to go slower.

Re: .75mm Nozzle and print speed

Posted: Wed Nov 13, 2019 10:16 pm
by airscapes
It is really no big deal, it is still faster with a .5 mm layer that is .8 wide, even running at 40/50mmS for a big flat model. Thanks for the validation everyone!