Tips for using the different nozzles sizes?

[BIKBart 3]

Hi Guys,

After a failed search on this forum I'll just ask it, do you have any tips and tricks for printing with the different nozzles sizes? I've only printed with the pre-installed 0.4 mm nozzle, but I'm tempted to switch to the 0.8 nozzle for bigger prints. What I'm looking for is a good starter point for the basic settings of:

- layer thickness

- printing speeds

- material choice

- printing temperature

- etc.

For instance, for bigger prints with the 0.8 nozzle I wouldn't mind visible layers, so what's a good starter point there?

If we gather all this information of all 4 nozzles sizes, maybe we can come up with a comprehensive nozzle guide? Would be a nice addition to the manuals? If this has already been covered please excuse me for posting this and help me find that specific post

Bart

[gr5 2,178]

No way to do comprehensive guide as people's desires are so varied plus you can't even recommend temperature as this varies even just by color of filament!

layer height

Anyway some guidelines - Printing up to around 50% to 75% layer thickness of the nozzle size is usually fine so for .4mm nozzle up to around .2mm or .3mm layers. For .8mm that would be around .6mm thick max (I'd stick to .4mm personally). And so on. e.g. I wouldn't go over .12mm layer height with .25mm nozzle.

volume

The area is the square of the diameter and resistance goes down linearly by the area so you can print faster (volume of plastic per second) on the "square law". Cura shows the volume if you hover over the speed (at least some versions do).

So that means for example if you normally print .2mm layer .4mm nozzle 50mm/sec you can multiple those 3 numbers to get a volume of 4mm^3/sec . But with the .8mm nozzle you can do 4X as fast no problem. So if you should be able to print 16mm^3/sec easily (e.g. .4 layer height .8 nozzle 50mm/sec). and of course you need to print so much slower for the .25mm nozzle (or .15mm or .1mm nozzles)

speed

For very good dimensional accuracy (corners not blobby) it's best to keep the speed low. For really beautiful parts you want to go no faster than around 25mm/sec regardless of layer height and nozzle size. This has to do with speed changes at corners. The printer has to slow down to 14mm/sec on a right angle corner so only slowing by about 2X is barely a problem but if you are at 50mm/sec or faster the corners are noticably bulging. This is regardless of nozzle size or layer height. That's why it's so great to print with a bigger nozzle instead of just printing faster.

temperature

You will get consistently better quality at lower printing temps but this means you also have to slow down as it's harder to get filament through the nozzle. For high quality 210-220C is a good compromise. For extra high quality print extra slow (10mm/sec?) and at 190C. That way the filament is more like cement and is better at not moving in the second before it cools. But really 220C is my favorite temperature. For the .8mm nozzle and larger it's best to print hotter as it is hard for the heat to penetrate to the center (unless you buy a 3dsolex race nozzle) and so ultimaker recommends printing a bit hotter with .8mm and larger nozzles.

[BIKBart 3]

Thanks Gr5, this is exactly what I was looking for. Interesting how a bigger nozzle has a large impact on the overall printing time, while keeping the actual print speed (movement of the head) relatively low.

You mention that the printer has to slow down to about 14 mm/sec for a right angle corner. Does the Ultimaker this? Is the speed dynamically calculated by Cura, based on the path the head needs to follow? I always thought that the speed is just a constant factor that doesn't change in the printing process. If it's dynamical, then it's insightful to know:)

[gr5 2,178]

Marlin does this. There is a setting called "jerk" which is not jerk but instead the max change in instantaneous velocity at a vertex. In other words take the vel vector before and after a vertex and subtract them. The magnitude of the difference vector is your speed change. That is kept to 20mm. So for 90 degrees the speed goes down to 14mm/sec. For sharper angles (say 180 degrees) that goes down to 10mm/sec). For very very slight angles the limiting vertex speed is quite high. Maybe as high as 1000mm/sec (which is faster than the max speed (300mm/sec) of the printer so it won't limit at all.

[krys 206]

Hi gang,

One thing I noticed over the weekend regarding nozzle sizes is this:

For a given layer height, switching to a larger nozzle size caused more filament to be used. At least that is what Cura 2.1.2 estimates.

For example, if I say I want 0.25 layer height and I use the 0.4mm nozzle, I get, say, 17m of filament estimated will be used. Keeping all else the same, and changing to the 0.8 nozzle, I get around 25m of filament that will be used.

I suspect this is because the infill line width will be that much wider, using more plastic. It probably would contribute to a stronger part too, but that is just a guess.

If you want to keep the amount of filament used down (at the cost of speed), then the smaller nozzle might help. ... Assuming Cura's estimates are reasonably accurate.

I did not think of upping the layer height beyond 0.25, however. So, if 0.4mm layer height is feasible with the 0.8mm nozzle, that might help offset things. Again, just a guess.

Anyway, this is just an observation I noticed. Hope it helps!

[BIKBart 3]

Thanks for the insight both of you! I have a lot of orders to finish with the 0.4 mm nozzle currently installed, but after that I'm definately switching to 0.8 to do some testing with larger objects and faster printing.

[Groaker 0]

#GR5 said

"There is a setting called "jerk" which is not jerk but instead the max change in instantaneous velocity at a vertex.  In other words take the vel vector before and after a vertex and subtract them. "

I can't blame GR5 for this error, as the term jerk is rarely used in mathematics. The change in velocity is called acceleration, and the change in acceleration is called the jerk. While almost everyone knows what acceleration is, jerk is usually reserved for son-in-laws. It is the third derivative of a curve. It is also called jolt surge or lurch. It is the only time I have seen this derivative used for consumer products Being able to specify this change in acceleration demonstrates the precision needed in a good 3D device.

For those of a masochistic academic nature:

fourth derivative -- jounce or snap -- change in the jerk

fifth -- crackle -- change in the jounce (and as follows logically)

sixth -- pop

seventh -- lock

eight -- drop

I have never seen (or used) a high order derivative that jounce.

I hope someone is still awake should they have read the post.

ciao

[gr5 2,178]

I put jerk in quotes because it's not the right word but it's the word that Marlin uses in the code and on the settings in the menu system.  So when Marlin or Ultimaker printers talk about "jerk" they are talking about an infinite acceleration - an instant change in velocity at a vertex (there's a lot of vertexes in a print - one for each gcode approximately).  The same word: "jerk" is used unfortunately in the firmware for: Marlin, Repetier, Sprinter, Redeem, and more.

The jerk setting on UM by default is 20mm/sec.  So if you are going into a 90 degree corner at 100mm/sec it will slow down to actually 14.14mm/sec at the corner (it's complicated).

Edited August 24, 2016 by Guest