Filamentcalculator
Know the impact of filament changes in diameter.
probably I should have a sensor for that too…
If your slicer working with ∅1,75mm and you using a ∅1,6mm you need to add 20% in flow. Also possible to have a 0.05mm change within a spool which is a 5% Flow change. And the same goes for you nozzle if it hasn’t exact the diameter you think it would.
Compared with the error you get when the filamentfeed is wrong is enormus… Its more important to get the filament flow within 1%
I have experimented with a filament sensor that meassure the distance and diameter that the filament actually is moving. Its very difficult to get filamentflow 100% and a feedback system that compensate for filamentflow and diameter will get a BIG inprovement in print quality. My sensor is working with I2C and Marlin 1.1.0 has support for it. Tere is also some support for filament diameter compensation, so the foundation for a feedback system is available in Marlin 1.1.0
Nozzle diameter does not influence how much material is fed through it. But for the rest… true, filament diameter influences flow a lot. Thankfully most filament is much more consistent today than it was a few years ago.
@Thomas_Sanladerer you are right that the nozzle didn’t influence the intake but the ouput [edit: the output length as the same volume from the intake need to get out]- so also accountable for under or overextrusion. And as the relation of area to diameter is not linear but exponential, the error is quite bigger for the nozzle … i calculated this
here.
@Ulrich_Baer idk, I always thought the amount of material I shoved into the nozzle would be equal to the amount that comes out the other side.
@Thomas_Sanladerer Yes sure bad wording sorry… the nozzle diameter will define the length of the material which is feed into. If this calculated length didn’t match the real diameter you will have over or under extrusion - e.g. if you extrude abrasive material or your nozzle gets worn out you have to increase the intake to fill the area and not getting underextrusion. The other applies if you think you using a 0.4 nozzle but you have a 0.35 und wonder why you print only looks ok when adjusting flowrate to -25%
@Ulrich_Baer nope, a mismatch of, say, a 0.35 physical nozzle to a 0.4mm in your slicer settings will print just fine, extrusion widths are often even deliberately set wider than the nozzle. If you turn the extrusion multiplier to 0.75% your prints will be heavily underextruded in any case.
@Thomas_Sanladerer you can set line width and nozzle seprately. The math clearly say that the area of a smaller nozzle diameter than expected will generate over extrusion. The smaller the nozzle the bigger the impact. You are right that the nozzle diameter will not impact the linewidth because that is defined by layerhight and flow not from the nozzle as one might think. The flow will squeeze to the calculated width.
Manually setting extrusion width will override any settings that would otherwise be auto-generated from the nozzle setting.
so will setting a smaller nozzle cause the slicer to calculate a smaller linewidth, hence getting an overlap as the real nozzle is bigger.
I think Thomas Sanladerer is right. The Slicer is calculating the needed material to extrude the given linewidth and layer hight. So if your nozzle is smaler than you specified this will not change. Therefore there is no over ord under extrusion (the amount of material keeps the same). The flow will change…(if the nozzle is to small the material needs to extrude faster to get trough the smaller hole, but it’s still the same amount of material). If you print to fast this might lead to underextrusion since the extruder can’t push the filament trough the hole. The extruder needs more force to push the filament trough a smaller nozzle.
@Ulrich_Baer You’re not making sense about nozzle size. Can you make a drawing of what you mean to say?
Nozzle size only matters because it creates some LIMITS to flow and possible strand dimensions:
Otherwise, regardless of nozzle size, the slicer pushes the right amount of volume to fill the space below the nozzle tip. If you say 0.6mm extrusion width, it will space the strands 0.6mm apart and push the right amount of plastic to fill a 0.6mm gap. Doesn’t matter if the nozzle is 0.4mm or 0.6mm.
“Its more important to get the filament flow within 1%”
No it’s not. If you measure the actual flow, you can see differences from 10% just for different temperatures/print speeds. Compensating for that is much more important then the diameter. So everything you doing on the diameter area is pretty much negated by much bigger variations you are already having without noticing it.
Has anybody ever actually shown superior print quality results with on-the-fly diameter compensation? I can believe it for homemade filament, but with commercial-grade filament?
For the last few years, I don’t even measure my filament diameter anymore, everything you buy from a reputable vendor is +/-0.05mm and varies slowly enough along the filament length that it’s pretty close to unnoticeable.
@Ryan_Carlyle as you said, you just want the correct ammount. if your slicer compensate wrong settings doesn’t mean they have no impact. If your slicer wouldn’t adjust the line width - these procentual changes would be needed to get your print. If you ever play with wireprinting you will understand as there the nozzle area and not the layer times the nozzle diameter define the volume.
@Ulrich_Baer I don’t even input my nozzle size in S3D. Just tell it the extrusion width I want, and that’s it. It makes no difference. Sometimes I forget which nozzle I have on a particular printer and don’t realize for months. A 0.5 and 0.6 print the same unless you want your extrusion width to be less than 0.6 or want to push a ton of flow rate.
Even with wireprinting, you can extrude strands wider or narrower than the nozzle. Molten filament is a liquid 
@Ryan_Carlyle yes not easy to make a .3 single walled print with a 0.6. And I am not sure there is no difference if you make singlewalled prints with a 0.5 wall - and you compare a 0.4 nozzle with a 0.5 nozzle. Its also a question of your nozzle geometrie how well you can overextrude.
It’s not overextrusion.
If you print a solid 10x10x10mm test cube and your printer extrudes more than 1cm³ of material, which has the nozzle increasingly digging through material from previous layers, that’s overextrusion. However, if you simply use wider tracks than your nominal nozzle width, that is not overextrusion.
For example, @Josef_Prusa MK2 uses up to 0.7mm extrusion width for fast prints with a 0.4mm nozzle. Slic3r also intelligently steps down extrusion width below the nominal diameter to fill thin gaps. Works perfectly.
right i should have called it “squeezed amount” from the beginning. That was misleading, sorry!
""I agree with those above. Nozzle size only effects the pressure in the melt chamber, not the overall rate of extrusion. Assuming your hotend can keep up with the flow demand and the drive doesn’t slip, the amount of material calculated by the slicer and extruded out the orifice will be the same whether you are running a 0.35mm nozzle or a 0.6mm nozzle or any other combination. Don’t believe us? How about taking the word of Taulman3d and MIT researchers who recommend intentionally entering larger than actual nozzle diameters in one’s slicing program to create thicker extrusions with T-glase filament to manipulate the optical qualities.
Calibrating the flow rate correctly is extremely important when printing large 100% solid objects, but with everyday printing a few percentage off will not have much of an effect. Still, a properly calibrated extruder will produce nicers prints, with much nicer looking top surfaces than one that is over/under extruding a bit.
The concern I see with using filament width sensors is that I have not yet seen a sensor setup that can address if there is any ovality in the filament, and it can be tricky to calculate the correct offset for when the measure area actually feeds into the nozzle. Not that a filament width sensor isn’t better than nothing, but I prefer just to print a single wall cube, measure the output, and manually adjust it until the print meets my expectations.
A larger factor in extrusion rates I see is the difference in how deeply the teeth on the drive gear/bolt dig into the filament. Extruders that use spring tension to grip the filament can vary significantly between filaments of different density. Assuming everything else is equal, some extruder designs calibrated perfectly with harder denser PLA filament will slightly under extrude when switched to other softer filaments like ABS, PETG, nylon, and especially TPU/ninja-flex. This is due to the softer filament being pressed ever so slightly further towards the centerline of the motor and effectively travelling slightly less distance with each revolution (similar to an under inflated tire getting worse gas milage). Cura and a few slicers have long used different extrusion multipliers to try to counter this effect. With many extruder designs switching to ever smaller diameter hobbed gears to maximize the available torque from the stepper motor, this effect gets more and more apparent the smaller the drive gear’s circumference becomes.
That’s why I create a different filament profile for every spool of filament I own, and do a thin wall calibration print at the start to get my flow as accurate as possible.