Bambu claims a lifespan increase of 50 % (see text) but at the same time showing an image that shows (if my math is not off) 10.3x more wear of the “normal” hardened steel hotend compared to the WC hotend.
My calculation:
Nominal diameter: 0.4 mm
WC hotend diameter after 20 kg fiber material: 0.403 mm (0.75 % wear)
“Normal” hardened diameter after 20 kg fiber material: 0.431 mm (7.75 % wear)
So either my math or Bambu’s marketing is off.
Or am I just missing something?
Area changes by the square of the radius, or 𝐴=𝜋(𝑑/2)²
The opening of a 0.400 nozzle is 0.12566 mm².
The opening of a 0.403 nozzle is 0.12756 mm², 1.494% larger than a 0.400 nozzle.
The opening of a 0.431 nozzle is 0.1459 mm², 14.9% larger than a 0.400 nozzle.
I seldom see mention of the outer tip dimensions, and I have not found the spec for a Bambu nozzle tip, but twice the opening is typical for nozzles. Assuming a new 0.4 nozzle has a tip diameter of 0.800 mm:
A nozzle tip worn down to a width of 1.020 mm would be 48% wider.
A nozzle tip worn down to a width of 1.614 mm would be 121% wider.
Even accepting the ad claim of a 50% increase in nozzle life, there is no cost benefit.
Tungsten carbide H2/P2S nozzles are $60 (currently on sale for $48).
Hardened steel nozzles are regularly $21.
That is true but extrusion width (which is for most extrusions important unless you do gap-infill spots) is - to my understanding - related to the diameter and not to the area of the tip opening. And flow is regulated by extruder gears (so same turning speed of the extruder gears will - within it’s pressure limits - extrude the same amount of filament, no matter if tip is 0.4 mm or 0.45 mm).
So I thought unless the opening width of the nozzle doesn’t exceed the minimum extrusion width and the area around the tip is still flat then the nozzle is still usable.
(just to explain why I used the diameter rather than the area)
And on this premise and considering the example measurements in Bambu’s picture the increase in lifetime of the WC hotend is far more than 50 %.
And this is what confuses me. Why would a company make this understatement?
But your calculation (using area) does come a lot closer to the 50 % than mine does so my assumptions about lifespan might be wrong.
Even though I’m doing FDM printing since a day or two and replaced and renewed a bunch on nozzles I never had relevant issues with the prints as long as the wear of the nozzle (inner diameter) didn’t reach the minimum extrusion width.
So I guess my assumptions aren’t completely wrong.
and replaced and renewed a bunch on nozzles I never had relevant issues with the prints as long as the wear of the nozzle (inner diameter) didn’t reach the minimum extrusion width.