MakerGear Forum

Does anyone know how much length of NinjaFlex 1.75mm diameter comes on a spool? How much weight (minus the spool)?

i think a spool is 1/2kg. not sure if that includes the spool or not. some mfg include the spool in the weight. i have scientific scale here accurate to 1/10th of a gram so as soon as i get a new spool here in a couple days i will weigh the whole thing to see if the spool is included. if it is i will weight an empty one to figure the actual total filament weight. then i can weight a length of filament. with that info i can figure out the length on the spool.

You'd think the manufacturer would just list this info since the slicing software tells you accurate filament length used.

haha you would think. its funny though i have never seen any spool of filament with the length per spool printed on it.

How can a slicer ever give accurate material usage estimates before starting a print?
It knows the cubic centimeter volume of the part model but how would it translate that to filament length needed.. Thus leading to filament cost pre-build?

The slicers have to know your filament diameter (prior to mm^3 extrusion) to properly calculate how much plastic to extrude. It uses that to send the G1 Exxx commands to advance the filament drive along, with 'xxx' being in millimeters (which is why the firmware needs steps/mm, because the firmware is what actually spins the steppers). There is a direct correlation between CC and meters of plastic used -- that's just math (41cm per CC). It's grams and meters that are plastic dependent.

from the Ninjaflex SDS here: http://www.fennerdrives.com/FetchFile.a ... 1b22ce9ad0

DENSITY: Approx. 1.2 g/cm3 (20°C)

does this help in calculations?

what is ABS, PETG and PLA density?

hybridprinter wrote:How can a slicer ever give accurate material usage estimates before starting a print?

It depends entirely on the values you provide:

• Input = filament diameter
• Output = extrusion width and thickness
• Extrusion Multiplier

The slicer will multiply the width x thickness x length of each extruded thread segment to get its volume, then add all those together to compute the object's total volume. The Extrusion Multiplier tweaks that number to account for all the nonlinearities in the extrusion process.

Dividing the total volume by the filament area (πd²/4) gives the filament length required for the object.

The density doesn't enter into those calculations, but Wikipedia gives you the (approximate) values for each type of plastic: multiply the total volume by the density to get the object's weight. You can also work backwards by weighing the final object, then dividing that by the volume to get the actual density; you can use that density for other objects made from that same filament.

Keeping "American" units straight can be challenging: metric is your friend.

My printer gets 40 rods to the hogshead and that's how I likes it!

just to follow up on this thread...

there is aprox 195,000mm per spool of ninjaflex.