You hate to see it happen; you look at a spool before starting a print and think “this should hopefully be enough to finish this print” and as luck would have it, it wasn’t - you come back to find your 3D printer air printing because it ran out of filament before the job finished. I have a quick tip that can help you avoid these problems in the future, all you need is a digital scale. Let’s get started.

As soon as you unpackage a new spool, grab your scale and find the mass of the full spool in grams. After you tare the scale to make sure it reads zero with nothing on it, place your spool onto it and subtract the filament weight (this should be listed on the spool or on its product page online), this is the weight of the spool. You can now come back later with your spool and measure again to find how much filament you have left. This isn’t 100% perfect, as there are a lot of variables affecting the weight measured, so leave yourself some margin of error when you are printing with it: if you need 50g of filament to finish a print but you have 51g, either don’t use that filament, use a runout sensor, or keep a careful eye on it near the end of the print to make sure it doesn’t run out. 

Before you do any 3D printing, be sure to weigh everything out.
Before you do any 3D printing, be sure to weigh everything out.

Your slicer will usually calculate the mass of the filament that will be used for a finished print, but that is reliant on you making sure that the density of the material you are printing is entered into the field within the slicer, otherwise its prediction can be significantly off. ABS is around 1g/cm3 and PLA is around 1.25 g/cm3 which means if you leave in one value and meant for the other to be entered, your filament estimate will be 25% off. 

Almost every slicer features a way to estimate material consumption of a given gcode.
Almost every slicer features a way to estimate material consumption of a given gcode.

I would suggest keeping a spreadsheet of all the different brands of filament you have used and the weight of the spools that the manufacturer uses, including an average spool weight as they tend to fluctuate. A good habit to have is to weigh your empty spools as well so you have a more concrete measure of the spool weight rather than just an estimate.

You don't need to get fancy with it, just having a document you can always come back to and confirm spool weights is enough diligence.
You don't need to get fancy with it, just having a document you can always come back to and confirm spool weights is enough diligence.

Another thing, make sure you maintain control of your filament. We have another article where I talk about how to avoid getting tangles in your filament, which is a possibility if you aren’t careful when handling your spools and let the end of the filament pass under a loop, which will over time tighten and tighten until it snags and ruins a print. Thankfully it is easily fixable!

Getting a tangle can ruin your prints, so be sure to take care of them before they become a problem.
Getting a tangle can ruin your prints, so be sure to take care of them before they become a problem.

I hope this gives you a better shot at success with your 3D printer, whether it’s trying to use that last bit of filament on some small print or if you’re questioning if you have just enough for a long one. And if you know you’re going to run out, MatterHackers fast and free shipping makes it really easy to restock. 

Happy printing!