3d Printing: What is a Kilogram of Filament?

Quick Answer: Sort of like this.... for this spool at least

One of the questions I see and hear a lot about 3d printing is how much can I print with a 1Kg spool of filament?

Well I have found the answer is not to terribly straight forward. First off... what kind of filament? They have varied densities so weight is actually a bad measure of how much you can print. IE ABS is around 1.02g per cc where PLA is around 1.24. This means a roll of ABS with 1kg of filament will be longer and produce more volume than a roll of PLA with 1kg of filament. Get some bronze fill and it could be over 3-4g per cc at low concentrations of metal powder. Sintering level filaments would be almost as heavy per cc as the metal itself so a kilogram would result in far less filament by volume of material.

Another major factor are your settings. One of the choices you have when slicing is how solid to print your objects. IE in the picture above I have a T-Rex skull and display base that I printed at 15% infill and all combined it weighs in at 32g. Same file, similar type of filament printed at 50% infill weighs 55g.

Another factor is of course waste. Just get a load of the T-Rex series I went throutgh.

Fine tuning first layer adhesion and balancing over extrusion can be... fun? 

So front right is the first print of the T-Rex I did on the PRUSA and the base and prop were in the same print. But if you zoom in on the jaw you can see some scabies or something goofy going on in the print, its worse on the back side of the skull. So.... I tweaked the settings a bit and the sequence on the left is what happened next. Head and or Jaw kept popping off. I finally got a jaw and skull to print only to find that when I went back to tweak and get the jaw and skull separate from the base I grabbed the wrong files. Which is the complete skull you see front left of the three whole ones. It goes to a full skeleton file and has a different mounting hole so it doesn't go on the display. Still had some jaw issues... figured that out (needed two processes in S3d, and slowed down the print when it got there). Had a couple more frustrating failures before finally giving in on using a brim on the skull to increase its print bed contact area and got a complete skull with nice print quality throughout.

All that to say, how much you get out of a spool will also be dependent on your success rate. If you look towards the back of the photo you will see my waste bin.

Birds nests, failed print bits, support material, perimeters etc... It adds up

Unless you have some very well defined prints going through a production process, odds are you are trying new prints and possibly new materials, different settings to tweak what is happening quality or speed wise for your prints etc... And you will have failures. Prints with overhangs will need supports. Things go wrong. I think I have all the waste from the freebie PRUSA filament roll in here. In this case it totaled about 180g of waste. This isn't counting the failed T-Rex sequence, the failed Voltron head and recorder bits you can see in the larger pic... so somewhere over 200g in failures/other out of ~1000g of material. So about 20-25% of the filament went into failure/support/other print material.

Here are some other pics and weights.

Chest, one shoulder, face, lion head, neck bits... ~154g. LOTs to go, just on the black lion... 4 more smaller lions to go after that. 

Dainty... only 70g. Nice show off piece

Not pictured is a Tower of Pi Pen holder I did for my wife and a couple of other Celtic book marks. Maybe 75g worth of material.

So if you have ever talked to a printing nerd about this topic and wondered why such a simple question doesn't seem to have an answer then perhaps this will have helped.