6

My Craftbot Plus Craftware slicer estimates cost per job based on filament prices I add as parameters. What costs per meter would you use? I created spreadsheets to calculate this for 1.75mm diameter filament and arrived at PLA = 6.6 cents per meter, ABS = 6.1 and PET XT = 18.6 cents per meter.

Edit: thanks for feedback! I paid \$22 per kilogram for PLA and ABS. I paid \$57 for .75 kilogram of Colorfab XT Black.

Jon Ericson
  • 101
  • 5
Dennis Rose
  • 61
  • 1
  • 1
  • 4

2 Answers2

6

This strongly depends on the cost of the spool in question. Prices are not consistent among materials at all; a spool of ABS can cost anywhere from \$15 to \$60 and the same price range applies to pretty much all other plastic.

For the purpose of this question I am going to assume that a 1 kilogram spool costs \$25 (regardless of material) but you can scale the figures to what is appropriate for your brand of filament.

ToyBuilder Labs lists the density of ABS at 1.04g/ml, whereas PLA is somewhat more dense at 1.25g/ml. As such, a 1kg spool of ABS would be 400 meters (1.75mm filament) or 156 meters (2.85mm filament). PLA would come out to 333 meters (125 meters for 2.85mm filament)

We thus have the following costs (cost per meter for 2.85mm filament in parenthesis):

  • ABS: 6.25 cents/meter (16)

  • PLA: 7.5 cents/meter (20)

The density of PETG is roughly the same as PLA, so they have the same cost per meter (for similarly priced spools).

In general, to compute the cost per meter, you would use the following formula:

$$[\text{\$/m}]=[\text{cost of 1 }kg] \times [\text{density in }g/mm^3] \times \frac{[\text{diameter in }mm]^2\ \times \pi }{4000}$$

Glorfindel
  • 177
  • 1
  • 3
  • 11
Tom van der Zanden
  • 15,037
  • 2
  • 37
  • 65
3

The simplest method is to divide spool price by its length. That's obvious I think. If PLA 1.75 (1kg net) has about 120m length and it costs 16usd then it looks like 1m costs arount 13c. =price/length

I think everyone can buy different filament at different price from different vendors so there is no good general price to enter into your slicer app. It has to be calculated each time you use new filament.

There are also other parts of the price. Electricity, time, wear, depreciation, know-how even the rent is some part of the ending price of the final product. Of course most of them are incalculable as they are permiles or so. But if you don't plan to sell it you can base on the filament price only.

darth pixel
  • 3,486
  • 1
  • 14
  • 20