A tool which allows the user to calculate the CO2 footprint of a part including the removed material. Maybe with a advise function helping you to find stock materials which require less machining.
The current CO2 footprint calculators like Granta ECO Materials Adviser only look at the positive volume of a part.
I would like to see a calculator which goes further.
The goal of the tool is to show a more realistic co2 footprint.
Example 1 - Milled part
You would like to make a nut which hexagonal sides and a " type thread. While modeling you choose a brass material which comes in bar form. The tool can now calculate how much material needs to be removed from the bar to create the designed part.
We now have:
The positive volume of the final part.
The negative volume which is removed from the bar to create the final part.
If the recyclability of the material and the production location are known we can include the amount of material wasted, to create the final part, into the calculation of the co2 footprint. If possible the tool could advise a different material or bar form (hexagonal?) which would result in less negative volume.
Example 2 - Cast Part
With any cast part an amount of material is removed after casting. This material is not used in the final part but these are essential to the production process.
The Pouring basin, Sprue, Trap, Runner, Gate and other crucial or performance improving cavities are also filled with material during the casting. This material is trimmed off usually immediately after the part is ejected from the mold. Most casting processes only allow for a certain amount of trimmed material to be added back into the process and in the end some of the trimmings will be disposed of.
By only using the positive volume of the final part the co2 footprint is inaccurate at best.
This method would also allow for more accurate comparison between production processes.
