5 ms·
We know enough from the article to be able to ballpark estimate it. Heat capacity of aluminum is 0.9 kJ/kg °C, and the latent heat of fusion is 390kJ/kg. The te
by jameshart 3y ago
We know enough from the article to be able to ballpark estimate it. Heat capacity of aluminum is 0.9 kJ/kg °C, and the latent heat of fusion is 390kJ/kg. The temperature they heat the aluminum to is 700°C, from presumably room temperature around 20°C - so 0.9*680 + 390 kJ/kg = 1002 kJ/kg is going to be the basic heating requirement, or as near as dammit 1MJ/kg. Getting that heat into the aluminum and then maintaining that temperature during the print presumably introduces some inefficiencies (induction furnaces can heat aluminum with about 40-50% efficiency), plus they have to move the mass of aluminum around with their print motors... but the heat to melt the aluminum feels likely to be the main energy sink. Inductively heated, with good crucible insulation, 2MJ/kg sounds like a reasonable energy budget?
For a comparison, that's about ten times the amount of energy you use running your microwave to heat up a ready meal, for every kilogram of aluminum you want to form.
- amelius 3y agoOk. How much less efficient is this process compared to mass-fabrication techniques?
- barelyauser 3y agoMass production is not only about energy efficiency. It is also about material efficiency and time efficiency. People want stuff NOW. Each process has its advantages. 3d printing can do stuff that mass fabrication techniques can't.
- Qwertious 3y ago>It is also about material efficiency and time efficiency. People want stuff NOW. Also, if you have a $1M machine then the machine-time really adds up.
- barelyauser 3y agoPrecisely. $1M and interest rates of 6% per year mean almost $7 per hour just to cover financing.
- jameshart 3y agoThat energy cost is intrinsic to aluminum casting. If you’re recycling aluminum like this, you are going to have that cost anyway - even if you use a different technique like rolling or pressing or extrusion to form the final pieces (that said I bet induction heating aluminum scrap to melting point is a lot less efficient than heating an ingot)