I needed to print some prototypes for moulded components for work this weekend and took the opportunity to find out the actual costs, compared with Chitubox’ estimates.
Chitubox 126.09ml / 138.7 g / 4.16089 $ / 9h8m30s
part full resin container 654g.
empty resin container 147g
Saturn initial time estimate 09h09m after 1 minute elapsed
Saturn revised time estimate 11h26m after 11 minutes elapsed (19 layers of 2501)
was still going when I went to bed… (no aurora when I checked
)
Filtered resin back into container 469g
I’ve just set it going again, 07:41 so it’ll finish some time around 7pm this evening. I’ll check that though it’s not really important.
so resin used, 654-469 = 185g.
There’s obviously some wastage when filtering & cleaning the print tank but 46g (24.8%) seems extreme. I didn’t weigh the wet filter paper, but the tank and yellow scraper were wiped down with no more than half a dozen sheets of something soft and beloved by Labrador puppies, again I didn’t weigh them before and after, and I’m not getting them out of the bin.
The density calculation suggests that Chitubox is using a density of 1.1 g/cm3 which is what’s printed on the Siraya FNG data sheet. They do specify this is liquid, I can’t imagine it changes very much as it solidifies, or the parts would come out at odd sizes, which they don’t.
The cost of resin seems to change with the weather, I recently bought 10kgs of FNG, but can’t find the reference. My previous purchase was 4kgs at $167.99 so $42/kg. Chitubox’ estimate is based on $30/kg, so I could update that.
I removed the supports whilst the parts were still green - they weighed 35g.
Part weight was 131g,
Hence total 166g.
I could believe 19g (10%) of wastage on the filter and loo roll, so my guess is that Chitubox does not allow for the supports when calculating resin use, which seems daft.
To check, I’ve gone back to Solidworks, the three parts have volumes of
32088.66 mm3
62350.47
13032.63
total 107471.76mm3 = 107.5cm3 which at 1.1 g/cm3 would weigh in at 118.2g.
That doesn’t tie in with Chitubox estimates, actual resin used or the final part weights!
Other costs - consumables - electricity will be negligible, as is bogroll.
Filter papers are £8.75/25 so £0.35 each, and I find I can use one filter about four times, by simply rinsing it. Say 10p per print.
Replacement FEP film is currently £6.10 for a Saturn. I’ve never needed but have some in stock, should I get a cut. There are recommendations to change the FEP every so often, but I’m in the “it ain’t broke” school of maintenance in this regard. When/if it becomes obviously opaque, I‘ll do it then. I’ve had the machine a couple of years now.
Isopropyl alcohol is £20/5 litres, and I’m guessing I might get 100 prints from a refill, which is about 6 litres in my wash tank. Say 25p per print.
If I assume a straight line allowance for the difference between Chitubox’ estimate and actual resin usage, I can simply multiply the actual resin cost per kg by a factor of 185/138.7 (ie 1.33) and put that in as the resin cost $56 or £47.90 if it’ll do GBP.
And add 35p for consumables. That makes this little job cost about £9.20 per run, and I’ll be doing three sets of bits, so I think I might want paying!
in any case it’s an interesting exercise to work out the likely cost of making something this way.