A Brief Look at the Time and Material Cost of 3D Printing

I feel like many people glorify 3D printing a bit more than it deserves. It has this mystique of “make anything you want” about it that does a wonderful job at glossing over the reality of it.

Let’s say I want to make some of these nifty little drawers. Each one of these has a volume of roughly 312 cm3. Roughly 4cm (~1.5″) per side and about 7.5cm (3″) deep. Not a particularly large amount of space, in my opinion, but to each their own.

Let’s talk material cost first. A fairly low cost PLA filament runs about $20/kg. 322g/3 drawers is about 107g each. Total cost is around $6.44 or $2.15 each. Not bad, really, but this also assumes no failure. Nothing about this print seems overly risky, but you never know. Also note that to print them two-tone as they are in the picture, you’d have to buy two different spools, not one, but that doesn’t really alter the $/g unless you get something fancy.

Do note, though, that the total print time is 37 hours and 18 minutes. Realistically that’s probably two days, unless you just happen to be around when the first one finishes, pull everything off warm, and fire it right back up.

Image acquired from Reddit.

The good news is that it’ll mostly do its thing without any significant intervention, but you still want to check it regularly, especially for the first few hours. If something goes pear shaped and you’re not around to stop it, it’ll usually keep running, use up filament, and make a mess. Spaghetti happens, goes with the territory. I’ve managed to avoid a failure quite as spectacular as this one, but I’m paranoid. The ones I would have had I caught early enough to stop. Not much I can do with a 22 hour print though.

Is that worth it for three little honeycomb drawers? Hard to say, really. I could not easily locate a comparable product. Mostly just standard floating shelves going for $30+ per piece/set. I suppose if you really liked the drawers and had nothing else in the world to do with your $300+ printer, then sure, it’s probably worth it.

This small lamp, on the other hand, is something I would find much more practical. It’s a bit smaller than it looks, a feature common to many printed objects. Spread across three print jobs, it’s total print time is around 14 hours. Using a slightly more decorative silk metallic filament it comes out to around $2.05, not including the lamp fixture and bulb. It’s only 89g of material, but the arms aren’t that long either. 140mm for the short one and 200mm for the longer one. You’re losing about 30mm per joint so 250mm (~10″) total length. That’s pretty short.

Still, that doesn’t really account for the cost of the printer or the opportunity cost of printing other stuff. I might go ahead and print it sometime in the next couple weeks, if only for the cuteness of a baby lamp. If nothing else it would make a good reading light near the bed.

Either way, that’s a quick look at the type of per object costs. Low material cost, very slow throughput. I don’t have a setup capable of measuring power usage, but I should consider doing that. Considering this thing is hot, it probably isn’t cheap to operate in terms of power.

There’s also the minor issue of taking the time to load the files, figure out which ones you need, and lay them out into separate print jobs with appropriate settings and layouts. I wouldn’t say it’s a ton of time, but for more complicated objects it can take an hour or two to identify everything, resize it, orient it, and check for overhangs. Something that’s only a few large pieces like the drawer bodies are pretty quick. I can’t tell you how much your time is worth, that’s for you figure out. I typically find the activity somewhat peaceful and entertaining.

I recently loaded some files my wife asked for that were apparently designed in inches instead of the usual mm. It took me a while to realize I had to change the scale from 100% to 2540% (100 * 25.4mm/inch) in order to get them sized correctly. If nothing else, it’s a great way to learn the metric system in a country that’s hell bent on using the “standard” system.

Y’all take care and stay safe out there.

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