When you’ve got a 3D printer, it can be tempting to try and 3D print everything. Sometimes, the best solution is to buy instead of printing. A little restraint and forethought can save you from making a costly mistake.
Here are some more items that you should think twice about before hitting print.
Electrical housings for high-voltage items
Don’t risk it
This one is non-negotiable, but it’s worth noting. Believe it or not, there are downloads on model repositories that are supposedly designed with high-voltage power supplies and capacitors in mind. Most 3D printed plastics fall short of the rigorous standards required for this purpose.
These enclosures should be strong, able to withstand high temperatures, flame-retardant, and resistant to arcing should it occur. Polyamide (PA), polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), and polyetheretherketone (PEEK) are common choices. Humble PLA, PETG, and ABS won’t cut it.
It’s worth adding that messing around with high-voltage electronics (like components you’d find inside a PC power supply) is something you should leave to the professionals.
Poorly designed load-bearing brackets and joints
The real cost of a 3D printing failure
You’re probably thinking that any “poorly designed” models should be avoided (and you’d be right), but the dangers are far greater when it comes to load-bearing items. One example of such a design is this 3D-printed monitor arm that was posted to Reddit (complete with a broken monitor).
The author’s takeaway was to not use 3D printing for everything. While that’s a valid point, commenters were quick to point out that the part was poorly designed. Such items should be oriented on the print bed in a way that promotes strength and avoids failure at the point where layers meet.
Run through a simple risk analysis before you print an object like this. Ask yourself what will happen if the part fails and the object falls. Can you live with the cost? Will you be hurt as a result? How much would buying a purpose-built item that’s made using more durable materials cost?
Shoes
This might be a controversial opinion, but I’ve yet to understand the fascination with 3D-printed shoes. I’ve yet to see a pair that looks particularly good. Being able to manufacture your own footwear is a novel concept, but there are some serious downsides to contend with.
Most shoes are printed with thermoplastic polyurethane (TPU), which can be notoriously hard to print with. In order to be flexible, you should use the softest TPU that your printer supports. The softer the TPU, the harder it is to print, and the slower you have to go. It’s also on the pricey side, with Prusa charging $42 for 500g.
Even though TPU has flex, it’s often not as soft as rubber, which can result in an uncomfortable fit. Another complaint I’ve seen is that these shoes can be quite slippery in wet conditions, since TPU doesn’t grip as rubber does. While TPU is regarded as being highly durable, layer adhesion can be an issue and often presents as a point of failure with 3D printed footwear.
You’ll need to print your shoes in a diagonal orientation for best results, which means that supports will be necessary. TPU is one filament type that adheres remarkably well to whatever it touches, which means that supports can be very difficult to remove unless you’re printing in a support material like PLA (which requires a dual-nozzle printer).
Each to their own, naturally. Just make sure you’re certain of your foot size before you commit to a 24-hour print with some pricey filament!
Enclosed PC cases
PLA and ATX don’t mix
There are enough 3D-printed PC cases out there that I’ll concede that printing an enclosure for your computer isn’t always a terrible idea (there’s even a subreddit dedicated to them). That said, there are some big questions to ask before you fire up the printer for your next rig.
Take MakerWorld’s ever-popular MODCASE HYPER ATX PC case. The author recommends printing it in PETG, which requires just shy of 2KG of filament. At Prusa prices, that’ll cost you just shy of $80 if you want it in a rather fetching matte black (assuming all build plates print perfectly first time).
PETG is recommended as it is more heat-resistant than PLA. While many have chosen to print their PC cases using PLA, this filament type has a glass transition temperature of around 65ºC. Computer components can greatly exceed this, which means you’ll need to be confident in your ability to maintain adequate airflow if you don’t want the case to warp and sag.
Then there’s the cost. You can buy a metal case with preinstalled fans for the same price or less than what it would cost you to print one. There are budget cases for smaller builds that cost less than $40, and very nice cases from brands like Lian Li and be quiet! for a bit more.
That said, if you’re looking for an open-frame case like a test bench, then you can do far worse than a 3D-printed model, which will cost significantly less in terms of materials.
Most models designed with AI
Reviews are your friend
Generative AI has finally made its way into the 3D printing world, and many printer owners aren’t impressed. It’s hard to avoid adverts for AI-powered 3D model authoring services on social media, and it’s equally hard to avoid AI-designed models on model repositories.
It’s not that they’re all bad, because they’re not. But you should be mindful of a few things before you waste your filament. Reviews are absolutely your friend here, ideally those with pictures. Someone has to test these things out, and if someone else has walked the path before then you should heed their advice.
A big red flag you should keep an eye out for is a listing that lacks real photographs, opting instead to show renders or AI-generated photos.
These aren’t the only items you should ideally avoid 3D printing at home. You should also avoid some of the models that the internet keeps telling you to print.