Best Practices For FDM Printing

May 10, 2025 by Al Williams 38 Comments

If you’ve been designing parts for 3D printing, you probably have some tricks and standards for your designs. [Rahix] decided to write out a well-thought-out set of design rules for FDM prints, and we can all benefit.

One of the things we liked about the list is that it’s written in a way that explains everything. Every so often, there’s a box with a summarized rule for that topic. At the end, there’s a list of all the rules. The rules are also in categories, including part strength, tolerance, optimization, integration, machine elements, appearance, and vase mode.

For example, section two deals with tolerance and finish. So, rule R2.8 says, “Do not use circular holes for interference fits. Use hexagon or square holes instead.”

We also appreciate that [Rahix] touched on some of the counter-intuitive aspects of designing for FDM printing. For example, you might think adding voids in your part will reduce the filament and time required to print it, but in many cases it can have the opposite effect.

Some of these — maybe even most of these — won’t surprise you, but you still might take away a tidbit or two. But having it all down in a checklist and then the ability to scroll up and find the rationale for the rule is great.

Do you have any rules you’d add? Or change? Let us know. Meanwhile, we were eyeing our favorites about adding machine elements to prints.

Scan Your Caliper For Physical Part Copies

May 9, 2025 by Al Williams 60 Comments

We’ve certainly seen people take a photo of a part, bring it into CAD, and then scale it until some dimension on the screen is the same as a known dimension of the part. We like what [Scale Addition] shows in the video below. In addition to a picture of the part, he also takes a picture of a vernier caliper gripping the part. Now your scale is built into the picture, and you can edit out the caliper later.

He uses SketchUp, but this would work on any software that can import an image. Given the image with the correct scale, it is usually trivial to sketch over the image or even use an automatic tracing function. You still need some measurements, of course. The part in question has a vertical portion that doesn’t show up in a flat photograph. We’ve had good luck using a flatbed scanner before, and there’s no reason you couldn’t scan a part with a caliper for scale.

This is one case where a digital caliper probably isn’t as handy as an old-school one. But it would be possible to do the same trick with any measurement device. You could even take your picture on a grid of known dimensions. This would also allow you to check that the distances at the top and bottom are the same as the distances on the right and left.

Of course, you can get 3D scanners, but they have their own challenges.

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3D Printed TPU Bellows With PLA Interface Layers

May 8, 2025 by Maya Posch 22 Comments

Of all FDM filament types, flexible ones such as TPU invite a whole new way of thinking, as well as applications. Case in point the TPU-based bellows that the [Functional Part Friday] channel on YouTube recently demonstrated.

The idea is quite straightforward: you print TPU and PLA in alternating layers, making sure that the TPU is connected to its previous layer in an alternating fashion. After printing, you peel the PLA and TPU apart, remove the PLA layers and presto, you got yourself bellows.

There were some issues along the way, of course. Case in point the differences between TPU from different brands (Sainsmart, Sunlu) that caused some headaches, and most of all the incompatibility between the Bambu Lab AMS and TPU that led to incredibly brittle TPU prints. This required bypassing the feed mechanism in the AMS, which subsequently went down a rabbit hole of preventing the PTFE tube from getting sucked into the AMS. Being able to print TPU & PLA at the same time also requires a printer with two independent extruders like the Bambu Lab H2D used here, as both materials do not mix in any way. Great news for H2D and IDEX printer owners, of course.

As for practical applications for bellows, beyond printing your own 1900s-era camera, accordion or hand air bellows, you can also create lathe way covers and so on.

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Liquid Silicone 3D Printing Is No Joke

May 7, 2025 by Tyler August 45 Comments

They might call it Levity, but there’s nothing funny about Rapid Liquid Print’s new silicone 3D printer. It has to be seen to be believed, and luckily [3D Printing Nerd] gives us lots of beauty shots in this short video, embedded below.

Smooth, and *fast*. This bladder took 51 minutes according to the RLP website.

Printing a liquid, even a somewhat-viscous one like platinum-cure silicone, presents certain obvious challenges. The Levity solves them with buoyancy: the prints are deposited not onto a bed, but into a gel, meaning they are fully supported as the silicone cures. The fact that the liquid doesn’t cure instantly has a side benefit: the layers bleed into one another, which means this technique should (in theory) be stronger in all directions than FDM printing. We have no data to back that up, but what you can see for yourself that the layer-blending creates a very smooth appearance in the finished prints.

If you watch the video, it really looks like magic, the way prints appear in the gel. The gel is apparently a commercially-available hydrogel, which is good since the build volume looks to need ̶a̶b̶o̶u̶t̶ ̶5̶0̶0̶ ̶L̶ at least 125 L of the stuff. The two-part silicone is also industry-standard and off-the-shelf, though no doubt the exact ratios and are tweaked for purpose. There’s no magic, just a really neat technology.

If you want one, you can sign up for the waiting list at Rapid Liquid Print’s website, but be prepared to wait; units ship next year, and there’s already a list.

Alternatively, since there is no magic here, we’d love to see someone take it on themselves, the way once equally exotic SLS printers have entered the DIY world. There was a time when resin printers were new and exotic and hobbyists had to roll their own, too. None of this is to say we don’t respect the dickens out of the Rapid Liquid Print team and their achievement–it’s just that imitation is the sincerest form of flattery. Continue reading “Liquid Silicone 3D Printing Is No Joke” →

3D Print Your Own Injection Molds, Ejector Pins And All

May 5, 2025 by Lewin Day 20 Comments

3D printing is all well and good for prototyping, and it can even produce useful parts. If you want real strenght in plastics, though, or to produce a LOT of parts, you probably want to step up to injection molding. As it turns out, 3D printing can help in that regard, with injection molding company [APSX] has given us a look at how it printed injection molds for its APSX-PIM machine.

The concept is simple enough—additive manufacturing is great for producing parts with complex geometries, and injection molds fit very much under that banner. To demonstrate, [APSX] shows us a simple injection mold that it printed with a Formlabs Form3+ using Rigid 10K resin. The mold has good surface finish, which is crucial for injection molding nice parts. It’s also fitted with ejection pins for easy part removal after each shot of injection molded plastic. While it’s not able to hold up like a traditional metal injection mold, it’s better than you might think. [APSX] claims it got 500 automatic injection cycles out of the mold while producing real functional parts. The mold was used with the APSX-PIM injection molding machine squirting polypropylene at a cycle time of 65 seconds, producing a round part that appears to be some kind of lid or gear.

This looks great, but it’s worth noting it’s still not cheap to get into this sort of thing. On top of purchasing a Formlabs Form3+, you’ll also need the APSX-PIM V3, which currently retails for $13,500 or so. Still, if you regularly need to make 500 of something, this could be very desirable. You could get your parts quicker and stronger compared to running a farm of many 3D printers turning out the same parts.

We’ve seen similar projects along these lines before. The fact is that injections molds are complicated geometry to machine, so being able to 3D print them is highly desirable. Great minds and all that. Video after the break.

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Hacking Different Sized Nozzles For AnyCubic Printers

May 3, 2025 by Lewin Day 11 Comments

If you’ve got a popular 3D printer that has been on the market a good long while, you can probably get any old nozzles you want right off the shelf. If you happen to have an AnyCubic printer, though, you might find it a bit tougher. [Startup Chuck] wanted some specific sized nozzles for his rig, so set about whipping up a solution himself.

[Chuck]’s first experiments were simple enough. He wanted larger nozzles than those on sale, so he did the obvious. He took existing 0.4 mm nozzles and drilled them out with carbide PCB drills to make 0.6 mm and 0.8 mm nozzles. It’s pretty straightforward stuff, and it was a useful hack to really make the best use of the large print area on the AnyCubic Kobra 3.

But what about going the other way? [Chuck] figured out a solution for that, too. He started by punching out the 0.4 mm insert in an existing nozzle. He then figured out how to drive 0.2 mm nozzles from another printer into the nozzle body so he had a viable 0.2 mm nozzle that suited his AnyCubic machine.

The result? [Chuck] can now print tiny little things on his big AnyCubic printer without having to wait for the OEM to come out with the right nozzles. If you want to learn more about nozzles, we can help you there, too.

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Prusa Mini with endoscope nozzle cam and pip preview

Prusa Mini Nozzle Cam On The Cheap

May 2, 2025 by Heidi Ulrich 2 Comments

Let me throw in a curveball—watching your 3D print fail in real-time is so much more satisfying when you have a crisp, up-close view of the nozzle drama. That’s exactly what [Mellow Labs] delivers in his latest DIY video: transforming a generic HD endoscope camera into a purpose-built nozzle cam for the Prusa Mini. The hack blends absurd simplicity with delightful nerdy precision, and comes with a full walkthrough, a printable mount, and just enough bad advice to make it interesting. It’s a must-see for any maker who enjoys solder fumes with their spaghetti monsters.

What makes this build uniquely brilliant is the repurposing of a common USB endoscope camera—a tool normally reserved for inspecting pipes or internal combustion engines. Instead, it’s now spying on molten plastic. The camera gets ripped from its aluminium tomb, upgraded with custom-salvaged LEDs (harvested straight from a dismembered bulb), then wrapped in makeshift heat-shrink and mounted on a custom PETG bracket. [Mellow Labs] even micro-solders in a custom connector just so the camera can be detached post-print. The mount is parametric, thanks to a community contribution.

This is exactly the sort of hacking to love—clever, scrappy, informative, and full of personality. For the tinkerers among us who like their camera mounts hot and their resistor math hotter, this build is a weekend well spent.

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