What Actually Causes Warping In 3D Prints?

October 14, 2024 by Dave Rowntree 35 Comments

The 3D printing process is cool, but it’s also really annoying at times. Specifically, when you want to get a part printed, and no matter how you orientate things, what adhesion aids you use or what slicer settings you tweak, it just won’t print right. [David Malawey] has been thinking a little about the problem of the edges of wide prints tending to curl upwards, and we believe they may be on to something.

Obviously, we’re talking about the lowest common denominator of 3D printing, FDM, here. Other 3D printing technologies have their gotchas. Anyway, when printing a wide object, edge curling or warping is a known annoyance. Many people will just try it and hope for the best. When a print’s extreme ends start peeling away from the heat bed, causing the print to collide with the head, they often get ripped off the bed and unceremoniously ejected onto the carpet. Our first thought will be, “Oh, bed adhesion again”, followed by checking the usual suspects: bed temperature, cleanliness and surface preparation. Next, we might add a brim or some sacrificial ‘bunny ears’ to keep those pesky edges nailed down. Sometimes this works, but sometimes not. It can be frustrating. [David] explains in the YouTube short how the contraction of each layer of materials is compounded by its length, and these stresses accumulate as the print layers build. A simple demonstration shows how a stack of stressed sections will want to curl at the ends and roll up inwards.

This mechanism would certainly go some way to explain the way these long prints behave and why our mitigation attempts are sometimes in vain. The long and short of it is to fix the issue at the design stage, to minimize those contraction forces, and reduce the likelihood of edge curling.

Does this sound familiar? We thought we remembered this, too, from years ago. Anyway, the demonstration was good and highlighted the issue well.

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Calculating The True Per Part Cost For Injection Molding Vs 3D Printing

October 14, 2024 by Maya Posch 45 Comments

At what point does it make sense to 3D print a part compared to opting for injection molding? The short answer is “it depends.” The medium-sized answer is, “it depends on some back-of-the-envelope calculations specific to your project.” That is what [Slant 3D} proposes in a recent video that you can view below. The executive summary is that injection molding is great for when you want to churn out lots of the same parts, but you have to amortize the mold(s), cover shipping and storage, and find a way to deal with unsold inventory. In a hypothetical scenario in the video, a simple plastic widget may appear to cost just 10 cents vs 70 cents for the 3D printed part, but with all intermediate steps added in, the injection molded widget is suddenly over twice as expensive.

In the even longer answer to the question, you would have to account for the flexibility of the 3D printing pipeline, as it can be used on-demand and in print farms across the globe, which opens up the possibility of reducing shipping and storage costs to almost nothing. On the other hand, once you have enough demand for an item (e.g., millions of copies), it becomes potentially significantly cheaper than 3D printing again. Ultimately, it really depends on what the customer’s needs are, what kind of volumes they are looking at, the type of product, and a thousand other questions.

For low-volume prototyping and production, 3D printing is generally the winner, but at what point in ramping up production does switching to an injection molded plastic part start making sense? This does obviously not even account for the physical differences between IM and FDM (or SLA) printed parts, which may also have repercussions when switching. Clearly, this is not a question you want to flunk when it concerns a business that you are running. And of course, you should bear in mind that these numbers are put forth by a 3D printing company, so at the scale where molding becomes a reasonabe option, you’ll also want to do your own research.

While people make entire careers out of injection molding, you can do it yourself in small batches. You can even use your 3D printer in the process. If you try injection molding on your own, or with a professional service, be sure to do your homework and learn what you can to avoid making costly mistakes.

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3D Printering: Listen To Klipper

October 8, 2024 by Al Williams 10 Comments

I recently wrote about using Klipper to drive my 3D printers, and one natural question is: Why use Klipper instead of Marlin? To some degree that’s like asking why write in one programming language instead of another. However, Klipper does offer some opportunities to extend the environment more easily. Klipper runs on a Linux host, so you can do all of the normal Linux things.

What if you wanted to create a custom G-code that would play a wave file on a speaker? That would let you have custom sounds for starting a print, aborting a print, or even finishing a print.

If you recall, I mentioned that the Klipper system is really two parts. Well, actually more than two parts, but two important parts at the core. Klipper is, technically, just the small software stub that runs on your 3D printer. It does almost nothing. The real work is in Klippy, which is mostly Python software that runs on a host computer like a Raspberry Pi or, in my case, an old laptop.

Because it is Python and quite modular, it is very simple to write your own extensions without having to major surgery or even fork Klipper. At least in theory. Most of the time, you wind up just writing G-code macros. That’s fine, but there are some limitations. This time, I’m going to show you how easy it can be using the sound player as an example.

Macros All the Way Down

Normally, you think of gcode as something like: G1 X50 Y50. Some of the newer codes don’t start with G, but they look similar. But with Klipper, G1, M205, and MeltdownExtruder are all legitimate tokens that could be “G-code.”

For example, suppose you wanted to implement a new command called G_PURGE to create a purge line (case doesn’t matter, by the way). That’s easy. You just need to put in your configuration file:

[gcode_macro g_purge]
gcode:
# do your purge code here

The only restriction is that numbers have to occur at the end of the name, if at all. You can create a macro called “Hackaday2024,” but you can’t create one called “Hackaday2024_Test.” At least, the documentation says so. We haven’t tried it.

There’s more to macros. You can add descriptions, for example. You can also override an existing macro and even call it from within your new macro. Suppose you want to do something special before and after a G28 homing command:

[gcode_macro g28]
description: Macro to do homing (no arguments)
rename_existing: g28_original
gcode:
M117 Homing...
g28_original
M117 Home done....

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Tinkering With Klipper: Making The ManiPilator Robotic Arm

October 6, 2024 by Heidi Ulrich 15 Comments

[Leo Goldstien]’s entry into the world of robotics has been full of stops and starts. Like many beginners, he found traditional robotics instructions overwhelming and hard to follow, bogged down with dense math that often obscured the bigger picture. So he decided to approach things differently and create something with his own hands. The result? A 3D-printed robotic arm he affectionately calls “ManiPilator.”

This article is the first in a three-part series documenting [Leo]’s hands-on approach to learning robotics from the ground up. Building ManiPilator became an opportunity to learn by doing, and the project took him on a journey of experimenting, failing, and eventually succeeding in tasks that seemed deceptively simple at first glance. Each hurdle provided him with insights that more traditional learning methods hadn’t delivered. Below is one of the videos [Leo] captured, to show one step in the process: doing a check using multiple motors.

To make his project work, [Leo] relied on open-source software like Klipper, piecing together code and hardware in a way that made sense to him. In sharing his story, he offers fellow beginners an approachable perspective on robotics, with practical insights and candid reflections on the challenges and breakthroughs.

[Leo]’s project shows that there’s more than one way to start exploring robotics, and that sometimes the best way to learn is simply to dive in and start building. Follow along with his journey as he tackles the complexities of robotics, one step at a time.

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Print Yourself Penrose Wave Tiles As An Excellent Conversation Starter

October 1, 2024 by Lewin Day 11 Comments

Ah, tiles. You can get square ones, and do a grid, or you can get fancier shapes and do something altogether more complex. By and large though, whatever pattern you choose, it will normally end up repeating on some scale or other. That is, unless you go with something like a Penrose Wave Tile. Discovered by mathematician Roger Penrose, they never exactly repeat, no matter how you lay them out.

[carterhoefling14] decided to try and create Penrose tiles at home—with a 3D printer being the perfect route to do it. Creating the tiles was simple—the first step was to find a Penrose pattern image online, which could then be used as the basis to design the 3D part in Fusion 360. From there, the parts were also given an inner wave structure to add further visual interest. The tiles were then printed to create a real-world Penrose tile form.

You could certainly use these Penrose tiles as decor, though we’d make some recommendations if you’re going that path. For one, you’ll want to print them in a way that optimizes for surface quality, as post-processing is time consuming and laborious. If you’re printing in plastic, probably don’t bother using these as floor tiles, as they won’t hold up. Wall tiles, though? Go nuts, just not as a splashback or anything. Keep it decorative only.

You can learn plenty more about Penrose tiling if you please. We do love a bit of maths around these parts, too. If you’ve been making your own topological creation, don’t hesitate to drop us a line.

See The Hands-on Details Behind Stunning Helmet Build

September 28, 2024 by Donald Papp 6 Comments

[Zibartas] recently created wearable helmets from the game Starfield that look fantastic, and we’re happy to see that he created a video showcasing the whole process of design, manufacture, and assembly. The video really highlights just how much good old-fashioned manual work like sanding goes into getting good results, even in an era where fancy modern equipment like 3D printing is available to just about anyone.

The secret to perfectly-tinted and glassy-smooth clear visors? Lots and lots of sanding and polishing.

The visor, for example, is one such example. The usual approach to making a custom helmet visor (like for Daft Punk helmet builds) is some kind of thermoforming. However, the Starfield helmet visors were poor candidates due to their shape and color. [Zibartas]’s solution was to 3D print the whole visor in custom-tinted resin, followed by lots and lots of sanding and polishing to obtain a clear and glassy-smooth end product.

A lot of patient sanding ended up being necessary for other reasons as well. Each helmet has a staggering number of individual parts, most of which are 3D printed with resin, and these parts didn’t always fit together perfectly well.

[Zibartas] also ended up spending a lot of time troubleshooting an issue that many of us might have had an easier time recognizing and addressing. The helmet cleverly integrates a faux-neon style RGB LED strip for internal lighting, but the LED strip would glitch out when the ventilation fan was turned on. The solution after a lot of troubleshooting ended up being simple decoupling capacitors, helping to isolate the microcontrollers built into the LED strip from the inductive load of the motors.

What [Zibartas] may have lacked in the finer points of electronics, he certainly makes up for in practical experience when it comes to wearable pieces like these. The helmets look solid but are in fact full of open spaces and hollow, porous surfaces. This makes them more challenging to design and assemble, but it pays off in spades when worn. The helmets not only look great, but allow a huge amount of airflow. This along with the fans makes them comfortable to wear as well as prevents the face shield from misting up from the wearer’s breathing. It’s a real work of art, so check out the build video, embedded just below.

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3D Printing On Top Of Laser Cut Acrylic

September 24, 2024 by Dave Rowntree 8 Comments

[Julius Curt] needed to mark acrylic panels with a bit more clarity than the usual way of rastering the surface, so they attempted to 3D print directly to an acrylic sheet, which worked perfectly. The obvious way to do this was to bond the acrylic sheet to the bed with glue temporarily, but another way was tried, and it’s much less messy and precarious.

The bond between a 3D print and acrylic is very strong

The first step was to create a 3D model which combined a constraining ‘fence’ to contain the acrylic panel with the required artwork floating above. It was easy enough to run the print long enough to build the fence, then pause the print mid-way to add the pristine panel and restart after a quick re-prime and wipe.

There were a few simple takeaways from the video below. First, to ensure sufficient tolerance between the fence and the panel, consider the layer width (plus associated tolerance when printed) and the laser kerf of your machines to ensure a not-too-sloppy fit. Secondly, that hot nozzle won’t do the acrylic surface any favours during travel moves, so enabling Z-hopping is essential!

Another use for this simple technique is to fully incorporate an acrylic sheet within a print by pausing at an appropriate height again, dropping the panel in, and continuing the print. A degree of overlap will lock the panel tight, with the plastic bonding very firmly to the acrylic, as [Julius] demonstrates in the video.

It’s always a delight to see how techniques can combine to create the desired effects. Here’s how to use a color laser printer and toner transfer paper to apply designs to a 3D printing front panel. Whilst we’re thinking about the multitude of uses for hacking with acrylic, what about not doing that and using corrugated plastic instead?

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