If you do FDM 3D printing, you know one of the biggest problems is sensing the bed. Nearly all printers have some kind of bed probing now, and it makes printing much easier, but there are many different schemes for figuring out where the bed is relative to the head. [ModBot] had a Voron with a clicky probe but wanted to reclaim the space it used for other purposes. In the video, also linked below, he reviews the E3D PZ probe which is a piezoelectric washer, and the associated electronics to sense your nozzle crashing into your print bed.
There are many options, and it seems like each has its pros and cons. We do like solutions that actually figure out where the tip is so you don’t have to mess with offsets as you do with probes that measure from a probe tip instead of the print head.
The difference between 3D printing and good 3D printing comes down to attention to detail. There are so many settings and so many variables, each of which seems to impact the other to a degree that can make setting things up a maddening process. That makes anything that simplifies the process, such as this computer vision pressure advance attachment, a welcome addition to the printing toolchain.
If you haven’t run into the term “pressure advance” for FDM printing before, fear not; it’s pretty intuitive. It’s just a way to compensate for the elasticity of the molten plastic column in the extruder, which can cause variations in the amount of material deposited when the print head acceleration changes, such as at corners or when starting a new layer.
To automate his pressure advance calibration process, [Marius Wachtler] attached one of those dirt-cheap endoscope cameras to the print head of his modified Ender 3, pointing straight down and square with the bed. A test grid is printed in a corner of the bed, with each arm printed using a slightly different pressure advance setting. The camera takes a photo of the pattern, which is processed by computer vision to remove the background and measure the thickness of each line. The line with the least variation wins, and the pressure advance setting used to print that line is used for the rest of the print — no blubs, no blebs.
We’ve seen other pressure-advanced calibrators before, but we like this one because it seems so cheap and easy to put together. True, it does mean sending images off to the cloud for analysis, but that seems a small price to pay for the convenience. And [Marius] is hopeful that he’ll be able to run the model locally at some point; we’re looking forward to that.
Do you like high-detail 3D models intended for resin printing, but wish you could more easily print them on a filament-based FDM printer? Good news, because [Jacob] of Painted4Combat shared a tool he created to make 3D models meant for resin printers — the kind popular with tabletop gamers — easier to port to FDM. It comes in the form of a Blender add-on called Resin2FDM. Intrigued, but wary of your own lack of experience with Blender? No problem, because he also made a video that walks you through the whole thing step-by-step.
Resin2FDM separates the model from the support structure, then converts the support structure to be FDM-friendly.
3D models intended for resin printing aren’t actually any different, format-wise, from models intended for FDM printers. The differences all come down to the features of the model and how well the printer can execute them. Resin printing is very different from FDM, so printing a model on the “wrong” type of printer will often have disappointing results. Let’s look at why that is, to better understand what makes [Jacob]’s tool so useful.
Rafts and a forest of thin tree-like supports are common in resin printing. In the tabletop gaming scene, many models come pre-supported for convenience. A fair bit of work goes into optimizing the orientation of everything for best printed results, but the benefits don’t carry directly over to FDM.
For one thing, supports for resin prints are usually too small for an FDM printer to properly execute — they tend to be very thin and very tall, which is probably the least favorable shape for FDM printing. In addition, contact points where each support tapers down to a small point that connects to the model are especially troublesome; FDM slicer software will often simply consider those features too small to bother trying to print. Supports that work on a resin printer tend to be too small or too weak to be effective on FDM, even with a 0.2 mm nozzle.
To solve this, [Jacob]’s tool allows one to separate the model itself from the support structure. Once that is done, the tool further allows one to tweak the nest of supports, thickening them up just enough to successfully print on an FDM printer, while leaving the main model unchanged. The result is a support structure that prints well via FDM, allowing the model itself to come out nicely, with a minimum of alterations to the original.
Resin2FDM is available in two versions, the Lite version is free and an advanced version with more features is available to [Jacob]’s Patreon subscribers. The video (embedded below) covers everything from installation to use, and includes some general tips for best results. Check it out if you’re interested in how [Jacob] solved this problem, and keep it in mind for the next time you run across a pre-supported model intended for resin printing that you wish you could print with FDM.
Some slicers have introduced brick layers, and more slicers plan to add them. Until that happens, you can use this new script from [Geek Detour] to get brick layer goodness on Prusa, Orca, and Bambu slicers. Check out the video below for more details.
The idea behind brick layers is that outer walls can be stronger if they are staggered vertically so each layer interlocks with the layer below it. The pattern resembles a series of interlocking bricks and can drastically increase strength. Apparently, using the script breaks the canceling object functionality in some printers, but that’s a small price to pay. Multi-material isn’t an option either, but — typically — you’ll want to use the technique on functional parts, which you probably aren’t printing in colors. Also, the Arachne algorithm option only works reliably on Prusa slicer, so far.
The video covers a lot of detail on how hard it was to do this in an external script, and we are impressed. It should be easier to write inside the slicer since it already has to figure out much of the geometry that this script has to figure out by observation.
Just about any 3D printer can be satisfying to watch as it works, but delta-style printers are especially hypnotic. There’s just something about the way that three linear motions add up to all kinds of complex shapes; it’s mesmerizing. Deltas aren’t without their problems, though, which led [Bruno Schwander] to undertake a trio of interesting mods on his Anycubic Kossel.
First up was an effort to reduce the mass of the business end of the printer, which can help positional accuracy and repeatability. This started with replacing the stock hot-end with a smaller, lighter MQ Mozzie, but that led to cooling problems that [Bruno] addressed with a ridiculously overpowered brushless hairdryer fan. The fan expects a 0 to 5-VDC signal for the BLDC controller, which meant he had to build an adapter to allow Marlin’s 12-volt PWM signal to control the fan.
Once the beast of a fan was tamed, [Bruno] came up with a clever remote mount for it. A 3D-printed shroud allowed him to mount the fan and adapter to the frame of the printer, with a flexible duct connecting it to the hot-end. The duct is made from lightweight nylon fabric with elastic material sewn into it to keep it from taut as the printhead moves around, looking a bit like an elephant’s trunk.
Finally, to solve his pet peeve of setting up and using the stock Z-probe, [Bruno] turned the entire print bed into a strain-gauge sensor. This took some doing, which the blog post details nicely, but it required building a composite spacer ring for the glass print bed to mount twelve strain gauges that are read by the venerable HX711 amplifier and an Arduino, which sends a signal to Marlin when the head touches the bed. The video below shows it and the remote fan in action.
Prints separating from the build plate or warping when you don’t want them to is a headache for the additive manufacturer. [CNC Kitchen] walks us through a technique to use that warping to our advantage.
Based on a paper by researchers at the Morphing Matter Lab at UC Berkeley, [CNC Kitchen] wanted to try making 3D printed objects that could self-assemble when placed in hot water. Similar to a bimetal strip that you find in simple thermostats, the technique takes advantage of the stresses baked into the print and how they can relax when reaching the glass transition temperature of the polymer. By printing joints with PLA and TPU layers, you can guide the deformation in the direction you wish, and further tune the amount of stress in the part by changing the print speed of different sections.
[CNC Kitchen] found that Hilbert curve infill slows the printer down sufficiently to create relatively stress-free sections of a print to create flat sections which is an improvement over the original researchers’ all TPU flat sections with respect to rigidity. We’ve covered how to reduce warping in 3D prints, but now we can use those techniques in reverse to design self-assembling structures. These parts, being thermoplastic, can also be heated, reformed, and then exhibit shape memory when placed back into hot water. It’s very experimental, but we’re curious to see what sort of practical or artistic projects could be unlocked with this technique.
[JanTec Engineering] was fascinated by the idea of using a 3D printer’s hot end to inject voids and channels in the infill with molten plastic, leading to stronger prints without the need to insert hardware or anything else. Inspiration came from two similar ideas: z-pinning which creates hollow vertical channels that act as reinforcements when filled with molten plastic by the hot end, and VoxelFill (patented by AIM3D) which does the same, but with cavities that are not uniform for better strength in different directions. Craving details? You can read the paper on z-pinning, and watch VoxelFill in (simulated) action or browse the VoxelFill patent.
With a prominent disclaimer that his independent experiments are not a copy of VoxelFill nor are they performing or implying patent infringement, [JanTec] goes on to use a lot of custom G-code (and suffers many messy failures) to perform some experiments and share what he learned.
Using an airbrush nozzle as a nozzle extension gains about 4 mm of extra reach.
One big finding is that one can’t simply have an empty cylinder inside the print and expect to fill it all up in one go. Molten plastic begins to cool immediately after leaving a 3D printer’s nozzle, and won’t make it very far down a deep hole before it cools and hardens. One needs to fill a cavity periodically rather than all in one go. And it’s better to fill it from the bottom-up rather than from the top-down.
He got better performance by modifying his 3D printer’s hot end with an airbrush nozzle, which gave about 4 mm of extra length to work with. This extra long nozzle could reach down further into cavities, and fill them from the bottom-up for better results. Performing the infill injection at higher temperatures helped fill the cavities more fully, as well.
Another thing learned is that dumping a lot of molten plastic into a 3D print risks deforming the print because the injected infill brings a lot of heat with it. This can be mitigated by printing the object with more perimeters and a denser infill so that there’s more mass to deal with the added heat, but it’s still a bit of a trouble point.
[JanTec] put his testing hardware to use and found that parts with infill injection were noticeably more impact resistant than without. But when it came to stiffness, an infill injected part resisted bending only a little better than a part without, probably because the test part is very short and the filled cavities can’t really shine in that configuration.
These are just preliminary results, but got him thinking there are maybe there are possibilities with injecting materials other than the one being used to print the object itself. Would a part resist bending more if it were infill injected with carbon-fibre filament? We hope he does some follow-up experiments; we’d love to see the results.
