An owl printed with detailed color patterns

New Method Accelerates Color 3D Printing

Multi-color 3D printing is notorious for being difficult to get right. Even with modern printers, you often end up using much more filament (and tool changes) than you would for a single-color print. [YKG3D] shows us a new method of color printing that needs far fewer tool changes.

Based on 2018 research, the new slicer rotates through its palette of colors each layer. Then, either by adjusting the amount of filament dispensed or by displacing the edges, the prominence of each color is adjusted. The result is smoother gradients and better color blending — and it prints faster too!

Of course, nothing is perfect: the more base colors you add, the thicker your apparent layer lines will be. For example, a 3-color print with 0.2 mm layer height will appear as having 0.6 mm layer height. A different issue happens when the walls get too steep; the color blending illusion starts to break down.

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Art of 3D printer in the middle of printing a Hackaday Jolly Wrencher logo

Giving Resin 3D Printers Another Shot After Six Years

My initial experience with a 3D printer came in 2020, when I got access to a buddy’s Creality LD-002R SLA printer. This was one of those awkward transition phases for SLA printers, where inefficient RGB LCDs finally got replaced by monochrome LCD panels, thus massively reducing the required exposure time and increasing the LCD panel’s lifespan.

The closely related Creality LD-002H is a monochrome SLA printer, but as this wasn’t the one that this friend opted for we had to learn the ropes on this more old-school printer. In terms of specifications this meant a build volume of 119 mm x 65 mm x 160 mm to play with and a claimed 26.1 µm resolution. Despite some struggles along the way, this machine churned out impressively high levels of detail with whatever cheap resin we threw at it, and even the post-printing processing became easy once we added a flex plate to the build plate and tweaked the cleaning and curing steps.

Despite all these positives, we both drifted away from resin printing, mostly due to the still messy and smelly printing process. FDM printers seemed like a better deal, especially after said buddy got his mittens on a used IDEX FDM printer. I would eventually go through a rather loathsome Creality Ender V2 experience before ending up with my current-day Elegoo Neptune 4, and resin printing seemed to be a thing of the past for me. Until recently, that is.

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Seven Ways To Install Magnets Into Your 3D Prints

Magnets are awesome, so it’s no wonder we love to add them to our 3D prints. Doing so in a way that will actually last is harder, with thermal creep being one reason a simple friction fit will loosen over time, and using super glue to hold a magnet in place can be messy. In a recent video, [Slant 3D] covers seven ways to install magnets in 3D prints without resorting to glue, along with the advantages and disadvantages of each.

With friction, the argument is that you can still use them, but you’d want to use something like cylindrical magnets rather than flat magnets to increase the friction with the thermoplastic. Using an arbor press rather than human primate hand power is also beneficial.

Rather than installing magnets halfway through a print with all the logistics that entails, you can use side slots to install said magnet into, which is much easier, but as with all embedded magnets, you get that plastic barrier between the magnet and its target.

Other methods involve using a bit of extra material that you need to push the magnet past, using something like an arbor press, so the magnets should never just fall out. A wildcard here: spherical magnets, which can be locked in using a similar method, while automatically orienting themselves to an opposing magnet.

The final tip is to never use two magnets in a magnetic lock. Instead, use a cheaper ball bearing or a similar plain metal part on one side instead. Magnets tend to be much more brittle than whatever stainless steel ball bearing or washer you can use on the other side.

Of course, people will always try to install magnets during an FDM print, but before they try to do that anyway, they really should learn about the fascinating ways in which magnets can ruin print beds, destroy nozzles, and otherwise make a total mess of a print. Magnets seem magical. Maybe they are.

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Automated Pressure Advance Using A Bed-Leveling Sensor

One of the most crucial aspects of FDM 3D printing is ensuring sufficient material is extruded. Determining the right flow rate can be done manually, but some printers these days automatically perform this adjustment, which is very convenient. [Stefan] of CNC Kitchen investigates how to add similar functionality using existing bed-leveling sensors.

A major complication with extrusion in FDM printers is that the flow rate has to fit the printing speed. However, you can’t just immediately speed up or reduce the flow rate, as the melting filament is flexible and thus acts like a spring, especially as the extruder is exerting significant force on the filament, which adds compression.

The moment you reduce or increase the speed of the nozzle, you can get over- or under-extrusion, but the delayed response by the extruded filament means that you have to adjust for this change in advance. Ergo, the name ‘pressure advance’, also known as the K-value. Obviously, this is a parameter that differs with each material, printer, and other factors, so a direct measurement is always the best.

In the Bambu Lab X1 FDM printer, a Lidar scanner was used to scan various test patterns to automatically determine the optimal setting. This was later moved to the purge section of the extruder in newer Bambu Lab printers. On other FDM printers, the only available sensor in that area is typically the pressure sensor for bed leveling. Could this sensor make a similar measurement?

This wasn’t just an idle thought, but was inspired by the Snapmaker U1, which runs open-source Klipper, with tantalizing glimpses of how it does pressure-advance sensing in its extruder. This extruder also only contains a load cell, as do some Prusa printers. These much more open printers thus provided a test bed for some experimentation.

With load cell data available, [Stefan] measured how various extrusion rates affect the load cell, which can then theoretically be correlated with the appropriate K-values for specific transitions. He created a calibration tool for a range of Prusa printers that works with stock firmware, though this is definitely still a work in progress. There are also a couple of similar open-source projects, such as this Auto PA Calibration project by [Mark].

Overall, K-value presets tend to work pretty well, but adding a pressure-advance calibration feature to existing FDM printers is definitely an interesting idea. There’s also the prospect of lateral sensing using this same bed-leveling sensor, which could allow the printer to sense much more than just the bed.

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Flex Filament Stuck To Your Build Platform? Reach For The Isopropanol

3D printing has been around long enough that everyone’s heard at least one weird trick regarding 3D prints. [Angus] of [Maker’s Muse] puts a few to the test, and came away with one solid tip for releasing TPU from a build platform to which it has unfortunately welded itself.

Flexible filaments tend to stick too well to build plates, which is why an interface layer like a thin layer of glue stick is called for. But what if one forgets to apply it before starting a print job? That can result in a print that is well and truly stuck. Peeling flex filament off a textured PEI bed is a bad time, because the print can tear and tends to leave little bits behind.

[Angus] heard that applying isopropyl alcohol helps release things in that case, so he gives it a try. Lo and behold, it seems to work! See for yourself at 18:10 in the video and keep it in mind if you end up in a similar situation. The print doesn’t exactly fall off on its own, but it does remain in one piece which is more than one can expect otherwise.

Watching isopropyl alcohol help release a stuck print is reminiscent of the way it also removes hot glue from just about any surface. The trick is getting the alcohol to wick in underneath for best results, and the same seems to be true with releasing TPU from a build plate.

One thing to keep in mind when evaluating tips and tricks from over the years is that the landscape changes. Something that maybe seemed to have potential years ago might not make much sense today. A good example is sugar as a bed adhesive, which [Angus] tries out. What started as an experiment in getting PLA to play better with glass build plates years ago doesn’t really carry over to now, with PEI-coated magnetic build platforms pretty much a solved problem. The more likely result nowadays is just a mess.

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Cut And Fold Your 3D Printer’s Next Cover

[cmh]’s ultra-simple top cover for the Snapmaker U1 3D printer has a 3D model, but don’t let that fool you. There’s no 3D printing at all involved in this project. Rather, the model is a reference shape for making an effective top cover out of cardboard or corrugated plastic sheet (also known as Coroplast) which is what [cmh] used.

The pattern can be cut from a single sheet, or from multiple pieces taped together.

Corrugated plastic is a versatile option for things like printer enclosures. It’s cheap, a good insulator, easy to cut, and available from just about any plastics supplier. We’ve made the case that they’re a good alternative to acrylic sheets for printer enclosures, but [cmh] goes even further with a design that requires no additional hardware whatsoever. Assembly doesn’t even require more than tape, really.

He provides a cutout diagram for pieces that, when assembled, make a sort of hat that is just right to cover the top of the Snapmaker U1 without obstructing the extruders. One can even lift the front panel to access the inside without removing the cover, which is a nice touch. Should one wish to add a viewing window anywhere, just cut out a square and tape a sheet of clear plastic over the hole.

For a 3D printer, an enclosure and top cover helps retain heat, block drafts, and keep dust (or curious fingers) away from the printer’s build area. The cover doesn’t need to be completely sealed to deliver those benefits, but if you do prefer your covers completely enclosed, a carefully-chosen IKEA storage box makes a conveniently great cover for the U1.

A clay vase sits in the center of a circular table, with an extruder in contact with the top surface. The extruder has a tube containing clay on the right side, with a motor mounted above an auger over the main nozzle.

Clay Extruder Enables Printable Pottery

Ceramic 3D printers, despite using the same fundamental mechanism as standard FDM printers, are much harder to find. Part of this comes down to the material properties of fired ceramics versus thermoplastics, but they’re also significantly harder to build; for example, in his ceramic printer build, [Joshua Bird] had to deal with severe material shrinkage, collapsing bridges, and the surprisingly abrasive effects of clay.

The centerpiece of the printer is the clay extruder: an air compressor pushes clay along a tube into the extruder, which uses an auger to squeeze the clay through the nozzle, while a gap at the top lets trapped air escape. The extruder has enough control for successful retractions, but rheology remained a challenge: the clay needed to be soft enough to flow through the nozzle, but stiff enough to form bridges without collapsing. [Joshua] thus pressurized the clay as much as possible, making it possible to use stiffer clay mixtures. The extruder’s greatest challenge was longevity: [Joshua] tried many 3D-printed plastic augers, but the clay abraded them all much too quickly, often in under an hour of use; a 3D-printed stainless steel extruder solved this.

Printing in ceramic isn’t a simple process: for each part, [Joshua] had to mix the clay, load it into the tube, clean the extruder, actually print the object, let it dry, fire it, apply glaze, and fire it again. The clay’s shrinkage during drying and firing destroyed many prints, but [Joshua] was nevertheless able to print a double-walled cup, a decorative climbing-themed cup, and even a chain-mail mesh.

The 3D printer’s motion system is a polar design, an adaptation of his earlier non-planar 3D printer, which might eventually make it easier to print overhangs. We’ve previously seen a similar auger-based clay extruder, an approach reminiscent of direct-granule FDM printing.