Large Format 3D Printer Is A Serious Engineering Challenge

July 27, 2022 by Danie Conradie 14 Comments

When you want to build a large format 3D printer, you can’t just scale up the design of a desktop machine. In an excellent four-part build series (videos after the break), [Dr. D-Flo] takes us through all the engineering challenges he had to contend with when building a 3D printer with a 4x4x4 ft (1.2 m cube) print volume.

For such a large print volume you won’t be printing with a 0.4 mm nozzle. The heart of the printer is a commercial Massive Dimension MDPH2 pellet extruder, capable of extruding ~1 kg of plastic per hour through 1.5 mm to 5 mm nozzles. To feed the extruder, [Dr. D-Flo] used a Venturi vacuum system to periodically suck pellets from a large hopper. The system is driven by compressed air, which can introduce moisture back into the carefully dried pellets. To reduce the humidity levels, the compressed air passes through a series of vertical aluminum tubes to allow moisture to condense and drain out the bottom.

At 8.4 kg, it needs a powerful motion platform to move it. [Dr. D-Flo] went with a stationary bed design, with the extruder pushed around by seven high torque NEMA23 motors on a large gantry built from C-beam aluminum extrusions. A machine this size needs to be very rigid with well-fitting parts, so [Dr. D-Flo] made heavy use of CNC machined aluminum parts.

To allow dynamic bed leveling, [Dr. D-Flow] made use of a Quad Gantry Leveling (GQL) scheme. This means that each of the four Z-actuators will dynamically adjust its position based on inputs from the leveling probe. The avoid stressing the corner mountings that hold the X-Y gantry to the Z carriage plates, he used radial spherical bearings at the mounting points to allow a few degrees of play.

The build plate consists of an aluminum plate bolted onto the base in 25 positions with springs for adjustability. A massive 6000 watt 220 V heating pad sticks to the bottom, while the actual printing surface is a large sheet of borosilicate glass. One major concern was the deflection of the build plate when heated to working temperature, but with all the adjustment options [Dr. D-Flo] was able to get height variation down to about 0.25 mm. This is within the acceptable range when printing with layer heights of 1 mm or more.

We’ve featured large scale 3D printers in the past, but none are quite as big the University of Maine’s building-sized 3D printer that can print a motorboat in one piece.

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A New Way To Produce PCBs With Your 3D Printer

July 26, 2022 by Tom Nardi 49 Comments

With the low-cost PCB fabrication services available to hackers and makers these days, we’ll admit that making your own boards at home doesn’t hold quite the appeal that it did in the past. But even if getting your boards professionally made is cheaper and easier than it ever has been before, at-home production still can’t be beat when you absolutely must have a usable board before the end of the day.

If you find yourself in such a situation, this new method of DIY PCB production detailed by [Adalbert] might be just what you need. This unique approach uses a desktop fused deposition modeling (FDM) 3D printer throughout all of its phases, from creating a stencil based on the exported board design, to warming the UV soldermask to accelerate the curing process. It may not be an ideal choice for densely packed boards with fine-pitch components, but could definitely see it being useful for many prototypes.

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Custom Raspberry Pi Case Shows The Whole Workflow

July 25, 2022 by Donald Papp 29 Comments

If you are a process junkie and love seeing the end-to-end of how a thing is made and with what tools, then watch [Michael Klements] show off his Raspberry Pi case design. His case has quite a few cool-looking elements to it, and incorporates 3D printing as well as laser-cut and clear bent acrylic for a gorgeous three-quarter view.

[Michael]’s write-up (and accompanying video, embedded below) are partly a review of his Creality 3D printer, and partly a showcase of his Raspberry Pi case design (for which he sells the design files for a small fee on his Etsy store.) But the great part is seeing the creation of every piece that goes into the end product. Not everyone is familiar with the way these tools work, or what they can create, so it’s nice to see attention paid to that side of things.

Both the blog post and the video nicely show off what goes into every part. The video opens with unpacking and setting up the 3D printer (skip ahead to 4:58 if you aren’t interested), followed by printing the parts, laser-cutting the acrylic on a K40 laser cutter, bending the acrylic using a small hand tool, and finally, assembling everything. For the curious, there are also links to the exact parts and equipment he uses.

Like we said, it’s part 3D printer review and part showcase of a design he sells, but it’s great to see each of the parts get created, watch the tools get used, and see the results come together in the final product. And should you wish to go in the opposite direction? A one-piece minimalist case for your Raspberry Pi is only a 3D printer away.

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Complex Movements From Simple Inflatables, Thanks To Physics

July 24, 2022 by Donald Papp 5 Comments

Inflatable actuators that change shape based on injected pressure can be strong, but their big limitation is that they always deform in the same way.

The Kresling pattern, which inspired the actuator design.

But by taking structural inspiration from origami, researchers created 3D-printed actuators that show it is possible to get complex movements from actuators fed by only a single source of pressure. How is this done? By making the actuators physically bi-stable, in a way that doesn’t require additional sources of pressure.

The key is a modified design based on the Kresling pattern, with each actuator having a specially-designed section (the colored triangles in the image above) that are designed to pop out under a certain amount of positive pressure, and remain stable after it has done so. This section holds its shape until a certain amount of negative pressure is applied, and the section pops back in.

Whether or not this section is popped out changes the actuator’s shape, therefore changing the way it deforms. This makes a simple actuator bi-stable and capable of different movements, using only a single pressure source. Stack up a bunch of these actuators, and with careful pressure control, complex movements become possible. See it in action in two short videos, embedded just below the page break.

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Automated Hotend Swapping For Less Wasteful Multicolor Printing

July 24, 2022 by Danie Conradie 16 Comments

Multicolor printing on FDM machines can be tricky to get working flawlessly, and purging hotends when changing colors can end up wasting a lot of filament and material. To solve this problem for the popular Prusa i3 and Ender 3 printers, [BigBrain3D] developed the Swapper3D, an automated system that swaps the entire hotend when the material is changed, eliminating the need for purging almost entirely. Video after the break.

The Swapper3D works very similarly to the tool-changing systems on CNC machines, and is just as satisfying to watch. A large circular carousel on the side of the machine holds up to 25 hotends, and in practice, a pair of robotic arms pop out the previous hotend, cut the filament, and load up the specified hotend from the carousel. This means you can have a separate hotend for each color or type of filament. Since most existing hotends also integrate the heating element, [BigBrain3D] created a special hotend assembly that can be robotically removed/inserted into the heater block.

The Swapper3D is designed to be used with existing filament changers like the Prusa MMU and the Mosaic Palette. Using these systems involves a lot of purging, to the point where you sometimes end up using more filament during purging than you need for the actual part. On one five-color demo print, the Swapper3D reduced the print time by 45% and the filament used by a massive 86%. It also helps to eliminate problems like stringing and color fading in multicolor prints. With those advantages, it looks like the Swapper3D might be a worthwhile upgrade if you do a lot of multi-color printing, even though it adds quite a bit of complexity to the printer.

For larger, more expensive machines, swapping the entire toolhead is becoming more popular, with even E3D stepping into the fray.

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A 3D printed roller coaster model with light strips modelling the trains

How To Make A Model Roller Coaster Without Any Moving Parts

July 20, 2022 by Robin Kearey 5 Comments

Roller coasters are not only great fun to ride, they’re also fascinating pieces of engineering. Building your own full-size coaster is sadly beyond most people’s means, so the average enthusiast will have to settle for simulation or modelling of their own designs. [Jon Mendenhall] is one of those who specialize in building model roller coasters and simulating their motion in intricate detail. His latest project is a scale model of VelociCoaster, a Jurassic Park-themed ride in Universal’s Islands of Adventure, that simulates the coaster’s ride without using any moving parts.

[Jon] achieves this by re-creating the trains’ motion using LED strips. A total of 3000 LEDs are spread along more than nine meters of track and make a mesmerizing light show of several trains whizzing along the track, accelerating and slowing down exactly like the real thing.

In his video, [Jon] explains the process of generating an accurate 3D model of the track starting from nothing more than an overhead view of the park as well as photos taken from various angles. The surrounding terrain and buildings are also included in his 3D model, as are the 128 supports that hold the track in place. The terrain and building were made from plywood and foam using a CNC machine, while the track and supports were 3D printed.

A Teensy microcontroller runs the whole show, with the LED strips split into five separate sections to allow a high enough frame rate for smooth animations. An infrared remote is used to start and stop the ride, as well as to adjust the speed; the model supports running the trains at a physically accurate speed, but because this looks rather dull, the regular setting is about three times as fast.

Looking for more roller coaster models? [Jon] made a similarly impressive model with a powered train before, and we’ve seen several models that actually coast along their tracks.

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3D Printed Skate Trucks Do Surprisingly Okay

July 20, 2022 by Lewin Day 18 Comments

If you can buy something off the shelf, there’s a good chance that someone has tried to 3D print their own version. [Daniel Norée] did just that with skateboard trucks, whipping up a design of his own.

The main body of the trucks is 3D-printed, as is the hanger. A 195 mm M8 threaded rod is then used through the center of the trucks in order to provide an axle for fitting the wheels and bearings themselves. He 3D-printed the parts using a carbon-fiber reinforced nylon with the slicer set up to maximize strength. In testing, they rolled around the neighbourhood just fine.

[Mayer Makes] found the design online, and 3D printed some using his own transparent high-impact resin, making a cool set of clear-ish trucks. It’s a tough material, which we’ve featured on this site before.

Those trucks ended up in the hands of [Braille Skateboarding], who put them through their paces. The trucks are loose, but take a good beating around the park. Eventually one of the trucks succumbs after landing many kickfilps and ollies on the concrete.

Other great skate hacks include casting your own wheels in a 3D-printed mold. Video after the break.

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