Destructive Testing Of ABS And Carbon Fiber Nylon Parts

PAHT-CF part printed at 45 degrees, with reinforcing bolt, post-failure. (Credit: Functional Print Friday, YouTube)
PAHT-CF part printed at 45 degrees, with reinforcing bolt, post-failure. (Credit: Functional Print Friday, YouTube)

The good part about FDM 3D printing is that there are so many different filament types and parameters to choose from. This is also the bad part, as it can often be hard to tell what impact a change has. Fortunately we got destructive testing to provide us with some information here. Case in point [Functional Print Friday] on YouTube recently testing out a few iterations of a replacement part for a car.

The original part was in ABS, printed horizontally in a Bambu Lab FDM printer, which had a protruding element snapped off while in use. In addition to printing a replacement in carbon fiber-reinforced nylon (PAHT-CF, i.e. PA12 instead of the typical PA6), the part was now also printed at a 45° angle. To compare it with the original ABS filament in a more favorable way, the same part was reprinted at the same angle in ABS.

Another change was to add a machine screw to the stop element of the part, which turned out to make a massive difference. Whereas the original horizontal ABS print failed early and cleanly on layer lines, the angled versions put up much more of a fight, with the machine screw-reinforced stop combined with the PA12 CF filament maxing out the first meter.

The take-away here appears to be that not only angles are good, but that adding a few strategic metal screws can do wonders, even if you’re not using a more exotic filament type.

Continue reading “Destructive Testing Of ABS And Carbon Fiber Nylon Parts”

Watch SLS 3D Printed Parts Become Printed Circuits

[Ben Krasnow] of the Applied Science channel recently released a video demonstrating his process for getting copper-plated traces reliably embedded into sintered nylon powder (SLS) 3D printed parts, and shows off a variety of small test boards with traces for functional circuits embedded directly into them.

Here’s how it works: The SLS 3D printer uses a laser to fuse powdered nylon together layer by layer to make a plastic part. But to the nylon powder, [Ben] has added a small amount of a specific catalyst (copper chromite), so that prints contains this catalyst. Copper chromite is pretty much inert until it gets hit by a laser, but not the same kind of laser that sinters the nylon powder. That means after the object is 3D printed, the object is mostly nylon with a small amount of (inert) copper chromite mixed in. That sets the stage for what comes next.

Continue reading “Watch SLS 3D Printed Parts Become Printed Circuits”

Vroomba Gets Upgrades And A Spoiler

[Electrosync] is the creator and driver of the world’s fastest robotic vaccum cleaner, the Vroomba. It’s a heavily modified roomba capable of speeds of around 60 kph, well beyond the pedaling speed of most bicyclists. Despite being rejected by Guinness for a world record, we’re fairly confident that no other vacuum cleaners have gotten up to these speeds since the Vroomba first hit the streets. That’s not going to stop [electrosync] from trying to top his own record, though, and he’s brought the Vroomba some much needed upgrades.

The first, and perhaps most important, upgrades are to some of the structural components and wheels. The robot is much heavier than comparable RC vehicles and is under much greater strain than typical parts are meant to endure, so he’s 3D printed some parts of the chassis and some new wheels using a nylon-carbon fiber filament for improved strength. The wheels get a custom polyurethane coating similar to last time.

Continue reading “Vroomba Gets Upgrades And A Spoiler”

Plastic Welding Revisited

Last time we talked about a video that purported to do plastic welding, we mentioned that the process wasn’t really plastic welding as we understood it. Judging by the comments, many people agreed, but it was still an interesting technique. Now [Inventor 101] has a video about plastic repair that also talks about welding, although — again, we aren’t sure all of the techniques qualify.

That’s not to say there aren’t some clever ideas, though. There are several variations on a theme, but the basic idea is to use a bolt or something similar in a soldering iron, metal reinforcement from things like wires and staples, and donor plastic from a zip tie. While we don’t think the nylon in a typical zip tie is the best way to repair anything other than nylon, if you were repairing something 3D printed, you could easily swap out the tie for filament of the same material, which — we think — would bond better.

Continue reading “Plastic Welding Revisited”

Conductive Tape Current Capacity Comparison

The world of DIY circuits for STEM and wearables has a few options for conductors. Wire with Dupont connectors is a standard, as is adhesive copper tape. There’s also conductive nylon/steel thread or ribbon. Which you choose depends on your application, of course, but as a general rule wire is cheap and ubiquitous while making connections is more challenging; copper tape is cheap and simple to use, but delicate and rips easily, so is best used for flat surfaces that won’t see a lot of stress or temporary applications; and conductive nylon thread or tape is better for weaving into fabrics.

The Brown Dog Gadgets team wanted to respond to a frequent question they are asked, what are the current limits for their Maker Tape (nylon/steel ribbon), so they ran some experiments to find out. In the name of Science you’ll see some flames in the video below, but only under extreme conditions.
Continue reading “Conductive Tape Current Capacity Comparison”

Tie-Dyed Filament Sings With Color

Manufacturers dye all sorts of 3D printer filaments on their factory lines; why can’t we? [Richard] takes this idea one step further by creating his own custom multicolored reels of nylon. Printing with these reels produces a vibrant pattern that simply demands our attention and  begs us to ask: how on earth..?

[Richard’s] tie-dye adventure is cleanly documented on the blog.  He simply spools a reel of nylon together and dyes subsections of the spool with a different color. With the filament “paletted” to taste, parts pop of the printer with an eye-catching rib pattern of color.

It’s worth mentioning that nylon is extremely hygroscopic, and dyeing filament in a bath full of colored liquid is sure to get it full of moisture. Then again, nylon’s capacity to absorb water might be why it dyes so well. Nevertheless, filament must be oven-dried (or equivalent) for a successful print. Post-drying, [Richard] doesn’t seem to be having any printing problems, and the results speak for themselves.

3D printers might be frequent fliers on these pages, but we still love seeing small modifications that enhance the visual appeal. What’s more, this trick delivers spectacular results with no modifications to the printer itself. Then again, if this job sounds like just too much work for you, we’d suggest using a sharpie.

Continue reading “Tie-Dyed Filament Sings With Color”

One-key Keyboard Is Exercise In Sub-millimeter Design

As [Glen] describes it, the only real goal in his decision to design his single-key USB keyboard was to see how small he could build a functional keyboard using a Cherry MX key switch, and every fraction of a millimeter counted. Making a one-key USB keyboard is one thing, but making it from scratch complete with form-fitting enclosure that’s easy to assemble required careful design, and luckily for all of us, [Glen] has documented it wonderfully. (Incidentally, Cherry MX switches come in a variety of qualities and features, the different models being identified by their color. [Glen] is using a Cherry MX Blue, common in keyboards due to its tactile bump and audible click.)

[Glen] steps though the design challenges of making a device where seemingly every detail counts, and explains problems and solutions from beginning to end. A PIC16F1459, a USB micro-B connector, and three capacitors are all that’s needed to implement USB 2.0, but a few other components including LED were added to help things along. The enclosure took some extra care, because not only is it necessary to fit the board and the mounted components, but other design considerations needed to be addressed such as the depth and angle of the countersink for the screws, seating depth and clearance around the USB connector, and taking into account the height of the overmold on the USB cable itself so that the small device actually rests on the enclosure, and not on any part of the cable’s molding. To top it off, it was also necessary to adhere to the some design rules for minimum feature size and wall thicknesses for the enclosure itself, which was SLS 3D printed in nylon.

PCB, enclosure, software, and bill of materials (for single and triple-key versions of the keyboard) are all documented and available in the project’s GitHub repository. [Glen] also highlights the possibility of using a light pipe to redirect the embedded LED to somewhere else on the enclosure; which recalls his earlier work in using 3D printing to make custom LED bar graphs.