Surface conductors on vacuum formed parts appear in many hacks, from cosplay armor to 3D touch pads and smart objects. But making them has always been painful. Either they had to be hand painted after forming, which looked sloppy and was labor intensive, or they had to be printed with some difficult to use stretchable ink tech. [Freddie Hong] and his group have another solution, using tech most hackers already have – a 3D printer and a vacuum former.
They 3D print the traces with conductive PLA filament directly onto a base plastic sheet, and then vacuum form the whole thing. The filament is happy to deform when heated – it’s printer filament.
We like this process. We’ve found conductive filament isn’t reliably resistive across vertical layers, but is reliable in the XY plane. Their method only requires one layer. Also, they suggest 3D printing a layer of non conductive PLA atop most of the conductor, like a PCB solder mask.
Conductive filament has a fair bulk resistance. They suggest electroplating it before applying the top mask layer. They also are exploring 3D printing logos, stripes, and such with colored filament, or even making surface detail like rivets on model parts or adding thickness where the plastic thins during vacuum forming.
Designing the 3D print requires guessing what bit of plastic sheet ends up where in the vacuum formed final part. His group used a commercial program, t-sim, to do the prediction and Grasshopper to import the result into Rhino3D. This seems a lot for a home hacker. Drawing lines on a test sheet and vacuum forming seems simpler.
Even if they don’t have one themselves, we’d wager the average Hackaday reader is at least vaguely aware of how a vacuum former works on a fundamental level. You heat up a plastic sheet until it’s soft, then use a vacuum pump to pull the ductile material down onto an object and hold it there while it cools off. It’s easy to build a vacuum forming rig yourself, but small commercial units are cheap enough that it might not be worth your time. If everything goes to plan, the technique is a quick and effective way of duplicating items around the home and shop.
So what’s the advantage? Well for one thing, it’s cheaper. Though admittedly, not by much. Going rate on Amazon seems to be about 90 cents per sheet for the real stuff, and some back of the envelope math shows the printed version coming in at around 30 cents given nominal filament costs. Whether or not those savings are worth the extra effort is certainly debatable.
But that’s not really the most interesting part. With printed sheets loaded into the vacuum former, you’ve got access to a much wider array of materials to work with. For example, [Nathan] shows off some very interesting flexible pieces he was able to produce using sheets of TPU. You can also experiment with different surface textures. These can not only be used to give your vacuum formed pieces a bit of interesting visual flair, but could actually have some practical applications. In the video we see how a printed mesh could be formed over a piece to create a conformal air vent or filter.
To be sure, there’s some room for improvement here. Not all the pulls were successes, and [Nathan] says getting the printed sheets up to the proper temperature can be tricky. But when it works, it works quite well, and we think there could be some untapped potential in this unexpected melding of new and old methods of at-home plastic production.
[Matterhackers] has a nice video tutorial on using vacuum forming to create plastic items. Sure, you have a 3D printer, but vacuum forming has some advantages if you are making thin and flexible items quickly. But don’t feel bad. The master item in the process is from a 3D printer. Like a mold, the forming won’t produce a duplicate of the master, called a buck. Rather, the buck provides something like a die that the plastic wraps around.
While obvious vacuum-formed items include such things as take-out food containers and plastic blister packaging for retail items, you can also make more substantial items. Apparently, all theStar Wars movies in the original trilogy used vacuum forming to create stormtrooper armor.
The first step is finding something that’s a bit easier to work with than glass. After testing various reflective materials such as PVC foil and painted PETG sheets by comparing the reflections of projected test patterns, [volzo] found that laminated polystyrene gave the most accurate results. If you just want to make a simple bent mirror, he shows how you can pop one of these sheets on a CNC router, make the appropriate cuts, and fold them into shape.
That part might seem a bit obvious, but what about a more complex shape? Here, [volzo] points to how the thin sheets of polystyrene also lend themselves to vacuum forming. As demonstrated in the video below, all it takes is a 3D printed plug and some basic equipment to rapidly produce mirrors in arbitrary shapes.
Now obviously the optical properties of such mirrors will leave something to be desired, but depending on your application, that might not be such a big deal. As examples [volzo] shows off a few projects using these custom mirrors, such as a tabletop camera that captures both sides of the table simultaneously and a circular projector. Laminated polystyrene could potentially even be used to create low-cost variable mirrors.
Retrocomputing is as much about physical preservation as it is about electronics and computer science. Plastic is an awful material when it comes to decade-long timescales, and the forces of sun, air and water are unrelenting on these materials. [Drygol] has long experimented with techniques to preserve and refresh keycaps, and decided to try some fun vacuum forming techniques for something new. It sadly didn’t go to plan, however.
The basic idea was to use a vacuum-forming machine to coat keycaps in a thin layer of translucent plastic, for both aesthetic benefit and to preserve them from falling apart. Initial small-scale tests were promising, creating a key with a tight, form-fitting blue plastic wrap through which the original labels were still visible.
However, scaling up the process proved fraught. Uneven heating of the plastic film and a lack of rigidity in the carriage used to stretch it over the keycaps led to poor results. The final product showed many wrinkles and was distinctly unappealing.
[Drygol] isn’t giving up however, and plans to build a new vacuum table with greater performance. We can imagine this technique being an accessible way to colorize keycaps for a vintage cyberdeck or chiptune rig, without permanently modifying the keys. If you’ve got the inside knowledge on how to make this work, sound off in the comments.
[Will Cogley]’s mechanized gauntlet concept sure has a hypnotizing look to it, and it uses only a single motor. Underneath the scales is a rod with several cams, each of which moves a lever up and down in a rippling wave as it rotates. Add a painted scale to each, and the result is mesmerizing. This is only a proof of concept prototype, and [Will] learned quite a few lessons when making it, but the end result is a real winner of a visual effect.
The gauntlet uses one motor, 3D printed hardware, and a mechanical linkage between the wrist and the rest of the forearm. Each of the scales is magnetically attached to the lever underneath, which provides some forgiveness for when one inevitably bumps into something. You can see the gauntlet without the scales in the video, embedded below the break, which should make clear how the prototype works.
The scales were created with the help of a Mayku desktop vacuum former by making lightweight copies of 3D printed scales. Interestingly, 3D printing each scale with full supports made for a useful mold; there was no need to remove supports from underneath the prints, because they are actually a benefit to the vacuum forming process. When vacuum forming, the presence of overhangs can lead to plastic wrapped around the master, trapping it, but the presence of the supports helps prevent this. 3D prints don’t hold up very well to the heat involved in vacuum forming, but they do well enough for a short run like this. Watch it in action and listen to [Will] explain the design in the video, embedded below.
[CutTransformGlue] recently posted a build video for “Making Rey’s Star Wars Blaster“, embedded after the break. The construction uses layered MDF sheets to build up the blaster, and it’s a treat to see it taking shape, ending with an amazing paint job. It’s a good way to learn about the techniques used to bring such props to life and help you hone your skills. But digging deeper led us down an awesome rabbit hole.
[CutTransformGlue] got plans for Rey’s Blaster from the Punished Props Academy – a prop and costume making team from Seattle committed to “transforming passionate fans into confident, skillful makers”. These folks have built a wide variety of projects ranging from guns, weapons, costumes, props and more, and are obviously extremely skilled at what they do. But they aren’t keeping those skills to themselves and in a series of posts and videos they are sharing with us such varied skills as Foamsmithing (gotta love that coinage), Molding, Casting, Painting, 3D printing, Vacuum Forming and electronics. If you’d like more information about supplies, check out the Tools and Materials section. And if all of this has given you the itch to build a Skyrim Wuuthrad or a Halo4 Sniper Rifle, head over to the amazing Free Blueprints section for a treasure chest full of downloads.
Like we said earlier, if building such stuff is your thing, it’s a rabbit hole from which you’ll find it extremely difficult to extract yourself. Have fun.