Liar’s 3D Printing: Multiple Colors With One Extruder

December 27, 2016 by Al Williams 12 Comments

Good 3D printers now have multiple hot ends. You ought to be able to print in different colors or print support material. However, a lot of us don’t have multiple hot ends. Turns out, you don’t have to have multiple hot ends to print in multiple colors. To accomplish that you need a lot of patience and the willingness to tell bald-faced lies. Don’t worry, though, you’ll only be lying to some computer hardware and software, so that doesn’t count.

You may have seen people talk about putting a pause between layers to switch from one color to another. That works, but it limits your options. For example, if you want to put some colored text on a different colored background, you have to either have the text poke out, or it has to be “under” the background. It can’t be flush if you only have a single extruder and hot end. My method is a lot more trouble, but it can generate good results.

Keep in mind, with hobby-grade printers, multiple color printing has a lot of problems even if you do have multiple extruders. This isn’t a panacea. But you can get results on par with a similar printer that has multiple heads.

Bottom Line Up Front

Here are a few pictures of test prints that use this technique. A Monoprice Mini printer with the stock extruder and hot end created them using different PLA filament. On the left is a test cube, with a color spot in the middle of the layers (as well as some spots on the top surface you can’t see). To the right is a plate with my call sign in a contrasting color. It is hard to tell in the picture, of course, but there is one surface. The text is at the same height as the yellow surface.

I didn’t spend a lot of time making these prints since I was more focused on perfecting the methodology. The layer heights aren’t very fine, the infill is sparse, and the print speed was fast. However, you could invest time into making better-looking prints. You can also use the usual techniques that you use with a “real” multi-extrusion printer (such as priming towers, ooze shields, etc.).

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Open-Source Parametric CAD In Your Browser

December 24, 2016 by Cameron Coward 46 Comments

Until recently, computer-aided design (CAD) software was really only used by engineering companies who could afford to pay thousands of dollars a year per license. The available software, while very powerful, had a very high learning curve and took a lot of training and experience to master. But, with the rise of hobbyist 3D printing, a number of much more simple CAD programs became available.

While these programs certainly helped makers get into 3D modeling, most had serious limitations. Only a few have been truly open-source, and even fewer have been both open-source and parametric. Parametric CAD allows you to create 3D models based on a series of parameters, such as defining a cube by its origin and dimensions. This is in contrast to sculpting style 3D modeling software, which is controlled much more visually. The benefit of parametric modeling is that parameters can be changed later, and the model can be updated on the fly. Features can also be defined mathematically, so that they change in relation to each other.

While still in its infancy, JS.Sketcher is seeking to fill that niche. It is 100% open-source, runs in your browser using only JavaScript, and is fully parametric (with both constraints and editable dimensions). At this time, available features are still pretty limited and simple. You can: extrude/cut, revolve, shell, and do boolean operations with solids. More advanced features aren’t available yet, but hopefully will be added in the future.

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3D Printed Circuit Boards… Sort Of

December 17, 2016 by Al Williams 16 Comments

Comedian Demetri Martin does a bit about the phrase “sort of”. He says:

“Sort of’ is such a harmless thing to say… sort of. It’s just a filler. Sort of… it doesn’t really mean anything. But after certain things, sort of means everything. Like… after “I love you”… or “You’re going to live.”

SCADboard is an OpenSCAD library that lets you create 3D printable circuit boards…sort of. The library lays out like a breadboard with two bus bars on each side and a grid of rows and columns. OpenSCAD modules provide a way to create a board, ICs, LEDs, wires and other fundamental components. You set a few initial variables (like the board thickness) then your code looks like this:

 wire(1,bln,1,e, neg); // Neg left trace to LED
 led(1,e+1, 1,e+2, yellowled); // LED
 wire(1,f, 1,i, pos); // LED Pos
 wire(1,j, 1,brp, resistor); // Resistor
 
 wire(3,c,3,h, pos); // Cap Pos
 wire(4,c,4,h, neg); // LED Resistor

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Make Your Own Arduino Header Pins

December 13, 2016 by Al Williams 61 Comments

There are two kinds of people in the world (and, no, this isn’t a binary joke). People who love the Arduino, and people who hate it. If you’ve ever tried to use a standard prototype board to mount on an Arduino, you’ll know what kind of person you are. When you notice the pins aren’t on 0.1 inch centers, you might think, “What the heck were those idiots thinking!” Or, you might say, “How clever! This way the connectors are keyed to prevent mistakes.” From your choice of statement, we can deduce your feelings on the subject.

[Rssalnero] clearly said something different. We weren’t there, but we suspect it was: “Gee. I should 3D print a jig to bend headers to fit.” Actually, he apparently tried to do it by hand (we’ve tried it, too). The results are not usually very good.

He created two simple 3D printed jigs that let you bend an 8-pin header. The first jig bends the correct offset and the second helps you straighten out the ends again. You can see the result in the picture above.

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Thirty Days Of 3D Printing Filament

December 10, 2016 by Al Williams 13 Comments

Our first 3D printers only printed ABS and PLA plastic. Yeah, we heard about PVA for support structures, but no one could get them to stick. There was also polycarbonate, but you had to have an all metal hot end with a fan to print that stuff. Now there’s a lot of variety out there: flexible, wood and stone, nylon, PETG, and more.

If you are still printing with just the old standards, you might enjoy [all3dp’s] comparison chart of 30 different filament types–that’s enough for one day a month–well at least for four months. It is too many for February, and a day short for the rest of the months. In addition to a table, there’s a short write-up about each type of plastic, its characteristics, and its technical data. There’s even magnetic PLA (see video below) which, in addition to being magnetic, will actually rust in water which might be good for some artistic prints.

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Speed Run [James Bruton’s] Star Wars Builds

December 10, 2016 by Rich Hawkes 4 Comments

We’ve been following [James Bruton]’s builds here on Hackaday for quite a while and he has built some impressive stuff. We love how he often doesn’t cover everything up, leaving enough room to admire the working bits under the hood. Just in time for the release of the new Star Wars movie, Rogue One, [James] put together an overview of his Star Wars robot builds.

The build summary includes his R6 droid, his GNK walking droid and the third revision of his BB-8 droid. [James Bruton]’s videos have tons of detail in them over many, many parts (for example, his BB-8 R3 playlist is 15 parts and his Ultron build currently has 26 episodes and counting!)

There’s a quick overview of each of the three robot builds in this video, and it includes links to the playlists for each build for those who want more detail. This is just what you need to glimpse all of the clever design that went into these wonderfully crafted droids. And if you haven’t seen it yet, you should check out his series elastic actuators that he’s working on for the Ultron build, they give a robot some relief from rigidity.

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Maybe You Can Print In Metal

December 9, 2016 by Al Williams 31 Comments

Let’s face it. Printing in plastic is old hat. It is fun. It is useful. But it isn’t really all that exotic anymore. The real dream is to print using metal. There are printers that handle metal in different ways, but they aren’t usually practical for the conventional hacker. Even a “cheap” metal printer costs over $100,000. But there are ways you can almost get there with a pretty garden-variety printer.

There’s no shortage of people mixing things into PLA filament. If you have a metal hot end and don’t mind wearing out nozzles, you can get PLA filament with various percentages of metal powder in it. You can get filament that is 50% to 85% metal and produce things that almost seem like they are made from metals.

[Beau Jackson] recently had a chance to experiment with a metal-bearing filament that has a unique twist. Virtual Foundry’s Filamet has about 10% PLA. The remaining material is copper. Not only do you have to print the material hot, but you have to print it slow (it is much denser than standard PLA). If it were just nearly 90% metal, that would be impressive, but nothing too exciting. The real interesting part is what you can do after the print is complete. (If you don’t want to read, you can always skip to the videos, below.)

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