Tool Changing

We sometimes forget that 3D printers are just CNC platforms with a hotend attached, and there a whole range of alternative tool heads to use. [Jón Schone] has been doing exactly that, and needed a way to quickly disconnect his hotend completely from his printer, so he 3D printed his own custom D-sub connector for both filament and wires. (Video, embedded below.)

[Jon] has added a number of upgrades for his Creality CR10 3D printer, including a quick change tool mount to allow him to also use a laser engraver and even a small spindle. When the hotend is removed there’s no way to quickly disconnect the wiring , so the print head is usually left connected and placed to one side of the printer. For a quick detach solution for both wiring and the Bowden tube, he first modified an off-the-shelf D-sub connector. The connector was relatively expensive, and the tube had a tendency to pop out, which led to some failed prints.

[Jon] wanted to use proper Bowden tube fittings inside the connector, so he designed and printed his own D-sub connector and bought loose contacts. Pushing the contacts into the housing turned out to be quite difficult to do without breaking them, so he’s working on making that process simpler. This is just one of many examples of 3D printing 3D printer upgrades, which has been a core feature of the RepRap project right from the beginning. Check out the video after the break

We have no shortage of 3D printer hacks and there will be many more to come. Some cool recent ones includes the Jubilee CNC that was built from the start with automatic tool changing in mind, and a printer that fits in your backpack. Continue reading “Feeding Both Filament And Electrons Through A Custom D-Sub Connector” →

E3D has introduced their latest answer to multimaterial printing at the Midwest RepRap Festival this weekend. Their research project into a 3D printer with the ability to change toolheads is the latest advancement in multimaterial printing. It’s a work of engineering brilliance, and they’ve already written up their teardown on how this all came to be.

While milling machines and other fancy industrial CNC have had tool changing for decades, and the subject has been pursued by the RepRap community for a few years now, it really hasn’t caught on. The question then is, what is tool changing on a 3D printer good for? The answer is multimaterial printing, and doing it in a way that doesn’t have the downsides of current methods of printing with multiple materials.

There are three current methods of printing in multiple materials. The first is putting two nozzles on the same extruder, but this has the downside of one nozzle interfering with the other. The second is pushing two different kinds of plastic through the same nozzle, such as in the E3D Cyclops, or Prusa’s multimaterial upgrade. This has the downside of cross-contamination, and you can’t print in materials that require different temperature profiles. The third method is simply using multiple carriages on the same machine, such as the lovely stuff from Autodesk or Project Escher. This last method is horrifically complex.

The answer the problem of multimaterial printing is hot-swapping toolheads, but to do this you need precision and repeatability. The folks at E3D have been working on this for years, and I remember seeing some experiments with electro-permanent magnets a few MRRFs ago, but now they finally have a solution. The answer is simply a cam that’s turned by a cheap hobby servo. This is kinematic coupling that allows the carriage to clamp onto a toolhead with 5 μm precision.

Right now, E3D’s experiments in toolchanging 3D printers have culminated in a single 3D printer featuring their toolchange carriage, four toolheads, some amazing linear rails, and a CoreXY configuration. The prints that are coming off of this printer are spectacular. There are four-color Benchies, and the drivetrain of a remote-controlled car with gears printed in Taulman plastic and a driveshaft printed in ABS. The car was a single print made with multiple hotends, demonstrating most of the problems of multimaterial printing disappear with the E3D swapping toolhead printer.