Filament printers are here to stay, and in the past year there have been a number of SLA and DLP resin printers that can create objects at mind-boggling high resolutions. Both of these technologies have their place, but printing really complex objects without also printing supports is out of the question.
[Brandon] has been working to create an open source printer using a different technology, selective laser sintering. That’s a laser melting tiny particles of stuff to create an object. This printer can work with any material that can be turned into a powder and melted by a laser, and also has the neat bonus of printing without any supports.
[Brandon]’s printer, Ester, uses small meltable polyester dust as both a print material and support structure. The object to be printed is created by shining a laser over a bed filled with polyester, drawing one layer, and putting another small layer of material over the previous layer.
The machine is using a diode laser, with a few experiments with a 1 Watt diode providing some very nice parts. The mechanics of the machine were built at [Brandon]’s local TechShop, and already he has an IndieGoGo for future development and a $3000 development kit. That’s a bit expensive as far as project printers go, but SLS is an expensive technology to get right; ‘pro’ SLS printers are in the hundreds of thousands of dollars.
Meet pwdr, the open source 3D printer that is a complete departure from the RepRaps and Makerbots we’ve come to love.
Instead of squirting plastic onto a build surface, pwdr operates just like the very, very expensive powder printers used in industrial settings. Pwdr uses gypsum, ceramics, and concrete for its raw stock and binds these powder granules together with water deposited from an inkjet cartridge.
Inside pwdr there are two bins, one for storing the raw material and another for building the part. The part to be printed is built one layer at a time, just like your regular desktop printer. After each layer is finished, a counter-rotating drum scrapes the raw material over the build area and another layer is printed.
There are a lot of advantages to pwdr versus the melted plastic method of printing used in the Makerbot; because each build is self-supporting, it’s possible to print objects that just couldn’t be made with an extruder-based printer. Pwdr also supports laser sintering, meaning it’s possible for pwdr to make objects out of ABS, Nylon, and even metal.
Right now, pwdr is still in the very early stages of development, but you can build your own powder printer from the files up on Thingiverse. Check out the video of pwdr printing after the break.
Continue reading “Pwdr, the open source powder printer”
[Markus Kayser] built an amazing solar powered SLS printer, but instead of using lasers and powdered plastics his machine uses the power of the sun to heat sand into complex shapes.
[Markus]’ printer uses the same concept as his earlier solar cutter – burning things with a magnifying glass. Interestingly, the printer isn’t controlled with stepper motors and reprap electronics – it’s completely cam driven. The solar panels only power the motor attached to the frame moving on bearings made from skateboard wheels.
We’d guess that [Markus] is using a little more than 2 square meters of Fresnel lenses in his project. Since solar irradiance is about 120 W/m² (PDF warning), [Markus] is concentrating a lot of energy onto a point the size of a quarter, which would be necessary to heat up sand to its 1500° C melting point. The resolution isn’t what you could get with a laser, but [Markus] was able to print an amazing bowl along with other complex 3d shapes.
Check out [Markus]’ video of the solar sinter printer after the break. There’s also a video of his previous experiment with the solar cutter.
Continue reading “Selective solar sintering with sand”