While his company, RepRap Ltd, provides open source, heavily-printable 3D printers, supplies and services online, Adrian Bowyer continues to invent and develop new ideas for open source 3D printing. The latest is a solenoid bed heater, a concept which Bowyer describes on his company blog.
Wanting to combine the concept of heated beds (invented by Chris Palmer aka “Nophead” in 2010) with removable steel sheets (invented by Josef Průša ), the RepRap inventor came up with a novel way to heat build platforms for material extrusion 3D printers. While heated beds ensure printed parts adhere to the build platform, removable sheets can be flexed to easily detach prints.
Bowyer’s idea is to use an electromagnetic attachment between the printer and the flexible sheet. The magnetic field holds the plate in place and is turned on or off when the printer’s bed heater is turned on or off. That way, once a print is finished, the magnets can be flicked off and the sheet can be removed. In the video below, YouTube user Kamera demonstrates how solenoids can be used to hold metal objects in place with an on/off switch.
He expands on this idea by imagining the printer’s hot end as a mechanism to push the flexible sheet off of the print platform when complete, making it possible for a new blank sheet to be loaded in order to begin a subsequent print. This process could be automated using a robotic arm similar to the method employed by Voodoo Manufacturing or we might imagine the printer’s extruder picking up a new sheet itself using a magnet or some other mechanism.
Bowyer envisions the solenoids under the bed powdered by pulse-width modulated electricity evened out by a capacitor acting as a low-pass filter. The magnets could then be operating continuously while the bed is heated, acting as both magnetic holders and heaters. For the flexible sheets, he hypothesizes the use of a ferromagnetic material that isn’t permanently magnetized so that the sheet doesn’t stick when the field is turned off. To see just how hot magnetic coils can get, check out the video below.
Having found no one else proposing this idea on the web, Boywer published his blog post in order to prevent it from being patented. This is only the most recent idea that he’s come up with and, while it is only a concept right now, it would not be surprising if he pursued it, since he has already begun exploring his other proposals for passive blocks for self-replicating 3D printers, open source oxygen concentrators , and an electric 3D printer in which an electric current is applied a vat of like a CT scan to create an object.
While all of the ideas are brilliant in their own way, the beauty linking them all together is that they’re all open source, which means that anyone can build on them and share their ideas freely in the hopes that, even if Bowyer himself doesn’t complete the task of creating a fully self-replicating 3D printer, or other project, someone else might.