Automated hotend exchange for less expensive multi-color printing

Multicolor printing on FDM machines can be tricky to get right, and purging hotends when changing colors can end up wasting a lot of filament and material. To solve this problem for the popular Prusa i3 and Ender 3 printers, [BigBrain3D] developed the Swapper3D, an automated system that swaps the entire hotend when the material is changed, almost eliminating the need for purging. Video after the break.

Swapper3D works very similarly to tool changers on CNC machines, and is just as satisfying to look at. A large circular carousel on the side of the machine can hold up to 25 hotends, and in practice a pair of robotic arms pull out the previous hotend, cut the filament, and load the specified hotend from the carousel. This means you can have a separate hotend for each color or type of filament. Since most existing hotends also incorporate the heating element, [BigBrain3D] created a special hotend assembly that can be robotically removed/inserted into the heating block.

Swapper3D is designed to be used with existing filament changers like the Prusa MMU and Mosaic Palette. Using these systems involves a lot of purging, to the point that you sometimes end up using more filament during purging than you need for the actual part. On a five-color demo print, the Swapper3D reduced print time by 45% and filament used by 86%. It also eliminates problems such as threading and fading of multi-color prints. With these benefits, it looks like the Swapper3D could be a worthwhile upgrade if you do a lot of multi-color printing, even if it adds a bit of complexity to the printer.

For larger and more expensive machines, swapping out the entire tool head is becoming increasingly popular, and even E3D is entering the fray.