Hangprinter is anopen-sourcefused deposition modeling delta3D printer notable for its unique frameless design. It was created by Torbjørn Ludvigsen residing in Sweden.[1] The Hangprinter uses relatively low cost parts and can be constructed for around US$250.[2][3][4][5] The printer is part of theRepRap project, meaning many of the parts of the printer are able to be produced on the printer itself (partially self replicating). The design files for the printer are available onGitHub for download, modification and redistribution.[6]
All parts of the Hangprinter Version 2 are contained within a single unit which uses cables to suspend the printer within a room, allowing it to create extremely large objects over 4 meters tall.[2][3][4][5]
To enable 3D printers to economically userecycled plastic feedstocks to enable distributed recycling and additive manufacturing (DRAM)[11][12] several types offused granular fabrication (FGF)/fused particle fabrication (FPF)[13] -based 3D printers have been designed and released with open source licenses. First, a large-scale printer was demonstrated[14] with aGigabotX extruder[15] based on the open source cable driven hangprinter concept. Then detailed plans usingrecyclebot auger techniques were released inHardwareX to build such a printer for under $1700.[16] This approach would further reduce the cost of using hangprinters to make large scale products as the cost of recycled shredded plastic is ~$1–5/kg while filament is generally around $20/kg.Makers that have built open source granulators[17] or have access to other types of waste plastic shredders (e.g. fromPrecious Plastic[18]) can generate feedstock for hanging waste printers for under $1/kg, which makes large scale production with a hangprinter competitive with any conventional manufacturing process.
In 2022, a patent describing the “Sky Big Area Additive Manufacturing” (SkyBAAM) system was granted to UT-Battelle, LLC, a nonprofit corporation that operates the Oak Ridge National Laboratory (ORNL). The patent describes the core features already featured in HangPrinter, causing controversy in the open source community. The RepRap project established a GoFundMe campaign to cover the legal costs in their upcoming action to challenge the patent.[19][20][21]
In May 2023 it was announced that the US Patent Office rejected the wide claims of the SkyBAAM patent and would be settling on a much narrower patent instead. Per a post on Torbjørn Ludvigsen's blog "They largely agreed with our analysis. They rejected all the patent's original claims. They accepted a narrower version of them."[22] Per the interpretation provided in that post the narrower patent would only cover cases where every detail provided is included in the design, instead of those designs with any of the described details.
