Hackaday Prize Entry: Printing Bones

You would be forgiven to think that 3D printing is only about rolls of filament and tubs of resin. The fact is, there are many more 3D printing technologies out there. Everything from powders to paper can be used to manufacture a 3D model. [Jure]’s Hackaday Prize entry is meant to explore those weirder 3D manufacturing techniques. This is a printer that lays down binder over a reservoir of powder, slowly building up objects made out of minerals.

The key question with a powder printer is exactly what material this printer will use. For this project, [Jure] is planning on printing with hydroxyapatite, a mineral that makes up about 70% of bones by weight. Printing bones — yes, they do that — is quite expensive and has diverse applications.

The design of this printer is about what you would expect. It’s a Cartesian design with a roller to distribute powder, a piston to drop the part down into the frame, and an industrial inkjet printhead designed for wide format printers. It’s a fantastic piece of work and one of the better powder printers we’ve seen, and we can’t wait to see what [Jure] is able to produce with this.

23 thoughts on “Hackaday Prize Entry: Printing Bones

    1. You could do it but it would require a really finely ground hydroxyapatite powder which is hard to make or very expensive. Also you would require a nozzle with much more dpi than what i have used

    2. Was wondering the same thing. The hollow/latticed structure of bones gives them a good strength-to-weight ratio. Could be a good material for RC planes if it can be printed.

  1. HA isn’t really that great at mimicking bones on its own though at a living or cellular level. It precipitates apatite in vivo great, and can glue itself to native bone to make a good mate. But cell’s don’t really live on mineral surfaces. Unfortunately, when you fire your green body, you’ll end up burning off anything more biocompatible you print with, so you’ll have to make the print mesoporous or something so you can get a good collagen/chitosan/whatever more biocompatible polymer coating after it’s all fired. If you only need the surface to populate, of course, you don’t have to be so worried.

    If all you wanted was a solid HA object though, just 3D print it, cast it in silicone, fill the cast with your HA slurry, bake a green body. Pop it out, and throw it in a kiln. Very little waste, and extremely easy. Heck, you can even do a lost PLA cast and make all sorts of funny shapes! I couldn’t get the resolution I needed from FDM, so I don’t know how successful this would be though, just an idea.

    1. One of the concepts of this project is to show that big advances in various technology could be achieved at home. Also I know that HA is not such a great material for bone printing, but it showed properties that make it quite hard to print, this way it was more of a learning challenge.

  2. Bear in mind that printing a homogeneous, low resolution bone like material of an arbitrary shape isn’t the same as building a living osteo tissue. It’s a pretty big difference actually. This is certainly a neat step but it’s also not reasonable to assume these could be printed and implanted along side living tissue as a bonafied drop in bone replacement. At least not in this implementation.

    1. You could still make a scaffold-like object that would be modeled using advanced calculations, which predict bone, cell and tissue growth. This has already been achieved.

  3. Misleading title as usual.
    A blemish strongly accentuated in HaD since Supplyframe bought it.
    It´s not even nearly “printing bones”, but yeah, Brian clickwhore as usual…

  4. If a biocompatible binder is used, how about printing custom replacement pieces for bones, seeding them with stem cells from the patient along with bone morphogenetic protein and something to cause angiogenesis so there will be blood vessels to connect to the patient’s circulatory system to keep the new bone alive.

    Got an arm all smashed up? Scan the other one, mirror image the scan then print new bones. Infest the scaffold with life and swap out the crunchy bits with new bones. Crushed a vertebra? Same thing. Print, juice it up, replace.

    Would just have to keep the patient stable during the prep process while the new bone is made.

    1. Yep this is one of the ways this could be used, but this is for people who have the ability to use living tissues and cells. As of now my schedule is packed with exams, working on project and designing new materials to use with the device.

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