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could someone print this prothesis?

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I am a revalidation ingeneer and I would like to find a light prothetic knee .

The normal "mass production" knees are around 370gram: this is to havy

The knee is for a little boy, 3 years old, his weight is around 12 kg.

A knee of 360 gram with al the other parts will make his leg more than 1 kg, somewhere around 10% of his weight!

I would like to have two parts printed in abs plastique, (the weight will be approximatif 70 gram for the plastique parts, there are some metal parts, 100 gramm, this makes the total weight 170 gram)

please contact me for sending the 3d files at


(I will pay for delivery and printing, I live in France, 56600 Lanester)

Thanks a lot!


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I will try to start the ball rolling, maybe others with more experiance will add better knowledge. I think the first question that came to my mind is, 'will it be implanted?' I'm going to assume not. if it is, that brings a whole lot of other questions beyond can it be printed. I think that the models would need changing to print, otherwise a lot of cleanup which would be needed and I'm not sure what the impact would be on an implanted, cleaned up model.

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Would be a fun little project to try but unfortunately all I have is PLA and that's not suitable for this. The model looks a bit tricky to print, it will need support for sure. It doesn't look TOO bad though and it should be possible to print it without too much hassle. Would probably need to adjust the holes post print but I doubt that's an issue. The reason the holes would need to be adjusted is because it's hard to print perfectly round holes vertically (at least in my experience).

A couple of thoughts on what you could do to make it easier to print: In the picture below I've put in three arrows that point to "trouble" areas (if printed in this orientation). These areas are so called overhangs that means the printer has to print in mid air or add support to be able to print it properly. If you taper the model slightly sort of like I tried to show with the curved lines it can be printed without support. Of course, that particular shape might be needed for the other hardware.

There's also a big circle cutout in the red part. I assume this is just for weight reduction? If so, you could modify the top arch to help the printer there as well as it will be a very steep angle at the upper part of the circle.

Of course, you can still print this with support but I personally try to design around having to use support to save the hassle and also to produce a better surface quality.

Sounds like a pretty cool job to have though :) I hope it works out for the little guy!

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Thanks a lot for your observations I Robert I,

You are wright the holes can be post print, (even the big one !?)


If you taper the model slightly sort of like I tried to show with the curved lines it can be printed without support

I will change my model as you proposed!

Thanks again!

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