[caption id="attachment_13087" align="aligncenter" width="500"] Univ. Nottingham-designed 3-D printed prosthetic with circuits, mobile joints[/caption] 3D printers have not yet fulfilled their promise as a source of custom-printed, just-in-time circuitboards and datacenter server components. (But they have been featured on TV as the source of murder weapons and slightly-too-personalized individual action figures, so at least that's something.) A London Science Museum exhibit is now showing how one might have changed the plot of the "Terminator" movies. If that wasn't enough, it's also demonstrating how to make hideously complex, expensive prosthetics cheaper and more available. One of the 600 3D-printed objects on display is a Terminator-lookalike prosthetic arm designed by a 3D printing research group at the University of Nottingham, to demonstrate how printers can create both strong structural pieces, multi-directional joints and electronics to power touch sensors as part of a single process. "It's a mock-up but it shows circuits that sense temperature, feel objects and control the arm's movement," according to Richard Hague, director of the university's Additive Manufacturing and 3D Printing Research Group. The design is a step up in complexity from Robohand, an open-source engineering project launched in 2011 to design printable prostheses for those who have lost fingers or hands. The project posted many of its designs, including a full set of anatomically driven mechanical fingers, online for free download. And both sets of projects are a big step forward in the manufacturing and availability of prosthetics, though still far behind the technology of two experimental projects designed to reinforce weak, squishy or absent human parts with shiny, new bionic versions. Parts from 17 manufacturers went into "The Incredible Bionic Man," a full-body robotic prostheses assembled from artificial organs, limbs and other parts to demonstrate the current state-of-the-art for a Smithsonian Channel documentary due to air Oct. 20. The robot is 6'7", able to stand and take a step with assistance; it contains a functioning heart, kidney, arms, legs, eyes and other parts. It also has a prosthetic, mobile face designed as a replacement for people who have lost noses or other features to accidents or disease. It's a one-off and the parts were donated, so the overall cost is a mystery, but the parts would list for about $1 million, according to the announcement. The documentary and the robot were designed to show how far medical research has come in replicating the functions of human limbs and organs, technology the London Museum exhibit suggests could soon be available as downloadable, locally printable designs. 3D printers have been used to create replacement human kidneys and livers, for example as well as to build parts for a live-firing rocket engine tested in August by NASA. So how soon will it be before datacenters can print their own blade servers, NICs and SSDs? It will probably be possible sometime soon, but maybe not advisable. A team from Microsoft Research and the University of Tokyo did demonstrate working computer circuits printed onto paper using an ink-jet printer and ink loaded with silver nanoparticles, but 3D printing is still better for building cases than circuits. The printers are not yet sophisticated enough to build both the structure of a circuit board and the conductive elements inside it at the same time, according to Matt Johnson, of conductive-ink manufacturer Bare Conductive, who was quoted in the announcement of the paper computer. "So many people talk about 3D printing an iPhone, when all you can actually do is print a few limited components of one," he said.   Image: Science Museum, London/ Jennie Hills