3D Printing News Briefs, March 24, 2021: NSWC Carderock Division, Tel Aviv University, Integza

In today’s 3D Printing News Briefs, we’re covering several different applications for which the technology can be used: maritime and military, electronics and medical research, and engines. A new digital scanning and inspection method for submarines is saving both time and money, while researchers in Israel figured out how to achieve one-step 3D printing of heart patches with built-in electronics. Finally, a YouTuber uses 3D printing to build an honest to goodness turbojet engine, and tests it out…in his attic. Read on to see what happened!

US Navy’s New Scanning & Inspection Method for Propulsion Shafts

New canning and inspection method for submarine, ship propulsion shafts saves time and money

The STAVE, or Shaft Taper Analysis Verification Evaluation, system was created to replace the traditional plug and ring gauge system used by submarines, nuclear aircraft carriers, and other ship classes using fixed-pitch propulsion shaft taper refurbishment. It’s a digital scanning technology and inspection process that’s meant to decrease the cost of shaft tooling, reduce manpower requirements for repairing shafts, and improve the quality and consistency of shaft tapers—all points that align with the Naval Surface Warfare Center (NSWC), Carderock Division’s strategic plan under sustainment-based technologies. A STAVE system is supposedly easy to implement, and saves money, as it’s able to inspect all nuclear aircraft carriers and submarine classes at a shipyard, without the Navy having to buy new gauges for shaft refurbishment. It also saves time, since rigger support and tail stock removal are not needed for setup, and it also creates a digital shaft record during construction and repairs. The Structures and Composites Division at NSWC Carderock has been working on STAVE for over a decade, and the system has finally been integrated into the US Navy’s fleet.

“Taper gauges are used to inspect shaft tapers when getting repaired. But they are expensive to build and maintain. A lot of rigging is required to lift the gauges, which are roughly 2,000 pounds. We came up with an idea to develop a solution to replace these gauges since they are heavy, cumbersome and involve massive logistic issues,” explained Anthony Brock, 3D Measurement Lead Engineer in Carderock’s Performance Evaluation Branch.

“The technology simply wasn’t there when we first started this process. But, in the last six or so years, 3D scanners have gotten to a point where they are good enough to measure large areas with extreme accuracy.”

STAVE has already been delivered to the Norfolk and Portsmouth naval shipyards, and the next step will be to deliver the system to Pearl Harbor and Puget Sound.

One-Step 3D Printed Heart Patches with Integrated Electronics

Schematics of the concept. Three distinct bioinks were produced: one composed of cardiac cell-containing ECM hydrogel to form the tissue, another composed of the conducting material of the electronics, and a third containing the dielectric material which passivates the electrodes,
leaving open conducting pads for point-sensing and stimulation. The bioinks were 3D printed together to engineer the electronic cardiac patch. The electronics within the patch can provide sensing of extracellular signals and stimulation for pacing.

To regenerate a diseased heart, cardiac tissue engineering can be used, with cells being seeded in or onto 3D biomaterials before they’re introduced to the injured area that needs repopulated. These materials basically imitate an extracellular matrix (ECM), acting as temporary scaffolds to support the cells and promote their reorganization into a working cardiac patch, and 3D printing can be used to precisely place the cells in the scaffold. Building on previous research into 3D printed cardiac patches, a team of researchers from Tel Aviv University published a study about their work developing a process for one-step 3D printing (see above schematic) of personalized cardiac patches that have built-in soft, stretchable electronics, for potential future applications such as drug testing or treatment of infarcted hearts.

The abstract reads, “The tissue is simultaneously printed using three distinct bioinks for the cells, for the conducting parts of the electronics and for the dielectric components. It is shown that the hybrid system can withstand continuous physical deformations as those taking place in the contracting myocardium. The electronic patch is flexible, stretchable, and soft, and the electrodes within the printed patch are able to monitor the function of the engineered tissue by providing extracellular potentials. Furthermore, the system allowed controlling tissue function by providing electrical stimulation for pacing. It is envisioned that such transplantable patches may regain heart contractility and allow the physician to monitor the implant function as well as to efficiently intervene from afar when needed.”

For more information, you can check out the full study here.

3D Printed Turbojet Engine by YouTuber

An eccentric maker named Joel, known as Integza on YouTube, creates videos centered around useful science and engineering projects, while also including some entertainment and 3D printing. He chooses his projects based on what he finds interesting, and recently that was a working turbojet engine, with many 3D printed components, which he actually tested out in his attic; that’s commitment, people! He began with an ill-fated attempt to 3D print the entire engine out of ceramic resin, which didn’t work too well, and he ended up forming some of the parts out of high-temperature fireplace cement in 3D printed molds. Integza also taught himself how to weld in order to make the combustion chamber, and eventually he created a legitimate working turbojet engine, which he successfully tested in what appears to be his attic.

“It seems like something isn’t quite right with this stubby little engine because the run is only brief and comes after several attempts and a few modifications,” The Drive staff writer Peter Holderith wrote. “However, this home-built turbojet runs for real, in this guy’s attic, and a lot of it is 3D-printed.”

To learn more about this turbojet engine project, and have a few laughs (an evil tomato supervillain randomly turns up?), check out the full video below: