3D Printing News Briefs, March 27, 2021: Sandia, Desktop Metal & Uniformity Labs, Thermwood

In today’s 3D Printing News Briefs, we’re discussing how 3D printed rocks are being used to detect earthquakes, aluminum sintering for binder jet 3D printing, and two pieces of interesting news from Thermwood about its additive manufacturing technology.

Using 3D Printed Rocks to Identify Early Signs of Earthquakes

Sandia National Laboratories geoscientist Hongkyu Yoon holds a fractured 3D printed rock. Hongkyu squeezed 3D printed rocks until they cracked and listened to the sound of the rocks breaking to be able to identify early signs of earthquakes. Photo credit: Rebecca Gustaf

Fracking, geothermal energy stimulation, and carbon dioxide sequestration can all lead to earthquakes, and while energy companies check for faults as often as they can, the unexpected can still happen. A team of geoscientists from Sandia National Laboratories wanted to learn how to better understand and detect these kinds of unexpected, energy exploration-triggered earthquakes, but they needed rocks that would fracture the same way each time pressure was applied in order to study the warning signs of fault failures. Unfortunately, natural rocks, even when collected from the same place, can have different layering and mineral orientation, and therefore different weak points. Together with researchers from Purdue University, the Sandia team 3D printed rocks on a ProJet 360 to study how pressure can transfer through pores down to fault lines, and also crushed 3D printed rocks that had specially added weak points to hear how different types of fault failures sound. The resulting sound data was then combined with a machine learning technique called a random forest algorithm to help identify patterns in the data in order to detect signals of possible seismic events. A large-scale computational model of past earthquakes was used to better understand how stress from water injection is transferred to a fault to cause these quakes.

Sandia geoscientist Hongkyu Yoon said, “It turns out we can use that variability of mechanical and seismic responses of a 3D-printed fracture to our advantage to help us understand the fundamental processes of fracturing and its impact on fluid flow in rocks.”

Another geoscientist from Sandia, Kyung Won Chang, said, “In general, we need multiphysics models that couple different forms of stress beyond just pore pressure and the deformation of rocks, to understand induced earthquakes and correlate them with energy activities, such as hydraulic stimulation and wastewater injection.”

Chang and Yoon are working together to apply and scale up machine learning algorithms to find hidden faults, and determine geologic stress signatures that could predict how intense a triggered earthquake will be. To learn more, check out the papers that were published about various aspects of this research, like stress transfer, here, here, and here.

Desktop Metal, Uniformity Labs: Aluminum Powder for Binder Jetting

Fully dense, sinterable 6061 aluminum with better than wrought strength will be available for binder jetting technology, marking a significant step forward for the AM industry as it is one of the most sought-after materials for use in automotive, aerospace and consumer electronics. Photo credit: Business Wire

Additive manufacturing companies Desktop Metal (NYSE: DM) and Uniformity Labs have spent several years collaborating to develop a breakthrough aluminum powder that makes it possible to sinter aluminum in binder jetting technology, and now it’s finally here. This new low-cost, raw material is able to print fully dense, sinterable aluminum 6061 that has better yield strength and ultimate tensile strength than wrought aluminum 6061, and it also enables compatibility with water-based binders as well. This is a major improvement over past aluminum sintering techniques: there’s no need now for coating powder particles, mixing in sintering aids, using binders with costly nanoparticles, or adding in other metals, like magnesium, lead, or tin. The two companies will continue working together to qualify their new powder and scale the production for commercial release; then, once the Uniformity 6061 aluminum is fully qualified, it will be exclusively available to use with Desktop Metal’s Production System platform.

“This breakthrough represents a major milestone in the development of aluminum for binder jetting and a significant step forward for the AM industry as it is one of the most sought-after materials for use in automotive, aerospace and consumer electronics. The global aluminum castings market is more than $50 billion per year, and it is ripe for disruption with binder jetting AM solutions,” said Desktop Metal’s CEO and Co-Founder Ric Fulop. “These are the best reported properties we are aware of for a sintered 6061 aluminum powder, and we are excited to make this material available exclusively to Desktop Metal customers as part of our ongoing partnership with Uniformity Labs.”

Thermwood Reveals Thermal Sensor Layer Automation System

Thermal Sensor Layer Automation System. Photo Credit: Thermwood

Because of a patented “Layer Time Control” feature, Thermwood’s Large Scale Additive Manufacturing (LSAM) machines can already print large thermoplastic composite structures, for multiple applications, that are fused almost perfectly. But now the company has introduced a new LSAM technical capability, called the Thermal Sensor Layer Automation System, that makes print temperature control totally automatic, which truly ensures total fusion between the printed layers. When it comes to 3D printing thermoplastics, different polymers have different ideal print temperatures for good fusion, and Thermwood’s new system uses a rotating, non-contact sensor to continuously measure a layer’s temperature right before a new material bead comes out of the nozzle, which means that the printer can automatically adjust the feed spring to get the optimal temperature for layer to layer fusion, which equals better part quality.

An advanced algorithm quickly processes data from the sensor to adjust print speed, which means that the CNC program is no longer in charge of the speed of printing: the LSAM control system responds to changes in the print environment automatically and takes care of it. With Thermwood’s new system, the optimal print temperature is now stored with the other parameters in the control for each polymer. So in order to print using a specific material, all you have to do is load the part program, choose your material, and push the “On” button, as the the whole build process is almost completely automated now, without requiring adjustments or input from a human machine operator. Thermwood has retrofits available as well, so existing LSAM customers can upgrade their existing systems to add the new Thermal Sensor Layer Automation System.

Speaking of Thermwood, the LSAM manufacturer has another piece of good news to share: its new line of lower-cost LSAM systems, called LSAM Additive Printers, is now available. Its existing systems are often used to fabricate large-scale fully-fused products, like aerospace molds and tooling, from reinforced composite thermoplastic polymers, including high-temperature materials like PEI and PSU, but clients have been requesting a smaller system that includes the features and print quality of Thermwood’s flagship LSAM systems, but at a lower cost. The new LSAM Additive Printers are “print only” machines build around its new 30 mm LSAM print head; for contrast, its normal 40-60 mm print heads weigh over two tons and require powerful servo drives. Thermwood re-engineered the gantry structure of its 5-axis CNC routers to handle the new print head, which, although smaller than the original, is still pretty big.

The new LSAM Additive Printers are fixed gantry, moving table designs, with can print parts up to four feet high, and the 30 mm print head is able to print up to 100 lbs of material an hour, at temperatures up to 450°C. It comes in two styles, with the first measuring five feet wide with ten feet of front to back motion, and vice versa for the second one, and the maximum table print weight is 1,000 lbs, though the second style does have an optional dual servo drive, which doubles the weight carrying capability. Other features include an optional enclosure that surrounds the machine, an optional dual hopper dryer for applications that change materials often, and Thermwood’s new Thermal Sensor Layer Automation System is also available on the new LSAM Additive Printers.