Steel in the News
Michigan Tech Scientists Build 3D Metal Printer
Posted by Tasha Weiss on December 11, 2013 at 6:02 PM
Until now, 3D printing has been a polymer affair, with most using the machines to make all manner of plastic consumer goods, from tent stakes to chess sets. However, a new 3D printer, developed by Michigan Technological University’s Joshua Pearce and his team, can create objects out of steel. The detailed plans, software and firmware are all freely available and open-source, meaning anyone can use them to make their own metal 3D printer. (The photo at left shows Michigan Tech's open-source 3D metal printer in action. Photo: Chenlong Zhang)
Pearce is the first to admit that his new printer is a work in progress. So far, the products he and his team have produced are no more intricate than a sprocket. But that’s because the technology is so raw. “Similar to the incredible churn in innovation witnessed with open-sourcing of the first RepRap plastic 3D printers, I anticipate rapid progress when the maker community gets their hands on it,” said Pearce, an associate professor of materials science and engineering/electrical and computer engineering. “Within a month, somebody will make one that’s better than ours, I guarantee it.”
Using under $1,500 worth of materials, including a small commercial MIG welder and an open-source microcontroller, Pearce’s team built a 3D metal printer that can lay down thin layers of steel to form complex geometric objects. Commercial metal printers are available, but they cost over half a million dollars.
His make-it-yourself metal printer is less expensive than off-the-shelf commercial plastic 3D printers and is affordable enough for home use, he said. However, because of safety concerns, Pearce suggests that for now it would be better off in the hands of a shop, garage or skilled DIYer, since it requires more safety gear and fire protection equipment than the typical plastic 3D printer.
In previous work, his group has already shown that making products at home with a 3D printer is cheaper for the average American and that printing goods at home is greener than buying commercial goods.
In particular, expanded 3D printing would benefit people in the developing world, who have limited access to manufactured goods, and researchers, who can radically cut the cost of scientific equipment to further their science, said Pearce. “Small and medium-sized enterprises would be able to build parts and equipment quickly and easily using downloadable, free and open-source designs, which could revolutionize the economy for the benefit of the many.”
“I really don’t know if we are mature enough to handle it,” he added cautiously, “but I think that with open-source approach, we are within reach of a Star Trek-like, post-scarcity society, in which ‘replicators’ can create a vast array of objects on demand, resulting in wealth for everyone at very little cost. Pretty soon, we’ll be able to make almost anything.”
The work is described in "A Low-Cost, Open-Source Metal 3-D Printer," to be published in IEEE Access (DOI: 10.1109/ACCESS.2013.2293018). The coauthors in the Michigan Tech Open Sustainability Lab are Gerald C. Anzalone, a lab supervisor and research scientist in Michigan Tech’s Department of Materials Science and Engineering; Chenlong Zhang and Bas Wijnen, Ph.D. candidates in materials science and engineering at Michigan Tech; Paul Sanders, an assistant professor of materials science and engineering; and Pearce.
Construction Spending Spikes to Four-Year Peak
Posted by Tasha Weiss on December 9, 2013 at 5:49 PM
An unusual surge in public construction in October pushed total construction spending to its highest level since May 2009 despite a dip in both private residential and nonresidential activity, according to an analysis of new Census Bureau data by the Associated General Contractors of America (AGC). Association officials urged lawmakers in Washington to make water and surface transportation investment a top federal priority.
“Nearly every category of public construction increased in October, according to the preliminary Census figures, although for the first 10 months of 2013 combined, public spending continues to lag the 2012 year-to-date total,” said Ken Simonson, the association's chief economist. “Meanwhile, residential spending slipped for the month but still showed strong year-to-date gains, and nonresidential spending remained stuck in neutral.”
Construction put in place in October totaled $908 billion, 0.8% higher than in September. But figures for August and July were revised down below levels that initially exceeded the current October estimate. The total for the first 10 months of 2013 was 5.0% above the year-to-date mark for the same months in 2012.
Public construction spending jumped 3.9% for the month but trailed the 2012 year-to-date total by 2.8%. The two largest public components were mixed: highway and street construction increased 0.6% in October and 0.3% year-to-date, while educational construction leaped 8.5% for the month but fell 8.5% year-to-date, Simonson said.
Private residential spending slid 0.6% for the month but still climbed 17% year-to-date. New single-family construction decreased 0.6% in October but soared 30% in the first 10 months of 2013 compared with 2012. New multifamily spending advanced 2.2% in October and 46% year-to-date.
Private nonresidential spending edged down 0.5% for the month and up 0.8% year-to-date, Simonson observed. The largest private nonresidential category, power—including oil and gas as well as electricity—plunged 5.7% and 5.8% over the two time periods. But the next three niches in size—manufacturing, commercial (retail, warehouse and farm), and office—rose for the month and year-to-date.
“Construction will likely display varied patterns in the next several months,” Simonson said. “Multi-family construction will keep burgeoning but single-family homebuilding may stall. Private nonresidential spending should benefit from more power, energy and manufacturing work. Public construction remains threatened.”
Association officials said Congress and the administration should keep public construction from returning to its recent slump by quickly completing Water Resources Development legislation that has already passed both houses and passing a new surface transportation bill next year that funds repairs to deteriorating highway, bridge and transit infrastructure. They added that any new transportation bill must include provisions to adequately fund the nearly depleted federal Highway Trust Fund.
“If Congress can act in a bipartisan way on transportation funding as it did on the Water Resources bill, it can avoid a cliff-like drop in highway spending,” said Stephen E. Sandherr, the association’s chief executive officer.
Steel Shots: Decision Delta
Posted by Tasha Weiss on December 6, 2013 at 5:36 PM
The new Shenandoah River Bridge superstructure consists of a five-girder, four-substringer system supported by five lines of delta legs - one for each girder. Photo: Courtesy of HDR, Keith Philpott, photographer
Just an hour’s drive west from Washington, D.C., the new Shenandoah River Bridge stands in aesthetic harmony with its surroundings.
The project exists within a unique ecosystem where the scenic Shenandoah River valley boasts steeply rising wooded mountains, a diverse wildlife habitat, rolling farmland and quaint, historic towns. Not surprisingly, the region has evolved into a desirable getaway from the frenzy of urban life.
With the subsequent increase in traffic, the West Virginia Department of Transportation - Division of Highways (WVDOT) determined that the winding two-lane road that carried West Virginia Route 9 (WV9) through the valley was no longer sufficient. In September 2009, it revealed the design for a new alignment: a four-lane divided highway using a bridge over the Shenandoah River. At the crossing location, the proposed grade was nearly 200 ft above the river, and the overall bridge length would be nearly 1,800 ft. While there are no navigation requirements for the river, the environmental constraints for the project and the relatively high cost of substructure units located in the valley dictated that the main span be approximately 600 ft in length. To accommodate these constraints, a three-span continuous deck truss configuration (400 ft - 600 ft - 400 ft) with short plate-girder approach units was initially selected during the design phase.
In early October 2009, WVDOT modified the procurement from design-bid-build to design-build and instructed contractors that they could bid the as-designed truss or develop and bid a different structure type, providing they addressed the following criteria:
- The chosen substructure locations for the deck truss bridge generally must be used, with very limited latitude.
- The established horizontal and vertical alignment could not be changed.
- Alternatives that required increased amounts of disturbance to the gorge slopes would not be considered.
- The use of a causeway or cofferdams, other than as shown on the plans for the as-designed bridge and/or in the Section 404 (of the Clean Water Act) Permit, would require re-permitting.
- The design must comply with all previously established environmental commitments.
Following concept approval, structural engineer HDR Engineering developed a delta frame design that delivered significant savings compared to proposals for more traditional designs and also resurrected a tried-and-true form that had been largely forgotten since the 1970s.
To learn more about this uncommon design resurrected by the new bridge, you can read the article from the December 2013 issue of MSC (available now!).
Lincoln Electric Broadens Cutting, Welding Portfolios with Recent Acquisitions
Posted by Tasha Weiss on December 5, 2013 at 4:52 PM
Lincoln Electric (an AISC member) has acquired an ownership interest in Burlington Automation Corporation, a designer and manufacturer of 3D robotic plasma cutting systems based in Hamilton, Ontario, Canada. Terms of the transaction were not disclosed.
"Burlington Automation broadens our portfolio of automated cutting and welding process solutions and strengthens our automation strategy," said Christopher L. Mapes, CEO of Lincoln Electric. "Their proprietary technology complements our current automated cutting and welding systems by enabling customers to increase productivity and improve quality while reducing capital investment and floor space.”
In separate news, Lincoln Electric announced that it has entered into a definitive agreement to acquire Robolution GmbH, a provider of robotic arc welding systems based outside of Frankfurt, Germany. The transaction was expected to close by the end of last month and terms were not disclosed.
AISC Detailer Training CDs Available for Download
Posted by Tasha Weiss on December 3, 2013 at 6:01 PM
AISC's detailing resources in ePubs have been updated with the addition of the very first detailer training CD collection from 2000, and the contents of those golden-oldie CDs are now downloadable by AISC members.
AISC and NISD jointly created a series of 12 detailer training CDs in 2000. These CDs contained MPG instructional videos and PDFs of example drawings covering the basics of the structural steel industry and 2D detailing. As a courtesy to AISC members, the contents of these CDs are available in AISC's ePubs collection.
To download the CD contents, go to AISC's detailing resources in ePubs.