This section was edited by Associate Editor Alan S. Brown.
DOWEL LOCKS TIGHT WITHOUT TOOLS
A new type of dowel promises to make it easier to assemble—and disassemble—ready-to-build furniture, point-of-sale displays, kitchen cabinets, and even surfboard fins and athletic shoe cleats. According to Lock Dowel of Fremont, Calif., the company’s lock dowel joints join without tools and never loosen or come apart unless removed on purpose. The locks are targeted at products that now use cam locks, screws, nuts and bolts, or glue.
The concept behind the technology is as elegant as it is simple. Each lock dowel joint consists of a dowel and a latch housing, product manager Fred Koelling explained. The latch housing contains a beveled split ring. The dowel looks like a rod with a large conical structure on one end (or both). The inside and outside of the cone are angled to match the bevel of the ring. When pushed into the ring, the cone forces it open. Once the cone slips through, the ring closes on the rod, called the latch saddle, and locks it into place.
To remove the dowel, a wedge or similar tool tilts the dowel (or the part to which it is attached). It can now slide out along the cone’s inner bevel. By adjusting bevel angles and ring size and composition, Lock Dowel can vary insertion and removal forces from 2.5 pounds to more than 200 pounds.
Almost anyone can push the dowels in without tools, Koelling said. Once the ring engages the latch saddle, neither vibration nor heavy use will cause the joint to loosen or fail. Nor are the dowels visible after assembly.
This makes them very attractive to ready-to-assemble furniture makers. “The fasteners are all hidden, so finished pieces look like case goods,” Koelling said. “You can disassemble and move a piece without weakening the joints when you put it back together. And you can number matching holes 1-2-3 and put pieces together like paint-by-numbers. So you’ve got instructionless and toolless assembly.”
He said that lock dowels have drawn interest from companies that want to slash assembly time. They include companies that ship unassembled furniture to distributors, kitchen cabinet contractors, and people who set up point-of-sale displays in stores.
Koelling originally invented the technology to attach fins to surfboards without screws because changing fins eventually loosened their attachment holes.
“Phil McConkey, a former NFL receiver, is on our advisory board, and when he saw that, he said, ‘You have to do these for cleats,’” Koelling said.
Lock Dowel’s all-plastic system makes cleats fast and easy to replace.
A PUSH FOR MICROWAVE SINTERING
Sometimes the best new material is not new at all, but rather an expensive material made cheaper. That is exactly what Joe Hines, CEO of Spheric Technologies, is proposing. He claims his line of microwave furnaces will slash processing times for ceramics and powder metals while they improve the materials’ properties.
Rustum Roy of the Pennsylvania State University pioneered microwave sintering 20 years ago. Spheric purchased key Penn State licenses covering the application of microwaves in materials processing. While the technology never really caught on in North America, it has become a staple in Asia. Spheric imports Chinese furnaces and resells them in the United States under Penn State’s application licenses.
Microwave furnaces speed sintering of ceramics and metals.
Tests by Alfred University’s NanoMaterials Innovation Center in New York found that Spheric’s continuous microwave furnace reduced sintering time for nickel-zinc ferrites to four hours from nine hours and used 70 percent less energy. It cut alumina sintering to six hours, from 15 to 20 hours, and used 65 percent less energy.
In both cases, microwaves yielded structures with finer grains than conventional sintering. As a result, the materials were denser, stronger, and tougher. They also deformed and cracked less during production. Hines said he achieves similar structural improvements with titanium powder and other powder metals.
The company recently filed for patents on microwave synthesis of lithium ferro phosphate and lithium titanate. Both are leading contenders for cathodes in lithium ion batteries used in electric and hybrid cars.
Microwaves are one of several ways to make the ceramic cathodes. Spheric’s method starts with unique starting materials and produces pure materials that need little refinement. Microwaving slices production time to 30 minutes from 10 hours with heat sintering. Hines said the materials have very fine grain structure that should permit faster recharging. If that proves the case, he will license the technology to companies that buy the furnaces.
Hines is also working with dental labs that mill presintered blocks of zirconia into crowns, bridges, and entire teeth, then sinter them into ceramic implants. “We can sinter that material in 60 to 90 minutes versus several hours in conventional furnaces,” Hines said. A small 4-inch x 4-inch batch furnace costs about $18,000, though some dental labs are interested in small continuous furnaces.
Dental ceramics are a huge business, with about 15,000 labs in the United States alone. Another possibility is powder metals processing to make gears and small, finely detailed parts that are too expensive to machine.
ROBOTS VEER OFF THE BEATEN PATH
Mobile robots are increasingly used to shuttle supplies and handle security in warehouses, factories, and hospitals. As intelligent as those machines are, they are not very flexible. They often must follow routes fixed by wires on the floor or defined by wall reflectors and ceiling beacons. If they run into an obstruction—a piece of machinery, a fallen pallet, or a worker—many simply stop and must be manually restarted. Most are too rigid for use in a factory built with reconfigurable work cells.
Adept Technology of Pleasanton, Calif., hopes to solve those problems with its new line of intelligent robots, the MT-400 for industrial use and the MT-490 for human interaction. Their vision guidance system frees them from floor wires, beacons, and reflectors, and their ability to use visual landmarks enables them to handle exceptions by automatically readjusting their routes. Adept acquired the robots with the purchase of MobileRobots Inc. in June 2010.
According to Adept’s global sales and marketing director, Rush LaSelle, the intelligent robots come with laser range finders and cameras for object recognition. “When we do demonstrations, we take them into a conference room and drive one around with a joystick,” LaSelle said. “It sees and maps the walls, the table, and the chairs in under 30 minutes.”
A new line of robots uses its vision system to navigate
the workplace more flexibly.
The robot really shines when people start moving the chairs around. It can triangulate from other features in the room, giving priority to the unchanging wall and the odometry data from its wheels, to determine its position. In a warehouse, where there are few walls, the robot’s lasers and camera scan the ceiling for unique features.
“Let’s say the robot needs to get to a bay in a warehouse and there are fallen pallets,” LaSelle said. “If the robot starts down the aisle and sees it is blocked, it can turn around and go down the next aisle and then enter the aisle from the other end.”
The robot is designed to work near humans. It will navigate around people if they are stationary; check their vectors and adjust its path if they are moving; or stop and rely on its bumpers if someone is moving too fast for it to get out of the way.
LaSelle said the mobile robots can provide a fully traceable path when transporting narcotics and regulated drugs in a pharmaceutical warehouse or a hospital.
The robots can be used for just-in-time service on packaging lines. “Intelligent robots can bring only what is required to load the machine, then take the finished goods back to another location in the warehouse,” LaSelle said. “They do it the same way every time, so you can plan and tighten your cycles, and you don’t have forklifts running around your production equipment.”
In a cell-based manufacturing facility, mobile robots could prove an important link in delivering on the promise of just-in-time manufacturing, he said.
LIGHTWEIGHT ALLOY SEEKS AIRCRAFT ROLE
A new aluminum-lithium alloy technology promises to slash the weight of aircraft primary structures by 20 percent, according to its manufacturer, Alcan Global Aerospace, Transportation and Industry. The new alloy, called Airware, can compete with and complement composites, Alcan said. Both Airbus and Bombardier have signed contracts to buy the alloy for new aircraft currently under development.
This is quite a turnaround for aluminum-lithium, which has been under development since the 1980s. The original idea was to incorporate lithium, the lightest metal, into aluminum to reduce density. Unfortunately, lithium also ranks among the most reactive of elements. The resulting alloys were lightweight, but had stability and weldability issues. During the 1990s, metallurgists improved welding and mechanical properties, but only if they made lithium alloys heavier and much more expensive.
A new family of aluminum-lithium alloys promises better mechanical
properties and lower density to compete with composites.
According to Bruno Chenal, Alcan’s director of innovation and technology, Airware has found a happy medium. Airware includes only 2 percent lithium. This proportion reduces the alloy’s density, and also increases such mechanical properties as strength, stiffness, toughness, and fatigue strength by more than 30 percent. The combination of improved properties and lower density enables manufacturers to reduce the weight of structural parts by 20 percent.
According to Chenal, Airware has two to three times the corrosion resistance of the best aluminum alloys. Ordinarily, corrosion attacks aluminum too fast to use with composites, which are impervious to its ravages. Alcan said that Airware will let engineers build components that combine aluminum and composites (think aluminum wing frames with composite skins) and not have to worry about heavy maintenance for 12 years.
Alcan has developed a technology to recycle the aluminum-lithium alloy, something that was impossible in the past because of lithium’s high reactivity. This is important because about 90 percent of the material is lost in machining and fabrication, and lithium is expensive to refine and to alloy. Recycling recaptures the lithium at much lower cost, making the alloy more affordable, Chenal said.
Airbus and Bombardier will use aluminum-lithium on new aircraft.
While aluminum-lithium cannot compete with composites on weight, it is close. It also uses existing metal machining and fabrication technologies, unlike composites, which require new layup equipment and ovens.
Airbus plans to use Airware 2050 plate and forging stock for its dual-aisle A350 XWB aircraft. It will go into the wing frame and some fuselage parts. It will constitute more than 20 percent of all materials used on Bombardier’s new CSeries single-aisle aircraft. Bombardier will use sheet and extrusions for fuselage skins, stringers, frames, and floor beams.