Designer's corner 833

Robotic deburring tool

While automated robots address operator safety and health concerns in welding, painting, material handling, and assembly applications, accuracy and chattering problems have hindered robots in edge-deburring operations.

A pneumatically driven, floating-head robotic deburring tool eliminates chamfer inconsistencies due to part tolerances and chatter. Air from one line spins the cutting file, while another line supplies air that applies axial force on the file. The floating head consists of a free-flying piston (FFP) with attached tungsten-carbide file.

Air pressure, supplied above the free-flying piston (FFP), applies a constant force to the edge. The FFP is extremely light, and has 0.32-inch axial play inside a brass cylinder bearing. The burr hugs the edge with constant force and provides quality chamfers at speeds over 12 inch/sec.

Robert Little, ATI Industrial Automation, Peachtree Center, 503-D Highway 70 East, Garner, NC 27529; (919) 772-0115 x122; FAX: (919) 772-8259; E-mail: [email protected].

Robotic deburring tool with floating head reduces operator safety and health consequences related to manual edge deburring.

Temperature stable servovalve

Temperature variations alter the characteristic output of pneumatic servovalves, and affect the pneumatic-cylinder force, position, or velocity. This compact, single-stage, pneumatic-torque motor minimizes temperature and pressure shifts with a design that symmetrically distributes thermal stress.

Its patented, all-welded torque-motor construction has 40% fewer parts, and its magnetic circuit design reduces size 30% for the same performance. The torque-motor suspension's high-net stiffness minimizes the impact of supply pressure variations on output.

John Buscher, J.H. Buscher, Inc., 227F Thorn Ave., Orchard Park, NY 14127; (716) 667-2003; FAX: (716) 667-2039.

Low-dross aluminum melter

Secondary aluminum melters lose up to 10% of their production from "dross," a by-product from the reaction of aluminum and oxygen present in the furnace. DC-plasma technology reduces dross by 60%, increasing production by about $2 million for the average aluminum recycler, and saving in the range of $600,000 annually in hauling and landfill costs.

A 500-kW DC-plasma arc furnace recovers as much as 99% of the aluminum contained in scrap metal. Inert argon gas provides a stabile non-oxidizing atmosphere that inhibits dross formation. Off-gasses preheat scrap material en route to the furnace giving a thermal efficiency of 70% compared to 20% for gas fired units.

Christine Hopf-Lovette, EPRI, 3412 Hillview Ave., Box 10412, Palo Alto, CA 94303; (415) 855-2733; E-mail: [email protected].

Thermal compensation mechanism

A dual-field-of-view missile seeker requires that two optical paths remain parafocalized over a 60C temperature range. Motor-driven focusing mechanisms are too bulky for this application, so a passive-mechanical system compensates for unwanted thermal-focus shifts.

Controlling the contact slope angle of each spacer interface, determining the number of interfaces, and selecting materials with proper thermal-expansion coefficients; provide a lightweight thermal-expansion compensation mechanism.

All spacer components fit within a 1.2-inch OD x 1.0-inch ID x 0.25-inch-long volume, and a compression spring between the retainer and lens 1 provides seating loads throughout the thermal operating range.

Don McCrary, Lockheed Martin, MP 940, 5600 Sand lake Rd., Orlando, FL 32819; (407) 356-0329; FAX: (407) 356-5072; E-mail: [email protected] .