Designer's Corner 351
March 20, 2000
Works when wet
Totally enclosed magnets and coils, an Armoloy-coated precision bearing rail, IP67 magnetic linear encoder, and glanded robotic cable protect this linear motor from the dampest of environments. Other benefits include low maintenance, high precision, and increased throughput. The wet environment ThrustTube motor is electronically identical to conventional brushless servomotors; and simple point-to-point moves or complex motion profiles can be achieved using industry-standard servo drives. A low motor time constant, ripple-free force (permitted by Hall effect or software sinusoidal commutation), and virtually perfect linear thrust (all coils cut all flux) ensure outstanding servo response.
Rob Houghton, Linear Drives Ltd., Luckyn La., Basildon Essex, U.K. 5514 3BV4; Tel: +44 1268 287070.
Shock controllers
Many stopping devices simply store energy. Having stopped the object, the device bounces back, contributing to part fatigue and maybe failure. Because SH Industrial Shock Absorbers dissipate energy as heat, they bring moving objects to rest with no shock or bounce-back. The piston, moving through its stroke, forces oil through a matrix of metering holes, compressing a closed-cell accumulator sponge. As a spring returns the piston to its original position, the sponge expands, forcing oil back into the bore. The SH range offers adjustable and non-adjustable full-threaded metric type shock absorbers together with fixed flange adjustable type up to 28 mm bore size.
Robin Hill, Hepco Slide Systems Ltd., Lower Moor Business Park, Tiverton Way, Tiverton, Devon, U.K. EX166TG; Tel: +44 1884 257000, Fax: +44 1884 243500, E-mail: [email protected] .
Six-action tooling
Not all die-cast tooling is configured alike. Traditional tooling built by four-slide die casters is limited to forward and back movements across the flat plane in the X and Y axes. Die-casting small parts with multiple features, however, requires more. Fishercast, diecaster of zinc alloy components, employs six-action tooling, or the ability to pull moveable slides away from the part in the X, Y, and Z planes for complex geometries. The cubical configuration of six-action tooling has the added advantage of extra rigidity. Because the tool's moveable and fixed halves apply a locking force directly opposite the injection force, there is no tool movement during injection. Tools assembled to tolerances of 6 0.0025 mm, furthermore, ensure a tight cavity seal that prevents flash from forming during the die-casting process. Net shape components emerging from the tool are ready to use with no trimming required.
David Wawrykow, Fishercast-Div. of Fisher Gauge Ltd., P.O. Box 179, Peterborough, Ontario, Canada K9J 6Y9; Tel: (800) 547-6905, Fax: (705) 745-8818, E-mail: [email protected].
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