Double Vision coil winders handle mandrels from 0.001 to 0.188-in. diameter, 65-in. long (different mandrel lengths are optional), metal or plastic filaments from 0.0004 to 0.025-in. round solid or tube, or ribbon, filament tensions from 0 to 80 gm (±0.1 gm), mandrel tensions between 75 gm and 4 kg, (±2 gm), coil angles of ±3° at ±0.02° resolution (with vision) and greater angles at lower resolution without vision. The winders program through a color touchscreen display and are Ethernet ready. Two independent machines stack on one frame to double production for a given floor space. |
A miniature coil and a human hair sit atop a penny. Applications for miniature coils include coil stents, catheters, motor coils, and heating elements. |
Machine vision in Double Vision coil winders from Engineering by Design, San Jose, www.ebdesign.comdetects wind angles, without physical contact, to 0.02°. Previous measurement techniques used a mechanical arm fitted with an angle sensor. But as wires get smaller, contact with the mechanical sensor arm changes the wind angle and introduces errors up to 2°.
"Machine vision eliminates the error and boosts control accuracy by a factor of 100, which equates to more consistent product and less waste," says EBD President, Dale Henson. "Maintaining a steady tension of 0.2 gm and a wind angle of 0.1° makes it possible to produce coils from 0.0004-in.-diameter platinum wire."
Automatic mandrel and filament tensioning and variablepitch control let the machine wind coils with multiple and repeating combinations of pitch, direction, and length. Closed-loopfilament tension and slack control maintain programmed tension at speeds to 6,000-mandrel rpm and faster. Brushless servomotors drive the traverse mechanism and both mandrel ends, eliminating a back shaft. The control system records statistical data for each wind including the mean and standard deviation of all measured variables to verify product quality and refine the process.
