Beyond Flat Cable: Internal cable
harnesses are less prone to damage. Along with "flatter" cross section
conductor wires, enforcement at bend point using rubbing and support
strips contributes to long life.
Problems occur with motion control positioning stages when drive and signal cables chafe or are bent too tightly, or when location of cable connectors makes servicing difficult. External cables are prone to damage by moving equipment or personnel and internal cables can take up useful volume.
To alleviate these concerns, engineers at Primatics have developed the PrimaFlex™ internal cable management system that relies on a proprietary wire harness cable design for long life—while at the same time taking up minimal internal volume to make room for other systems such as I/O cables or vacuum lines for component-handling effectors.
Mechanical Engineering Manager Phil Williams notes in looking at high-flex round conductor ribbon cables based on the technology in printers and plotters, the design team could only come up with a lifetime 20 percent of the 100 million flex cycles needed. Part of the solution was to use a laminated polyester cable where the conductor strands have a flat, high aspect ratio of 0.003 inches in height and 0.026 inch in width. The engineers also noted that with longer cable lengths and high velocity motion, the cables are not stiff enough to "push" themselves—hence the use of high-performance thermoplastic strips molded onto the cable to help support it where needed. In addition, strips of thermoplastic are placed on covers and other areas to act as low friction bearing surfaces where the cable (with a similar protective layer) might rub against.
CONTACT:Kyle Tomson, Primatics Inc. Tel (541) 757-9678; Fax (541) 757-9653; e-mail: firstname.lastname@example.org://rbi.ims.ca/3845-500