Electronic Let-Off Control for Jacquard Looms
topic
Electronic let-off control on Jacquard looms uses load cell warp tension measurement with closed-loop feedback to the let-off motor maintaining constant tension independent of beam diameter change as yarn is consumed, with tension uniformity of plus or minus 3 percent across the warp beam width being the performance specification, and with let-off control being particularly critical in Jacquard weaving where the variation of picks raised per pick across the warp width creates variable warp consumption rates that fixed let-off mechanisms cannot accommodate.
Role
Maintains the consistent warp tension that figured fabric quality requires by compensating for the variable warp consumption of Jacquard shedding where different end positions experience different raising frequency depending on their position in the design programme, with electronic tension control being essential for preventing the warp tension variation that would otherwise accumulate over long Jacquard runs and manifest as gradually changing weave density or pattern distortion in the finished fabric.