ARCHIVED TECH TIPS

When using an automatic web guide system on an unwind stand, where the unwind moves laterally, side to side, a lead-out idler roll MUST be included that moves with the unwind stand's motion. If this idler roll is not present in the control scheme, chances are the unwind will oscillate or "hunt" continuously, decreasing the accuracy of the guide and increasing your maintenance department's headaches. The web guide control's web detector (edge, line or centerline resolver) must be mounted AFTER the moving lead-out idler roller.

When using an automatic web guide system on a rewind stand, where the rewind moves laterally, side to side, a lead-in idler roll MUST be included that is stationary. This roller must not move with the rewind stand. The web guide control's web detector must be mounted prior to the stationary idler. In other words, the stationary idler roller must be mounted between the web detector and the rewind stand. The web guide system will continually oscillate if you do not maintain this control scheme. One more thing about guiding a rewind stand in this fashion; keep in mind, this is not a web guide system in the true sense of the phrase. This is really a chasing operation. In other words, you are not positioning the web where is it supposed to be in the process; instead, you are moving the rewind to wherever the web goes. You are in essence chasing the rewind to the web.