Tips

A web guide system that oscillates or in other words, continually "hunts" back and forth as it attempts to correct for web position errors can cause web handling and maintenance headaches. Web wrinkles and undue stress on the web can occur when the web is not positioned properly due to web guide oscillation. Web guide system actuators will endure excessive wear and tear due to constant back and forth motion.

When confronted with excessive oscillation, many maintenance personnel will assume the problem is electronic in nature. They will frequently adjust gain control, edge sensor dead band and speed of correction in an effort to eliminate the oscillation problem. Oftentimes, these fixes do not correct the root of the problem and over time, oscillation problems will return.

Most of the time, web guide oscillation or "hunting" problems are rooted in mechanical issues not electronic.

When web guides oscillate, all moving parts should be checked for mechanical "play". Over time, as web guide system age, their mechanical components can loosen and excessive side to side movement or "play" will show itself. Accumulated side to side play in web guide systems will cause excessive oscillation. Worn mechanical components should be replaced so mechanical side to side play is kept to a minimum. This will solve most problems with web guide oscillation.

It is also very important that the web moves when the web guide moves. The web cannot be allowed to slip across the web guide positioning roller face. This condition will also cause web guide oscillation.

A web guide system is only as accurate as the mechanical components. Ideally, a web guide system should only move when it sees an error. If there are no errors, there is no motion, but the guide must be operating perfectly.

When web guide problems arise, trouble-shooters will nearly always be more effective when they look first to the mechanics of the system.