Volume 7 Issue 2 February 2006
Making IG Remakes Less Common
by Mike Burk
We have all heard the saying “the cure is worse than the disease.” In Latin the phrase is aegrescit medendo meaning the disease worsens with the treatment. This may be the case with the production line repair of insulating glass (IG) units.
Manufacturers routinely remake IG units before the units or windows ship to the customer. IG units are remade for a variety of reasons. They may not meet quality requirements, may have been damaged in the process or they may have been misplaced. Although remakes can be a major burden on the production line, it is far less expensive to replace defective units before they leave the factory than to replace the unit after it has been installed. Insulating glass units that fail at a customer location will still have to be remade and will still impact production but perhaps more importantly, the failure may damage the window manufacturer’s reputation severely.
Because of the negative impact remakes have on the production process, many manufacturers take steps to reduce these. Investigation and correction of the root cause can bring about an immediate reduction in the quantity of remakes. However, some manufacturers attempt to reduce remakes by implementing a production line repair program. This often involves placing an associate in the production line to inspect and repair visual defects as the units are manufactured.
In many cases, these repair associates reopen completed or partially built IG units in order to “salvage” grids, spacers, glass or perhaps the unit itself. In actuality these units are often of poorer quality and more likely to fail after the attempted repair. The associate’s goal may be to clean a streak or spot on the glass. He may try to straighten a muntin or remove some contamination. Many times the goal is to replace one lite of glass due to a scratch or damaged edge. These are all good intentions, with possible disastrous results. The repair process actually creates additional damage.
Attempting to spot clean glass usually will result in bigger spots with more streaks. In order to be cleaned correctly, the lite must be rewashed through the glass washer. If the glass is to be rewashed, it must be completely free of sealant. Any portion of sealant remaining on the glass will contaminate the washer, usually on the pinch rolls, rendering the washer inoperable.
If the unit is opened to straighten a muntin or remove contamination, the spacer may be bent or damaged. If the spacer has been distorted in any way, the units should be remade. Even if it can be confirmed that the spacer has not been damaged, and the sealant has not been contaminated or deformed, the unit must repeat the sealing process.
When a lite of glass is removed from a completed or partially completed IG unit, some of the sealant will inevitably adhere to the glass. Unless the spacer is remade, there may be insufficient sealant remaining on the spacer to guarantee adhesion and a sufficient moisture barrier. In many cases the replacement lite is cut by hand. Hand-cutting may produce an inaccurate cut, an out-of-square lite or rough edges. Any of these conditions may cause the unit to fail prematurely.
In addition, the production line repair process raises many safety issues. Removing and replacing lites and units from in-line conveyors may expose the associate to pinch points and lifting injuries. Handling damaged or cracked lites greatly increases the opportunity for glass breakage and lacerations.
If you are completing production line repairs in order to reduce remakes presently, consider reassigning these associates to a quality process role. Utilize their expertise to investigate the root causes.
Find the source of the defect and fix it. Stop wasting production time repairing and remaking units. Start manufacturing nulli secundus IG units—units that are second to none.
Mike Burk serves as training manager for GED Integrated Solutions in Twinsburg, Ohio. He can be reached at MBURK@gedusa.com.
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