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October  2004

IG Instructions

“The pressure never lets up. Doesn’t matter what you did yesterday. It’s tomorrow that counts. So you worry all the time.”
This might sound like the daily lament of an insulating glass (IG) supervisor. The quote is attributed by George F. Will in his book “Bunt” to Stan Coveleski, who played professional baseball. The quote continues “Lord, baseball is a worrying thing.” I know some IG line managers might replace the word baseball with insulating glass. 

Performance Woes
One of the things IG line managers worry about is their performance measurement. It seems that no matter how many units they produced today, it wasn’t enough and they will need more tomorrow.

Methods of performance evaluation used in the IG industry range from simple daily production statistics to sophisticated calculations based on quantity, quality, remakes and attendance. By far the most common method is units per shift or units per labor hour. Managers that attend the IG supervisor workshops offered by our company commonly express concern when units per shift or units per labor hour are used to evaluate their performance. They realize that these are not legitimate or stable measurements. The number of units produced during a given period varies due to many circumstances beyond their control. 

Unit size is one variable that can seriously affect the quantity of units produced. Does your production schedule include large units or small units that are easy to handle? A fluctuation of sizes skews the productivity measurement. Does the batch include large quantities of the same size units for new construction or different size units destined for the replacement market? Large quantities of the same size units can inflate production numbers while mixed sizes can mistakenly indicate poor performance.

There are many other variables that may distort measurement. Is the impact of internal grids or muntins considered in the analysis? Grid assembly, handling and insertion may reduce the quantity of completed units. Does the production manager select the easier schedule and leave the difficult items for the next shift? Schedule selection and shift staffing can cloud performance evaluation. Do staffing calculations include only direct labor from the IG department? 

A Midwest IG manufacturer producing units for the pre-manufactured housing market boasts of routinely operating at a rate greater than 54 units per labor hour. This is possible using an automated spacer system with one operator, one washer loader, two stackers, one unloader and one sealer. With six operators, pre-cut glass and few internal grids, this manufacturer regularly produces more than 2,800 units in 8.5 hours of production. Does this indicate that a butyl spacer/tape operation with four operators, producing 1,100 units per eight-hour shift or 34 units per labor hour is less productive? It is impossible to determine using units per labor hour.

Review Existing Methods
Evaluating existing methods and considering new options can be beneficial. One manufacturer found success by switching from units per shift to a simple calculation based on the consumption of raw glass. The square footage of glass consumed, minus glass used for remakes or repairs was multiplied by the cutting yield to give an indication of the department’s performance. Large units impacted the regular flow and pace of IG production. The large glass was difficult to handle, the grid patterns were more complex and as a result production slowed. Since larger units required more time, measuring the amount of consumed glass proved to be a more direct indicator. Factoring out the glass used in remakes and repairs prevented production of poor quality units just 
to inflate production numbers. Including the glass yield encouraged the use of optimization for remakes and repairs.

In order to improve the operation of your IG department you must develop and implement fair and meaningful manager evaluation. You and your manager will be accurately aware of “what you did yesterday” and where to improve because, “Its tomorrow that counts.”

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