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Preactor gives clarity to production scheduling at Libbey Glass
mai 2015
Libbey has its roots in East Cambridge, Massachusetts, home of the New England Glass Company which was founded in 1818. William L. Libbey took over the company in 1878 and renamed it the New England Glass Works, Wm. L. Libbey & Sons, Proprietors. In 1888, facing growing competition, Edward Drummond Libbey moved the company to Toledo, Ohio. The Northwest Ohio area offered abundant natural gas resources and access to large deposits of high quality sand. Toledo also had a network of railroad and steamship lines, making it an ideal location for the company. In 1892, the name was changed to The Libbey Glass Company.

The glass making process was much different than it is today. At the time, the principal product was cut glass. Work was done slowly by hand methods and years of practice were needed to develop the necessary skills. Following WWII, Libbey discontinued the production of handmade glassware and began to concentrate on the automatic high volume techniques that would help Libbey become America's most recognizable name in glassware.

With innovation as its cornerstone, Libbey quality, consistency, and exceptional customer service have become the standard in the industry. Libbey continues to invest in state-of-the-art production equipment and faster and more efficient manufacturing technologies, allowing it to create the most significant introductions in the foodservice and consumer markets.

Libbey has many factory constraints that were handled via spreadsheets and tribal knowledge.  Due to the manual nature there was a lot of room for error and the planners and schedulers knew there were opportunities that were being overlooked since the information was so spread out among multiple individuals.  It has always been the belief that if a schedule could decrease job change times, Libbey could increase machine output and thus have more product to sell and a subsequent increase in revenue.  That was the driving goal behind pursuing Preactor– being able to have more output to grow Libbey’s business.  Preactor offered a systematic solution to do all of the gyrations that planning and scheduling staff had been doing manually but in a much more time effective manner. 

Any solution had to include many factors, many of which interacted with another to increase the dimensionality of the problem. "Clearly, modeling Libbey’s production processes would take time, with a great deal of input from Libbey and careful analysis," says Fraser Bonnett, president of Quinn & Associates, the reseller of Preactor licenses and service provider. The scheduling solution needed to consider the following constraints to production at the Toledo Ohio facility:
  • Limitations on the number of setups per day
  • Sequence Dependent Changeovers based on over 40 different attributes
  • Constrained by a maximum glass flow between furnaces
  • Group by product families that share common support equipment), within the group, rank by Shape, Part Number, and Due Date
  • Only Schedule an item on a production line if ALL  items in a group of orders can run on this line

The complexity of the solution required the Preactor 400 APS solution with a custom scheduling rule. The solution uses information from two systems: Libbey’s ERP system and its shop floor and data maintenance system, developed by Libbey. Based on the Libbey planning horizon, the scheduler has Preactor shuffle all of the current and new work orders through the Libbey APS Rule to produce a schedule that adheres to the factory constraints.  The MRP planner does have to manually review the schedule for critical due dates and modify the schedule as needed to accommodate these. 

The biggest benefit to date is that Libbey is not wasting time and resources for last minute schedule changes.  The key information that is in Preactor lets the planners and schedulers know at all times if Libbey exceeding any of the constraints. If so, the planners and schedulers are able to approach the situation proactively and look for solutions rather than reacting to last minute constraint problems. Brian Schankin, Production Engineering Manager, says “Preactor does a pretty good job with trying to handle our system of extremely complex rules and constraints.  The system is pretty flexible and allows us to modify certain things to make the model better and more useful”. Vickie Straube, MRP Planner, adds, “I like the immediate information regarding our resource constraints”. Jennifer Butler, the Master Scheduler, observes, “Our requirements were very complex and required a lot of communication and changes with Quinn & Associates.  Most changes were completed that day so that we were able to continue our testing and parallel phases without missing a beat”.

These improvements in Toledo production scheduling have Libbey considering deploying Preactor at other Libbey sites. Mr. Bonnett reflects on the project, “There were significant issues encountered at Libbey, not least their change of Project Manager a third of the way into the project.  However, the technical team at Libbey were excellent and very committed to the project and I don’t think I have ever encountered a customer who devoted as much time to detailed testing of the progressive releases of the Preactor model. “