Increasing throughput isn’t necessarily about going faster. “You have to earn the right to go faster,” said Rich Holland, senior director of manufacturing, TreeHouse Foods, Princeton, Ky. It’s like the old adage, work smarter, not harder. In other words, sometimes slowing down increases productivity.

This is a pillar of Princeton’s approach to continuous improvement: Rate lock is the system’s overall speed that determines centerline.

The set point for a machine or operating system, centerline is a visual cue for line workers to easily understand the setting, said Ken Allen, plant manager, TreeHouse Foods, who presented a breakout session on rate lock at the American Bakers Association technical conference. “If there’s a machine set point on a cartoner, for example — maybe there’s a dial indicator or gauge that has a slide on it — we visibly mark it so the operators can see where the machine needs to be set,” he said.

Going faster is the natural inclination for an operator to increase throughput, but it’s actually counter-productive. “What really happens is losses crop up in the system,” Mr. Allen cautioned. Some drawbacks include product variation, increased scrap and reduced packaging precision.

Mr. Holland compared it to driving a car.“My car can do 160 mph, but that’s not how fast I drive it to work every day,” he said. “You find the sweet spot and cruise.”

When Princeton implemented rate lock and set the centerlines in the appropriate places — Mr. Allen warned that centerlines cannot be set downstream from a variable speed — the lines reached a steady state.

First, Mr. Allen designated a model line to optimize. He defined the grouping method based on the product run and set the centerline from there. Then he put the rate lock into practice on a line capable of running 5,600 lbs per hour that averaged 4,400 lbs, or a 78% OEE. Once the proper centerline was established, the line had a 12% rate reduction and a new target lock rate of 4,920 lbs. “With that slow down, we lost the peaks, but we also lost the valleys,” Mr. Allen said. Now the line runs at a 91.4% 
OEE. “Since I’ve been in this role, we’ve never sped a line up.”

With a good system, autonomous manufacturing happens.“In that case, you should be doing a lot of work before the machine ever gets to you,” Mr. Allen suggested. “Don’t ever stop improving. The operators are the voice; let them tell you where the changes are needed.”

As Mr. Holland professed at the technical conference, a bakery can invest in the industry’s most state-of-the-art equipment, but without properly training employees, it’s a moot point.

With all the investments made into the Princeton plant, people are the heart of the matter. “Employee engagement is always top of mind,” Mr. Allen said. And it’s permeating other TreeHouse facilities. “We’re definitely using Princeton as a model,” added Terry Melton, director of operations, TreeHouse Foods.

When it comes to continuous improvement, especially in a bakery the size of TreeHouse’s Princeton facility, it’s easy to miss the forest for the trees. In other words, large investments coupled with daily operational improvements don’t always yield immediate results. Sometimes it’s about perspective.

“It’s easy to look at it on a micro level and think things aren’t changing at the pace you want them to,” Mr. Allen said. “But then you think back to two, three or five years ago and realize we’re doing things today we wouldn’t have dreamed possible. It’s amazing the things we’ve empowered our people to do.”