Clear constraints on bottling lines using simulation

Insights ascend to the counter-intuitive when consumer goods manufacturer boosts productivity.

By Creighton Fearrington, PMP December 6, 2019

When decisions are made in desperation and without line intelligence, it is often reactionary and based on guesswork and hope, rather than verifiable outcomes. Left unchecked, this can surface as company-wide inclination to patch problems rather than implement reliable and replicable solutions that will have a dramatic effect on overall equipment effectiveness (OEE) and productivity.

Bottlenecks on bottling lines

A well-known global consumer goods manufacturer had several bottling lines that were underperforming. Pressure was increasing for the company to make upgrades and improvements to meet its key performance indicators (KPIs), mitigate investment risk and meet growing market demand. Its lines needed to operate more efficiently and profitably. Its goal was always clear: Increase production

The manufacturer decided to pilot changes on one line before universally reconfiguring the others.

Prior to Polytron’s engagement — and fixated on line speed and throughput — the client determined that one of the machines on its line needed to be replaced as the culprit of poor performance and limited capacity.

The new machine had the capacity to run at 300 bottles per minute (bpm), when coupled with improved bottle handling, but would that be enough to achieve the output goal?

Without clarity, the problem-solving turned myopic as the client focused on line speed. What was needed was to clearly see that the breadth of the issue extended across the entire line.

Polytron was hired as an industry expert that not only knew the business, but also understands bottling line operations and can demonstrate with strategic certainty how the desired business outcomes can be achieved.

Starting with a comprehensive line audit, Polytron’s engineers observed and assessed the line while collecting baseline performance data. Then, an exact 3D simulation model of the production line reflecting the existing conditions and inefficiencies was created. This digital twin mirroring the one on the plant floor allowed testing of nearly any imaginable scenario. It was a pre-visualization of how well the line could run when optimized.

Not only was it clear what had to be done, the simulation suggested some surprising and even counter-intuitive insights, prompting a roadmap of next steps. The model created confidence to make the right decision for the business.

Counter-intuitive insights

Polytron’s PolySim is a 3-D animated simulation of a line (see Figure 1). This visualization predicted that, after replacing the culprit machine with one with a higher throughput, problems would arise elsewhere on the line.

  • Anytime one machine in the line faulted, it almost immediately stopped all upstream machines, creating “micro stops” and significant performance losses.
  • Each machine on the line was operating as an “island of automation,” being stopped and started arbitrarily based on line faults and backup conditions governed more by the instincts of the operators and less by good information.
  • The breadth of the compounding issues was becoming clear.

The new machine could run at 300 bpm and was enlisted to increase the overall pace of the line. Along with the blow molder, it could oversupply the filler when set at 250 bpm.

Subsequently, attention turned to the machines downstream of the filler. They needed to be set at progressively increasing bottling rates, with the capability to modulate speeds based on bottle population.

Finally, Polytron engineers suggested adding two minutes of post-filler bottle accumulation. This would buffer downstream hiccups and keep the filler, which was the line constraint, running optimally. Without the modeling, it would have seemed ridiculous to slow the line down to increase throughput.

When slower means faster

By adding two minutes of buffer to the line, integrating machine, conveyor controls and modulating machine speeds around a target filler speed of 250 bpm, the client could achieve twice the OEE and a much higher output of the line — more than two times what they were achieving. How? Surprisingly, by slowing the line down. The client’s vice president of Global Engineering and his team were shocked to realize that slowing the line down increased output.

To everyone’s surprise, the changes made to this one line would be so effective that one or two of the other lines previously needed to meet market demands could be moth-balled temporarily. Shutting down these lines would reduce operational costs and eliminate, or at least postpone the need for a multi-million-dollar capital expansion.

Author Bio: Creighton Fearrington, PMP, is a project manager at Polytron Inc. with 20 years of electrical engineering experience in all phases of manufacturing project management, leading teams to innovate and implement solutions in the consumer products, pulp and paper, beverage bottling and medical device industries. He has been with Polytron for 10 years and has a BSEE from North Carolina A&T State University.