May 3, 2023

Overview
Grantek was approached by a long-time client (30+ years of successful projects) in the food manufacturing space in Ontario about a potential project on one of their packaging lines to increase Overall Equipment Effectiveness (OEE). The client was seeing a bottleneck in a 30-year-old case packer that they wanted to speed up. The issue was that the 30-year-old case packer was not in the budget to be replaced and the current mechanical and electrical design was restricting the machine from running any faster than it already was. Any downtime on the case packer was very difficult to recover from, as the machine was right at the limit of its throughput capacity.

Challenges
Grantek came in to perform an electrical assessment to see if any improvements could be made to the 30-year-old case packer. It was noticed that two of the case packer axes were major contributing factors in slowing the cycle of the machine down. From the assessment, Grantek was able to identify and begin generating a solution to speed the machine up. These two axes were very simple in mechanical design and easy to access. They were currently being controlled by AC motors on a variable-frequency drive (VFD). Grantek was able to reach out their electrical suppliers and motion control specialist partners to specify servo motor replacements for the AC motor/VFD combination on these axes. The servo motors would allow for precision control and increased speeds of the identified axes.

Solutions
The solution that Grantek architected did not require the high-cost replacement of the 30-year-old control system running the case packer. The solution would leverage integrating the servo motor control into an existing nearby Rockwell Automation ControLogix PLC with interlocks being exchanged with the 30-year-old case packer using Profibus and Ethernet/IP. Grantek was able to setup a test bench in office and achieve sub 30 millisecond response time of the proposed interlock network between the two PLCs. This proof-of-concept test bench was critical for Grantek’s solution to work.

During the implementation of the solution, the client came to Grantek with an issue regarding mounting the new servo motors to the existing axes. The components were initially sold as bolt on components, but once received, it was noticed that this was not the case. Grantek was able to quickly generate CAD designs for mounting solutions that the client ended up using and fabricating. The design of the mounting brackets was not originally in Grantek’s scope, but when the client had nowhere else to go, they called on Grantek for assistance.

Grantek successfully implemented its proposed solution of replacing the AC motors/VFDs to servo motors. The result was a 5-10% OEE increase of the machine, depending on what product size they were running. The servos also proved to reduce downtime due to the improved recovery action from jams/faults with the servo motors. The customer was ecstatic with this result. The overall cost of this project was about one tenth of the cost of a new case packer for them. With such successful implementation of this project, the customer is looking at upgrading other aging equipment versus buying new ones.