Calculating basic performance indicators for the smart factory: Overall Production Effectiveness (OPE)

How to get started with the smart factory’ is a question of interest not only to bloggers in the field, but to the entire SMT industry. As the head of the smart SIPLACE SMT factory in Munich, I am intimately familiar with the concerns that worry people considering to set up such a factory. Where do I start? What tools actually help us to improve our production efficiency? Does it make sense to integrate a certain tool into our existing production concept? What follow-up investments will be required? Is our staff sufficiently trained to take advantage of the benefits of automation? Yes, all beginnings are difficult, and everyone knows that there are no one-size-fits-all solutions.
That’s why we took steps to identify specific improvement potentials in our operation in order to establish the foundation for a smart factory. To accomplish this, the SMT production team in Munich developed and introduced a new in-house planning tool. We call it Overall Production Effectiveness (OPE for short), an advanced version of OEE. We want to use the results to identify potential investments that will help us improve our efficiencies across the entire manufacturing process.How does OPE work?

OPE vs. OEE: Finally a view of the entire manufacturing process

Unlike Overall Equipment Effectiveness (OEE) or Overall Line Effectiveness (OLE), Overall Production Effectiveness (OPE) looks at the entire manufacturing process, including unconnected processes that cannot be captured on the machine or line level. This means that it includes activities like selective soldering, testing and manual assembly stations in order to identify productivity killers across all production steps.
OPE = Equipment availability multiplied by the performance and quality factor

To calculate OPE, the Equipment Availability and Performance and Quality KPIs are multiplied with each other. In contrast to the OEE calculation, the production employees collect the data for the OPE calculation themselves via forms that are posted on the factory floor. As a next step, we want to digitize this system so that we can collect and analyze the data more quickly and efficiently.

Let’s look at how this works, using the Equipment Availability KPI as an example. Standstills and their causes are being recorded on a form directly at the machine. The operator can pick from eight categories (Software, Hardware, Material Fault, Operating Fault, Setup, Maintenance, New Product Introduction, and Other) and enter comments. Next, all standstill data for a period is collected and the effective activity time computed for each machine. The results for the connected processes (lowest values only) are then multiplied with the results for the unconnected process steps to produce the total availability, giving us with a highly realistic picture of the overall equipment situation.

We compute the Performance and Quality KPI in a similar manner. Empirically checked part production times relative to the actual production times (which are determined across process steps via route cards) indicate the performance factor. The quality rating is generated automatically via the flying prober and the AOI system. All results – including all error messages and comments – are made available to our production staff on a summary form directly on the line. The benefit: all causes of errors and all responsibilities are clearly visible and available to all. Since the data is collected predominantly by the production staff, its valuable process expertise flows directly into the efficiency calculation, which the production management in turn uses as a foundation for future investment decisions.

With OPE to the smart factory

You are probably asking yourself what evaluating the overall production efficiency has to do with setting up a smart factory. Since introducing OPE two years ago, we have found that exploiting even small automation potentials is critical for setting up an efficient smart factory. OPE identifies where seemingly small weak spots are located in the production flow that can turn out to be major efficiency killers in the overall process. And this is where we take action. It also means that smart, targeted investments are no longer a question of volume in many cases. They focus instead on synchronizing the production process in order to balance the given infrastructure with the equipment and personnel situation. Only if we manage to optimally control all processes on and around the production line will we be able to fully exploit the huge performance potentials of modern SMT equipment ranging from the line to the material management systems. OPE also helps us to keep an eye on these aspects and run individual efficiency assessment. Against this backdrop, OPE has proven to be an important major internal planning tool in our smart SMT production in Munich. Do you know of any other tools for identifying smart potential investments? I look forward to your comments.

 

by Alessandro Bonara

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