Creating clarity with OEE

In ancient times, those seeking advice asked the Oracle of Delphi to clear the mists of the future. On the other hand, the experts at the Immendingen TechCentre rely on analysing Overall Equipment Effectiveness (OEE) when it comes to future-proof production solutions for the medical industry.

“In the age of precision and innovation, uncertainty is paradoxically the greatest challenge for suppliers to the medical industry,” says Michael Paulus, Head of TechCentre Immendingen at Starrag Vuadens, in Switzerland, during discussions with customers. “How can I be sure that the machine I buy today won’t be outdated tomorrow and make me work inefficiently?” customers ask.”

This is particularly important for manufacturers of medical products who demand the highest levels of accuracy and reliability. Michael continues: “Even the smallest deviations can have serious consequences in medical technology. Our customers, therefore, expect machines that are not only precise but also extremely reliable.” The challenge is guaranteeing this precision in a production environment increasingly characterised by rapid market changes and high flexibility requirements.

“From this point of view, the Starrag ‘Bumotec’ product range deals with the issue of Overall Equipment Effectiveness (OEE),” explains Michael. Bumotec experts use OEE as an essential performance indicator for evaluating the productivity and efficiency of devices and machines.

“OEE is a precise key figure in daily plant management, as it evaluates the actual utilisation of the machines during the planned production time. This allows us to specifically identify and eliminate inefficiencies and sources of loss within operational production times to increase efficiency and profitability,” adds René Benninger, Business Development Manager for Medtech at Starrag Vuadens. OEE provides a comprehensive assessment by considering three main factors: Availability, Performance and Quality. Availability describes the percentage of time the equipment is available for machining during the scheduled production time. Higher availability means minimal downtimes and optimum utilisation of the devices.

Performance rates how efficiently the device works during operation – compared to its maximum possible speed.

Michael says: “Slow cycle times and minor failures reduce performance and overall productivity. A higher performance indicates that the device works closer to its maximum capabilities.”

Success stands and falls with the third factor: Quality. This is because it measures the proportion of products manufactured following quality standards compared to total production. It takes into account errors, rework and rejects. High quality shows that the manufacturer effectively controls the process and complies with the specified quality standards. Bumotec analyses typical problems and develops targeted strategies to improve overall performance.

100% in sight

To calculate the OEE, the availability, performance and quality are multiplied together. The final result is a percentage value. Michael continues: “The ideal would be 100% because it stands for perfect performance, where the equipment works with maximum availability, speed and quality without interruptions or defects.”

The six major loss categories in production are the loss of availability due to equipment failures, material bottlenecks and stoppages, loss of performance due to machine wear, inferior materials and labour shortages, and loss of quality due to rejects and reworking. Michael says: “The system manufacturer can influence all these losses.” Bumotec focuses on optimising set-up times and minimising production waste.

More efficient machining thanks to reduced set-up times

A practical example from a Starrag customer shows how set-up times can be reduced. The supplier manufactures jaw parts in various sizes and shapes from standardised stainless steel directly from the round material bar. This enables stable clamping and makes pallets superfluous. All parts are produced in a single pass and completely deburred – so set-up and waiting times with further processing are eliminated.

The uniform raw material results in a large amount of swarf, which can be easily managed thanks to a robust production solution with high-pressure flushing. Efficient programme and tool management and an adapted finished part removal system ensure smooth operation. Tools are changed during production, and critical dimensions are manufactured adaptively and measured in-process.

The experts took a similar approach to another challenging application. The customer machines a diverse portfolio of parts, from batch size one to series production, from various materials and designs. This requires particularly flexible machine kinematics with easy changeover, thanks to the machining centres that can be adapted to different production requirements without great effort.

Teamwork reduces production waste.

OEE has also proven itself many times in practice regarding production waste. The subtleties often make the decisive difference. This includes effective chip management and a continuous raw material supply, such as a bar magazine. These measures ensure reliable, continuous operation and minimise unplanned downtimes.

Cooperation between machine manufacturers and customers is of central importance here. “Only through close dialogue can we ensure that the customer’s specific requirements are met and that the production processes run optimally,” explains Michael. Customer service- before and after the purchase- an equally important element in the OEE process.

Summary: More time for effective management

The benefits of a successful OEE process are enormous. Continuous production overnight and at weekends ensures maximum capacity utilisation, even with small batch sizes. The sets produced are processed immediately, which significantly reduces throughput times. The costs for operating materials are now minimal, as hardly any collets, pallets and fixtures are required.

“The basic accuracy of customer products has increased and remains consistently high. Using bar material eliminates the need for cutting to size, simplifying the production process and making material handling more efficient.” A positive side effect is that personnel expenses will also fall.

The OEE process is also well received by customers. Michael concludes: “A medium-sized user told us briefly and concisely about the advantages of a successful OEE process: ’In the morning, I stock up on materials, set up a few tools if necessary. I can then concentrate on running the business all day.’ That proves an optimally applied OEE process increases efficiency and productivity, reduces operating costs, and ensures quality.”