Goodbye Delphi, hello clarity: OEE provides an overview

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micromechanics

Goodbye Delphi, hello clarity: OEE provides an overview

In ancient times, those seeking advice asked the Oracle of Delphi to clear the mists of the future. The experts at the Immendingen TechCentre, on the other hand, 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, 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 “How can I be sure that the machine I buy today won’t be outdated tomorrow and make me work inefficiently?”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. Paulus: “In medical technology, even the smallest deviations can have serious consequences. Our customers therefore expect machines that are not only precise, but also extremely reliable.” The challenge now is to guarantee this precision in a production environment that is increasingly characterised by rapid market changes and high flexibility requirements.

“From this point of view, the Starrag product area ‘Bumotec’ deals with the issue of overall equipment effectiveness (OEE),” explains Paulus. OEE stands for ‘Overall Equipment Effectiveness’ and is used by Bumotec experts as an important performance indicator for evaluating the productivity and efficiency of devices and machines.

OEE: Proven in everyday operations

“OEE is a precise key figure in daily plant management, as it evaluates the actual utilisation of the machines during the planned production time,” explains Paulus. “This allows us to specifically identify and eliminate inefficiencies and sources of loss within operational production times in order to increase efficiency and profitability,” adds René Benninger, Business Development Manager Medtech at Starrag Vuadens SA. OEE provides a comprehensive assessment by taking three main factors into account: 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 – in comparison to its maximum possible speed.

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

Success stands and falls with the third factor: Quality. This is because it measures the proportion of products manufactured in accordance with 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.

“ With an OEE process, we can specifically identify and eliminate inefficiencies and sources of loss within operational production times in order to increase efficiency and profitability.”

René Benninger, Business Development Manager Medtech

100 per cent in sight

To calculate the OEE, the three main factors – availability, performance and quality – are multiplied together. The final result is a percentage value. Paulus: “The ideal would be 100 per cent, 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: Loss of availability due to equipment failures, material bottlenecks and stoppages; Loss of performance due to machine wear, inferior materials and labour shortages as well as loss of quality due to rejects and reworking. Paulus: “All of these losses can be influenced by the system manufacturer.” Bumotec focuses on optimising set-up times and minimising production waste.

Mouthpieces off the shelf: 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 the use of pallets superfluous. All parts are produced in a single pass and completely deburred – set-up and waiting times in 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 as well as an adapted finished part removal system ensure smooth operation. Tools are changed during production, critical dimensions are manufactured adaptively and measured during the process.

Paulus: “These measures have enabled us to increase efficiency considerably and significantly reduce set-up times.”

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

Teamwork reduces production waste

OEE has also proven itself many times in practice with regard to production waste. The subtleties often make the decisive difference. This includes effective chip management and a continuous supply of raw material, for example through 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 Paulus. An equally important element in the OEE process is customer service – not only before, but above all after the purchase. Customised advice during the sales process ensures that the right machine is selected for the respective requirements.

However, the process reliability “acquired” with this decision can be significantly increased if the system manufacturer supports the user with processes in all situations. Customer service therefore plays a central role – from the right advice to predictive maintenance and the early detection of potential faults in order to reduce downtime and increase overall productivity.

“ The basic accuracy of customer products has increased and remains at a consistently high level.”

Michael Paulus Head of TechCentre Immendingen

Summary: More time for effective management thanks to OEE

The benefits of a successful OEE process are huge. 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 at a consistently high level,” emphasises Paulus. Today, material logistics is hardly an issue. Benninger: “The use of bar material eliminates the need for cutting to size, which simplifies the production process and makes material handling more efficient.” A positive side effect: Personnel expenses will also fall.

The OEE process is also well received by customers. Paulus: “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 and can then concentrate on running the business all day.’ That proves it: An optimally applied OEE process not only increases efficiency and productivity, but also reduces operating costs and ensures quality.”