In this interview, an expert gives fascinating insights into the opportunities presented by the MTM method.
Increasing competitive pressures, burgeoning costs, time demands and demographic change mean that we must find effective ways of optimising manual production. But where’s the best place to start? And wouldn’t it be even better if we could analyse and evaluate processes and work bench design in advance – in other words, during the planning stage? The term “MTM” often crops up in this context. However, what is the MTM method and how is it actually used in practice? Dr. Steffen Rast has a wealth of experience in this area. He has worked for Deutsche MTM-Gesellschaft Industrie- und Wirtschaftsberatung mbH, a subsidiary of MTM ASSOCIATION e. V., since 1999 and has headed up the company’s ergonomics division since 2016. In this interview, he unpacks the MTM method, explaining how processes and ergonomics can be objectively described, evaluated and planned in a forward-looking way.
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MTM method made easy
What is the MTM method? How should it be understood?
“MTM stands for ‘methods-time measurement’ and is used to describe, analyse, evaluate and plan all manual tasks. The MTM method is primarily employed in industry, but can also be applied in the administrative sector or small workshops. The universality of the MTM method results from the fact that it involves breaking down all manual movements into a series of basic motions.
For all these basic motions, there are process “building blocks” with standardised, objective values that are specified in “time measurement units” (TMUs). One second is approximately 27.8 TMUs; 1667 TMUs correspond to one minute. The MTM process can therefore be used to determine a target time for each manual task by adding together the TMU values of the individual process building blocks. Pen and paper can be used or software is available to help – for example, MTM-Easy. The MTM method can also be used in conjunction with motion capture and virtual reality.
When it comes to optimising an existing work bench on a manual assembly line, for example, an assessment can be made for the work bench based on target times. The comparison reveals any scope for improvement. However, an even better approach is to apply the MTM method in advance – in other words, when planning assembly work benches – as this clearly cuts costs. As a rule, the MTM method should be applied as early as possible.”
Where does the MTM method come from? Who developed it?
“The work of American building contractor Frank Bunker Gilbreth provided crucial impetus for the development of the MTM method. At the start of the 20th century, he discovered that all human movements come down to 17 basic motions. He called these “therbligs” – an anagram of his surname. He developed special symbols to represent these basic motions. Several people then built on Gilbreth’s ideas, including Asa Bertrand Segur. Finally, in 1948, the book “Methods-Time Measurement” by Harold Bright Maynard, John Lenhard Schwab and Gustave James Stegemerten was published – and this was the real launching point for the MTM method.
This was the birth of the original MTM system now referred to as MTM-1. Maynard, Schwab and Stegemerten provided the crucial insight that 80 percent of all manual tasks contain the following motions: reaching, grasping, moving, positioning and releasing. They filmed every individual movement being performed thousands of times – by men, women, people with short and long arms and so on – to enable them to determine basic motions and corresponding standard times.
The MTM method can be used to determine something such as: What is the standard time taken to reach for a part that is lying on its own on the table? Or for a part that is lying beside others on the table?
This forms the basis for determining, for example: What is the standard time taken to reach for a part that is lying on its own on the table? Or for a part that is lying beside others on the table? All of that’s possible using the MTM method. After the “U.S. MTM Association for Standards and Research” had been established in 1951, the MTM method finally arrived in Europe and reached Germany in 1962. At that point, companies from various industries founded the German MTM association, Deutsche MTM-Vereinigung e. V., now called MTM ASSOCIATION e. V. It is our goal, as set out in the association’s constitution, to publicise the MTM method. We have been very successful in achieving this in the last few decades. Alongside this, the association’s Deutsche MTM-Gesellschaft Industrie- und Wirtschaftsberatung mbH subsidiary offers a wide range of MTM-related services.”
MTM method and ergonomic assessment using EAWS
What role does the MTM method play in ergonomic assessment? Can MTM also be used in this context?
“The holistic view of human work is becoming increasingly important. It’s therefore crucial to determine times using the MTM method and assess ergonomics at the same time. The two are closely related and complement each other. The goal should always be work benches of an age-appropriate design that continue to be suitable for employees as they get older. After all, work must encompass productivity and health and safety. What’s more, prospective ergonomics – considering ergonomic principles during the planning stage – is always better and more cost-effective than corrective measures. Companies can prevent high levels of strain for employees and avoid potential risks by taking a forward-looking approach when planning whole factories. In this respect, too, we can assess, evaluate, categorise and design in advance.
For the ergonomic assessment, we use the Ergonomic Assessment Worksheet (EAWS) method to evaluate the physical workloads on the whole body and the hand-arm system. This is a worldwide standard for ergonomic work system design. The EAWS has been validated by the human factors and ergonomics community and is internationally standardised, which is important for trade unions and works councils.
The EAWS is used to assess the individual physical workload at a work bench. Of course, each person is different, but there are comparative values and thus reliable standard values to work with. In the ergonomic assessment using the EAWS, you assign points for the individual workloads and add them up. These values can be classified using a traffic light system. Green work benches have 0 to 25 points, amber work benches have between 25 and 50 points, and more than 50 points corresponds to a red work bench. We can also transparently show how much it costs to make appropriate ergonomic improvements.”
Let’s say we have an amber work bench. What happens next in this case?
“Even amber work benches can be associated with a high risk if an employee repeatedly performs the same activity at it over several years. Measures therefore have to be considered. We apply the STOP principle to all existing work benches that we check, even if only to determine times using the MTM method: S = substitution, T = technical design, O = organisational design, P = personnel design.
Substitution involves establishing a new procedure for lengthy or time-consuming processes and using this in place of the old procedure. There may be overlaps with the technical design, such as when using robots to fix screws to specifically take strain off employees. The organisational solution is classic job rotation. Let’s assume that at the first work bench the employee’s right arm is under strain, at the second the left arm and at the third both hands. In this case, you plan it so that the employee switches between the different work benches in a single shift.
Behavioural ergonomics is also an important factor. This refers to the ergonomically correct behaviour of the employees at the work bench.
At the end, there is an aggregated risk that I can calculate and assess extremely well using the EAWS. In terms of personnel solutions, behavioural ergonomics is a classic approach. This refers to the ergonomically correct behaviour of employees at the work bench. It’s about using a work bench in an ergonomically correct way, for example performing processes optimally and using the right tool.”
Does the time factor also play a role in the analysis of physical strain?
“Yes, absolutely. While we determine the workload intensity using the EAWS, we use the MTM method to calculate the duration of the workload. This then leads to a simple formula for ergonomic assessment: risk = intensity points multiplied by duration points. The duration points are determined based on the dynamic or static actions – we can calculate these using frequencies. To do so, we apply the MTM method.”
MTM method and EAWS in use at SIKO GmbH
Could you give us a practical example of the MTM method and EAWS in use?
“The example of SIKO GmbH, a company that produces sensors and positioning systems, springs to mind. Production was moved to a new building. As part of the relocation, the company’s new processes were examined and evaluated in advance, with comparison made to the situation before the move. Numerous aspects played a role, including the design of the assembly work benches and the actual tasks. We also looked at environmental influences, the use of tools, material supply and logistics. item ergonomic assembly work benches are now used throughout production.
We used the MTM method and the EAWS to analyse and evaluate the company’s methods in terms of both time and ergonomics. This formed the basis for our proposals, which were incorporated into the planning of the new assembly work benches in the new facility. It was a clear instance of prospective ergonomics planning. As I said, you can describe and evaluate work benches in advance, and this is also true in this case: How do I prevent strain? When planning the factory, what’s the best set-up for the work benches? How should certain work benches be linked, for example from logistics to actual production or to the inspection process?
At SIKO, it was crucial that work benches were height-adjustable to give employees the flexibility to switch between sitting and standing. But ergonomic, individually adjustable lighting and the arrangement of the work benches also played a role. The MTM process with its standardised building blocks and the ergonomic assessment using the EAWS provided valuable assistance in this regard.”
What experience have you had with item?
“We have a long-standing and successful working relationship with item. From work bench design to intralogistics processes – item offers outstanding complete systems. Thanks to the profiles supplied by item, it’s possible to implement a wide variety of things, in work bench design or material supply, for example. We complement each other perfectly.
We have a lot of links with item and propose item solutions to various companies. item is an integral part of our toolbox.
In this instance, item invited us to work with and support SIKO. We have a lot of links. You can find item products in many factories across a range of industries – because of the flexible item profiles and the attractive solutions offered. We propose item solutions to various companies. item is an integral part of our toolbox, both for ready-made and customised solutions.”
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