Research: Anna wants to improve the working conditions of vehicle assemblers


The growing amount of choices that buyers of motor vehicles have been given during the past few years, to customize their vehicles, is positive for the customers, while it causes problems for the vehicle assemblers. But there is a way of facilitating the work and to ease the mental strain of the assemblers. This is shown in the doctor’s thesis that Anna Brolin presented on 2 June. Anna is a PhD student at the School of Engineering Science at the University of Skövde.

The modern manufacturing industry is in the middle of a shift from mass production of volume products to increased customization. This means that the production systems must be able to handle changes regarding customer needs and demands, new technology and environmental standards.

– As customers we see the possibilities in that we can choose a particular rear view mirror or special functions on the steering wheel for example. But this in turn leads to an increased number of product variations which ultimately need to be taken care of at the assembly stations. This then leads to repercussions for the individual assembler and his/her working conditions. Many assemblers feel that the mental strain has increased, says Anna.

In order to deal with this problem and to ensure that the assemblers are able to do efficient and precise work, it is essential that the information that is presented is well-drafted and that the presentation is carried out in a satisfactory manner.

Anna conducted a study of the literature available in the fields of manufacturing, assembly and usability as well as that of the basic cognitive capabilities of human beings in regard to using and processing information such as for example memory. This study identified a framework of suitable factors that can be used to measure the cognitive performance of a human being in connection to manufacturing and production.

– I then studied how these factors are used in manual assembly, by means of case studies and observational studies. The results show that in order to achieve a positive effect in the assembly work it is necessary to be aware of how the material and the information is presented to the assemblers.


– Traditionally, the assemblers make use of a so called material façade. It is a shelf where the components lie, and these are gathered with the help of a list of item numbers. This is a time-consuming and not very efficient method. A solution to this could be a kit, a box with pre-assembled components. In an experiment two different types of kits were compared with the use of a material façade – one unstructured kit and one structured kit. In the latter all of the components are placed in order, while the unstructured kit is unsorted.


Regardless of the kit that is used there is no need for a list of item numbers. Instead the assembler can use instructions with pictures or photographs that show what each component looks like, which is something that also reduces the mental strain of the assembler. When there is an increased number of product variations in the material flow it is also easier if the assembler uses a kit.

The results of the experiment show, among other things, that the use of a kit (whether structured or unstructured) is advantageous in comparison to the traditional material facade, especially when using a structured kit combined with the use of instructions and photos. In addition, the use of an unstructured kit may lead to increased efficiency and a reduction of the perceived workload. Even if an unstructured kit might not be as advantageous as the use of a structured kit, the former may generate a lower lost, due to for example a lower time requirement and reduced need of storage space.

– The work is carried out with an even flow based on an assembly line. If a product type that is not handled very often then appears all of a sudden it may cause extra mental strain. Instead of searching for odd components in the material façade the assembler will know that the component is to be found in the kit and is quick and easy to locate.

After completing her studies at among other places Volvo Cars and Volvo Trucks, at Scania and even at Saab, Anna would also like to put her theories into practice.

– I hope to continue to conduct research within this field and examine how to go about reducing the mental strain of the assemblers “in real life” with the help of my results. In my doctor’s thesis I have concentrated on the vehicle industry, but it ought to be possible to use my research in other areas such as manufacturing or in companies where large amounts of information and material are handled.

Anna’s doctor’s thesis has the title “An investigation of cognitive aspects affecting human performance in manual assembly”.  She defended it at one of the University of Skövde’s longest standing partner universities, Loughborough University, in England. She will there be awarded the title of PhD at the department of Mechanical, Electrical and Manufacturing Engineering.

Main Supervisor: Professor Keith Case, Loughborough University
Supervisor: Dr. Peter Thorvald, University of Skövde

Anna Brolin

Anna Brolin, PhD student at the School of Engineering, University of Skövde, defended her thesis during the first week of June at Loughborough University in England. She is hoping that her research will lead to better working conditions for vehicle fitters, first and foremost.