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Funded PhD position; in in Energy & Process Technology-Development of a flat spectrum filter for 3D printed custom-made hearing protection; at University of Twente; in Netherlands


Are you passionate about high-end technological design? Do you want to continue developing your skills with a combination of education and work?About Comfoor B.V.We think that having control over sound is important to enjoy life to the fullest. By means of modern and innovative high-quality products and services, Comfoor B.V. aims to protect as many people as possible against loss of hearing, and be the best supplier of ear moulds and hearing protection. Comfoor – situated in Doetinchem for more than 30 years – is market leader in the Netherlands, offering products in the fields of sound experience, hearing protection and hearing devices. The company has been growing fast in recent years and currently employs about 150 driven employees and exports her products worldwide.About Pluggerz Pluggerz is a leading brand of Comfoor. Pluggerz develops, produces and markets standard and custom-fit hearing protectors (otoplastics). The earplugs dampen sound up to a safe level, while retaining the ability to communicate clearly. Pluggerz earplugs have been specifically designed for a wide variety of activities, including swimming, motorcycle riding, attending concerts or simply to get some quiet to read a book. But Pluggerz also develops professional earplugs for working situations. In this field Pluggerz is the only provider with a full-service concept that totally burdens the customer.

Job description

The Professional Doctorate in Engineering (PDEng) programme Energy & Process Technology offers you a 2-year position combining post MSc education and a design project to be carried out at Comfoor B.V.

The educational programme, carried out at the University of Twente, will have an in-depth and broadening character with ample attention for professional development and will be partly tailored to the design project. In collaboration with Comfoor B.V. in Doetinchem you will work on high level, creative new designs for complex issues.

Background of the project: If hearing protection is (legally) mandatory, custom-made hearing protection is the best option. The hearing protection fits comfortably (and is therefore used more) and it attenuates noise to a safe level but still allows communication with colleagues for instance. The attenuation of sound due to any hearing protection depends on frequency. Simpler hearing protection products generally reduce higher frequency sounds a lot more than lower frequency sounds. However it does affect communication with colleagues. Especially in dangerous situations, where e.g. a colleague shouts to prevent a hearing protection wearing worker from being injured, it is clear that the speech clarity is of major importance. Hence, although excellent hearing protection and speech clarity seem contradictory in hearing protection devices, it is the aim of this project to proof otherwise.

Aim of the project: Design, build and test an energy-efficient passive acoustic filter to be used inside Comfoor B.V. 3D printed hearing protection devices, to filter noise evenly over all frequencies (a flat spectrum filter). The resulting filter should, as best as possible, evenly filter all audible frequencies. The filter should easily and safely fit into the 3D printed hearing protection devices of Comfoor and manufacturing should be as energy-efficient as possible. The project will lead to a product: a flat spectrum hearing protection device.

Design concept: After designing various concept designs, all will be manufactured for testing (at both UT and Comfoor). The assessment of the manufacturing process will be given special attention. The separate filter will be tested for its flat filter performance in a test setup, which will be built within the scope of the project. In addition, perceptive tests will be conducted to test the performance of the filter within the hearing protection device and whether it meets Comfoor’s perceptive performance.

Your profile

  • You hold a MSc degree with a Mechanical Engineering background, or a related discipline;
  • You have demonstrated affinity with design and multidisciplinary assignments;
  • You have a passion for finding solutions for complex technological issues;
  • You have excellent collaboration and communication skills;
  • You are self-starting and self-motivating, willing to take initiatives and feel the responsibility for your own project;
  • Candidates with a non-Dutch qualification and who have not had secondary and tertiary education in English can only be admitted with an IELTS-test showing a total band score of at least 6.5, internet TOEFL test (TOEFL-iBT) showing a score of at least 90, or a Cambridge CAE-C (CPE).


Please send the following documents before 31-10-2017 through the link below:

  • Letter of motivation
  • Curriculum vitae
  • List with grades of courses attended
  • References and, if applicable, a list of publications.

Contact information

If you have any further questions about this vacancy of the PDEng programme in Energy & Process Technology, please contact Y.H. Wijnant:


Telephone: +31 53 489 3635

Our offer

Comfoor B.V. offers you a very challenging position for two years in an inspiring multidisciplinary and international environment. In the time we will provide you with a tailor made post-master design programme that has an educational component (~50%) as well as a design project (~50%). You will be supervised by a team of experts from both Comfoor B.V. and the University of Twente. The educational component will be chosen to closely match the project as possible. With respect to planning, preferably and where possible, courses and project start and progress in parallel.

The salary will be € 1828 gross per month.

On successfully completing the programme, you will receive a certified degree. You will be entitled to use the academic degree PDEng and will be registered as a Technological Designer in the Dutch register kept by the Royal Institution of Engineers in the Netherlands (KIVI).


The organization

The University of Twente. We stand for life sciences and technology. High tech and human touch. Education and research that matter. New technology which leads change, innovation and progress in society. The University of Twente is the only campus university of the Netherlands; divided over five faculties we provide more than fifty educational programmes. We have a strong focus on personal development and talented researchers are given scope for carrying out groundbreaking research.

We are an equal opportunity employer and value diversity at our company. We do not discriminate on the basis of race, religion, color, national origin, gender, sexual orientation, age, marital status or disability status. Because of our diversity values we do particularly support women to apply.

The Faculty of Engineering Technology (ET) is one of the five faculties of the University of Twente. ET combines Mechanical Engineering, Civil Engineering and Industrial Design Engineering. Our faculty has approximately 1800 bachelor and master students, 400 employees and 150 PhD candidates. The departments of the faculty cooperatively conduct the educational programmes and participate in interdisciplinary research projects, programmes and the research institutes: MIRA, CTIT, SBE and IGS.

Deadline: October 31, 2017.

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