UNIVERSITY OF TWENTE
CHAIR OF APPLIED LASER TECHNOLOGY

The Chair of Applied Laser Technology of the University of Twente in Enschede, the
Netherlands, is dedicated to fundamental research on laser-material interaction, as well as innovative measurement and control strategies for processing materials with high power lasers. New processes are developed, including micromachining using ablation by ultra short pulses in the femto- and pico second regime. Further, measurement and control strategies are developed for processes like laser-cladding and welding. Currently the Chair is involved in the FAB2ASM project. Within this project the following position is available: PhD RESEARCHER in CLADCONTROL PROJECT.

This project falls within the research programme of the Materials Innovation Institute (M2i), and aims at enhanced reliability of laser cladded industrial products through online feedback process control, and falls within the research programme of the Materials Innovation Institute (M2i, www.m2i.nl).
The main aim of this research proposal is to develop production methods and tools needed to achieve a high degree of reliability and integrity of the laser cladded components and simultaneously attaining high laser cladding (production) rates. Such methods and tools should be amenable to easy implementation and integration in manufacturing industry and be suitable for different materials combinations without the need for any trial and error approach.

Industries often experience that clad layers develop cracks either during production (hot cracking) or during storage (delayed cracking) or during subsequent machining or in service due to relaxation of residual stresses. The high cooling rates and differential
shrinkages involved in the laser cladding process are responsible for such tensile residual stresses which can easily exceed the yield strength of the clad material resulting in cracking and/or deformations.
Thermal and thermo-mechanical FEM models capable of predicting melt pool characteristics, clad geometry, distortion and cracking due the thermal stresses and their gradients as a function of the laser processing parameters will be developed and experimentally validated. Such models will provide guidelines for the development of the feedback controller of the cladding system and other tools. A database (DB) architecture will be designed such that it will be able to suggest suitable laser processing conditions for the chosen material combination and clad characteristics. All existing data and results of this research will be incorporated for industrial use.
Relations between laser processing conditions (power, cladding speed, laser beam size and shape, powder feed rate, initial substrate temperature) and the resulting clad
properties (clad geometry – height & width, micro-structure, hardness, dilution at the
interface region, residual stresses, wear at ambient and elevated temperatures and any other relevant properties) will be studied. Such relationships will be established for different substrate/clad materials combinations typical in industry.

PROFILE

The candidate should have
· A Masters degree in Mechanical Engineering, preferably in Production
Technology/Engineering or Mechatronics or Materials Technology with Distinction
or Honours,
· Experience and knowledge on materials processing with lasers, preferably on
surface cladding and/or alloying,
· Hands on experience with operation of laser systems, robots and associated
controllers,
· Sufficient knowledge and experience with different materials testing and analyses
techniques (optical and electron microscopy, wear, harness and mechanical
strength testing)
· Good programming skills with Matlab, C++, FemLab or Ansys or similar
· Some knowledge of optics for lasers and their design
· Some knowledge of database development
· A good analytical mind and a high degree of initiative.
You are proficient in spoken and written English. You have written reports and papers in the English language. Finally, you have well developed social skills to co-operatively work in our research group as well as with the other partners in the project.

APPOINTMENT AND SALARY

We offer a challenging position in the exciting field of laser materials processing. You are offered a project and employment for a period of four years, in accordance with the conditions and salary of M2i with corresponding broad package of secondary benefits.


INFORMATION AND APPLICATION

For further information about this position you can contact prof.dr.ir. Bert Huis in ‘t Veld
(a.j.huisintveld@ctw.utwente.nl, ++ 31 (0)53 4892527), or you can visit our website,
http://www.wa.ctw.utwente.nl/news/vacancies.doc/
You are invited to send your application together with curriculum vitae and a list of
publications by email to a.j.huisintveld@ctw.utwente.nl, with reference to FAB2ASM.


KEYWORDS

Laser, cladding, control