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SUMMARY:Virtual MEchanics GAthering -MEGA- Seminar: Flexure pivot oscillat
 ors for mechanical watches
DTSTART:20210311T161500
DTEND:20210311T173000
DTSTAMP:20260408T080224Z
UID:cb3bb294bbe2cf39a5d388ec19079d33ab0d4a949d131870f6b0a152
CATEGORIES:Conferences - Seminars
DESCRIPTION:Etienne Thalmann (INSTANT-LAB\, EPFL)\nAbstract It appears th
 at the concerted efforts of the watchmaking industry are leading towards a
  limit in mechanical watch accuracy. The general consensus in horology is 
 that the time base's quality factor needs to be improved in order to signi
 ficantly increase timekeeper accuracy. The solution appears to be flexure 
 oscillators in silicon. Indeed\, flexure oscillators eliminate contact fri
 ction by using the elastic deformation of slender beams to guide the motio
 n of an inertial body and monocrystalline silicon minimizes internal frict
 ion. The results is a significant improvement in quality factor in compari
 son to the traditional balance and hairspring oscillator. It is however no
 t sufficient to increase the quality factor to reach accurate timekeeping.
  The period of oscillation of the time base must stay as regular as possib
 le regardless of changes in operating conditions such as amplitude of osci
 llation\, orientation with respect to gravity\, temperature and shocks. Th
 is research focuses on minimizing the effects of amplitude (i.e.\, isochro
 nism defect) and gravity that arise from the use of flexures. The first te
 chnical contribution is to note that the isochronism defect is a second or
 der phenomenon\, and to deal with it by modifying the second order behavio
 r of flexure spring stiffness or inertia. The second technical contributio
 n is a design method to reduce the effect of gravity for all orientations 
 of the time base by ingeniously placing the flexures and exploiting the po
 sition of the center of mass. These findings were embodied in two novel fl
 exure pivot architecture. A silicon prototype satisfying typical mechanica
 l watch specifications was manufactured and used to validate our concepts 
 experimentally.\n\nBio Etienne Thalmann received the MSc degree in Mechan
 ical Engineering from EPFL in 2015. He conducted his Master’s thesis in 
 control systems at the Swiss Center for Electronics and Microtechnology (C
 SEM)\, for which he was awarded the Hilti Mechatronic Prize. He then joine
 d the Patek Philippe Chair in Micromechanical and Horological Design (Inst
 ant-Lab) at EPFL\, where he completed his PhD on flexure pivot oscillators
  for mechanical watches in 2020. He is currently continuing his research o
 n flexure oscillators with Prof. Simon Henein as postdoctoral researcher a
 t Instant-Lab.
LOCATION:https://epfl.zoom.us/s/84678428267 Passcode: 174387 https://epfl.
 zoom.us/s/84678428267
STATUS:CONFIRMED
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