The rotor spinning process for fibre
At Teijin Twaron in Arnhem new ways of producing fibres are being
One of the interesting new techniques is "The Rotor Spinning Process".
In principle, this process looks a lot like the making of sugarfloss
(or cotton candy) at the carnival / fair. Here, however, we deal with a
polymer-filled disc with tiny holes. The polymer is pressed, due to the
centrifugal forces, through the holes to the
outside. The process is already in operation at the company; At Teijin
Twaron there is also a pilot machine in which variations in
process and geometry can be tested.
The liquid polymer solidifies and becomes a thin filament on the
exterior boundary of the machine. The purpose of the work during the
week "Math with Industry" with the mathematicians is to verify an
existing model on the basis of a momentum equation and mass
balances and if possible to improve the model.
A first order approximation of the path the filament makes (without
modeling air friction) in the space between disc and exterior boundary
of the machine exists already. Also a description of the path in which
water cooling and air friction is available. However, the model can be
improved; certain states of the rotor spin process should be
approximated in a better way.
The purpose of the modelling in some
more detail reads:
1) Try to determine the situation (process and geometry) in which a
continuous filament can be generated. Breaking of filaments may cause
problems in the use of the material if the length of the filament is
below a critical length.
2) Try to determine the circumstances (process and geometry) in which
the length of a broken filament can be determined beforehand. In this
case, fibres can, in principle, be produced.
3) Determine the effect of the temperature, rotor speed, etc. in the
present operating situation in order to achieve a robust production