JavaScript is disabled for your browser. Some features of this site may not work without it.
TRANSIENT BEHAVIOR OF THE PLANAR-FLOW MELT SPINNING PROCESS WITH CAPILLARY DYNAMICS

Author
Theisen, Eric
Abstract
Planar-flow melt spinning (PFMS) is a single-stage rapid
manufacturing technique for producing thin metal sheets or ribbons.
During the processing molten metal flows through a nozzle onto a
moving substrate where a puddle is formed. This study focuses on
the time dependent behavior of the process and looks at the puddle
dynamics during the cast. Understanding how the issues of heat
transfer, fluid flow and contacting dynamics influence the quality
of the cast ribbon are the primary focus of the study. The
commercial acceptance of PFMS requires ribbons to be cast with good
quality (e.g. uniform thickness).
There are a large range scales that are relevant to the ribbon
product. Thickness variations occur on the macro-scale over the
length of the cast (50 m). There is a steady decrease in ribbon
thickness over the length of the cast. There is also a periodic
variation on the length scale of the wheel circumference (2-3 m).
Steady mass, momentum and energy balances are used to understand
these long length-scale thickness variations.
There are also thickness variations that occur on smaller scales,
cm to mm. A periodic thickness variation across the width of
the ribbon is a common defect observed in our casting, referred to
as the cross-wave defect. The molten metal puddle is subject to
capillary vibrations. We find that these oscillations correspond to
the cross-wave defect.
Motivated by the physics of the cross-wave defect, a more
generalized problem of the vibrations of coupled capillary surface
is identified. The motions of the puddle are similar to the
classical problem of the vibration modes of a `plucked' sphere. In
considering the possible modes of vibration for a droplet confined
between two plates, we find a novel vibration mode where the
center-of-mass oscillates. This model is extended to account for a
droplet confined within a tube, with two sections of the droplet
extending from each end. Restricting to quasi-steady interface
shapes, we find a translational vibration mode which can occur with
lower frequency than the traditional Rayleigh modes. The vibration
frequencies are compared to experimental values.
Description
Paul H. Steen, Timothy J. Healey, Nicholas
J. Zabaras, Steven J. Weinstein.
Sponsorship
Eastman Kodak
Graduate Research Fellowship, NSF
DMI-0500311, -0500408.
Date Issued
2006Publisher
Metallurgical and Materials Transactions B
Subject
planar-flow melt spinning; capillary vibrations
Previously Published As
Byrne et al, Capillary puddle vibrations linked to casting-defect formation in planar-flow melt spinning. Met. Trans. B. 36B, p. 445-456, 2006
Type
dissertation or thesis