Analysis of chatter marks damage on the Yankee dryer surface
of a tissue machine
, Oscar de la Torre, Eduard Egusquiza
Center for Industrial Diagnostics, Universitat Politècnica de Catalunya, Av. Diagonal 647, 08028 Barcelona, Spain
Received 23 December 2011
Accepted 25 February 2012
Available online 8 March 2012
A tissue machine suffering from Yankee chatter marks has been experimentally investi-
gated. A series of vibration measurements during normal operation at various Yankee
speeds on both the creping and the cleaning blade holders have been carried out. The anal-
ysis in a frequency range up to 20 kHz has permitted to identify speed dependent fre-
quency peaks and broadband high frequency vibration content on the creping zone.
Hence, an experimental modal analysis of the creping blade and holder has been carried
out with the machine stopped to identify its natural frequencies. As a result, resonance
conditions have been identiﬁed due to the gearbox excitation originated by the meshing
process. The study of the corresponding mode shapes has permitted to understand the
vibration behavior and its relationship with the damage. To solve the problem, the creping
blade holder structure has been redesigned to detune the resonances. Since this overhaul,
comparable measurements have conﬁrmed a signiﬁcant reduction of vibrations and high
frequency noise. The appearance of chatter marks has been minimized.
Ó 2012 Elsevier Ltd. All rights reserved.
The drying section of a tissue machine consists of a large-scale Yankee cylinder internally heated with pressurized steam
that removes the water content of the previously formed and pressed wet ﬁber web at the end of the paper making line. For
that purpose, the Yankee drier is equipped on one side with a pressure roll that attaches the sheet on its surface and a doctor
blade that removes and crepes it at the opposite side thus creating the tissue (see Fig. 1). In this process it is necessary to
apply an adhesive substance to coat the Yankee surface in order to well attach the sheet and to improve the blade perfor-
mance at the blade–sheet–coating interface. A good coating layer should present a hardness gradient along its thickness with
higher values next to the metal Yankee surface and lower ones next to the sheet . In this way, the Yankee surface is well
protected against blade friction or penetration and at the same time it facilitates adhesion at the pressure roll. In order to
remove contamination build-up on the surface of the Yankee both inside and outside the web, a cleaning blade is also ap-
plied just after the creping and before the coating shower. The blades are supported by aluminum beams, commonly referred
to as blade holders, which in turn are connected to a positioning system.
One potential problem associated to the creping process is the so called blade chatter which can cause defects in the
sheet as well as damage to the Yankee surface. Blade chatter takes place when the tip of the blade moves out-of-plane
due to vibration and a stick–slip motion between its surface and the coating layer develops . If the forces involved are
strong enough, the blade can eventually mark the metallic Yankee surface as shown in Fig. 2. In this case, it is said that
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E-mail address: email@example.com (X. Escaler).
Engineering Failure Analysis 23 (2012) 44–54
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Engineering Failure Analysis
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