Embedded Sensing System for Paperboard Tubes
Huldah Gronvall/ Prof.
Dept of Civil & Environmental Engineering
the past few decades, due to increased speeds and capacities of
manufacturing equipment, there has been a steady increase in the
performance requirements for spirally-wound paperboard tubes (also
known as "cores") on which paper, film, metals, and
textiles are wound.
tubes are usually made from recycled paperboard materials like
cardboard boxes and office paper. Such paperboard tubes range
in size from diameters as small as 1 inch to as large as 36 inches
with tube-wall thicknesses from as little as 0.1 inches to 1.0
inch. The mechanical and physical properties of paperboard tubes
have significant influence on numerous production variables including
speed of the winding operation, amount of material that can be
wound on the tube, and long-term stability of the material on
the tube. The moisture content (MC) in particular is a key physical
property that influences many mechanical properties of a core.
Bank's Composite Structures Research Group at the University of
Wisconsin-Madison is working with Sonoco Products Company, the
world's largest manufacturer of paperboard tubes, to develop new
embedded sensing technologies for these tubes. The objective of
this research is to develop a method that provides a fast, accurate,
non-destructive, and perhaps contact-less way of measuring the
MC in these cores. Presently, the most accurate way to measure
the MC of paperboard is by calculating the difference between
a sample's "original" weight and that of its "dried"
weight. By this method, the weight difference between the "wet"
and "dry" condition is used to calculate the moisture
content as follows:
to this method, however, is that a sample has to be drawn from
the paperboard. In other words, a piece of the core has to be
destructively removed to use for the oven-drying. A prevailing
objective of the current project is to develop a non-destructive
method to measure MC. This objective is presently being explored
through strain-gauging cores and finding a relationship between
mechanical strain and MC.
Sonoco is examining ways to develop an inventory-control system
for paperboard tubes using Radio Frequency Identification (RFID)
Tags. The contact-less aspect of this research involves interfacing
a MC sensor with this inventory system so that the MC of these
tubes can be read at any point in storage, shipment, and/or distribution.
The principal, guiding objective is that such a system would supplant
today's rudimentary methodologies which are currently
characterized by destructive and/or inaccurate MC-measuring techniques
including oven-drying and moisture meters that use electrical
resistance to measure MC. Non-destructive, remote techniques for
measuring tube properties, such as those being developed through
these joint efforts, would be of great interest - and value -
to the industry.