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Curl and twist measured with a new instrument

When a sheet of paper loses its planar shape and deforms, the phenomenon is described as a combination of curl and twist. These are dimensional stability phenomena common to all paper products. Curl and twist occur because of a combination of non-symmetric paper structures with asymmetry in the interaction with the environment.

If you want to measure curl and twist for quality control in a production laboratory, high levels of automation are needed to have a sufficiently large sample throughput. The CurlOMeter is a new instrument which characterizes the out-of-plane stability using modern measurement technique.

Modern measurement technique for automation

The Curl-O-Meter builds on modern shape acquisition technology and image analysis to limit the need of operator time. An IR-drying station induces out-of-plane deformation in a quick and reproducible way. In this mode of operation the instrument can handle up to 40 samples per hour. Additionally, the new instrument can be operated to replicate measurement strategies based on humidity changes, which is the traditional way to characterize curl.

An automatic sample feeding and ejection unit gives high sample throughput without need for operator assistance. The viewing system is easily programmable to perform measurements on samples of non-standard shape and size.

A final prototype of the CurlOMeter measures curl and twist to describe the out of plane deformation of paper and paperboard.


Marco Lucisano
+46 768767285
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Characterizing the out-of-plane dimensional stability of paperboard, Lucisano, M.F.C. (2010), Control Systems, SCPI, Stockholm.

A new instrument for measurement of the out-of-plane dimensional stability of paperboard
Lucisano, M. F. C. and Vomhoff, H. (2010)
PaperCon 2010, TAPPI, Atlanta.

A new instrument for measurement of the out-of-plane dimensional stability of paperboard
Lucisano, M. F. C., Nilsson, M. and Cochard J. (2007)
International Paper Physics Conference, Appita, Carlton.