A model has been developed to predict the bonding behavior of nonwovens during the ultrasonic bonding process. The model includes the following subprocesses: mechanics and vibrations of the web and horn, viscoelastic behavior of webs and heat generation, and heat transfer. Each subprocess was modeled first and then combined together with the boundary conditions to develop an overall process model. The compressional behavior and thermal conductivity of webs will be discussed and their appropriate equations have been chosen for model. A Finite Element Method (FEM) was used to solve the above coupled model. Subsequently, the heat generation rate and the temperature change during the bonding process were calculated.
References
1.
BaxerS., “Thermal Conductivity of Textiles,” Proceedings of Physical Society, London, Vol. 58, 1946, p. 105.
2.
BenatarA., and GutoskiT., “Ultrasonic Welding of PEEK Graphite APC-2 Composites,”Polymer Engineering and Science, Vol. 29, No. 23, 1989, p. 1705.
3.
BombergM., and KlarsfeldS., “Semi-Empirical Model of Heat Transfer in Dry Mineral Fiber Insulations,”Journal of Thermal Insulation, Vol. 6, 1993, p. 156.
4.
CarnabyG.A., “The Compression of Fibrous Assemblies with Applications to Yarn Mechanics,”Mechanics of Flexible Fiber Assemblies, Sijthoff and Noordhoff, Alphen aan den Rijn, The Netherlands; Germantown, Maryland, U. S. A., 1980.
5.
ChapmanA.J., Fundamentals of Heat Transfer, New York: Macmillan Publishing Company, 1987.
6.
ChernyakB. Ya., “The Process of Heat Formation in the Ultrasonic Welding of Plastics,”Welding Production, Vol. 2, August, 1973, p. 87.
7.
DunlopJ.I., “Characterizing the Compression Properties of Fiber Masses,”Journal of Textile Institute, Vol. 65, 532, 1974, p. 532.
8.
EppsH.H., “Effect of Fabric Structure on Insulation Properties of Multiple Layers of Thermally Bonded Nonwovens,”INDA Journal of Nonwovens Research, Vol. 3, No. 2, 1991, p. 16.
9.
FloodG., “Ultrasonic Bonding of Nonwovens,”Tappi Journal, May, 1989, p. 165.
10.
FloodG., “Ultrasonic Energy, a Process for Laminating Bonding Nonwoven Web Structure,”Journal of Coated Fabrics, vol. 14, Oct., 1984, p. 71.
11.
FloodG., “Ultrasonic Bonding of Nonwovens,”1988 Nonwovens Conference, p. 75.
12.
FloydK., and OzsanlavV., “Application of Ultrasonics in the Nonwoven Industry,” EDANA's 1988 Nordic Nonwovens Symposium, p. 120.
13.
HearneE.R., and NossarM.S., “Behavior of Loose Fibrous Beds During Centrifuging, Part I: Compressibility of Fibrous Beds Subjected to Centrifugal Forces,”Textile Research Journal, Vol. 52, October, 1982, p. 609.
14.
HuangH., and Usmani, Finite Element Analysis for Heat Transfer, Springer-Verlag London Limited, 1994.
15.
LandLeverkusen W., “Investigations into the Process of Ultrasonic Welding,”Kunststoffe, Vol. 68, No. 4, 1978, pp. 16–18.
16.
MatsyukL.N., and BigdashevskiiA.V., “Ultrasonic Welding of Polymeric Materials,”Soviet Plastics, Vol. 2, 1960, p. 70.
17.
MuellerD., and KlockerS., “Development of a Complete Process Model for Nonwovens Thermal Bonding,”International Nonwovens Journal, Vol. 6, No. 1, 1994, p. 47.
18.
ObendorfS.K., and SmithJ.P., “Heat Transfer Characteristics of Nonwoven Insulating Materials,”Textile Research Journal, Vol. 56, 1986, p. 691.
19.
ReddyJ.N., An Introduction to the Finite Element Method, McGraw-Hill, Inc., 1993.
20.
RustJ.P., “Effect of Production Variables on Properties of Ultrasonically Bonded Nonwovens,” M.S. Thesis, School of Textiles, Fiber and Polymer Science, Clesmon University, 1985.
21.
SchoppeeM.M., “A Poission Model of Nonwoven Fiber Assemblies in Compression at High Stress,”Textile Research Journal, Vol. 68, 1998, p. 371.
22.
SebestyenE., and HickieT. S., “The Effect of Certain Fiber Parameters on the Compressibility of Wool,”Journal of Textile Institute, Vol. 62, 1971, p. 545.
23.
StanekL.H., and SmekalJ., “Theoretical and Experimental Analysis of Heat Conductivity for Nonwoven Fabrics,”INDA Journal of Nonwovens Research, Vol. 3, No. 3, 1991, p. 30.
24.
StasaF.L., Applied Finite Element Analysis for Engineers, New York: Holt, Rinehart and Winston, 1985.
25.
TolunayM.N., DawsonP.R., and WangK.K., “Heating and Bonding Mechanisms in Ultrasonic Welding of Thermoplastics,”Polymer Engineering and Science, Vol. 23, No. 13, Sept. 1983, pp. 726–733.
26.
UdomkichdechaW., “On the Compressional Behavior of Bulky-fiber Webs (Nonwovens),” Dissertation, NCSU, 1986.
27.
VolterraE., and ZachmanoglouE.C., Dynamics of Vibrations, Ohio: Charles E. Merrill Books, Inc., 1965.
28.
Van WykC.M., “Note on the Compressibility of Wool,”Journal of Textile Institute, Vol. 37, 1946, T285.
29.
WooS.S., ShalevI., and BarkerR., “Heat Moisture Transfer Through Nonwoven Fabrics Part I: Heat Transfer,”Textile Research Journal, Vol. 64, 1994, p. 149.
30.
WoolR.P., and O'ConnorK.M., “A Theory of Crack Healing in Polymers,”Journal of Applied Physics, Vol. 52, No. 10, Oct., 1981.
