Optimized Needle Boards Based on Simulations of Needle Punch Patterns

Needle punching is a well-established method to bond nonwovens mechanically. In this process thousands of barbed needles penetrate simultaneously into the nonwoven. Hereby, fibers captured by a needle are drawn through the layers of the nonwoven to solidify them. The resulting properties of the needle punched nonwoven depend significantly on the machine and process parameters: needle density, needle arrangement, feed per stroke and belt speed.

One measure of quality is based on the number of needle punches per area which should be as homogeneous as possible. Any kind of stripes in vertical, horizontal or diagonal direction caused by structures in the needle punch pattern should be avoided. Fraunhofer ITWM has developed in close cooperation with Oerlikon Neumag Austria a software tool to simulate the needle punch pattern and optimize the positions of the needles in the board according to specified process settings.

© Oerlikon Neumag Austria
Needle Board of the Company Oerlikon Neumag Austria

Evaluation Criteria Based on Simulated Needle Punch Patterns

Hereto, Fraunhofer ITWM has generated different evaluation criteria to quantify the quality of needle punch patterns according to homogeneity and streakiness. These criteria have been implemented embedded in a graphical user interface on the one hand for engineers to evaluate in advance effects about needle punch patterns with respect to process conditions and modifications and on the other hand as the basis for systematic optimization leading to automatic design of needle positions in the board.

The secondary conditions by construction, operating points and finally also shape distortion through the process are included. Herewith, it is possible to develop simulation based customer-specific needle boards with improved nonwoven properties.

© Fraunhofer ITWM
Needle Punchs
Vernadelter Vliesstoff- Ausschnitt: Dichteverteilung
© Fraunhofer ITWM
Needle-Punched Nonwoven: Density Distribution
© Fraunhofer ITWM
Needle-Punched Nonwoven: Direction Distribution

Type of Project: Industry Project
Project Partner: Oerlikon Neumag Austria