The stretching and elongation of filaments in the Nonwoven Spunmelt Machine are achieved through a process called drawing. Drawing is a critical step in the extrusion process, and it involves stretching the molten polymer filaments to achieve the desired thickness, denier (fiber size), and orientation. Here's how the drawing process works:

Extrusion of Molten Polymer:

The process begins with the extrusion of molten polymer through spinnerets, which are metal plates with tiny holes or nozzles.

Spinneret Design:

The design of the spinneret plays a crucial role in determining the characteristics of the filaments. Spinnerets may have various hole shapes, sizes, and arrangements.

The spinneret design influences the structure of the extruded filaments, including their cross-sectional shape, orientation, and arrangement.

Drawing in the Air Gap:

After extrusion through the spinnerets, the filaments enter a region called the "air gap." In this zone, the filaments are exposed to ambient air, and drawing occurs.

The speed of the conveyor belt or drum and the rate of extrusion contribute to the drawing process. The difference in speed between the extrusion rate and the conveyor speed causes stretching and elongation of the filaments.

Cooling and Solidification:

As the filaments are drawn, they undergo rapid cooling, which is essential for solidifying the structure and setting the properties of the filaments.

The cooling process helps maintain the stretched and elongated form of the filaments, preventing them from reverting to their original state.

Orientation and Alignment:

Drawing not only elongates the filaments but also imparts orientation to the polymer molecules within the filaments. This orientation contributes to the strength and other mechanical properties of the resulting nonwoven fabric.

The degree of orientation can be controlled by adjusting the drawing conditions and parameters.

Collecting on Conveyor Belt or Drum:

The drawn and solidified filaments are laid down onto a moving conveyor belt or drum in a random or oriented arrangement, depending on the specific requirements of the nonwoven fabric.

Bonding and Finishing:

The laid filaments are bonded together using methods such as thermal bonding, chemical bonding, or mechanical bonding to create a coherent nonwoven fabric.

Additional cooling and finishing steps may be applied to the bonded fabric to achieve the final desired properties.

By carefully controlling the drawing process, manufacturers can achieve the desired thickness, denier, and strength characteristics in the nonwoven fabric produced by the Spunmelt Machine. The drawing process is a critical step in tailoring the properties of the final product to meet specific application requirements.