Page 139 - Industrial Cutting of Textile Materials

126 Industrial Cutting of Textile Materials

Fig. 9.14 Powered multibelt cradle by Eastman to feed material on a single-ply cutter directly
from its roll.

9.3.4 Vacuum system
Cutting tables are most often equipped with a vacuum system to secure the material
during the cutting process and to ensure a high degree of accuracy in the cut compo-
nents. The tables have a cutting surface (a fixed sheet or a conveyor belt) with internal
air channels – to let the air go through – and are equipped with powerful suction blow-
ers. By help of the vacuum system, the pressure is lowered in a plenum on the cutting
table. The pressure differential between this plenum and the atmosphere applies a
strong and even holddown force to the material on the table. It stops the material mov-
ing while it is being cut and makes sure the cut components stay in place while the
rest of the job is still in the process. To create the plenum on the cutting table, porous
materials (which allow the air pass through), like most parts of textiles, have to be
covered with a lay of air impenetrable PVC cover.
As the most part of power consumed by the cutter is spend to generate vacuum, special
attention is put to the efficient vacuum supply during the cutting process. Most often, a
vacuum regulator adjusts automatically the configuration of the vacuum supplied area so
that the strongest vacuum is focused on the cutting tool action area to ensure maximally
high cutting precision. Reduced vacuum level is supplied to other parts of the cutting table
to keep the material ply fixed during the cutting. In the area with already cut components,
the vacuum is not supplied to reduce power consumption and ease unloading of the cut
components. If the cut components are small and light and their kitting is complicated,
light air suction can be applied also in take-off zone to keep the cut components in place.
For the cutters with a static table, the cutting surface is divided into two inde-
pendently controllable vacuum areas. The vacuum is activated in the area where cut-
ting process is taking place. In the part of the cutting table where cut components