Page 171 - Industrial Cutting of Textile Materials

158 Industrial Cutting of Textile Materials

Fig. 10.6 Laser processing surfaces: perforated plate (A), honeycombs (B), and a grid
structure used on Eurolaser cutters (C).

10.3.1.2 Metal grid

Using metal grid in a shape of web, honeycombs, and others (see Fig. 10.6B and C),
the laser beam can pass cleanly through the cut material reducing underside reflec-
tions (which are the reason of burning of the back side of the material). The grid kind
of surface also provides free airflow under the cut material to exhaust cutting fumes
easily from the work area avoiding deposition of debris on the reverse side of the cut
material. Combined with an air suction system, the grid surface is ideal for cutting
light, thin, and instable materials such as textiles.

10.3.2 Extraction/ventilation system
The thermal decomposition of cut materials results in aerosols, dust particles, and
fumes (gases). They can reduce cutting quality, contaminate cut material surface and
focusing lens, create marks on the material surface, and pose a particular health risk
if inhaled. Therefore, the emissions have to be constantly extracted and, depending
on the application, filtered and discharged into the ambient air. By help of special ex-
traction system, the smoke particles and soiling created in the laser cutting process are
drawn away above and below the treated material. Properly positioned fume extraction
also prevents or minimizes underside marks caused by cutting structure of the table.

10.3.2.1 Lower extraction
A special air suction system located beneath the cutting surface collects cutting emis-
sions and leads them away (see Fig. 10.7A). Under the processed material ply, it lowers
pressure and ensures that thin, flexible materials lay on the cutting surface evenly, pre-
venting cut materials from slipping and small cut parts from lifting. Often the level of
the vacuum and the sections of the table that are exhausted can be adjusted individually
depending on the treatment, material properties, and size of the treated material ply.
Energy costs can be reduced by switching off segments which are not in the work area
of the laser beam.