Page 32 - Industrial Cutting of Textile Materials

Lay planning and marker making in textile cutting operations 19

The width of a marker has to be determined when beginning the marker-making
process. This is affected by following fabric parameters:
The smallest fabric width in each roll used in a specific order;
●
The width of selvedge.
●
The width of the marker is calculated using following principle:
Marker width = fabric widthselvedge width – k
–
æ æ 12 cmfor woven fabrics,and öö
-
ç : k safety allowancce ç 24 cmfor elastic knitted fabriics ÷÷
–
è è øø
The safety allowance k takes into account probable irregularities during the spread-
ing process:

During spreading, it is not possible to align fabric plies with perfect precision.
●
The width of a fabric may change slightly.
●
As fabrics most often are wound in rolls in full width, they are unrolled and tradition-
ally spread with the face side up (see Section 4.3), and a full set of pattern pieces for each
article are placed in a marker. The larger and more important pattern pieces are placed first,
followed by the subordinate and smaller pieces. The pattern pieces in the marker have to
be placed as tightly as possible to make the most efficient use of the fabric. As the shapes
of garment pattern pieces are often complex, 100% utilization is not practical, 70% fabric
utilization is considered as good, and 80%–85% is considered as very good.
Markers were originally drawn on paper or directly onto the fabric at full size,
using the pattern pieces cut from stiff cardboard. Current practice makes wide use
of specialized software, and markers are created on a computer screen at a reduced
scale. Computer-produced markers are printed out at full size on special paper (see
Section 4.2.9) and transferred to a cutting section for the manual spreading and cutting
processes. During the automated cutting process, the printed marker only ensures the
recognition of cut components. It can be replaced with component marking, labelling,
or recognizing by the help of an overhead projector (see Chapter 9, Section 9.3.8).

3.6 The influence of textile material properties on the
marker-making process

The qualities of a fabric will influence the marker-making process and the effective
use of the fabric/marker potential.

3.6.1 Plain fabrics without nap

All the pattern pieces of one article must be laid in the same direction within a marker
to eliminate different colour shades arising in components that have been cut in dif-
ferent directions. If pattern pieces from other articles are also included in the marker,
they may be laid in the opposite direction.