were first established. Each course step was carried out repeatedly by an expert according to statistical norms. In order to determine in which steps and for which model CAD can be more productive, the data obtained for both methods was compared with respect to the individual time value of each course step and the total time values. Furthermore, the possible causes of the results obtained were discussed and suggestions were put forward.
Introduction
• Devices
performing high-tech services in the apparel industry are commonly referred to
as ‘CAD/CAM’. In the apparel industry, CAD systems are mainly used in various
processes such as garment design, pattern preparation, pattern grading and
marker making. CAM systems include computerized sewing machines, fabric
spreading & cutting systems, and mover systems used during the sewing
process of apparel production.
• Marker
- Marker is a thin paper which contains the patterns of all the components needed to produce the garment ensuring the least fabric wastage.
- Marker is made according to the order sheet provided by the buyer.
- Size wise garments quantity is important information to make the actual marker.
- Marker length parameters
- Patterns for how many sizes of garments are being used to make the marker
- How many garments will be produced by one lay of fabric?
- Length of cutting table.
- Production planning.
- Efficiency of marker.
Note:Marker width is kept equal to
the minimum fabric width.
Pattern
•
Pattern is a paper that is so thin. It is the
copy of design which for essential for garments product. In clothing industries
the design means determine the space the shape and developing the pattern
according to it. The traditional method is to it make a concept of drawing and
then copy or model it on a dummy mannequin. Now -a-days design can be collect
from the following source.
•
Designer own thinking or self creativity.
•
Developing.
•
Copying.
•
Marker efficiency
•
The ratio of area for pattern pieces that are
placed on the marker to the total area of the marker expressed as percentage is
called marker efficiency.
•
Marker efficiency is calculated by two
parameters which are :
•
Total area of all the patterns in marker.
•
Total area of that marker.
•
Marker efficiency formula
Marker efficiency=(area of the patterns in the marker ÷ area
of the marker)×100
•
Higher the marker efficiency, least the fabric
wastage.
•
Lower the fabric wastage means higher the
profit.
•
Importance of marker efficiency
- Marker
efficiency is the important part of garments manufacturing. Direct cost of
garments could be utilized by marker efficiency. Salary of a marker
planner truly depends upon the capability to increase the marker
efficiency.
Marker efficiency is determined by fabric utilization, the percentage of the total fabric that is actually used in garment parts. The area not used in garment parts is waste. Marker efficiency depends on how tightly the pattern pieces fit together within the marker. The total surface area of the pattern pieces is compared to the total area of the marker to calculate the percentage of fabric that is used. This is determined automatically by marker-planning software. If marker-making and marker planning technology is not available, the area of each pattern piece may be determined by a perimeter – a mechanical device that calculates the surface area as the outline of the pattern is traced. Factors that affect marker efficiency are fabric characteristics, shape of the pattern pieces, and grain requirements.
- Factors on which marker efficiency depends on
1.Skill of marker maker: Marker efficiency depends on
the skill, cordiality, sense of responsibility, experience and technical
knowledge of marker maker. The more the trial of marker making, the more
possibility of more marker efficiency.
2.Size of garments: The more sizes patterns are
included in marker, the possibility of more marker efficiency. But increase of
huge sizes patterns, the result may be opposite.
3.Length of marker: when the marker length is more
than it is easier to place the patterns in it which causes more marker
efficiency. But illogical increasing of marker length may decrease the marker efficiency.
4. Pattern engineering: sometimes pattern can be
modified by changing design, dividing the pattern into two or by other pattern
engineering technique which may increase the marker efficieny.
5. Types of fabric: marker efficiency is more for symmetric
fabric. Because, here it is possible to place the pattern in different
direction. But, for asymmetric fabric, marker efficiency is low due to the
difficulties of placing pattern in marker.
6. Method of marker making: marker efficiency is more
for computerized method then manual method. But it is more time consuming
system. Marker efficiency may be more than computerized system increase of
extreme skilled and experienced marker maker.
7. Width of the marker: Marker efficiency is more for
more width of marker. Because it is easier to plan to place the patterns in
marker when its width is more. But it is not true for illogical increasing of
width.
Objectives of Marker Efficiency
·
Examine how fabric utilization affects marker
efficiency.
·
Enumerate the factors affecting material
utilization.
·
To minimize the production cost.
·
To reduce the fabric wastage.
·
Time saving.
Problems of marker making
• Grain
line: grain line is more effective constraint of marker marking
because of grain line. Sometimes it is tough to place the pattern onto the
marker, even though it is possible the wastage become higher.
• Fabric
characteristics: fabric which can retain the same appearance while
turning in 180° angle called symmetric fabric. They required no special
attestation no special attestation during marker making. Asymmetric fabrics are
those which cannot retain the same appearance while turning in 1800
angle. Nature of the fabric may sometimes regard as a constraint of marker
making.
• Design
of garments: sometimes garments may require special design like
mirror image, the some appearance in lower front and lower front part in this
case both the fabric and pattern pieces should be laid down with special care so
that we can get desired design and get a better garments.
• Production
Planning: production planning includes the rate of production, types
of garments, sixes of garments etc. when an order is placed for quantity of
garments, it normally specifics a quantity of each size and color if the sewing
room requires the cut components urgently. The marker planner has to make two
types of marker.
Methods of marker making
Mainly there are two methods of marker making:
Ø Manual
method of marker making
Ø Computerized
method of marker making
Manual marker efficiency calculation:
Small size
Sleeve
length= 18.28cm
Sleeve
width= 39.11cm
Sleeve area= 563.27cm
Front
part length=Back part length= 59.69cm
Front
part width=Back part width= 42.67cm
Front
part area=Back part area= 1002.79cm
Total
area=Sleeve area + Front part area +
Back part area
=
563.27+1002.79+1002.79
= 2568.85cm
Large size
Sleeve
length= 22.86 cm
Sleeve
width= 45.21cm
Sleeve
area= 813.81cm
Front
part length=Back part length= 64.77cm
Front
part width=Back part width= 47.75cm
Front
part area=Back part area= 1217.67cm
Total
area=Sleeve area + Front part area +
Back part area
=
813.81+1217.67+1217.67
= 3249.16cm
Marker
length= 193.04cm
Marker width
= 149.86cm
Marker area =
193.04+149.86
= 11389.36cm
Marker efficiency=(area
of the patterns in the marker ÷ area of the marker)×100
={(2568.85+2898.14+3249.16)÷11389.36}×100
= 77%
Computerized
marker efficiency calculation:
Total
piece of pattern=48
pattern
width =152.4 cm
pattern
length =626.64 cm
Marker
efficiency=80%
• Graphical
chart
• Discussion
• in
this table, the time difference between the manual and CAD methods increases as
one moves from Model-1 to Model-4; in other words, from the simple model to the
more complicated one.
• Figure
5 shows the graph obtained as a result of a comparison between the manual and
CAD methods with regard to time-related data for the four models .
• At
this point, the time values increase in the manual method as one moves from Model-1
to Model-4, whereas the values for the CAD system remain within a close range.
• Findings
obtained after the data in Table 3 were assessed by the Mann Whitney Test, as
shown in Table 4. The ‘P’ value was seen to have reached its lowest level in
Model 3, which has the longest pattern perimeter due Time-related data obtained
as a result of studies conducted can be seen below in Table 3. As can be seen
to having long sleeves. It has also been observed that the ‘P’ value reached
its second lowest level in Model 4, which has the highest number of pieces.
• Moreover,
in the assessment of total times for all models, where P:0.0304 (P<0.05),
the difference stemming from the comparison of the manual method with CAD has
been found to be in favour of CAD
• Time-related
data obtained as the result of studies carried out in order to make a
comparison of manual and CAD systems is seen in Table 5. An examination of
total values of time-related data will reveal the fact that the time periods
related to CAD are shorter than those for the manual system. The graph obtained
as a result of a comparison of time-related data found for manual and CAD
systems in Model 1 is shown in Figure 6.
• As
can be seen at this point, the situation which was in favour of the manual method
in the first, second and third stage has started to change in favour of the CAD
method starting from the fourth stage, as the number of sizes and consequently
the patterns to be processed increased, and this continued in the same manner
at an increasing pace until the end of the eighth stage.
• Findings
obtained as a result of assessment of data given in Table 5 by means of the
Mann Whitney Test are shown in Table 6 together with the comparison of findings
related to the manual method for each stage.
• Keeping
in mind that one of the most important aims of using CAD is to minimise the
waste of fabric, patterns for 4 models were placed on a 120-cm wide fabric
using manual and CAD systems, in accordance with distribution of sizes shown
in Table 7, markers prepared and marker lengths measured .
Comments
• In
the study, the following results were obtained on the basis of the CAD and
manual methods.
• In
the preparation of main size patterns, the manual system seems to be superior
due to the fact that the main size patterns are prepared in advance manually
and then digitised. These methods were preferred since the system operators do
not have sufficient qualifications.
• The
results obtained in the first stage are associated with the above mentioned application.
• In steps such as checking, correcting and
putting necessary allowances on main size patterns, no significant difference
has been found between the two methods, due to effects of personal skills and
productivity in particular.
• Since grading main size patterns, checking
graded patterns and making arrangements prior to marker making procedures
demand manual labour and time, it is only natural for the CAD systems to be
advantageous in these steps.
• During marker-making preparation, checking,
correcting and plotting procedures, neither method was found to be superior to
the other, which was unpredicted.
• In assessing the total times for all stages,
the level of significance between the two methods was found in favour of CAD,
as predicted.
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