Cutting room
management
Assignment 1
Part A
Find out new development in new spreading technology and prepare a
comprehensive note.
The laying up fabrics on cutting table one ply top of another is called spreading or
laying. The spreading can be done in two ways.
1. Manual spreading
2.machine spreading
Manual spreading
In this method two operators should work together to lay the fabrics in cutting
room. In this method the cloth s pulled carefully from the fabric roll by hand s cut
to appropriate length.
Machine spreading
In this method stead of two operators the machine carries the lies of fabric from
one end of the cutting table to preordain length along the cutting table.
Over the years the parts in spreading machines are developed. That machines has
included like ply cutter device, clothing inspection lights, motors to drive the
carriage, automatic catchers to hold the ply end in place, photoelectric edge
guiders, turning table, tension and threading bars, ply counter etc..
By using these machines spreading can be done in high quality.
Spreading cutting table
Spreading cutting table has many components. They are braced fame heavily
laminated wooden to and steel legs. That table contains the weight of the lay and
spreading machine. For accurate cutting, the surface area must be smooth in the
cutting table.
Modern spreading cutting table
These kind of cutting tables are consist with the compressed air and a vacuum so
that a heavy lay can be floated and moved with case, while a high loose lay can be
sucked down and established for cutting. These machines are used in computerized
cutting system.
Spreading machines categorized in to mainly two groups
1. Stationary
2. Travelling
Stationary spreading machine
This is consisting with a pair of upright posts and a rod.
the air of posts is fixed and level at both edges of the cutting table and the rod,
which asses through the centre core of the bolt of fabric, is mounted on top of the
posts.fabrc is dispensed from the roll by pulling.
Travelling spreading machine (developed)
This can be categorized in to two groups.
1. Hand propelled machine
2. Power propelled machine(developed)
Tubular spreading machine
Tubular spreading machine spreading machines. Tubular spreading machine, is an
automatic cloth spreading machine designed to spread tubular knit fabric in faceto-face from either flat-folded bundles or rolled goods
Fully automatic spreading machine (developed)
Spreading machines to spread any kind of fabric without tension and edges are
perfectly aligned
-Cradle with single conveyor belt: Single conveyor belt prevents from marking of
the fabric and problems caused by loose threads falling between rollers on multiple
conveyor belt system.
- Easy loading and unloading rolls: Loading point from floor 1, 40mts for standard
machine
- Automatic unwinding and winding up fabric: It makes easily and faster changing
fabric roll.
- Adjustable edge side alignment by double sensor
-Spreading machine drives by encoder: The encoder system, allows programming
automatically any marker length. You can spread the marker beginning to any part
of the spreading table reaching perfect ends.
-Digital touch screen: Instructions by easily and graphic characters, particular
adjustments for any kind of fabric.
- Device to spread fabrics roll in reverse way: If fabrics come rolled inside out way,
machine can spread automatically without changing roll face.
- Automatic cutting device: Adjustable in speed, adjustable in length and with
double speed IFS (impact free system).
- Spreading machine security sensors emergency stop: To prevent any accident in
the cutting room.
Section B
a) State all the conventional cutting equipment, use in a cutting room of a
garment factory.
1. Shears
Hand shear
Electric hand shear
2. Straight knife
3. Rotary knife
4. Band knife
b) Select two of them you have mentioned above and compare them in all
aspects
Rotary knife
It has circular blade
Cut one way thrust
Not suitable to cut sharp edges
Eg.V shapes
Not much suitable for bulk
production
Straight knife
It has straight knife
Cut two way thrust
Suitable for all kind of shapes
Suitable for bulk production
c. write a comprehensive note on the computerized cutting technology.
Computerized cutting systems are achieving more widespread use as technology
costs decrease and labor costs rise. The computer control machine doesnt work in
its own. The information must feed to the computer. Then the computer send
signals to the head of the machine to cut required according to shapes. In this
system the movement of cutting head is controlled by the computer.
Main arts of the computer controlled system
Cutting table with nylon bristles
The cutting table is used for lay the fabrics. The nylon bristles support the fabric
lays and allows the passage of air through the table to create vaccum.This helps to
reduce the fabric ply height and helps to hold the material tightly.
Cutting head
Cutting head is consisting with knife, automatic sharper, pneumatic controls and
servomotor. The servomotor in the cutting head rotates the knife to the position of
cut.
Carriage
It has three synchronized servomotors. Two of them drive the carriage on the tracks
on the table. The third one servomotor positions the cutting head on beam across
the width of the carriage.
Vacuum motor
It creates a vacuum to reduce the height of sead.and hold it tightly.
c) Write a short note on the new cutting technologies developed to cut
fabrics
Laser cutting
Laser cutting technology is not merely a static manufacturing process. It allows
for designer intervention at any point during the cutting process. In the textile,
the laser cutter was halted during cutting and the material was moved on the
laser bed before cutting was recommenced, thus creating a broken and overlaid
pattern. The designer is able to see the cut mark on the computer screen just
prior to its execution. This enables the designer to interact during the cutting
process, to intervene and stop the laser in order to rethink part of the design if
required. It is a small window of opportunity which allows for a more
spontaneous interaction between the designer and the technology.
In this system a laser beam is used. It can be focused on to a very small sot .
25mm to produce the cut. This high concentration of energy at the spot of
cutting first heat u the material at that point a finally cut the material through
vaporization.
Textiles suitable for cutting with a laser include materials as different as linen,
cotton, silk, felt, and more.
The main components of the system
A computer
Stationary gas laser
A cutting head with system of mirrors
Disadvantages
Possibility of edge fusing
Accuracy is not perfect
More suitable for single ply cutting
Water jet cutting
There are two main steps involved in the water jet cutting process.
First, the ultra-high pressure pump or Electric Servo Pump generally pressurizes
normal tap water at pressure levels above 40,000 psi (2760 bar); to produce the
energy required for cutting.
Second, water is then focused through a small precious stone orifice to form an
intense cutting stream. The stream moves at a velocity of up to 2.5 times the speed
of sound, depending on how the water pressure is exerted.
The process is applicable to both water only and abrasive jets. For abrasive cutting
applications, abrasive garnet is fed into the abrasive mixing chamber, which is part
of the cutting head body, to produce a coherent and an extremely energetic abrasive
jet stream.
Plasma torch cutting
Plasma cutting is one of the thermal cutting processes.
The plasma - an extremely energy-rich and electrically conductive gas flow -melts
the work piece locally.
In the cutting torch, the liquid cutting medium evaporates as it flows past an
electric heating element.
At the same time, the in-flowing liquid raises the negative cathode of the positive
cutting nozzle.
Also-called pilot light arc ignites, and the cutting medium, which is now gaseous,
is partially ionized. Even before the cutting torch gets close to the work piece,
plasma is ignited, and as a result it is far easier to apply the plasma cutting torch
when cutting begins.
As the cutting torch comes closer to the surface of the work piece, the cutting jet
focuses the cutting jet on the work piece, which likewise has positive polarity.
The process of switching over automatically from the pilot arc to the actual arc
ensures that the work routine is harmonious.
In this system plasma torch is used to provide a gas discharge.
The effect is a finely focused flame. This finely focused flame can be used to cut
fabrics. This is also suitable for cutting single plies.
