Tài liệu về máy cắt vải ngành may Cutting Machines - Methods of Fabric Cutting

Southeast University
Department Of Textile Engineering
I/A 251,252 Tejgaon Dhaka Bangladesh
Cutting:
To make a complete garments, cutting is necessary. Cutting means to out
the garments pieces from lays of the fabric with the help of
templates(markers).Generally the marker is applied (drawn, traced, sprayed,
clipped, pinned) to the top ply of a lay.
Objectives of cutting:
The objectives of cutting is to separate fabric parts from the spread of the
lay according to the dimension of the marker for the purpose of garments
making according to the pattern pieces.
Requirements of fabric cutting:
In order to achieve these objectives, certain requirements must be fulfilled-
Precision (Exactness) of cut.
Clean edges.
Un fused edges.
Support of the lay.
Consistent cutting
There are mainly three types of cutting technique-
1.Completely by manual-Hand operated scissors.
2.Manually operated powered knife.

Straight knife.

Band knife.

Round knife.

Die cutter.


Notcher cutter.

Drill.

3.Computerized technique.

Knife cutting.

Cutting by water jet.

Leaser cutting.

Plasma torch cutting.

Specification
Motors: Available with 1 Phase Motor of
110 V and 220 V & with 3 Phase Motor of 220
V and 380 V.
Speed: With Single / Dual speed, Variable
speed is not available.
Blades: High Speed Steel is standard blade.
Optional blade/s are carbon steel, Teflon
coated, wave edges, height:-10-13”, Width-
1.5-3cm, thickness 0.5mm
Belts: Fine, medium, coarse, rough,
waterproof are available.
Weight: 34 lbs; 15.4 kgs.
Horsepower: . 65 hp .1 ph & .93 hp .3 ph.
Knife :

Motor
Knife
Safety Guard
Handle
Base plate
Stand
Straight Knife Cutting
Machine
•
Firstly, switch on this cutting machine.
•
Then, place the cutting machine at any corner of the table.
•
Then switch on the blade.
•
Then the operator moves the machine by hand through the
stationary fabric layers and cut along marker lines until
finish the marker.
•
The greater the power of the motor , the heavier the
machine .
1.The motor power needed is determined by-
2.The height of the lay
3.The construction of the fabric.
4.The curvature of the line being cut.
5.The stroke of the blade
Advantages of Straight knife cutting Machine
•
Comparatively cheap & and can be cut many
plies at a time

•
Higher lay of height can be cut very easily.
•
Round corners can be cut more precisely than
even round knife.
•
Production speed is very good.
•
Garments components can be directly separated
from fabric lay.
•
Fabric can be cut from any angle.
Disadvantages of Straight knife cutting Machine
•
Sometimes deflecting occur due to the weight of
the motor.
•
Knife deflection is high in risk, when any height
is to high.
•
Sometimes accident may happen.
Features of Band Knife Machine:
1. This machine worked as saw
mill technique.
2. Not possible to cut fabric
directly from lay.
3. Block pieces of fabric required
in bundle form to cut by this
machine.
4. Blade moving vertically

through a flat working table.
5. Machine remains stationary
and fabric is moveable.
6. Specially used to cut small
parts more accurately.
Advantages of Band Knife cutting Machine
1. Straight and accurate cutting from the first layer to the bottom layer
2. Air blowing table provides air cushion for material easy movement
3. Equipped with knife sharpening device, sharpening underneath table
no metal pieces on table surface
4. High accuracy and vertical cutting finish
5. Adjustable knife running speed
6. Special bearing guide design to keep knife moving in same position

Disadvantages of Band Knife Machine:
1. Fabric wastage is high.
2. Work load high.
3. Push cutting needles in better vision but is more dangerous.
A water jet cutter, also known
as a waterj et, is a tool capable
of slicing into metalor other
materials (such as granite)
using a jet of water at high
velocity and pressure, or a
mixture of water and an
abrasive substance. The
process is essentially the same
as water erosion found in
nature but greatly accelerated
and concentrated.

Advantages to Waterjet Cutting
Waterjet cutting has many
applications, and there are many reasons why
waterjet cutting is preferable over other cutting
methods. Listed below are several advantages,
along with a brief explanation.
In waterjet cutting, there is no heat generated.
This is especially useful for cutting tool steel and
other metals where excessive heat may change
the properties of the material.
Unlike machining or grinding, waterjet cutting
does not produce any dust or particles that are
harmful if inhaled.
The kerf width in waterjet cutting is very small,
and very little material is wasted.
Disadvantages of water jet cutting
machine:
One of the main disadvantages of water jet cutting is
that a limited number of materials can be cut
economically. While it is possible to cut tool steels,
and other hard materials, the cutting rate has to be
greatly reduced, and the time to cut a part can be very
long. Because of this, water jet cutting can be very
costly and outweigh the advantages.
Another disadvantage is that very thick parts can not
be cut with water jet cutting and still hold dimensional
accuracy. If the part is too thick, the jet may dissipate
some, and cause it to cut on a diagonal, or to have a
wider cut at the bottom of the part than the top. It can
also cause a ruff wave pattern on the cut surface.

.
Round knife
Eastman's 548 Cardinal is the standard by which
all round knife cutting machines are measured.
The most popular standard round knife cutter in
production today, with a myriad of blade sizes,
motor and standard configurations, the Eastman
548 is in most industry cutting rooms.
1. Elements of round knife are-
a) A base plate.
b) A handle for the cutter to direct blade.
c) A circular blade rotating so that the rotating edge cuts
downwards into the fabric.
d) An electric motor
2. Blade diameter very from 6 cm to 20 cm.
3. Blade is circular and has a very sharp edge.
4. Blade is driven by electric power.
5. The circular knife is driven by 1000-3500 r.p.m.
6. Blade edges-
7. Waved edge.
8. Toothed edge.
9. Circular edge.
Advantages of Round Knife cutting machine.

Suitable for cut single ply as well as multilayer
also
(say 20-30 layers).

Suitable for small scale cutting.


Easy to operate.

Suitable to cut the larger parts of garments.
Disadvantages of Round knife cutting machine.

Not suitable for curved lines because, the blade does
not strike all the plies simultaneously at the same point.

Round knife is used only for straight lines as lower
lay of relatively few plies.

Not suitable for large production.

Possibility of accident is high.

Difficult to cut small components.

Needs skilled operators.
Future of ply cutting
•
Flexible software control of cut
speed and
• knife-speed to increase
throughput
•
Software screens and manuals
available in
•
many languages
•

Metric and Imperial data
capabilities
•
State-of-the-art embedded digital
motion
Windows operating system:

Fully network-compatible

Easy-to-use graphical user interface (GUI)

Sophisticated cut data file handling

Modify notch and cutter parameter
prevention

Preview piece cutting sequence

Display cut pieces as cutting progresses

Continuous display of operating parameters:
Vacuum level, cut speed, etc.

Pre-loaded with library of expert setup files

providing initial Knowledge-Base

Storage of cutting setup parameter files for
Feature of Die cutter Machine:
 Fast die change and set-

uptimes
 Driven pinch rollers
 In feed and out feed conveyers
 Moveable control console for
easy operation
 Language-selectable keypad
with inch or millimeter readout
 PLC controlled servomotor
indexing
 Automatic or manual operation
 Adjustable cutting stroke

Very accurate and excellent for small components

The greater the blade movement , the faster the blade
cuts the fabric & the more rapidly.

The operate can be easily & push the Machine.

Mainly used for mass production of slow chang items.

Dies having the exact shape of the garment pieces.

Some dies are sued over a long period.

TECHNICAL SPECIFICATIONS OF LASER CUTTING MACHINE

• Cutting Speed
• Up to 90 in/s, 5400 in/min, (2.3 m/s)
• Rapid Speed

• Up to 120in/s, 7200 in/min, (3 m/s)
• Acceleration
• Up to 2g (20 m/s
2
)
• Repeatability
• +/- 0.004" (0.1 mm), (+/- 0.001" optional)
• Cutting zone (W X L)
• 70" (1.8 m) x 52" (1.3 m)
 Very safe, totally enclosed cutting area with safety interlocks.

PC Windows based, user friendly, interactive operation with a click of the
mouse.
 Compatible with most CAD/CAM software (HPGL, Gerber cut file, DXF etc.)
 The conveyor is composed of proprietary lattice surface which allows for
cutting with virtually no back reflections .
 Simple design, optimized by incorporating the highest quality, readily
available, off-the-shelf components, guarantees maximum.
 Advantages of laser cutting over mechanical cutting include
easier workholding and reduced contamination of workpiece.
 Precision may be better, since the laser beam does not wear
during the process.

There is also a reduced chance of warping the material that is
being cut, as laser systems have a small heat-affected zone.
 Some materials are also very difficult or impossible to cut by
more traditional means
 The main disadvantage of laser cutting is the high power
consumption.
 Industrial laser efficiency may range from 5% to 15%.

 This will depend on type of laser and how well the laser is
matched to the work at hand.
 Depth micrometer: “Mitutoyo”
make.
 Range: 0 – 25mm with least
count of 0.01mm

Cutting angle: 45º

Paint: Powder coated

Power : 230 Volts, 50Hz, single
phase