Study on straight knife fabric cutting machine.
Experiment Name: Study on straight knife fabric cutting machine.
Theory:
Straight knife is the most useful cutting instrument in apparel cutting. In apparel industry, more than 99% cases this knife is used. This machine is called straight knife cutting machine because its cutter is straight in shape. It is used for both woven & knit fabric. In this machine different types of straight knife are used according to the different cutting objects. This machine provides good efficiency.
Objective of the experiment:
1) To Learn about different parts straight knife cutting machine.
2) To learn about the working principles of a straight knife cutting machine.
Apparatus:
1) Straight knife cutting machine.
2) Cutting Table.
3) Fabric.
Machine Specification:
Brand : YAMATA
Model : FY - 103
Origin: Chine
Motor R.P.M : 3000
Name of the machine parts:
Base Plate.
Four Wheel
Pressure foot.
Motor Stand
Sharp Mechanical Base
Sharp Belt
Three pinion shaft
Leaver
Sharp on leaver
Operating handle
Power cable carry handle
Motor
Oil Can
On/Off Switch
Figure:
M/C description:
a) A base plate :To ensure support of the body.
b) An electric motor: Transmit motion to blade.
c) Handle: To help operators for operating machines.
d) Knife: It cut the fabric
e) Knife guard: It used as safety device to prevent any accident
f) Grinding wheel: Used to sharp the knife during cutting.
g) Stand: The backbone of the machine
h) Roller wheel: To move the machine over cutting table easily.
Features
1.Cutting knife is straight in shape.
Blade length – 10”-13” (10-33),
Blade width – 1.5 cm,
Blade thickness - .5 mm,
2.Knife is driven by electric power.
3.Grinding wheel is present to sharp the knife during cutting.
4.The machines consist of base plate, electric motor, handle, knife, knife guard, stand, roller wheel.
5.Base plate usually on roller wheel.
6.Handle for the cutter to direct the blade.
7.Blade edge: Straight edge, Weave edge, saw edge, scattered edge, but straight edge is mostly used.
Working principle:
Two kind of power are required to operate a straight knife.
Motor power drives the reciprocating blade.
Operator power drives the knife through the lay.
The motor power needed is determined by
Height of the lay.
The construction of the fabric.
The curvature of the line being cut.
The stroke of the blade.
The greater the power of the motor the heavier will be the machine. The taller stand, the thicker its cross-section and the greater its width, adding resistance to the forward movement on a curve. The greater the blade movement the faster the blade cuts the fabric and the more rapidly and easily the operator can push the machine. Operator effort is affected by the weight of the motor, the shape of the stand, handle height, stroke, sharpness of blade and the effect of the base plate rollers on the table surface.
Advantages
1. Comparatively cheap.
2. Can be easily transferred from one place to another place.
3. Round corners can be cut more precisely than even round knife.
4. Production speed is very good as up to 10 heights can be cut at a time.
5. Garment components can directly be separated from fabric lays.
6. Fabric can be cut from any angle.
7. Most commonly used in garments industries of Bangladesh (99%).
Disadvantages
1. Sometimes deflecting may occur due to the weight of the motor.
2. Knife deflection is high in risk, when any height is too high.
3. Sometimes accident may happen.
Precaution to avoid blade deflection:
1. Reducing lay height.
2. The weight of the motor should be light.
3. The operator should be skilled and conscious.
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