Cutting

• Cutting:

cut out the garment pieces from the lays of fabric with the help of cutting template or marker

or

process of separating garment parts from the fabric lay in precise size and shape

Cutting

• Requirements of fabric cutting : Precision of cut : must be cut precisely to the

size and shape of the pattern; It depends on The method of cutting adapted The marker planning Marker making/duplicating Condition of the cutting machine Skill ness and attentiveness of the operator Clean edges: Fabric edges should be smooth and

clean, the raw edges of the fabric should not show fraying or snagging

Cutting

Unfused edges: Heat generated from the friction, leads fused the raw edges of thermoplastic fiber fabrics, in extreme cases,

difficult to separate individual plies

Forced separation leads snagged edges, and in cases hard edge is uncomfortable in wear

Remedies:

• Use anti-fusion paper between the layers.

• Use silicon lubricants on to the blade.

• Spraying the blade with air coolant lubricant.

• Slowing down the speed of the blade.

• Reducing the height of the lay.

• Use well sharpened blade.

Cutting Support of the lay: Surface of the lay should

be strong enough to bear the weight of cutting lay and allow the movement of the cutting machine

cutting system must allow the blade to penetrate the lowest ply of the spread

Consistent cutting

cutting should be consistent disrespecting cutting method

Top to bottom ply of a lay should be in same size and shape

Cutting

• Methods of cutting: 1. Completely manual technique-Hand operated

scissors.2. Manually operated powered knife

a. Straight Knifeb. Round knifec. Band knifed. Die cuttere. Notcherf. Drill

3.Computerized technique.a. Knife cuttingb. Cutting by water jetc. Laser cuttingd. Plasma torch cutting

Cutting

1. Completely manual technique-Hand operated scissors.

Various types of scissor are normally used when cutting only single or double plies

Advantage:

• Suitable for small production.

• Easy to operate.

• Used for tailoring & domestic purposes.

• Used in garments manufacturing.

• Suitable for making sample garments.

1. Completely manual technique-Hand operated scissors.

• Disadvantage:

Time consuming method.

High labor cost per garment.

Fabric wastage is very high.

Limitation to use in garments industry.

Cutting• Straight Knife:

widely used cutting machine which cut fabrics in bulk with high precision

Features: Cutting knife is straight in shape.

Blade length= 10’’-13”Blade width= (1 ½ -3) cm.Blade thickness= ½ mm.

Knife is driven by electric power Grinding wheel is present to sharp the knife during cuttingThe machine consists of base plate, electric motor, handle, knife, knife guard, stand, roller wheel Handle for the cutter to direct the blade

Most commonly (99%) used in the RMG industry of Bangladesh.

Straight knife machine

Round knife

Drill

Band Knife

Plasma Torch Cutting

Water Jet Cutting

Water Jet Cutting

Laser Jet

Straight Knife Machine• Machine description:Components of a straight knife machine are

– An electric motor: to run the machine.

– Base plate: Usually in rollers for ease movement.

– Handle: to direct the blade.

– Knife: reciprocating motion

– Knife guard: for safety

– Grinding wheel: To sharp the knife during cutting

– Stand.

– Roller wheel: To move the machine over cutting table easily

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:

- The height of the ply.

- The construction of the fabric.

- The curvature of the line being cut.

- The stroke of the blade.

Straight Knife• Advantages:

– High production cutting machine.– Possible to cut fabric directly.– Possible to cut larger height of the fabric lay.– Both sharp corners and heavy curves could be

cut.– Blade could be sharpen by attaching grinding

wheel during cutting.– High cutting speed.– Comparatively cheap.

Straight Knife Machine

Disadvantages:

-Blade deflection occurs, so in some cases fabric cut pieces can be found faulty.

- If depth of the fabric is higher, the possibility of deflection of the blade is more.

- The machine is not ergonomic; Intensity of the accident is comparatively higher.

Straight Knife Machine • Precaution to avoid blade deflection:

– Reducing the lay height.– The weight of the motor should be light.– The operator should be skilled and conscious.– Speed of the machine may be reduced.

Straight Knife Machine• Factors considered for choice of cutting: • Type of the fabric: Technique should be such as that it should not

damage the fabric. In case of natural fiber fabric, all methods may be applied, but Laser and Plasma method is not suitable for Man Made Fiber fabric.

• Accuracy of cutting: for higher accuracy, computerized method may be adapted & for lower accuracy, manual technique may be suitable.

• Available of cutting machine: machine is available to suit the cutting technique.

• Volume of cutting: For small amount of cutting, round knife is suitable and for large volume of cutting, straight knife is suitable.

• Quality of cutting: Computerized cutting methods are suitable for high quality fabric cutting and manually operated powered knife is suitable for comparatively lower cutting quality.

• Time factor: For urgent requirement of fabric cutting, straight knife is more suitable as that technique requires comparatively less preparatory time.

Straight Knife Machine• Reasons of fused edge in cutting:

– The build up of heat in the knife comes from the friction of the blade passing through the fabric.

– If the fabric is made of thermoplastic fiber such as polyamide or polyester.

– High ply height causes fused cutting edge.– If blade is not well sharpened, the cutting edge

may be fused.

Fused Edge• Remedies:

- Use antifriction paper between the layers.

- Use silicon lubricants on to the blade.

- Height of the ply should be reduced.

- Slowing down cutting speed

- Use well sharpened blade.

Fabric Cutting