anand jadhao cutting ppt

8/3/2019 Anand Jadhao Cutting Ppt

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CUTTINGOFTHE FABRIC

The term is used in the sense of cutting room, an areawhich normally includes the activities of marker planning,spreading and preparation for sewing, as well as beingused to refer to the actual cutting out of garment partsfrom the lay


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OBJECTIVEOFCUTTING:-

The objective of cutting is to separate fabric parts asreplicas of the pattern pieces in the marker plan. In

achieving this objective , certain requirements must befulfilled :-

Precision of cut

Clean edges Unscorched, unfused edges

Support of the lay

Consistent cutting


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Methods of cutting :-1. Hand Shears2. Straight Knife

3. Round Knife

4. Band Knife5. Notchers

6. Drills and Thread Markers

7. Computer controlled Cutting Knives

8. Die Cutting

9. Laser Cutting

10. Plasma Cutting

11. Water Jet Cutting

12. Ultrasonic Cutting


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1. Hand Shears-

Used when cutting only single ordouble plies.

Flexible enough to accommodateany pattern construction andpattern shape

Time consuming leading to highlabour cost per garment


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2. Straight Knife-

Versatile , portable, cheaper than bandknife, more accurate on curves than around knife, relatively reliable and easy to

maintain

Elements consist of a base plate, usually onrollers for easy movement, an upright orstandard carrying a straight, vertical bladewith varying edge characteristics and anelectric motor above it, a handle for thecutter to direct the blade, and a sharpeningdevice


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3. Round knife-

Elements of a round knife are a baseplate, above which is mounted anelectric motor, a handle for the cutter todirect the blade, and a circular bladerotating so that the leading edge cutsdownwards into the fabric

Used only straight lines or lower lays of

relatively few piles

Not suitable for cutting curved lines


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4. Band knife-

Comprises a series of three or morepulleys, powered by an electricmotor, with a continuously rotatingsteel blade mounted on them. Oneedge of the blade is sharpened

Used when higher standard ofcutting accuracy is required thancan be obtained with a straight knife


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5. Notchers-

Specialized notching equipmentprovides greater accuracy because aguide lines up the notcher with the cutedge to give consistent depth of notch

at a consistent right angle to the edge

The hot notcher incorporates aheating element in order that theblade my slightly scorch the fibres

adjacent to the notch in order toprevent it fraying and disappearing


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6. Drills and ThreadMarkers-

Used to mark position of pockets,darts and similar features

Drill mounting includes a motor, a

base plate with hole to allow the drillto pass through, and a spirit level toensure that the base is horizontal andhence the drill vertical.

If it is important that no mark remains

on the fabric, a long thread may bepassed through the lay which is thencut with scissors between each ply,leaving a few centimeters visible oneach garment


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7. Computer controlled Cutting Knives-

Provides most accurate possible cutting, at high speed

Made up of a table with a cutting surface consisting of nylon

bristles

The carriage supporting the cutting head has twosynchronized servo-motors. A third servo motor positions thecutting head on a beam across the width of this carriage.

The cutting head contains knife, automatic sharpener and afurther servo-motor which rotates the knife to position it at atangent to the line of cut on curves


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8. Die Cutting-

Process involves pressing a rigidblade through the lay of the fabric

The die is a knife in the shape of

a pattern periphery, includingnotches

Provides a high standard ofaccuracy of cutting but, because

of the cost of dies, they areappropriate in situations wherelarge quantities of the samepattern shape will be cut


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9. Laser Cutting-

A laser produces a beam of lightwhich can be focused into a verysmall spot (0.25mm), producing avery high energy density

Cutting takes place by vaporization.

Charring is prevented by the use ofa jet of inert gas which alsoremoves debris and smoke fromthe cutting area

If several plies are cut, theaccuracy is not perfect as it is a Vcut rather than a straight line.

There is also risk that the edgesmay fuse together


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10. Plasma Cutting-

Originally developed to satisfya demand for high qualitycutting on stainless steels and

aluminium but it can also beused to cut textile materials

Cutting is achieved by means

of a high velocity jet of hightemperature ionised gas(argon)


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11. Water Jet Cutting-

A very high velocity, smalldiameter stream of water iscreated by applying highpressure water to a nozzle

The high pressure jet acts asa solid tool when itencounters the material to becut, tearing the fibres onimpact

Here the jet of water isnormally caught and drainedaway


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12. Ultrasonic Cutting-

Uses an ultrasonically driven knifeblade

Disposable knife blades savesharpening time and for 10-14days

Upto 10 plies can be cut and lowvacuum only is needed


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FEEDMECHANISM Feeding of fabric past the needle

Construction of seams and formation of stitchesand formation of stitches that hold them together

Three sewing machine parts constitute feedmechanism

- Presser foot

- Throat plate- Feed dog


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PRESSERFOOT Upper part of the feeding combination that holds

the fabric in place for the feeding action and stitchformation

Attached to presser bar Controls the amount of pressure placed on the

fabric when it is fed through the machine

Assists in operation of feed dog

Higher speeds may require more pressure

Most common is the flat presser foot


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Throat plate

The throat plate has stitching guide lines on it andhas a hole for the needle to pass through to the bobbincasing.

The throat plate is a removable part, which protectsthe bobbin and underside of the sewing machine.

The throat plate has seam guides. Always verifythat the machine seam guide is accurate with theneedle position you are using.

Its function is to provide a flat smooth surface overwhich the fabric passes as a successive stitches are

formed.


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Feed dog

Feed dogs are the critical component of a "dropfeed sewing machine.

Feed dogs are a teeth-like part that works withthe presser foot to pull your fabric through themachine.

A set of feed dogs typically resembles two or threeshort, thin metal bars, crosscut with diagonal teeth,which move back and forth in slots in a sewingmachine's needle plate.


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1. Drop feed2.Differential feed3.Compound feed4.Puller feed

5.Unison feed system6.Needle feed

Feed mechanismcan be classified in thefollowing types.


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DROPFEEDSYSTEM

Drop Feed is basic material feed system

where the feed alternately engages anddisengages with the underside of material.

It is suitable for general sewing operationson any material which has no particularsewing problems.


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DIFFERENTIALFEEDSYSTEM

Differential Drop Feed is a differential feedwhich utilizes two independently driven feed

dogs.

The stroke of each feed dog can be adjustedseparately. If the stroke of front feed dog isgreater than the fabric may stretched toprovide a more stretchable seam.


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COMPOUNDFEEDSYSTEM

Compound Feed is a combination of synchronizeddrop feed and needle feed.

Feeding occurs while the needle is still in thematerial by combined motion of needle bar and thefeed dog.

Since needle holds the plies of material inregistration of feeding this reduces pucker and slippage

between the plies of material.

Used mainly for edge stitching, checks and stripes


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PULLERFEEDSYSTEM

Usually accomplished by feed rolls rollers.

Material passes between rolls, between upper roll

and bed or between lower roll and presser foot.

A feed roll is mechanically driven to transport thematerial.

Generally suitable for straight runs or large radiuscurves only.


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UNISONFEEDSYSTEM

Unison feed is the combination of feedingmechanism which provide needle feed in addition topositive top and bottom feeding.

It is variable in the sewing of especially those with

tacky surfaces and it can achieve seam joining anedge binding without ply shift.

It is used for operations on materials that have verylow friction coefficient and for operations that are

thick and heavy.


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NEEDLEFEEDSYSTEM

It is the system in which needle itself movesforwards and backwards.

The needle enter the fabric moves back with it as itmove along the begin the next stitch.

It is particularly useful in bulky sewing situation .


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anand jadhao cutting ppt

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