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DOUBLE NEEDLECHAIN STITCH

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STITCH CLASS 400 : MULTI THREAD CHAIN STITCH

This stitch type is formed by inter-looping of two or more groups of thread.

Stitch formation in the stitch type 401

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MACHINE COMPONENTS

Thread tension mechanism

• Thread tension Nut• Tension post holder• Thread Eye-let ( 5 nos. )• Thread take-up plate• Needle Thread Guard

Needle bar and lever Mechanism

• Needle lever• Needle Bar guide and clamp• Ball joint

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Feed Mechanism

• Feed-dog• Feed rocker arm• Rear puller• Feed-dog slots

Looper Mechanism

• Looper • Looper Rocker• Take-up Rod• Looper Holder Bracket

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Presser Foot Mechanism

• Presser Bar• Presser Screw• Lifter Lever Spring• Presser Foot Lifter Lever• Presser Bar Guide• Presser Bar Spring

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NEEDLES

Schmetz- UY113GS

Organ – UO113GS

Groz-beckert- TVx64

Needles and needle sizes

Schmetz

UY113GSNm 75 Nm 80 Nm 90 Nm 100

Organ

UO113GS#11 #12 #14 #116

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Incorrect threading may cause:

• Skip stitch

• Thread breakage

• Uneven stitch formation

Threading of the machine is very important

THREADING

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MACHINE SPEED

Chain stitch machine can have a speed up to 8000rpm

Model Max. speed Standard speed

DBF1404P 4500 4000

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FEED MECHANISM

Unison Feed Mechanism:

It is a combination of three feed mechanisms

• Conventional feed mechanism

• Needle feed mechanism

• Alternating presser foot

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TIMING OF THE LOOPER TO NEEDLES

Angle for installing the looper and position of the looper holder bracket

There should be a clearance of 0~0.1mm between the point of the looper and the scarf of the needle

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LOOPER LEFT – RIGHT MOVEMENT and LOOPER SETTING DISTANCE

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ADJUSTING THE TIMING OF THE RETAINER LOOPER

Position of the retainer loop

There should be a clearance of 0.5mm between the needle and the point of the retainer looper. Adjustment is made by loosening b as shown in the fig.

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Timing of the retainer looper to the needle

When the needle, moving from top to bottom ofIts stroke, enters the triangle of the looper thread, the retainer Looper should be at the extreme right end of its travel

The clearance between the retainer looper and the right side of looper should we 0.5 mm.

The clearance between the retainer looper and the top surface of the looper blade at 0.1mm

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ADJUSTING THE NEEDLE GUARD

Position of the needle guard

When the needle is closest to needle guard, there should be clearance of 0~0.1mm between the right side of the needle and the guard.

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ADJUSTING THE FEED DOG & STITCH LENGTH

When needle bar is at top of its stroke, the feed dog teeth should be 1~1.2mm above the top surface of the needle plate.

Stitch length

The stitch length can be adjusted from 2 to 5 mm.

Stitch length (mm)

Number of stitches

Within1” within 30mm

2 13 15

3 8.5 10

5 5 6

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ADJUSTING THE PRESSER FOOT

Presser foot pressure should be as light as possible yet, sufficient to feed the fabric.

Position of the presser foot

Accurate placement so that the needle can drop correctly to the centre of the needle drop hole on the presser foot

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ADJUSTING THE STITCH FORMATION

Thread tension adjustment

It can be adjusted by adjusting the mount tension devices on the machine ( The tension should be as light as possible ).

Position of the needle thread eyelets

Secure needle thread eyelets should be at the top end of the slot. ( The needle thread eyelets can be raised to tighten the needle thread )

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APPLICATION OF DNCS

• Inseam of jeans, trousers• In Jackets seams• Sewing sides of slacks• Hemming or welting garment parts• Attaching lining tapes• Joining seat of slacks

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VARIATIONS IN DNCS

Variations in bed type

• Cylindrical bed- feed of the arm• Raised bed• Flat bed

Variations in number of needles

• 2 needle double needle chain stitch machine• 4 needle double needle chain stitch machine• 12 needle double needle chain stitch machine• 33 needle double needle chain stitch machine