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THREAD & SEAM CONSTRUCTION BY MACKENZIE WALTON MARCH 2012
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Feb 10, 2016

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THREAD AND SEAM CONSTRUCTION

THREAD & SEAM CONSTRUCTIONBY MACKENZIE WALTONMARCH 20121Thread sizing conventions

Common types of sewing threadTHREAD BASICS

2Thread size is determined the same way that yarn size is determined for textiles. While there are different systems, they are all based on weight and length specifications, and not by diameter as might be assumed.

METRIC TICKET (Nm) # of 1,000 metre lengths in 1,000 grams

COTTON COUNT (Ne) # of 840 yard hanks in 1 poundTEX grams per 10,000 metres

DENIER grams per 9,000 metresThread Size

3Thread Size

4Thread SizeGENERAL GUIDELINES FOR THREAD SIZE SELECTIONSEWING THREAD SIZES BY TEXFABRIC WEIGHT (GSM)FABRIC WEIGHT (oz/yd2)GARMENT EXAMPLES 18, 2465 - 1402 - 4T-shirts, Lingerie24, 27, 30140 - 2004 - 6Shirts, Dresses30, 40200 - 2756 - 8Light-Weight Bottoms40, 60275 - 4008 - 12Light-Weight Denim60, 80, 105400 - 50012 - 15Heavy-Weight Denim5COTTON THREAD

Generally provides good sewing performance but strength and abrasion resistance is inferior to synthetic threads of equal thickness

Mostly used for piece-dye itemsShrinkage may cause puckering after wash/dyeCan be mercerized reduces shrinkage, increases strength and luster, improves dye up-takeCommon thread types

6COTTON THREAD

MERCERIZATIONCommon thread types

COTTON THREAD

CHANGES DURING MERCERIZING PROCESS

A. Fiber level1.Swelling2.Cross sectional morphology changes from beam shape to round shape.3.Shrinkage along with longitudinal direction.

B. Molecular level1.Hydrogen bond readjustment2.Orientation (parallelization) of molecular chains in amorphous region along the direction of fiber length.3.Orientation of the crystallinity in the direction of the fiber length.4.Increased crystallinity

7SPUN POLYESTER THREAD

Made with staple polyester fibers. Provides good sewing performance, good dimensional stability and good stitch locking properties due to the fibrous surface.Resistant to sunlight and chemicalsStronger than cotton, including 4X better abrasion resistanceIdeal for light to medium weight fabricsCommon thread types

8CORESPUN POLYESTER THREAD

Made by spinning staple polyester or cotton fibers around a continuous filament polyester core. Provides enhanced strength and elongation while maintaining stitch locking ability and can be run at higher speeds without breakages.Higher machine speeds mean an increase in productivity by up to 21%Best thread for heavy fabrics, like denim and outerwearMore consistent sewing quality due to better loop formation and resistance to damageMost expensive general purpose sewing threadCommon thread types

9TEXTURED FILAMENT THREAD

Continuous filaments of polyester or nylon are entangled by various methods to create softness and bulk. Ideal for overlocking and the looper of coverseams, these threads provide excellent coverage for raw edgesMost economical threadSoftness makes it ideal for lopping threads that sit close to the skinExcellent elasticity for stretch fabric applicationsOften found in intimates, baby clothes, and athletic wearCommon thread types

10OTHER THREAD TYPES

Mono-filament Invisible ThreadEmbroidery ThreadElastic ThreadSpecialty Lurex, IndigoLocked Filament ThreadGlow in the DarkCommon thread types

11LUBRICATION

Regardless of construction, all threads are finished with a lubricating coating. This facilitates the passage of the thread through the machine and needles, reducing friction and heat that can cause damage.

LIFE SPAN

Under optimal conditions, thread will last about 18 months before the lubricants start to break down and thread quality starts to deteriorate. Unsurprisingly, most factories do not store thread in optimal conditions and so this period is usually much shorter.Common thread types12Needle sizing conventions

Different Needle TypesNEEDLE BASICS

13Needle Sizing

14Most sewing is done with rounded-point needles. Actual cutting points are only used for leather and similar fabrics. SetPoints are normal, lightly rounded points used for wovens, while knits demand more rounded needles, referred to as ball points

Different levels of roundness are identified with letter markersNeedle Types

15R = Normal roundfor light woven fabrics

SPI = Acute roundFor densely woven fabrics

SES = Light BallFine to medium knits, fine denim, medium to heavy wovens

SUK = Medium Ball Stonewashed denims, corsetry

SKF = Heavy BallFine elastic materials, coarse knits

SKL = Special BallMedium to coarse elastic materials, coarse knits, lycraNeedle Types

16The fabric and end use will determine the thread size and type, and needle type that you will use. The chosen thread will determine the needle size. There will be a range of possible thread sizes and types that can be used with any given fabric, depending on the application.Needle-Thread Pairing

17Seam Types

Stitch Types

Applications

What makes a good seam

SEAM CONSTRUCTION

18Superimposed Seams (basic simple seam)

Lapped Seams Lapped felled seams

Flat Seams

Bound seams

Edge finishingSeam Types

19SUPERIMPOSED SEAMS

STANDARD SEAM FRENCH SEAM

Seam Types

20LAPPED SEAMS

LAPPED SEAM

FELLED SEAMSeam Types

21FLAT SEAMS

Seam Types

22BOUND SEAMS

Seam Types

23EDGE FINISHING

Seam Types

24301 - LOCKSTITCH

Basic 1-needle straight stitchUses least amount of threadTightest and most secure stitchHigh abrasion resistance due to low profile on the fabricNo stretchStitch Types25304 - ZIGZAG

1-needle zigzag lockstitchCan stretch, and can provide edge coverageUsed to apply lace or appliquesUsed for bar tacks and button holes

Stitch Types26101 - CHAINSTITCH

Formed using 1 thread only no bobbin or looperOn its own it is only suitable as a basting stitchBlind hemming is a variation of this stitch

Stitch Types

27401 - CHAINSTITCH

Formed using 2 threads needle and looperAppears the same as 401, but is much more secure and durableAbility to stretchExcellent for setting elasticFrequently used for topstitching and for lapped seams on high-wear garments like denimLess thread passes through the fabric than on a lockstitch, which can reduce seam pucker404 Zigzag chainstitch

Stitch Types

28406 and 407 COVER STITCH

406 uses 3 threads, 407 uses 4Excellent stretch. 407 has the most stretchExcellent strengthLooper stitches are more efficient because you dont have to change a bobbinLess thread passes through the fabric than on a lockstitch, which can reduce seam puckerIncreased seam bulkIncreased costStitch Types

29503 2-THREAD OVEREDGE SERGE

Formed using 1 needle and 1 looper threadNo structural strength only suitable for coverage of inner seam allowances

504 3-THREAD OVEREDGE SERGE (OVERLOCK)

Formed using 1 needle thread, 1 looper thread, and 1 cover threadMost common for overlocking, and often used for sewing seams on knit fabricStitch Types

30512 and 514 MOCK SAFETY STITCH

Formed using 2 needle threads, 1 looper, and 1 cover threadCommon for seaming knits, and can be used for wovens as wellOnly 514 should be used on knits as it has better stretch

Stitch Types

31515, 516 SAFETY STITCHES

A combination of an overedge stitch with a 401 chainstitch515: 4-thread safety uses a 503 overedge serge516: 5-thread safety uses a 504 overlock stitchStitch Types

32FLATLOCK 600 CLASS

Formed using 2 4 needle threads plus 1 looper thread and 1 cover threadFabric edges butt together but do not overlapHighly elastic seams with very low profile for maximum comfortEfficient to sewVery high thread consumptionCommon for performance and scuba wearStitch Types

33SPECIALTY STITCHES

Pick Stitch - classicPick Stitch on knitsStitch Types

34SPECIALTY STITCHES

Whip StitchBlanket Stitch (single buttonhole)Stitch Types

35TensionSPIThread ChoiceStitch ChoiceNeedle TypeNeedle ConditionSeam WidthAdditional ElementsElements of a Good Seam36SEAM PROBLEMS

Seam PuckerGrinningSkipped StitchesBroken Needle ThreadsBroken Bobbin ThreadsNeedle Damage on FabricSeam SlippageTrouble Shooting37SEAM PROBLEMS

Seam PuckerGrinningSkipped StitchesBroken Needle ThreadsBroken Bobbin ThreadsNeedle Damage on FabricSeam SlippageTrouble Shooting

38SEAM PUCKER

Bad tensionBad feedFabric-Thread instabilityUneven shrinkage during finishingThread-bloat from washingStructural jamming/Inherent puckerTight weaving does not have enough room between yarns for threadSewing caused yarns to be pushed out of place

Trouble Shooting

39SEAM PROBLEMS

Seam PuckerGrinningSkipped StitchesBroken Needle ThreadsBroken Bobbin ThreadsNeedle Damage on FabricSeam SlippageTrouble Shooting

40Grinning

Loose tensionIncorrect stitch choiceLockstitch is the tightest stitch and will grin less than other stitchesTrouble Shooting

41SEAM PROBLEMS

Seam PuckerGrinningSkipped StitchesBroken Needle ThreadsBroken Bobbin ThreadsNeedle Damage on FabricSeam SlippageTrouble Shooting

42SKIPPED STITCHES

Bad tensionMachine timing is offBobbin hook or looper is not entering needle thread loop at correct timeIncorrect needle choiceThe wrong needle can cause problems in creating the needle thread loopDamaged needleIf the needle is bent, or is striking the throat plate, it may not create the loop in the right place for the hook to catchTrouble Shooting

43SEAM PROBLEMS

Seam PuckerGrinningSkipped StitchesBroken Needle ThreadsBroken Bobbin ThreadsNeedle Damage on FabricSeam SlippageTrouble Shooting44NEEDLE THREAD BREAKAGE

Tight tensionTrapping at package baseSnarling before tension discPoor needle choiceIf eye is too small, there will be increased frictionExcessive heatPoor quality threadTrouble Shooting45SEAM PROBLEMS

Seam PuckerGrinningSkipped StitchesBroken Needle ThreadsBroken Bobbin ThreadsNeedle Damage on FabricSeam SlippageTrouble Shooting46BOBBIN/LOOPER THREAD BREAKAGE

Tight tensionBadly wound bobbinIncorrect fit of bobbin caseTrapping at package base (for loopers)Trouble Shooting47SEAM PROBLEMS

Seam PuckerGrinningSkipped StitchesBroken Needle ThreadsBroken Bobbin ThreadsNeedle Damage on FabricSeam SlippageTrouble Shooting48NEEDLE DAMAGE

Incorrect needle/thread choiceDamaged needle

Trouble Shooting49SEAM PROBLEMS

Seam PuckerGrinningSkipped StitchesBroken Needle ThreadsBroken Bobbin ThreadsNeedle Damage on FabricSeam SlippageTrouble Shooting

50SEAM SLIPPAGE

Problem is with the fabric not the stitchLow yarn count, and continuous filament yarns that dont grip each other well are to blameVery minimal improvement can be achieved through increasing seam allowance, adding topstitching, or changing to a lapped felled seamWhen possible, seams can be fusedBest option Change fabricTrouble Shooting

51THE END

BY MACKENZIE WALTONMARCH 201252