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THREAD & SEAM CONSTRUCTION
BY MACKENZIE WALTONMARCH 2012
• Thread sizing conventions
• Common types of sewing thread
THREAD BASICS
Thread 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 pound• TEX grams per 10,000 metres
• DENIER grams per 9,000 metres
Thread Size
Thread Size
Thread Size
GENERAL GUIDELINES FOR THREAD SIZE SELECTION
SEWING THREAD SIZES BY TEX
FABRIC WEIGHT (GSM)
FABRIC WEIGHT (oz/yd2) GARMENT EXAMPLES
18, 24 65 - 140 2 - 4 T-shirts, Lingerie
24, 27, 30 140 - 200 4 - 6 Shirts, Dresses
30, 40 200 - 275 6 - 8 Light-Weight Bottoms
40, 60 275 - 400 8 - 12 Light-Weight Denim
60, 80, 105 400 - 500 12 - 15 Heavy-Weight Denim
COTTON THREAD
Generally provides good sewing performance but strength and abrasion resistance is inferior to synthetic threads of equal thickness
• Mostly used for piece-dye items• Shrinkage may cause puckering after wash/dye• Can be mercerized – reduces shrinkage, increases
strength and luster, improves dye up-take
Common thread types
COTTON THREAD
MERCERIZATION
Common thread types
SPUN 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 chemicals• Stronger than cotton, including 4X better abrasion
resistance• Ideal for light to medium weight fabrics
Common thread types
CORESPUN 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 outerwear• More consistent sewing quality due to better loop
formation and resistance to damage• Most expensive general purpose sewing thread
Common thread types
TEXTURED 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 edges• Most economical thread• Softness makes it ideal for lopping threads that sit close
to the skin• Excellent elasticity for stretch fabric applications• Often found in intimates, baby clothes, and athletic
wear
Common thread types
OTHER THREAD TYPES
• Mono-filament ‘Invisible’ Thread• Embroidery Thread• Elastic Thread• Specialty – Lurex, Indigo• Locked Filament Thread• Glow in the Dark
Common thread types
LUBRICATION
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 types
• Needle sizing conventions
• Different Needle Types
NEEDLE BASICS
Needle Sizing
Most 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 markers
Needle Types
R = Normal round• for light woven fabrics
SPI = Acute round• For densely woven fabrics
SES = Light Ball• Fine to medium knits, fine denim, medium to heavy
wovens
SUK = Medium Ball• Stonewashed denims, corsetry
SKF = Heavy Ball• Fine elastic materials, coarse knits
SKL = Special Ball• Medium to coarse elastic materials, coarse knits, lycra
Needle Types
The 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
• Seam Types
• Stitch Types
• Applications
• What makes a good seam
SEAM CONSTRUCTION
• Superimposed Seams (basic simple seam)
• Lapped Seams • Lapped felled seams
• Flat Seams
• Bound seams
• Edge finishing
Seam Types
SUPERIMPOSED SEAMS
STANDARD SEAM FRENCH SEAM
Seam Types
LAPPED SEAMS
LAPPED SEAM
FELLED SEAM
Seam Types
FLAT SEAMS
Seam Types
BOUND SEAMS
Seam Types
EDGE FINISHING
Seam Types
301 - LOCKSTITCH
• Basic 1-needle straight stitch• Uses least amount of thread• Tightest and most secure stitch• High abrasion resistance due to low profile on
the fabric• No stretch
Stitch Types
304 - ZIGZAG
• 1-needle zigzag lockstitch• Can stretch, and can provide edge coverage• Used to apply lace or appliques• Used for bar tacks and button holes
Stitch Types
101 - CHAINSTITCH
• Formed using 1 thread only – no bobbin or looper
• On its own it is only suitable as a basting stitch• Blind hemming is a variation of this stitch
Stitch Types
401 - CHAINSTITCH
• Formed using 2 threads – needle and looper• Appears the same as 401, but is much more
secure and durable• Ability to stretch• Excellent for setting elastic• Frequently used for topstitching and for lapped
seams on high-wear garments like denim• Less thread passes through the fabric than on
a lockstitch, which can reduce seam pucker• 404 – Zigzag chainstitch
Stitch Types
406 and 407 – COVER STITCH
• 406 uses 3 threads, 407 uses 4• Excellent stretch. 407 has the most stretch• Excellent strength• Looper stitches are more efficient because you
don’t have to change a bobbin• Less thread passes through the fabric than on
a lockstitch, which can reduce seam pucker• Increased seam bulk• Increased cost
Stitch Types
503 – 2-THREAD OVEREDGE SERGE
• Formed using 1 needle and 1 looper thread• No 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 thread
• Most common for overlocking, and often used for sewing seams on knit fabric
Stitch Types
512 and 514 – MOCK SAFETY STITCH
• Formed using 2 needle threads, 1 looper, and 1 cover thread
• Common for seaming knits, and can be used for wovens as well
• Only 514 should be used on knits as it has better stretch
Stitch Types
515, 516 – SAFETY STITCHES
• A combination of an overedge stitch with a 401 chainstitch
• 515: 4-thread safety uses a 503 overedge serge
• 516: 5-thread safety uses a 504 overlock stitch
Stitch Types
FLATLOCK – 600 CLASS
• Formed using 2 – 4 needle threads plus 1 looper thread and 1 cover thread
• Fabric edges butt together but do not overlap• Highly elastic seams with very low profile for
maximum comfort• Efficient to sew• Very high thread consumption• Common for performance and scuba wear
Stitch Types
SPECIALTY STITCHES
• Pick Stitch - classic• Pick Stitch – on knits
Stitch Types
SPECIALTY STITCHES
• Whip Stitch• Blanket Stitch (single buttonhole)
Stitch Types
• Tension• SPI• Thread Choice• Stitch Choice• Needle Type• Needle Condition• Seam Width• Additional Elements
Elements of a Good Seam
SEAM PROBLEMS
• Seam Pucker• Grinning• Skipped Stitches• Broken Needle Threads• Broken Bobbin Threads• Needle Damage on Fabric• Seam Slippage
Trouble Shooting
SEAM PROBLEMS
• Seam Pucker• Grinning• Skipped Stitches• Broken Needle Threads• Broken Bobbin Threads• Needle Damage on Fabric• Seam Slippage
Trouble Shooting
SEAM PUCKER
• Bad tension• Bad feed• Fabric-Thread instability
• Uneven shrinkage during finishing• Thread-bloat from washing
• Structural jamming/Inherent pucker• Tight weaving does not have enough room
between yarns for thread• Sewing caused yarns to be pushed out of place
Trouble Shooting
SEAM PROBLEMS
• Seam Pucker• Grinning• Skipped Stitches• Broken Needle Threads• Broken Bobbin Threads• Needle Damage on Fabric• Seam Slippage
Trouble Shooting
Grinning
• Loose tension• Incorrect stitch choice
• Lockstitch is the tightest stitch and will grin less than other stitches
Trouble Shooting
SEAM PROBLEMS
• Seam Pucker• Grinning• Skipped Stitches• Broken Needle Threads• Broken Bobbin Threads• Needle Damage on Fabric• Seam Slippage
Trouble Shooting
SKIPPED STITCHES
• Bad tension• Machine timing is off
• Bobbin hook or looper is not entering needle thread loop at correct time
• Incorrect needle choice• The wrong needle can cause problems in
creating the needle thread loop• Damaged needle
• If the needle is bent, or is striking the throat plate, it may not create the loop in the right place for the hook to catch
Trouble Shooting
SEAM PROBLEMS
• Seam Pucker• Grinning• Skipped Stitches• Broken Needle Threads• Broken Bobbin Threads• Needle Damage on Fabric• Seam Slippage
Trouble Shooting
NEEDLE THREAD BREAKAGE
• Tight tension• Trapping at package base• Snarling before tension disc• Poor needle choice
• If eye is too small, there will be increased friction
• Excessive heat• Poor quality thread
Trouble Shooting
SEAM PROBLEMS
• Seam Pucker• Grinning• Skipped Stitches• Broken Needle Threads• Broken Bobbin Threads• Needle Damage on Fabric• Seam Slippage
Trouble Shooting
BOBBIN/LOOPER THREAD BREAKAGE
• Tight tension• Badly wound bobbin• Incorrect fit of bobbin case• Trapping at package base (for loopers)
Trouble Shooting
SEAM PROBLEMS
• Seam Pucker• Grinning• Skipped Stitches• Broken Needle Threads• Broken Bobbin Threads• Needle Damage on Fabric• Seam Slippage
Trouble Shooting
NEEDLE DAMAGE
• Incorrect needle/thread choice• Damaged needle
Trouble Shooting
SEAM PROBLEMS
• Seam Pucker• Grinning• Skipped Stitches• Broken Needle Threads• Broken Bobbin Threads• Needle Damage on Fabric• Seam Slippage
Trouble Shooting
SEAM SLIPPAGE
• Problem is with the fabric – not the stitch• Low yarn count, and continuous filament yarns
that don’t grip each other well are to blame• Very minimal improvement can be achieved
through increasing seam allowance, adding topstitching, or changing to a lapped felled seam
• When possible, seams can be fused• Best option – Change fabric
Trouble Shooting
THE END
BY MACKENZIE WALTONMARCH 2012