C O AT S
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S E W I N G
S O L U T I O N S
Solutions to Sewing Problems
Contents
Common Sewing Problems
Needle Thread Breakage
Bobbin / Looper Thread Breakage
Thread Fusing
Skipped Stitches
Imbalanced / Variable Stitching
Staggered Stitching
Variable Stitch Density
Seam Pucker
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Common Sewing Problems
Causes and Remedies
There can be many reasons behind the problems that arise while sewing and knowing the cause of these problems
and a solution for each particular cause is essential. These problems can be minimised by avoiding errors during
handing of materials / machines and by following the right working methods.
Some common sewing problems are;
Needle thread breakage
Bobbin or looper thread breakage
Thread fusing when the machine stops
Skipped stitches
Imbalanced / variable stitching
Staggered stitching
Variable stitch density
Seam pucker
The causes and solutions for each of the above problems are discussed in the following sections.
Needle Thread Breakage:
Cause
Remedy
Misaligned off winding from
Ensure that the overhead guide is directly above cop stand
thread package
pin, at 2 times the height of the thread package. Use a
foam pad to prevent package tilting
Trapping at package base
Reduce the thread stand height to prevent vibration and
spillage. Use a foam pad to prevent trapping after spillage
Thread trapped at thread guide
Can occur after thread breaks. Rethread correctly
Snarling before tension disc
Increase the wraps on pre-tension thread guides and reduce
Excessive tension
Use a stronger thread or adjust tension
disc tension. Ensure discs are smooth
Broken check spring
Replace and adjust
Sharp edges on throat plate, hook point,
Polish rough edges and replace if necessary. Replace the
needle guard, bobbin case,
needle being used with a higher quality needle
needle groove or eye
Thread fraying at needle
Use finer thread or coarser needle, as appropriate
Excessive needle heat; groove or eye
Improve the fabric finish. Change to a better needle, style and
blocked with melted fabric
finish. Apply needle lubricant via thread. Use a needle cooler
Hook overheating
Ensure adequate oil supply. Check the needle to
hook clearance
Poor quality thread
Change to a correctly finished thread of better quality
Bobbin or Looper Thread Breakage:
Cause
Remedy
Badly wound thread on the bobbin
Adjust bobbin winder alignment. Use pre-wound bobbins
Tension too tight or bobbin over-running
Adjust bobbin case tension. Insert a washer or
a spring to prevent over-running
Sharp edges on bobbin case or spring or
Polish edges and correct surfaces
looper eyelet
Bobbin case not fitting correctly
Check the size / type of bobbin for flange distortion
Thread Fusing when the Machine Stops:
Cause
Remedy
Poorly finished or incorrect thread
Use better quality thread
Densely woven fabric that is poorly or
Improve fabric finish. Change to more suitable
harshly finished
needles. Apply needle coolants
Damaged or overheated needle
Change the needle.
after thread breakage
Cause
Remedy
Hook, looper or needle failing to enter
Check machine clearances and timings. Check if the needle
thread loops at the correct time
is inserted and aligned correctly. Use a needle with
a deeper scarf
Thread loop failure caused by incorrect
Change needle size / style
needle size / style for thread size / type
Thread loop failure due to incorrect setting
Reset to standard and check loop formation
of thread control mechanism causing
with a strobe
thread loop starvation
Flagging of fabric due to poor presser foot
Re-adjust the presser foot pressure. Change the
control or too large a throat plate hole
throat plate to match the needle
Needle deflections or bent needle
Use a reinforced needle, reset the needle guard
and replace the needle
Incorrect sewing tension in the needle or
Re-adjust the tensions
under threads
Poor thread loop formation
Check with a strobe. Change to superior spun polyester or
filament based corespun threads
Imbalanced / Variable Stitching:
Cause
Remedy
Incorrect sewing tensions
Check for snarling, adjust thread tensions
Incorrect threading
Rethread machine
Needle thread snagging on bobbin case or
Polish bobbin case surfaces. Reset positioning finger
positioning finger
and opening finger
Variable tension due to poor
Switch to superior quality threads
thread lubrication
Staggered Stitching:
Cause
Remedy
Needle vibration or deflection
Increase needle size or change to a reinforced
Incorrect or blunt needle point
Change the needle
Incorrect needle-to-thread size relationship
Change needle or thread size as appropriate
Feed dog sway
Tighten the feed dog
Poor fabric control, presser foot bounce
Reset the presser foot. Change the feed mechanism
or tapered needle
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Skipped Stitches:
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Variable Stitch Density:
Cause
Remedy
Poor fabric feed control
Increase the presser foot pressure. Change to a more
positive feed mechanism
Seam Pucker:
Cause
Remedy
Variable differential fabric feed
Improve the fabric feed mechanism. Replace worn out
High thread tension
Keep the bobbin tension as low as possible and set the
Incorrect thread balance
Ensure proper balance between the top and
Improper thread type
Use threads with controlled
feed dogs. Reduce the maximum sewing speed
needle thread tension accordingly
bottom thread
elongation. Properly maintain tension guides
As a Coats customer, you have access to the finest technical expertise in the thread industry. Our technical
consultants are available to assist you in finding solutions for all your shop floor issues. They can give you insights on
improving your sewing processes, which will help you deliver products with better quality.
www.coatsindustrial.com
November 2014
