What are words the elements to measure stitch quality

What are the elements to measure stitch
quality?
Stitch quality is measured with :
•
Stitch size.
•
Stitch tension.
•
Stitch sequence.
•
Elasticity.
•
Resilience.
•
Elongation.
•
Fabric distortion.
•
Yarn severance.
•
Abrasive strength.
Principle of Lock Stitch Formation
•
Stitch class-300 is called lock stitch. It can be formed by the
interlacing of two or more threads.
•
One group of thread is passed through the fabric and
interlaced with the another group of thread and formed lock
stitch.
•
One set of thread is called is needle thread and another set

of thread is called bobbin thread.
Lockstitch utilizing a rotating hook invented by Allen B
Wilson. This is employed on many modern machines.
The following are the steps referred as the principle of stitch
class-301 formation :
Step-1
•
After finishing 2nd stitch the needle and the sewing thread are in
the top position, preparing for next stitch.
•
In this situation thread take up lever goes to its maximum
position and fabric has advanced one stitch.
•
Needle is entered with threads through the fabric and reached to
its lowest position.
• Again needle moves up a bit and stops for a while. At that time thread
take up lever also moves downwards and a loop is formed due to the
upward moving of needle. The formed loop is called needle loop.
Fig : Step-1
Step-2
• It is informed that, the hook of bobbin holder always rotates
at half circle.
• Due to rotation of the half circle bobbin holder hook catches
the needle loop and moves the needle loop over the bobbin
case.
• Interlacement takes place between the loop of bobbin
thread and needle thread.
Principle of Lock Stitch Formation
Fig : Step-2
Step-3

• Needle start to move up wards with needle thread and
take up lever also starts to move upward. As a result,
needle loop pulls the bobbin thread upward.
• In the mean time fabric is also moves one stitch forward
due to feed dog mechanism.
Principle of Lock Stitch Formation
Fig : Step-3
Step-4
• Loop clears bobbin and take-up draws to loop closed.
• It should be remembered that tension of bobbin thread and needle
thread should be proper for correct appearance of stitch formation.
So that it must be adjusted before sewing start.
• Needle thread tension can be adjusted by tensioning disc and thread
guide path changing.
• Bobbin thread tension can be adjusted by small screw which is
attached on the case through tightening and loosening.
Principle of Lock Stitch Formation
Fig : Step-4
Step-5
• In this stage, needle descends to lowest point to
stroke.
• New loop has been formed and is passing around
bobbin.
• Loop is pulled up to complete the stitch.
Principle of Lock Stitch Formation
Fig : Step-5
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