The document describes the principle of chain stitch formation, specifically a multithread chain stitch. It involves interlooping threads from multiple groups to form the stitch. The process occurs in three steps: 1) the needle enters the fabric and a loop is formed, 2) the looper passes through the new loop and an interlacement occurs under the fabric, 3) the looper enlarges the new loop so the needle can pass through it, forming the next old loop. Diagrams illustrate each step of the multithread chain stitch formation process.

1. Principle of Chain Stitch Formation
• Chain stitch is made by using one or more group of
threads.
• The stitch which is formed by two or more group of
threads is called multi thread chain stitch.
• In this stitch, the loop of one group threads is bounded
by interlooping with loop of another group of threads.

2. Interlooping two types of threads to form chain stitch

3. Stitch type -401 is multithread chain stitch and the
followings are the steps referred as the principle
of stitch type-401 formation:
Step-1
• Needle is entered through the fabric with the thread &
reaches to it’s lowest position.
• Needle rises to form loop and looper starts forward.
• A new loop is formed when needle moves upward a
little.
• Looper enters needle thread loop.

4. Fig : Step-1

5. Step-2
• Needle rises and looper passes fully into loop. New loop is caught
by the looper (above the needle eye below the old loop).
• Feed moves material to the next stitch position and looper swings
to other side of needle with avoiding motion.
• Needle descends through triangle.
• Interlacement is occurred under the fabric (between the new loop
& old loop).
• In that time fabric is also moved one stitch forward, due to feed
dog mechanism.
Principle of Chain Stitch Formation

6. Fig : Step-2

7. Step-3
• The looper enlarges the new loop. So that the needle
again entered through the fabric, it passes through the
loop.
• Needle continues rise and looper starts its return
stroke.
• The looper leaves the loop, which held on the needle
blade. This loop now becomes the old loop.
Principle of Chain Stitch Formation

8. Fig : Step-3

9. Thanks to All

10. Thanks to All