Here in this article, you will learn Principles of Lock and Chain Stitch Formation and Its Differences with phase wise details.
The Principles of Lock Stitch Formation
- Lock stitch m/c requires two groups of threads to form a stitch.
- A needle thread that feeds from the top & a lower thread from a bobbin.
- A rotary hook catches the needle thread loop as it passes around the bobbin &
interlocks the two threads.
- The lock stitch m/c can be distinguished by the winding device provided for the bottom
Phases of Lock Stitch Formation
Phase-1: The needle is inserted into the material
Phase-2: As the needle moves up-wards from its lowest position the needle thread forms a loop which is caught by the point of the hook.
Phase-3: The hook enlarges the needle thread loop.
Phase-4: In this phase, the thread loop is guided around the bottom thread of the spool.
Phase-5: The beginnings of interlacing will be done in this phase.
Principles of Chain Stitch Formation
- The needle is entered through the fabric with the thread & reaches to its lowest position.
- Needle contain old loop around its blade
- When needle moves on upward there will be the formation of a new loop.
- The new loop is caught by the looper (above the needle eye below the old loop)
- The needle moves upward
- The old loop is cast off from the needle blade and slides on the base of the new loop, which is still held by the looper.
- Between the new and old loop, an interlacement is to be formed under the fabric
- In that time fabric is also moved one stitch forward due to the feed dog mechanism.
- The looper enlarges the new loop so that when needle again entered through the fabric it passes through the loop.
- Then the looper leaves the loop, which held on the needle blade.
- This loop now becomes the old loop.
Difference Between Chain Stitch and Lock Stitch
|Stitches are formed by two or m regroups of threads, needle thread & looper thread.
|There will be at least two types of threads, one is needle thread and other is bobbin thread.
|The Threads are bound together by interlacing and interloping.
|The Threads are only bound by interlacing.
|Looks like lock stitch at the top side and double chain at under.
|The visibility look of a lock stitch is the same on both sides of the fabric.
|Strength is higher than look stitch.
|Lower strength than chain stitch.
|Possibilities of seam pucker formation are less compare to lock stitch.
|Possibilities of seam pucker are more than chain stitch.
|Extensibilities is 30%
|Same, sometimes less than chain stitch.
|No need of back tacking at finishing end, but secured by one (cm) thread at finishing the end.
|Stitches are secured by back tacking at the starting and finishing the end.
|m/c speed 8000 spm (stitch per min)
|m/c speed 6000 spm.
|Thread consumption is high.
|Thread consumption is less.
B.Sc. in Textile Engineering (Major in Apparel Manufacturing Technology) (BUBT)
EMBA (Studying) (JnU)
Email: [email protected]