Principles of Lock and Chain Stitch Formation
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 group of threads to form a stitch.
- A needle thread that feeds from the top & a lower thread that 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 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
- 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 formation of 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 enlarge 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
|Chain Stitch||Lock Stitch|
|Stitches are formed by two or m re groups 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 top side and double chain at under.||The visibility look of lock stitch is same in both sides of the fabric.|
|Strength is higher than look stitch.||Lower strength than chain stitch.|
|Possibilities of seam pucker formation is less compare to lock stitch.||Possibilities of seam pucker is 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 end.||Stitches are secured by back tacking at starting and finishing 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)
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