Classification of stitching machines
Classification of stitching machines
Stitching machines are classified based….
- Machine head.
- Number of needles
- Type of stitch
- Needle bar movement.
- Type of construction.
a). Machine head:
Depending on the shape of sewing machine (specifically based on needle post) head they are classified as …
i. Flat bed machine: This type of machine used for stitching flat materials /operations. This is most common machine used in upper stitching.
ii. Post bed machine: This machine is used to stitch partially closed/ closed uppers, which is not possible to stich using flatbed machine. The work area of the machine is raised above (like a post) which allows to stitch a particular area of a closed /partially closed easily. The height of post varies depending on type of application. This also used in stitching leather goods, boots, gloves etc..
iii. Cylinder arm : As the name states, this machine has cylinder arm (horizontally). Because of this horizontal arm , it is easy to work on the closed upper. It is easy to work on long boots /bags on this machine.
b) Number of Needles:
Some times a parallel stitch is needed on upper. Even though this can achieved with singles needle machine, the quality can be achieved by multiple needle machine. Generally double or triple needle or more needle machines are in use. So, depending on the needles, these are called as “Double needle machine”, “Tipple needle machine” etc. .
c) Type of stitch: This can be lock stich or a chain stich.
- Lock Stitch: Lock stitch is named because of two threads, upper and lower forms a Lock. The upper thread runs from a spool and pass through needle. Lower thread comes from a bobbin, which is located in lower section of the machine.
To make one stitch, the machine lowers the threaded needle through the material into the bobbin area, where a rotating hook catches the upper thread. The hook mechanism carries the upper thread entirely around the bobbin case, so that it has made one wrap of the bobbin thread. Then the take-up arm pulls the excess upper thread (from the bobbin area) back to the top, forming the lockstitch. Then the feed dogs pull the material along one stitch length, and the cycle repeats.
Ideally, the lock stitch is formed in the center of the thickness of the material.
- Chain Stitch : A Chain stitch is technique generally used in embroidery in which series of loops are formed with chain like pattern. Typically chain stitch is formed by one thread only but chain stitch can also be made by two or more threads.
There are different variations of lock stiches : Ex. Knotted chain stich, Open chain stitch, Braided stitch etc.
- In Basic Chain stitch, needle first go through the material. As the needle rises upward, the friction of the thread against the material form a small loop on the underside of the material. That loop is caught by a circular needle which is beneath the work. The machine then moves the material forward projecting the loop on the underside from the previous stitch. The next drop of the needle goes through the previous loop. The circular needle then releases the first loop and picks up the new loop and the process repeats.
- The Double chain stitch uses two threads. It is rarely used in today’s machines except for ornamental purposes because it uses a lot of thread. It is found in bulk material packaging, where it is used to close big bags. In this case it is useful to allow an easy opening of the bag.
The biggest disadvantage of chain stitch is, if one stitch broken the whole stitch becomes weak.
d) Needle Bar Movement: In general needles or needle bars moves in vertical direction. Needle bar movement plays an important role while forming the loop. In some machines needle bar moves in other direction also. For example, in of zig-zag stitching the needle bar is moves in vertical as well as horizontal.
e) Type of Construction: Depending on type of materials and specific demand, the sewing machines are of
- Light sewing machine
- Medium sewing machine
- Heavy sewing machine
Medium sewing machines are most commonly used in footwear industry.
Resources : https://en.wikipedia.org/wiki/Lockstitch