TOPIC 1-SEWING MACHINE GUIDE

A sewing machine is a mechanical (or electromechanical) device that joins fabric using thread. Sewing machines make a stitch, called a sewing-machine stitch, usually using two threads although machines exist that stitch using one, three, four or more threads.

An innovation (apart from electricity) of sewing machine includes the ability to zigzag and to make more sophisticated stitching patterns.

The following are the 2 main categories of sewing machine.

Domestic sewing machines

These are designed mainly for one person to sew individual dresses while using a single stitch type. Modern sewing machines are designed in such a way that the fabric easily glides in and out of the sewing machine, speeding the stitching process and saving time and energy. Some key points for domestic sewing machines are as follows.

• Domestic sewing machines are usually used in homes by people simply interested in sewing.
• These are commonly used by people in a variety of projects for dressmaking, and for stitching simple home furnishing items.
• With little changes, these machines can perform a variety of stitch types.
• Domestic sewing machines usually work on lightweight fabrics or work pieces.
•  These machines run on significantly smaller motors compared to that of the industrial sewing machines.

Industrial sewing machines

• Industrial sewing machines are a heavy-duty version of a standard basic sewing machine, and it is used in garment and other related industries.
• Industrial sewing machines are used for mass production.
• These are heavy-duty machines that work thousands of stitches per minute.

• An industrial machine is well equipped with a clutch and large servo motor.
• Industrial machines are mainly designed to perform one single specific function in assembly line based factories.
• Some industrial machines are designed to operate heavier than normal material.
• Mainly, mass production requires an industrial sewing machine, which is designed to sew heavy material speedily, such as leather, canvas, and vinyl, at one time.
• The industrial machines are named based on the function that they serve. Typical names for industrial machine class include pocket setter, buttonhole, and programmable pattern sewers, etc. For instance, a pocket industrial machine can sew 2,000 pockets in an eight-hour production cycle.
• Programmable machines can store 10–30 or more patterns in the memory.
• Special purpose industrial machines can give better output in production, for example, buttonhole machines, pocket setter, pattern sewer.

Industrial sewing machines are larger, faster, more complex, and more varied in their size, price and task.

Comparison between domestic and industrial sewing machines:

-          The industrial machine is faster, stitching from 3000–6000 stitches per minute, while the fastest domestic sewing machine stitches not more than 1500 stitches per minute.

-          The presser foot on a power machine is raised and lowered with a knee lift to a special foot pedal. On domestic machines, it is generally operated manually using a lever at the back of the needle bar.

-          Lubrication is done automatically in industrial sewing machines whereas it is done manually in domestic sewing machines.

A sewing machine is an expensive piece of equipment therefore it should be chosen wisely;

• Consider the cost of the machine.
• Buy from a reliable dealer.
• Make sure that the spare parts and servicing are locally available.
• The purpose of the machine whether for domestic or for business purpose.
• Choose a versatile machine.
• Check that all parts of the machine are in good working order.

See that there is manual of instruction supplied with the model

Types of sewing machine

Though there are different types of sewing machine but mainly, three types are considered for sewing, as given below.

1.   Mechanical sewing machines

2.   Electronic sewing machines

3.   Computerized sewing machines

1. Mechanical sewing machines

These machines are less expensive and are the simplest type of sewing machines in terms of build. They are the hand-operated sewing machine and treadle sewing machine.

Hand-operated sewing machine

        i.     This is the simplest form of domestic sewing machine which is operated by hand.

       ii.     A handle is attached to the flywheel which is detachable and is used to operate the machine.

     iii.     A hand-operated sewing machine is generally used for domestic purpose for simple projects as it does not work very speedily.

     iv.     This machine is suitable where there is no electricity supply.

Figure 1. 1; hand operated sewing machine. Photo credits; ivm 101- sewing machine operator

Treadle sewing machine

-          This machine is the same as a hand-operated sewing machine but it is operated by feet, with an additional stand attached to the machine.

-          A belt is attached to the lower stand passing through the balance wheel and driven by feet.

-          These machines run faster than the hand-operated sewing machine.

-          This machine is also suitable for the places where there is no electric supply.

-          When handling the treadle sewing machine, both the hands of the Operator are free to handle the fabric. Hence, this speeds up the work of sewing.

Figure 1. 2; treadle sewing machine. Photo credit, ivm 101.pdf

2. Electronic sewing machine

There are many more features in an electronic sewing machine than in a mechanical sewing machine.

-          These sewing machines run faster than manually operated machines.

-          In the electronic machines, balance wheel comes to motion by a belt, which is attached to an electric motor.

-          A single motor is attached to the electronic sewing machines and this motor supplies power to the needle.

-          It is essential to control the speed of this machine by putting pressure on an electronic foot pedal.

-          Practice is essential to handle an electric sewing machine.

3. Computerized sewing machines

·       These sewing machines are very fast and specific to use.

·       These machines are similar to the electronic sewing machines. However, a computerized sewing machine works with the help of various software.

·       Computerized sewing machines allow the Operator to tailor the functions according to the sewing needs. A computerized sewing machine functions very appropriately in designing and stitching various components of the garment like sleeves, yokes, pockets, etc. These advanced computerized machines have an LED display or LCD display or touch screen. They are multi-function machines and are expensive.

Sewing Machine Classification Based on Its Bed Type:

The machine bed is the lower part of the machine and feed dog and loopers are positioned beneath it. Table-1 shows the various kinds of machine beds along with their uses.

The bed of a sewing machine is that part of the sewing machine on (or against) which the fabric rests while it is being sewn. The classification of sewing machine bed types or shape types is done based on the manner in which the fabric falls, behaves and travels with respect to the bed during the course of sewing, to enable easier movement of materials around the machine.

Table 1. 3; bed types.

Classification of Sewing Machine Based on specific function:

The sewing machine classification based on the machine type is given below.

Table-3: Classification of sewing machine based on machine type.

The basic structure of sewing machine is the same whether it is hand-operated sewing, treadle sewing machine or electric sewing machine. The basic parts of sewing are listed below.

Figure 1. 4 ; sewing machine parts. Photo credits; blogspot.com.

1. Spool pin: It is fitted on top of the arm to hold the reel.

2. Thread guide: It holds the thread in position from the spool to the needle.

3. Tension disc: The two concave discs put together with the convex sides facing each other. The thread passes between the two. The tension of the thread is adjusted by a spring and nut which increases or decreases pressure

4. Take up lever: It is a lever fitted to the body of the arm. It’s up and down motion feeds the thread to the needle and tightens the loop formed by the shuttle.

5. Needle bar: This is a steel rod to hold the needle at one end with the help of a clamp. Its main function is to give motion to the needle.

6. Bobbin case: This moves into position to catch the top thread and form the stitch as the needle is lowered into the bobbin chamber.

7. Presser foot: It is fixed to the presser bar to hold the cloth firmly in position when lowered.

8. Presser foot lifter: A lever attached to the presser bar for raising and lowering the presser foot.

9. Stitch regulator: This controls the length of the stitch.

10. Bobbin winder: A simple mechanism used for winding thread on the bobbin.

11. Fly Wheel: When this is made to revolve, it works the mechanism of the motion

12. Clutch or Thumb Screw: This is in the center of the fly wheel and it engages and disengages the stitching mechanism.

13. Slide Plate: A rectangular plate, which facilitates the removal of the bobbin case without lifting the machine.

14. Needle Plate or Throat Plate: A semi-circular disc with a hole to allow the needle to pass through it.

15. Feed dog: This consists of a set of teeth fitted below the needle plate. It helps to move the cloth forward while sewing.

16. Face plate: A cover which on removal gives access to the oiling points on the needle bar, presser bar and take-up lever.

17. Spool pin for bobbin winding: Spool of thread is placed on this at the time of bobbin winding.

Other important parts of the sewing machine.

a)     Shuttle: used for holding bobbin and bobbin case which carries the lower thread.

b)    Bobbin: detachable part of the machine that carries the under thread.

c)     Treadle: the operator treadle or presses this part of machine to move or drive the machine.

d)    Reverse lever: help reversing feed-dog when reinforcing stitches at the start and end of stitching operation.

e)     Stop motion screw: used for stopping needle movement when bobbin winding.

f)     Needle clamp: used for tightening and loosening the needle on the needle bar

g)    Pressure regulating screw: used to regulate the amount of pressure that presser foot exerts on different fabric weights or thickness when stitching.

Different machines have separate attachments for different sewing processes such as hemming, gathering, etc., but they operate differently on various makes of machines. They include;