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Sewing machine fundamentals, principles of stitching
- 1. PRESENTED BY Dewan ShafiurRahman Md. Jamil Hasan BGMEA University of Fashion and Technology Department of textile engineering Apparel Manufacturing Engineering
- 2.
- 3. Mechanical systems for assembly (Sewing machine fundamentals, Principles of stitching)
- 4. Introduction 4 A sewing machineis a machine used to stitch fabric and other materials together with thread. A sewing machine has some fundamentals through which it can perform. Type of stitch, seam or any other specific operation are greatly dependent on the fundamentals of the sewing machine. So It is necessary to know the fundamentals of a sewing machine.
- 5. 5 Objectives To knowabout the fundamentals of a sewing machine. To know the type of sewing machine on the basis of the casting. To know about the lubrication system. To know about stitch forming principles. To know about the feed system.
- 6. 6 Sewing machine fundamentals Theparts of a sewing machine which are required to form a stitch, sew a seam, or perform a specific sewing operation are known as sewing machine fundamentals. Sewing machine fundamentals include: A Casting A lubrication system A stitch forming system A feed system
- 7. The Casting The machinecasting is the metal form that provides the exterior shape to the machine. Shapes of machine can vary according to the type of bed and the sewing function that is to be performed and how piece goods are to be prepared. The casting houses the internal workings that operate the sewing and feeding mechanism. Gears Shafts Cams The casting determines the bed type and location of the cloth plate. 7
- 8. 8 The Casting (Bedtype) Flat-bed machine Raised bed machine Post bed machine Side bed machine Cylinder bed
- 9. 9 Flat-bed sewing machine Features: Flatbed/ Fully Submerged Bed Types ideal for small parts and where positioning parts to the needle is a "slide" from the tabletop The large working area allows a wide range of application; the material can easily be guided around the needle and the pressure foot. The basic type is used for all kinds of flat sewing work. Stitch type: Lock stitch Chain stitch
- 10. 10 Raised bed sewingmachine Features: The entire machine is mounted on the top of the table. It is used when the garment to drape away from the needle for better handling is needed It facilitates the assembly of pre sewn parts and is especially suitable fir the fitting of accessories and special attachment . Stitch type: Lock stitch Chain stitch
- 11. 11 Post bed sewingmachine Features: The needle plate and foot are mounted on a tall post that facilitates sewing in tight spaces like inside sleeve, cap, or shoes. It is also suitable for button sewing and bar tacking. It is used extensively in the making of clothing for knitted fabrics. Stitch type: Lock stitch Chain stitch
- 12. 12 Side bed sewingmachine Features: This type of machines are specialized for sewing at edges need only a small working area. It is used for sewing sleeve seams, inseams, or out seams on pant legs, or other long seams in tight places. Stitch Type: Chain stitch Over-edge stitch
- 13. 13 Lubrication system Lubrication factorsare the prime factors in maintenance, downtime, efficient operations and long life time of various parts of the machine. The mechanical parts of sewing machine like any other mechanical parts are need to be lubricated (oiled) to reduce friction and keep mechanical parts moving freely. High speed and temperature increase the need for lubrication because of increased friction. There are two types of lubrication systems available. Manual Automatic
- 14. “ 1414 Manual Lubrication System Inthe former case oiling is done manually. In these machines no special mechanism for oiling is present. These machines are also called as dry head machines. The conventional sewing machine at homes is also an example in which manually oiling is done.
- 15. “ 15 Automatic Lubrication System Inautomatic oiling systems different parts work in combination with each other to ensure the effective supply of oil to the required parts like- Oil pump Wick felt Oil gauge and oil sight window Oil distribution network (oil pipes)
- 16. 16 White Automatic Lubrication System OilPump Wick felt Oil gauge
- 17. 17 Stitch forming system Stitchforming system are the mechanical parts that when correctly synchronized forms stitches, seams and then stitching. Various stitch forming mechanisms are: Thread control devices ( thread guides and thread tensions). Needles Bobbin case, bobbin and hooks Loppers Spreaders
- 18. 18 Stitch forming system ThreadControl Devices Thread control devices include thread guides, thread tensions and take-up. which are necessary to provide uniform thread flow. Thread guide Thread guides control the position and movement of thread. Damaged or faulty thread guides can damage sewing thread and cause thread breakage
- 19. 19 Stitch forming system Threadtake-ups Thread take up control the supply of thread required to form each stitch. It gives extra thread to the needle to form the stitch but takes it away to set the stitch. Tension Devices Tension devices controls the flow and tension in the thread going to form a stitch. Tension in the thread determines the balance and tightness of a stitch. Tensioning devices consist of a pair of tension disks, a spring and a thumb nut that can be adjusted to control the ease with which thread passes between the disks.
- 20. 20 Stitch forming system Hook Ahook is a rotating device encompassing the bobbin case that picks up the needle thread loop to form a lock stitch. Needles Needles carry the thread through the fabric so a stitch can be sewn.
- 21. 21 Feeding System The materialhandling components of machine are also called as the feeding system. For a precise line of stitches to be formed fabric must be moved through the stitch forming area of the machine with accuracy and precession. The feeding system usually consists of the following parts: The presser foot The throat plate Feeding mechanism
- 22. 22 Feeding System The presserfoot The presser foot is the upper part of the feeding mechanism. It is mainly responsible for applying pressure and proper holding of the fabric. The presser foot also controls the amount of pressure as if light fabric is being sewed than more pressure will be implemented however if heavy fabric is being sewed than pressure in the presser foot is lowered to some extent .
- 23. 23 Feeding System The ThroatPlate Throat plate is a metal plate that is present directly under the needle. Throat plate has openings for needle and feed dogs.
- 24. 24 Feeding System Feed Mechanism Feedmechanism control the direction of fabric movement and the amount of fabric movement for each stitch. Feed mechanism affect stitch length and the rate of travel.
- 25. Conclusion In our presentationwe have discussed on sewing machine fundamentals which are the most important requirements for sewing operation in a sewing machine. We have also discussed on principles of stitching including some parts and some mechanisms. Those things are very important for sewing. We can say that they are the integral parts of sewing operation. This is all about our presentation. 25