PRESENTATION ON FEEDING MECHANISM: PRESENTATION ON FEEDING MECHANISM SUBMITTED BY Rahul Anand NIFT,Kolkata DROP FEED: DROP FEED The simplest sewing machine feed system, and still the commonest, is known as the drop feed, it is also known as the regular feed . The three machine parts that constitute the drop feed or regular feed are the pressure foot, the throat plate or needle plate and the feed dog. PRESSURE FOOT: PRESSURE FOOT The pressure foot is required to hold the fabric down firmly against the throat plate. The pressure feet are available in a great many types, both to match the varieties of feed dog which exist and to perform additional functions. The materials for pressure foot is according to the need. FEED DOG: FEED DOG The purpose of the feed dog is to move the fabric along by a predetermined amount between successive stitches. The feed dog consists of a toothed surface which rises through the openings in the throat plate. THROAT PLATE: THROAT PLATE It is also known as needle plate. It is the passive part of the feed system. Its function is to provide smooth, flat surface over which the fabric passes as successive stitches are formed. PROBLEMS OF DROP FEED SYSTEM: PROBLEMS OF DROP FEED SYSTEM The problem arises that the friction between the bottom ply and the feed dog is normally greater than that between intervening plies. The tendency is for the lower ply to be taken satisfactorily through the machine by the feed dog and the top ply to be retarded by the pressure foot. The problem is known as inter-ply shift . DIFFERENTIAL BOTTOM FEED: DIFFERENTIAL BOTTOM FEED In this feed mechanism the feed dog consists of two sections, one behind the other. Differential feed is available on chainstitch, overedge and safety stitch machines as well as lockstitch machines . There are two types of differential feeds, series and parallel differentials. Dry head over lock machine ADJUSTABLE TOP FEED SYSTEMS: ADJUSTABLE TOP FEED SYSTEMS The general arrangement of such top feed systems is that the presser foot is in two sections, one holding the fabric in position while the needle forms the stitch and the other having teeth on the lower side and moving or walking in such a way that the top ply is taken along positively while needle is out of the material. It can be used in machines for sewing light weight fabrics without any inter ply shift. 1- Needle lockstitch machine with automatic thread trimmer having bottom and variable top feed NEEDLE FEED: NEEDLE FEED Needle feed is the feed system in which the needle itself moves forwards and backwards. The needle enters the fabric, moves back with it as it is moved along to begin the next stitch. It is particularly useful in bulky sewing situations such as when quilting through the fabric and wadding. 2-needle, Needle-feed, Lockstitch Machine WALKING FOOT FEED: WALKING FOOT FEED The walking foot is combined simultaneous feed action of a set directional foot feed and a drop feed. This feed does not push the fabric; it caries the fabric. This type of feed is needed for certain thick operations. It is of two types: spring action walking foot, driven walking foot. UNISON FEED SYSTEM: UNISON FEED SYSTEM Unison feed is a further combination of feeding mechanisms which provides needle feed in addition to positive top and bottom feeding . It is valuable in the sewing of especially those with tacky surfaces, and it can achieve seam joining an edge binding without ply shift. It is used for operations on materials that have very low friction coefficients and for operations that are thick and heavy. PULLER FEED SYSTEM: PULLER FEED SYSTEM Usually accomplished by feed rolls; "rollers". Material passes between rolls, between upper roll and bed, or between lower roll and presser foot. A feed roll is mechanically driven to transport the material. Commonly used in association with any other feed system. Generally suitable for straight runs or large radius curves only. ROTARY FEED: ROTARY FEED There are two types of rotary feeds, twin action and single action. The double rotary moves the cloth with the combined action of two rotating wheels. The feed surface of each wheel is either toothed or knurled. PLATFORM FEED: PLATFORM FEED The platform feed carries the fabric on a platform which is situated above the machine bed. The plane of the platform is parallel to the bed plane. It has a needle hole and can be called a kinetic throat plate. The platform feed has a foot clamp as its complementary feed link. It secures the fabric to the platform during the feed cycle. WHEEL FEED : WHEEL FEED *A rotary wheel with a movement in the direction of feed. *Incorporates a friction surface or clamping surface that feeds or assists in feeding the goods. *Continuous motion wheel feed must work in unison with a needle feed . REVERSE FEED: REVERSE FEED * The reverse stitch length may be capable of providing as long of a stitch length as the forward feed does, or it may be limited to providing an average reverse stitch length or a maximum reverse stitch length shorter than the forward feed stitch length. *The ability of the reverse feed to feed material may be equal to or less than the ability of the forward feed to feed material. CLAMP FEED : CLAMP FEED A clamp or clamps from above the material and pressing downward, effectively holding the material between itself and the machine bed or a clamp or clamps above and below the material, holding the material firmly between the upper and lower clamps. The linkage moves the clamp and material under the needle as the stitches are formed. The movement of the clamp and material can be in any direction or follow any pattern provided for in the linkage drive mechanism. THANK YOU : THANK YOU HAVE A NICE DAY !!!!