sewing machine Feed mechanism

© SOFT Student Handouts,By, Sunil Talekar, Sr. Faculty, SOFT-Pune

Feed mechanisms is the basic motion of needles, loopers and bobbins, the material being sewn must move so that each cycle of needle motion involves a different part of the material. This motion is known as feed mechanism. For general categories, there are: drop feed, needle feed, Differential bottom feed mechanism, puller, Unisom feed mechanism, Adjustable top feed mechanism.

Besides these general categories, there are also uncommon feed mechanisms used in specific applications like edge joining fur, making seams on caps, and blind stitching.

WHAT IS FEED MECHANISM

FUNCTION OF FEED MECHANISM

Function: • To advance the fabric in the feeding

zone of the sewing machine. • To decide the length of individual

stitch (spm) • Appropriate feed mechanism is

sleeted to confirm case in sewing • Operation & to avoid different

sewing faults.

FEED TYPES

Types: Drop feed mechanism. Differential bottom feed mechanism. Adjustable top feed mechanism. Needle feed mechanism. Unisom feed mechanism. Puller feed m mechanism.

DROP FEED MECHANISM

DROP FEED MECHANISM

DROP FEED MECHANISM

PROBLEMS OF DROP FEED

• When two plies fabrics are sewn- lower ply moves forward by the help of feed dog but foot.

• So two plies of fabric can not move forward at the same speed. As a result lower ply is more fed than upper ply.

• This is called ply shifting/differential feeding pucker/feeding pucker.

• Sometimes roping is occurred during making of hem for ply shifting.

• It pitch of stitch s pitch of feeding dog same then fabric may be damaged for repeating contact of feed dog teeth & fabric at the same place.

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• Used for stitching slippery fabric as well

heavy material like leather, carpet etc.

NEEDLE FEED

• On the needle feed, the needle moves to and from as well as up and down. • The other is a normal machine in which

the needle only moves up and down.• Needle feed mechanisms are good at

preventing the layers of material from slipping, which can be especially important for slick fabrics.

• Since some needle feed mechanisms do not put pressure on the fabric the way feed dogs do, they will not leave any marks on delicate fabric.

NEEDLE FEED

NEEDLE FEED

The three main types of needle feed mechanisms are • the upper pivot, • the central pivot and • the parallel drive.

Pivoting needle feed mechanisms move the needle at an angle to help feed the material through the machine, while parallel drives only move the needle back and forth.

• The needle bar, which carries the needle, is held in a frame, and its motion is pivoted from a point on the frame farthest from (or far from) the needle.

• The needle will enter the goods at a leading angle from the centerline of needle travel, and will exit the goods at a trailing angle from the centerline of needle travel.

• In other words, the needle enters the goods at a certain angle and exits at a different angle.

• This would seem to disrupt the material and the stitching process, but in practice it does not.

NEEDLE FEED- UPPER PIVOT

• The needle bar, which carries the needle, is held in a frame, and its motion is pivoted from a point near the middle of the frame.

• The needle will enter the goods at a greater leading angle from the centerline of needle travel than with the upper pivot system described above, and will exit the goods at an equally great trailing angle from the centerline of needle travel that it entered with.

• In other words, the needle enters the goods at a certain angle and exits at a different angle.

• This would seem to disrupt the material and the stitching process, but in practice it does not, except with thicker or heavier goods.

• There is less momentum of the needle bar frame in motion than with the upper pivot system, and higher stitching speeds can be reached.

NEEDLE FEED- CENTRAL PIVOT

NEEDLE FEED- THE PARALLEL DRIVE

• The needle bar, which carries the needle, is held in a frame, and its motion is always parallel in relation to its prior and successive movements.

• It remains perpendicular to the material at all times. For example, if the needle enters the goods at 90 degrees to the materials' surface, the needle will remain at 90 degrees through its travel, and will exit at the same 90 degree angle.

• It is the type of needle feed suitable for stitching the heaviest and thickest of materials.

• The mechanism involved in a parallel drive makes for a more expensive unit and will generally have a slower stitching speed.

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.

WHEEL FEED

• Has either an intermittent motion or a continuous motion.

• Continuous motion wheel feed must work in unison with a needle feed.

• Applicable to all types of sports shoes, shoes, children shoes, boots and other footwear and handbags sewing.

UPPER AND LOWER WHEEL FEED.

• Wheel feed system where an upper and lower wheel are both driven.

• The material is fed between the wheels.

• There is positive feeding pressure both the top and bottom of the material at the same time



ROTARY WHEEL FEED.• Mechanical foot

or bit, with teeth or friction surface or a smooth surface, that transports or assists in the transport of material. Often a foot working in unison with a drop feed.

• Has a directional movement in which the material is fed.

• May push downwards into the material to capture material between itself and another feed component or against the bed or a plate on the bed.

ROTARY WHEEL FEED.

ROTARY WHEEL FEED.

ROTARY WHEEL FEED.

ROTARY WHEEL FEED.

ROTARY WHEEL FEED.

ROTARY WHEEL FEED.

VIBRATING PRESSER FOOT.

Jump foot.* A vibrating presser foot whose forward and backward motions are not driven, but spring loaded.* will usually incorporate a lifting motion on the return stroke.* Usually incorporates a lifting motion with the backward stroke. This allows the foot to clear the material and to drop relatively straight down onto any raised or uneven portion of the material without interference.* Commonly called a walking foot, feeding foot, or top feed.

VIBRATING PRESSER FOOT.

ALTERNATING PRESSER FEET

*A pair of feet that alternately press against the material.


*While one foot is pressing against or feeding the material, the other foot is raised clear of the material.


* he vibrating foot will feed or assist in feeding while the rising and descending foot will hold the material down between feeding motions.


*One foot is typically a vibrating presser foot while the other foot is typically a rising and descending presser foot.


* The rising and descending foot is often called a lifting presser foot.


Walking foot.*A vibrating presser foot with a lifting motion on the backward (return) stroke.


*Often part of an alternating presser foot assembly and commonly used in conjunction with compound feed or a drop feed.

REVERSE FEED* The ability to feed material opposite of a machines' normal direction of 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.

REVERSE FEED*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.

DECORATIVE PATTERN STITCHING PROGRAMMABLE SEWING MACHINE

BOX-X PROGRAMMABLE SEWING MACHINES and ELECTRONIC TACKERS

*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.

CLAMP FEED

POCKET DECORATION PROGRAMMABLE SEWING MACHINES

LABEL SEWING / ATTACHING PROGRAMMABLE SEWING MACHINES

*The clamp or clamp set is driven by linkage.*The linkage moves the clamp and material under the needle as the stitches are being formed.

CLAMP FEED

AIR BAGS PROGRAMMABLE SEWING MACHINES

BOX AND BOX X PROGRAMMABLE SEWING MACHINES FOR WEBBING

*The movement of the clamp and material can be in any direction or follow any pattern provided for in the linkage drive mechanism.

CLAMP FEED

PULLER FEED

*Usually accomplished by feed rolls; "rollers".*Material passes between rolls, between upper roll and bed, or between lower roll and presser foot.

PULLER FEED

*A feed roll is mechanically driven to transport the material.

PULLER FEED

*Commonly used in association with any other feed system.

*Generally suitable for straight runs or large radius curves only.

PULLER FEED

PULLER FEED• Modification of drop feed system.

• A pair of roller used.

• These rollers give a pulling motion on the fabric behind the presser foot.

• Top roller is generally driven by machine whitest the lower one moves due to control & presser of the top roller .

• The surface speed of puller roller is slightly higher then the feed dog speed to presser ply shifting roping.

• Useful in multi needle machine specially for W/B making.

PULLER FEED*Where material passes between two rolls, the second roll may also be driven.

DIFFERENTIAL BOTTOM FEED




• Modification of drop feed system.

• In the feed mechanism the feed dog consists of 2 section one at back & one at front of the needle.

• Mechanism of each section of feed dog is like the drop feed system. But the speed of each part can be adjusted separately.

• Extensively used for stretchy materials.

COMPOUND/NEEDLE FEED

*A combination of needle feed and drop feed.

*The term is often used erroneously to indicate any combination of feed systems.


• Another name of needle feed mechanism is “Needle feed”.

• Needle itself moves forwards & backward. • Needle penetrates the fabric enters into the

note of the feed dog & for the advance movement of 1 stitch length of fabric feed dog & needle pass the fame distance at the same time.

• Then needle rise up & moves to form the next stitch with one step advance.

• Practically useful in bulky sewing situation such as when quilting through the fabric, wadding & for slapping fabrics

• For the change of stitch length, setting of bath needle & feed dog should be changed.


http://www.youtube.com/watch?v=90Gt0ydA1Zo


UNISON FEED

UNISON FEED

• AKA “walking foot system because the presser foot has two independently driven section; the holding & the holding & the feeding feet.

UNISON FEED

• Mode by combination of needle feed & positive top & bottom feed.

• In this system one presser foot is inside the other presser foot & gives movement at different times.

• The inside presser foot & needle are driven at the same time toward the same direction.

• No possibility of ply shifting.

• Suitable for sewing stitch fabric & for bulk seam in heavy weight materials.

UNISON FEED

• Normally not so used unless special case.

http://www.youtube.com/watch?v=nb9luOvPJ6A

Thank you

Sources: You tube, Wikipedia

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