Feed Mechanism in Sewing Machine:
Feed system, feed types and feed mechanisms are interchangeably used terminologies in different literature. Feed mechanism in sewing machine is essential for ensuring smooth fabric movement during stitching. Various types of feed mechanisms are used based on the sewing application and fabric type. Mainly three parts – presser foot, throat plate and feed dog are responsible for feeding to take place, the needle also plays an important role in some of the feed types. Needles penetrate the fabric for stitch formation, and intermittent feeding of fabric is necessary for ensuring stitch formation takes place in continuous longitudinal form. The universally used feed system in sewing machines for fashion and commodity apparel manufacture is called drop oscillation feed or simply the drop feed from the bottom, which accounts for more than 90% of sewing machines installed in factories.
Different Types of Feed Mechanism in Sewing Machine:
Many feeding systems have been invented for sewing textile products in order to accommodate the range of different types of operations and feed the material correctly as required for effective stitch formation. The feed mechanism on a sewing machine could be categorized based on its application and end-use as-
- Manual feed
- Drop feed
- Four-motion drop feed
- Differential drop feed
- Problems in Drop Feed
- Variable top and bottom feed
- Differential feed
- Top Feed Mechanism
- Vibrating Presser Foot
- Alternating Presser Foot
- Needle feed
- Upper Pivot Needle Feed
- Central Pivot Needle Feed
- Parallel Drive Needle Feed
- Compound feed
- Unison feed
- Puller feed
- Wheel Feed
- Cup feed
- Clamp feed
1. Manual feed:
It is also known as free motion or darning feed. In this kind of feed mechanism in sewing machine, the operator moves work under the needle. The sewing machine has an upright motion presser foot which grips the fabric prior to the entrance of the needle into the fabric, and releases to permit the worker to handle the fabric between each stitch. This feeding system is commonly utilized for darning, embroidery, freehand quilting, etc.
2. Drop feed:
The drop feed mechanism (Figure 1) uses a feed dog below the throat plate that raises up through the plate, grips the fabric counter to the presser foot to transport the fabric by one stitch, and then drops below the plate to come back to its original position.
a) Four-motion drop feed:
In the four-motion drop feed, the feeder engages the underside of the fabric ply intermittently and is set up (timed) to engage the material when the needle has risen clear from the top ply of the fabric (Figure 2).
The feed is named ‘four motion’ as it has four movements:
- Motion 1 – Rising above the plate to contact the fabric.
- Motion 2 – Feeding the fabric the required stitch distance.
- Motion 3 – Descending beneath the plate to release contact with the fabric.
- Motion 4 – Travelling back underneath the plate the required distance to repeat the feeding process.
b) Differential drop feed:
This system employs two feed dogs set in series that are driven in a similar manner to the single four motion drop-feed dog (Figure 3). This feed system makes it possible to control the ratio of feed between the two feed dogs. By feeding more with the back feed dog than the front feed dog (in the same stitch cycle), it is possible to stretch the bottom ply of the fabric. Conversely, by feeding more with the front feed dog than the back feed dog, it is possible to introduce fullness into the bottom ply.
c) Problems in drop feed:
While sewing with two plies of fabric, the lower ply moves forward by means of a feed dog positively but not the upper fabric plies. Therefore, two fabric plies are moving at different speed, that is, the lower ply at a faster speed than the upper ply. This is known as differential feed pucker or feed pucker.
If the pitch of the feed dog teeth and the stitch are the same, then there is more possibility of fabric damage as the teeth of the feed dog and the fabric have repetitive contact at the same area.
3. Variable top and bottom feed:
This feed mechanism is a combination of a feeding foot synchronised with a bottom four-motion drop-feed system (Figure 4). These feeding mechanisms are often used for sewing high-friction materials such as simulated leather and composites, where the use of a static presser foot is unsuitable.
4. Differential feed:
Differential feed (Figure 5) utilizes a two-piece feed dog located beneath the throat plate that rises up and grips the fabric against the foot and then advances the fabric. The front (main) and rear feed dog could be fixed to move at the same or different speed/distances. When the rear feed dog is moving at a faster rate compared to the front, the fabric will be stretched. In contrary, when the front feed dog is moving faster than the rear feed dog, the fabric is gathered (shirring).
5. Top feed mechanism:
In a top feed mechanism, the presser foot is made in two different sections. One section of the presser foot holds the fabric panel during the stitch formation by the needle and another presser foot has length on the lower side and wakes in a manner that the top ply is moved along positively when the needle is in and out of action on the fabric. A combination of adjustable feed and differential bottom feed can cause gathering of the top ply or bottom ply.
a) Vibrating Presser Foot:
In the case of a vibrating presser foot, the forward and backward motions of the presser foot are not driven; however, they are spring loaded as shown in Figure 6. The presser foot has teeth that aids in the movement of fabric along with the feed dog. It has a vibrating motion forward with the feeding process and backward with the return stroke. Generally it is constructed with a lifting motion during its return stroke to enable the presser foot to clear the fabric and to lower comparatively straight down onto an uneven section of the fabric without interference. It is commonly known as a walking foot or top feed.
b) Alternating Presser Foot:
It has a couple of presser feet that alternately press against the fabric (Figure 7). When one foot is aiding in moving the fabric along, the other foot is raised to clear the fabric. These actions will take place alternatively. Out of two presser feet, one is normally a vibrating presser foot whereas another presser foot is a rising and descending one. The vibrating foot will facilitate in fabric feeding and the rising and descending foot will grip the fabric down between feeding motions.
6. Needle feed:
Needle feed (Figure 8) utilizes a feed dog beneath the throat plate that rises up through the plate, presses the fabric counter to the foot, in combination with the sewing needle, which is lowered through the fabric and then both the sewing needle and the feed dog move the fabric by one stitch. Then they separate and return to their respective original positions for the next stitch formation.
Needles come into the fabric and stay in the fabric when moving the fabric perpendicular to the needle’s normal direction, thus feeding the fabric along with the feed dog. It prevents the upper, middle and lower layers of fabric panels from slipping apart. It does not require any pressure from the top surface of the fabric during feeding, which could be useful for stitching delicate fabrics where the impression of the feed dog will be marked on the fabrics. It is commonly used in combination with drop feed and/or with upper feed. It is predominantly utilized in bulky sewing circumstances such as quilting fabric and for sewing heavy materials like leather, carpet, etc. The three main kinds of needle feed mechanisms are upper pivot needle feed, central pivot needle feed and parallel drive needle feed. The pivoting needle feed devices move the needle at a definite angle to assist the feeding of fabric; however, parallel drives simply move the needle back and forth.
a) Upper Pivot Needle Feed:
The needle bar, which holds the sewing needle, is detained in a frame, and its movement is pivoted from the frame far from the needle. Hence, the sewing needle goes into the fabric at a leading angle with respect to the centerline of the needle and will exit the fabric at a trailing angle. This would appear to disturb the fabric and the sewing process, but practically it does not.
b) Central Pivot Needle Feed:
In this system, the needle bar, which holds the needle and its movement, is pivoted at a point which is nearer to the middle of the frame. The sewing needle enters the fabric at a larger leading angle from the axis of the needle than the upper pivot system and exits the fabric at an equally larger trailing angle. There is less impetus of the needle bar in motion than the upper pivot system, and higher stitching speeds could be achieved.
c) Parallel Drive Needle Feed:
The needle bar, which secures the needle, is permanently parallel relative to its earlier and successive movements. It remains perpendicular to the fabric during entry as well as exit from the fabric. This kind of needle feed is appropriate for sewing higher grams per square meter (GSM) fabrics.
7. Compound feed:
It is a combination of a drop feed mechanism and a needle feed mechanism. Feeding of fabric happens while the needle is in the fabric by means of combined motion of needle bar and feed dog. Compound feed (Figure 9) utilizes a feed dog beneath the throat plate that raises up and presses the fabric against the presser foot in combination with a needle, which is still in the fabric, moves the fabric together by a one stitch. Then the needle is out of the fabric and moves to its respective position to form the next stitch with one step advance. This kind of feed mechanism is useful in bulky sewing circumstances like quilting the fabric, wadding and for slapping fabrics. In this feed mechanism, the change of stitch length warrants setting of both needle and feed dog.
8. Unison feed:
Unison feed as shown in Figure 10 is the conjunction of a needle feed and a compound feed mechanism. As the needle penetrates the fabric, the top (presser foot) as well as the bottom feed dogs compress the fabric, and all three components (feed dog, presser foot and needle) move the fabric by one stitch, then all are released from the fabric as the presser foot drops to hold the fabric, and all return for the next stitch.
The word unison feed is utilized in two different manners. One is its application to any of two or more feed systems working in combination. A second application is to depict the uncommon feed system of a vibrating presser foot, along with needle feed, and a drop feed, working in combination, but from a one-piece frame. This is the only feed mechanism where it is impossible for the upper and lower feed mechanisms to become out of synchronization. All other kind of feed mechanisms are synchronized by linkage or electronic controls system.
9. Puller feed:
A puller feed is a method for providing a positive control of all fabric plies as they depart basic feeding mechanisms such as drop feed in the sewing machine. In this kind of feed mechanism, feeding is normally carried out by feed rolls as shown in Figure 11. The fabric passes between an upper roller and a sewing bed, or a lower roller and a presser foot. These feed rollers provide a dragging motion on the fabric behind the foot. The top roller is normally driven by the machine and the lower roller moves due to the pressure of the top roller. The surface speed of the puller roller is slightly higher than the speed of the feed dog to presser ply shifting roping. It is useful in multi-needle machines particularly for attaching the waist band.
10. Roller / Wheel feed:
The wheel feed mechanism shown in Figure 12 uses a roller that moves the fabric one stitch at a time, in a ratcheting motion. In this kind of feeding, the foot has small rollers to enable easy movement of fabric. Wheel feed is more suitable under circumstances where the fabric to be sewn would be damaged by the tooth of the feed dog such as products like vinyl plastic and some leather products.
11. Cup feed:
A cup feed system as shown in Figure 13 utilizes one or two cup-shaped wheels that squeeze the edge of the fabric, allowing the sewing needle to sew across the edge of the material. It is generally called a fur machine, as it is perfect for sewing the narrow strips together to make a fur coat. In this kind of feed mechanism, the sewing needle works in the horizontal path and feeding can be done by moving the fabric between the two rotating discs or by moving the fabric between a disc and a presser surface.
12. Clamp feed:
A clamp feed clamps the material from above and presses downward, effectively holding the material between itself and the machine bed or a clamp, as shown Figure 14.
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. The movement of the clamp and material can be in any direction or follow any pattern provided for in the linkage drive mechanism.
Conclusion:
Feed mechanism in a sewing machine plays a crucial role in achieving consistent and precise stitching. The choice of feed mechanism in sewing machine depends on the type of fabric, the thickness of materials, and the specific sewing application. Understanding the functionality of each feed type ensures optimal sewing performance, fabric handling, and stitch quality. For specialized tasks, selecting the right feed mechanism is essential to achieve professional results.
References:
- Karthik, T., Ganesan, P., & Gopalakrishnan, D. (2016). Apparel Manufacturing Technology. In CRC Press eBooks. https://doi.org/10.1201/9781315367507
- Nayak, R., & Padhye, R. (2015). Garment Manufacturing Technology. In Elsevier eBooks. https://doi.org/10.1016/c2013-0-16494-x
- Sinclair, R. (2015). Textiles and fashion : materials, design and technology. In Woodhead Publishing eBooks. http://ci.nii.ac.jp/ncid/BB18427651
- Rathinamoorthy, R., & Surjit, R. (2015). Apparel Machinery and Equipments. In WPI Publishing eBooks. https://doi.org/10.1201/b18903
