Different Weft Insertion Techniques in Weaving
Yash Ajit Patil
Aditya Birla Fashion and Retail Ltd. Bangalore.
First of all will understand what is weft? Weft is the yarn which runs perpendicular to the selvedge/warp. The density of the weft yarn i.e., PICKS PER INCH (PPI) will defines the rate of production. When weft is inserted from one side of the loom to the another side of the loom from warp shade, then it is called as pick. Likewise number of picks needs to be inserted into the warp shade so that fabric will be manufactured. There are different types of mechanisms available to insert the weft into the warp shade. In this article will discuss basic weft insertion mechanisms.
Types of Weft Insertion Mechanisms:
- Shuttle less
- Fluid weft insertion mechanism.
- Water jet
1. Weft insertion by shuttle:
Shuttle weft insertions carried out on shuttle looms, which was used for centuries to produce fabric and still in local area it is being used. Basically the shuttle is made from wood and it is provided with a rod inside it, which can carry a pirn. A pirn is a kind of bobbin on which the yarn is wound and this pirn will be kept inside the shuttle, and it will delivers the weft yarn for every subsequent picks. There are different types of shuttles and those are being used based on requirements. Also based on weft break stop mechanisms and pirn change mechanisms the pirn can change. Approximately the speed is 80 to 220 RPM.
2. Shuttle less:
As a name suggest the weft is inserted without shuttle. The shuttle is having some limitations, those limitations has been covered in shuttle less machines. The biggest limitation of shuttle is the amount of weft yarn carrying by the pirn, as the quantity over the pirn is less the loom has to stop frequently for changing the pirn. So that ultimately the efficiency of the loom will be hampered. On another side the shuttle is in bigger size. So that as per as the shuttle size is concern, the warp shade also need to be open more than the dimensions of shuttle because the shuttle should not strike / abrade to the warp yarn, as the yarn may be delicate, there is chance of damaging or decreasing the strength of yarn. Here is the second limitation, as warp shade needs to be open more than the size of the shuttle, it will take more time to open and close and this is the second reason that the efficiency drop down of the loom.
Projectile is a metal devise looks like a bullet. It is having a clamp like structure in from generally called as a gripper. This gripper is useful to hold the weft yarn during insertion into the warp shade. As a 1st successful shuttle less weaving is introduced by Sulzer in 1952. In this machine it is required to use number of projectiles, and this is based on width of the machine. Approximately the speed is 300 RPM. In this machine the weft is being inserted from only one side. Like the gripper holds the weft yarn from cross-wound bobbin, it goes through the warp shade by taking weft yarn, it will leave the yarn at the another end, at a same time at the left side the yarn will be cut, then same gripper will fall down onto the conveyer and next gripper comes into the place to insert the new weft. And this cycle will be repeated. There are different types of projectiles with different dimensions, and different weights based on the yarn it is used.
In rapier weaving, weft insertion is done in following way:
There is one giver and one taker, two rod like structures is there. Giver is having gripper which will catch the weft yarn from the cross wound bobbin from left side of the loom, it propels up to the middle of the loom, while moving towards the mid of the loom taker will also move towards mid of the loom. Both comes exactly in middle, and the system is provided in such a way that while going backward towards their respective original position, the giver will leave the weft free end and that will be automatically grabbed by the taker. As taker goes to original position along with that it will carry weft yarn also. Approximately the speed is 500 RPM. And ultimately weft will be laid down into the shade of the warp. There are two types of the rapier looms.
- Rigid rapier
- Flexible rapier
a. Rigid rapier: Rigid rapier is rod like structure which will not change it’s own shape and this types of looms requires more space for foundation. In this again two types are present like,
- Single Rigid Rapier
- Double Rigid Rapier
b. Flexible rapier: Flexible rapier as name suggests it’s a flexible. The flexible material is responsible to insert a weft into a warp shade. After insertion it will be wound. In this type of machine the space required is less. Again in this 2 types are there, like:
- Signal Flexible Rapier
- Double Flexible Rapier
Following fig shows a difference between single, double and flexible rapier.
C. Fluid weft insertion mechanism:
As name suggests the fluid weft insertion mechanism uses a fluid to insert a weft yarn into the shed. The classification is as follows:
The weft is being inserted into the shed by the help of jet of compressed air. Approximately the speed is 1000 RPM. Here are the nozzles used to jet a compressed air, so that the weft will be transferred from one side of the loom to another side of the loom. There are main nozzles and relay nozzles. Here we cannot process a filament yarn because there are high chances of disturbing the yarn structure. Before connecting air with nozzles that air should be purified/filtered. If any dust particles present in air then there are high serious chances of blocking of nozzles.
The weft is being inserted into the shade by the help of jet of compressed water. Approximately the speed is 1500 RPM. Here also nozzles used to spray the water, so that weft will be transferred from one side to another. Here only hydrophobic material can be processed like synthetic material only. The water requirement is more in this system, along with that water pH has to be maintained. Also water needs to be filtered. There should not be any dust particles in water, if any dust particles present then there are high serious chances of chocking/blocking of the nozzles.
In conclusion, the world of weaving has seen remarkable advancements in weft insertion mechanisms, each with its unique advantages and limitations. From the traditional shuttle weaving to modern shuttleless options like projectiles and rapier looms, to the innovative fluid weft insertion methods using air-jet and water-jet technologies, the textile industry has evolved significantly. These innovations have not only increased weaving efficiency but have also expanded the range of materials that can be processed. The choice of weft insertion mechanism depends on factors such as fabric type, speed requirements, and the nature of the yarn. These developments continue to shape the future of textile manufacturing.
- By Textilecoach, (Jan 15, 2021), Weaving | Loom Specifications | Classification of Loom, https://www.textilecoach.net/post/weaving-loom-specifications-classification-of-loom
- By Mazharul Islam Kiron, (August 28, 2022), Basic Weaving Mechanism of Loom, https://textilelearner.net/basic-weaving-mechanism-of-loom/
- By Mazharul Islam Kiron, (August 19, 2022), Rapier Weaving Machine: Types, Weft Insertion System, Electronic Control and Development, https://textilelearner.net/rapier-loom-types-weft-insertion/
- By Mazharul Islam Kiron, (May 16, 2012), Water Jet Loom: History, Working Principle, Advantages and Disadvantages, https://textilelearner.net/water-jet-weaving-machine-loom/
Q1. What are the ways of inserting weft yarns during fabric construction?
- Shedding: Separating the warp sheet into 2 layers
- Picking: Insertion of weft into shade by the help of shuttle or shuttle less mechanism.
- Beat up: Pushing the last laid weft up to the fell of the cloth.
Q2. What is the weft feeler mechanism?
Ans: Weft feeler mechanism is the task to check the presence of weft yarn and I’m case weft yarn exhausted allow to activate pirn changing mechanism.
Q3. Who drives the weft?
Ans: Actually, in auto loom bottom shaft drives a weft. And for shuttle less machine a separate motor given to drive a weft mechanism.
Q4. Why water-jet is only suitable for hydrophobic material?
Ans: Basically, water-jet uses a water to insert a weft yarn. If cotton is processed on water-jet machine then there are chances of absorbing water and may change properties. So that hydrophobic material can only be processed.
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- Rapier Weaving Machine: Types, Weft Insertion System, Electronic Control and Development
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Founder & Editor of Textile Learner. He is a Textile Consultant, Blogger & Entrepreneur. He is working as a textile consultant in several local and international companies. He is also a contributor of Wikipedia.