Defintion: Loom is the machine which is used to manufacture the fabric by the interlacing of two or more sets of yarn.
In earlier years, there were shuttle looms which are used for manufacturing of cloth. But due to their limitations such as low productivity, lower fabric quality & higher manufacturing cost, there is a need of shuttleless looms which runs at very high speed with better quality of fabric as compared to shuttle looms. Shuttleless looms are the loom in which the weft pick is inserted by some another media instead of the shuttle.
According to the media used for the insertion of weft pick into fabric, the shuttleless loom can be classified as below –
In projectile looms instead of the shuttle the weft is inserted by means of the projectile, that’s why these looms are called as a projectile loom. The small projectile is also called as a gripper. The projectile has the spring loaded jaw in between which it grips the weft end and carry along with it throughout the shed.
The loom in which only single projectile is used such loom is called as single projectile looms. In this type of loom there is a need of picking and checking mechanism on both the sides of a loom which makes the loom complicated as well as these looms are not able to run at a very high speed that’s why in today’s era single projectile looms are nowhere available in the industry.
On the other hand, the looms on which multiple numbers of projectiles are used such looms are called as multiple projectiles looms. In this type of loom, the picking of the projectile is taken place preferably from the left-hand side of the loom and on the right-hand side, the checking mechanism is placed where the projectile is received. Then from receiving side, the projectile is again brought to the picking side by means of the conveyor chain. The maximum possible RPM of this loom is 600.
The number of projectiles required depends on the width of the loom. These looms are most preferably used for manufacturing heavy fabrics. These looms are available in the maximum width of 520 cm.
Rapier looms can be classified according to different criteria as given below
1) Number of rapiers
2) Rigidity of rapiers
3) System of weft insertion
Number of rapiers
According to this, there are single rapier, double rapier, and twin rapier looms.
In the case of single rapier, there is only one rapier head used for the insertion of weft pick which inserts the picks on its alternate traverse. As it inserts the pick on alternate traverse the loom speed remains limited. These looms are mainly rigid rapier looms
Whereas in the case of double rapier looms, two rapier heads are used out of which one is giver rapier and the second one is taker rapier. Double rapier loom may be rigid rapier loom or flexible rapier loom. In this, the weft end is carried by the giver rapier up-to-the center of cloth & taker rapier takes that weft pick from middle of the cloth to the other side.
In twin rapier loom there are two shades are formed and two pairs of rapier heads insert the weft pick into the respective shed. These looms are used for manufacturing of face to face warp pile structures.
Rigidity of Rapier
Rigid Rapier – In this type, the rigid rod or the tube is used to which the rapier head is firmly connected. This rod is made up of lightweight steel alloys or of plastic reinforced with carbon fibre. Single rapier looms are the rigid rapier type.
Flexible Rapier – In this type, the flexible tape is used to which the rapier head is connected. These flexible rapier tapes are made up of plastic with reinforced carbon fibres. Rigid rapier looms occupy more space to overcome this problem flexible rapier looms were developed.
System of weft insertion
Dewas system (Tip to tip transfer)
In this system, the tip of the weft pick is positively gripped & transferred from one rapier head to another rapier head at the center of the loom. The rapier heads used in this system are specially designed.
Gabler system (Loop Transfer)
In this system, the one end of the weft pick is gripped by the gripper on one side of the loom and moving rapier carries the weft along with it in the loop form up to the center of the loom from where this loop is straightened by another hand side rapier. The design of rapier head used in this method is very simple in nature.
These looms are classified by type of jet media used for weft insertion.
In this type of loom, the jet of either water or air is used for insertion of weft pick. The loom in which the jet of air is used for insertion of weft pick is called as air jet loom. These looms are able to run at a very high speed as there are no any solid media used for insertion. In today’s market, these looms are available with maximum 2000 RPM.
The loom in which the jet of water is used for the insertion of weft is called as water jet loom. These looms are only suitable for the weaving of hydrophobic yarns (synthetic fibres). These looms are capable of running at 1800 RPM. This technology is new so that these looms are not widely available but as it has various advantages it will make its own place in the textile market.