- 1-Single phase weaving machines
- 2-Multiphase weaving machines
- is divided into two.
1-SINGLE PHASE WEAVING MACHINES
Single-phase weaving machines perform the basic weaving operations, namely shedding, weft insertion and pitching, once in a single course of the machine.Fabric formation occurs by the continuous repetition of the machine course in succession.In the definition of single-phase weaving machine, the type of weft insertion system, shed opening system and other mechanisms of the weaving machine is important.Almost all of the weaving machines used in the weaving industry today are single-phase weaving machines.Only some special weaving machines fall into the category of multi-phase weaving machines.In the development of single-phase weaving machines, most weft insertion systems have been studied in order to increase their production.
2-MULTIPHASE WEAVING MACHINES
The developments in the textile industry in recent years have shown that remarkable developments are inevitable, especially in the field of weaving.Manufacturers have to present their new approaches, which are new in many respects, to fabric manufacturers.These developments in weaving have to target higher speeds without losing sight of product quality.Even though the single-phase weaving machines with shuttle and hook, which have the most common usage area in the sector, have almost reached the last point they can reach for weaving productivity with their constructions, it is also an inevitable fact that technology will not know any limits.That's why machine manufacturers have to give importance to R&D studies continuously.
SINGLE PHASE WEAVING MACHINES
Single-phase weaving machines perform the basic weaving operations, namely shedding, weft insertion and pitching, once in a single course of the machine.Fabric formation occurs by the continuous repetition of the machine course in succession.In the definition of single-phase weaving machine, the type of weft insertion system, shed opening system and other mechanisms of the weaving machine is important.Almost all of the weaving machines used in the weaving industry today are single-phase weaving machines.Only some special weaving machines fall into the category of multi-phase weaving machines.In the development of single-phase weaving machines, most weft insertion systems have been studied in order to increase their production.
SINGLE SHUTTLE WEAVING MACHINES:
In single-shuttle weaving machines, the weft yarn goes back and forth between the shuttle slots located on the right and left of the sash, on the shuttle path on the tee, by means of the shuttle at each shed.This process continues until the weft tube inside the shuttle is empty. When the weft tube is empty, it is automatically replaced with a new one by the battery assembly. The launch of the shuttle takes place with the striking arm.Impact devices come in a variety of shapes.Except for the weft insertion systems of single-shuttle weaving machines, all the basic elements and processes are the same as for single-phase weaving machines.
MULTI-SHUTTLE (CASE) WEAVING MACHINES:
Conventional shuttle looms with only one slot on each side of the loom are called. Such looms have only one shuttle and therefore they weave fabric with a single color uniform weft yarn. Shuttle looms with two or more slots placed on one side or both sides are called case looms. For fabrics that require two or more colored wefts, it is moved up or down. Only one shuttle continues at a given time. Generally, each slot contains a shuttle with a different color weft thread. The cases move vertically and the appropriate shuttle to be used in the mouthpiece comes to the level of the striking arm. In this way, different color weft variations can be made. Sometimes different types of weft yarns are used instead of yarns of different colors to give an effect to the fabric. In the early days, it was developed and used in counters with a rotating shuttle slot on the left side of the counter, as in pistols with a rotating cartridge bed and revolver. These are called turntables. Today, these looms are not used due to their speed and limited possibility of using different colors and types of wefts. Box weaving machines are no longer produced because the automatic bobbin changer cannot be combined with the box movements.
SHUTTLE-FREE WEAVING MACHINES:
The most important developments in increasing the weaving machine and thus its production have been on the weft guide systems. In weaving machines with shuttle, the weight of the weaving machine limits the speed of the weaving machine. These weaving machines are generally called shuttleless weaving machines. Shuttleless weaving machines are highly advanced weaving machines with the use of electronic devices. Production rates are very high. In order to be able to work efficiently at high production speeds and to produce defect-free, quality fabric, other working units are developed with computer aid in modern weaving machines without shuttle, and additional devices are made to increase efficiency and quality.
HOOK WEAVING MACHINES
These are the systems in which weft registration is made by means of holder heads mounted on needles. These looms can be designed as a system in which a single hook (rapier) passes the entire warp width and weft registration, or they can be arranged as a system in which two hooks enter the shed from two separate sides of the loom and transfer the weft thread from one to the other in the middle. It is divided into 8 subclasses as flexible hook looms and 2 bands with flexible hooks). Although flexible hook looms are generally with double hooks, models with single flexible hooks are also encountered. Single, double, telescopic models of rigid hook weaving machines also have twin hook models that weave carpets or velvet face to face. In addition, double hook looms can be in two different structures as Loop transfer system (Gabler) and end transfer system (Dewas system) according to the transfer shape of the weft yarn in the middle of the shed.
The systems in which weft insertion is done with donor and receiver hooks placed on flexible or rigid arms are called hooked weft insertion systems. Hook weaving machines, which are among the shuttleless weaving systems, have been developed in different ways since the day they were first produced and have become very common. Hook systems are called rapier or skewer systems in the market.
Features: Weft thread of hooked weft insertion system is under control during weft insertion. For this reason, the hook weft insertion system is referred to as positive weft delivery. In other weft insertion systems (with shuttle, shuttle, jet), the weft carrier and therefore the weft yarn is not under control during insertion. For this reason, systems other than hooked are referred to as negative weft conduction. It can work with all types of yarn as it can throw the weft yarn under control in hook systems. It is possible to work up to 16 weft colors in hook systems. Therefore, it is suitable for all kinds of fabric weaving. It is preferred because it provides advantages especially in different types of yarn and colored upholstery fabrics. In hook systems, although the production speed varies according to the width of the fabric, it can reach a maximum of 170 wefts/min at 700 cm width and 360 wefts/min at 400 cm widths.
Hook weft insertion systems are widely used. Since all kinds of yarn can be used, it is used in the weaving of almost all types of fabrics, from upholstery fabrics to towels, from plain weaves to velvet. It is also preferred that the number of weft colors is higher than the others. Hooked weft insertion systems are also used in carpet and velvet weavings that are woven face-to-face due to the fact that hooks can be used on top of each other. Hook systems are preferred especially in businesses that weave different fabrics and change types frequently.
Hook weft insertion systems are divided into groups with single and double hooks, structurally as rigid and flexible hooks, according to the number of hooks. Single hook systems have been replaced by double hook systems over time due to their low efficiency and difficulty in use in wide widths. It is produced as flexible and rigid hooks in double hook systems. Double hook systems have two hooks, one for the receiver and the other for the transmitter.
Rigid Hook Weft Insertion Systems
Rigid hooks have less vibration due to the profile (pipe or U) used. They take up a lot of space due to the hook guards protruding from the machine edge. For this reason, wide combs are not preferred in widths. However, rigid hook systems are used in large weaving machines such as carpet machines. There is no need to add a guiding element to the tee, as rigid hooks do not need to be guided in the muzzle.
Flexible Hook Weft Insertion System
Flexible hook systems have been developed because rigid hooks take up a lot of space. Elastic bands must be made of steel or carbon fiber reinforced high performance synthetic materials. Flexible band rapier weaving machines are the most used machines in the weaving industry. Although they are widely used, their disadvantages should not be ignored. For example; The problem of stretching and vibration requires the most perfect possible settings for the yarn transfer. Due to the thread transfer between the donor and receiver hook, especially in the middle of the shed, the transfer of the thread between the hooks creates a problem. Flexible hooks must be guided so that they can move smoothly in the mouthpiece. Guiding is provided by guides mounted on the tee.
In the hook system, weft accumulators are used for weft feeding, as in the shuttle. After the weft accumulators, the weft control system controls the weft yarn. Weft control systems stop the machine in case of yarn breaks. After weft control, weft guide guides direct the weft to the weft feeders. In the hook system, weft dispensers can work with yarns of different numbers and types. Also up to 16 colors on new machines Hooks consist of two parts, the strip part and the clamp part. The tape part connects the clamps with the weft insertion system.
AIR JET WEAVING loom ( MACHINE )
By creating a jet-shaped air flow with sufficient pressure, the weft yarn is accelerated with this air flow and passed through the nozzle. air jet weft insertion is called. In air jet weft insertion, weft insertion occurs as a result of high pressure air being sprayed by the main and auxiliary jets and the weft is carried by this air flow.
There is no carrier mass in the air-jet system, weft conveying completely by compressed air flow is happening. Since there is no such thing as giving the weft yarn to the carrier mass in air-jet systems, it can work faster than other systems. Since there is no carrier mass, there are no mechanical parts such as hitting and braking, so it is less noisy. In the air-jet system, auxiliary jets should be used in order to throw the weft over longer distances regularly. The use of auxiliary jets can damage the warp threads, even slightly, such as shuttle guides. Hollow special profile combs are used to prevent the compressed air from dispersing in the air-jet system. Although the air-jet demands vary according to the width of the loom, today, a maximum of 170 wefts/min at a width of 1100 cm. It can go up to speed.
Production speed is very high in air jet weaving machines. However, problems such as dispersion and mixing arise in the weft yarn carried in the shed by the air jet. This situation brings limitations especially in terms of yarn type and structure. For example, using fancy weft yarns on air-jet weaving machines is quite problematic. For this reason, air-jet weft insertion systems are preferred for fabrics woven with the same type of yarn. In addition, it is used in towel weaving and multi-phase systems with sequential sheds. Air-jet weaving machines are very efficient in weaving fabrics that do not use fancy yarns, such as poplin, denim, cord type fabrics, woolen fabrics for upper clothing, lining and topwear fabrics from plain filament or textured filament yarns in the weft density range of 2-100 per centimeter.
Main Jet
It is the element that directs the weft forward with the compressed air coming out of it. The main jet performs the main function in the weft insertion process. In the air-jet machines produced today, the main jets work in pairs, fixed and mobile, one after the other. Fixed main jets feed the weft from the weft accumulator to the moving main jet. The movable main jet throws it to the mouthpiece with compressed air. The movable main jets move with the tambourine. Thus, weft insertion can be provided at different positions of the shed.
Auxiliary Jets
In wide-width weaving machines, the first speed given by the main jet is not sufficient to convey the weft yarn through the shed as desired. For this reason, auxiliary jets are placed at regular intervals along the width of the loom to help carry the weft yarn in the shed.
Profile Comb
The comb structure is different so that the compressed air does not scatter in the air-jet system. The comb is produced as a hollow to guide the sprayed air.
Weft Feeders
Weft accumulators used in the air-jet system are winding and feeding at high speeds in accordance with the system. Therefore, there is a balloon breaker in front of them to prevent yarn ballooning due to high draft.
Working Principle
The weft yarn comes to the weft accumulators (weft feeders) after being unwound from the fixed weft bobbins. Tension control is also carried out in the weft regulators, and the weft yarn is wound in the reserve winding section at a length determined according to the width of the reed, with a rotation determined according to the twisting direction of the yarn. The delivery of the weft yarn from the exit eye of the regulator is controlled by an electronic pin. The weft yarn coming out of here is given to the main air jet nozzle by passing through the guides and weft control units. The main air jet nozzle gives the weft yarn its initial velocity with compressed air and moves it in the shed. In order not to disperse the air flow, the comb structure is hollow, unlike other systems. In wide-width weaving machines, the first speed given by the main jet is not sufficient to convey the weft yarn through the shed as desired. For this reason, auxiliary jets are placed at regular intervals along the width of the loom to help carry the weft yarn in the shed. Auxiliary jets lined up along the entire length of the reed they help the nozzle to blow the weft through the reed guide. In order to obtain a straight yarn path, the position of the auxiliary jets relative to the card guide channel is of great importance.
MULTIPHASE WEAVING MACHINES
If more than one weaving process is carried out in different places at the same time in a weaving machine, these are called multiphase weaving systems. In these machines, more than one weaving unit is synchronized. By opening the mouthpiece in more than one place at the same time, weft insertion and tambourine operations are also performed. Multiphase weaving machines are divided into two:
CIRCULAR WEAVING MACHINES
It has been developed for the production of tube fabric used in the sack and packaging industry. They are machines in which four or eight shuttles pass one after the other, following a circular shuttle path, through a undulating nozzle. An electromagnetic block moves in a circular motion. It carries the wefts by pulling the metal shuttles to itself. The beat is made with a toothed roller.
FLAT MULTI PHASE WEAVING MACHINES
In these machines, the weaving process is done in many places at the same time. Small weft carriers move through the mouthpiece that opens in front of them, and carry one weft thread length to the width of the fabric. The number of mouthpieces is equal to the number of wefts placed. Padding is continuous and is usually carried out with a profiled rotary comb. The working speed is not very high, on the other hand, the weft registration speed is 2000m/min. These are the machines around. Although row nozzle and wave nozzle systems have been considered, they have not gained commercial importance.
