- denim fabric
Posted by %PM, 10% 467% 2023 13%:%January in Weaving Read 613 times
Denim fabric was first produced in France and Italy in the 19th century for the use of workers. It got its name from the south of France where it first touched. De Nimes from the city.
Later, when the United States of America made this product first a workwear and then a cultural item, it was adopted by the masses and became an important fashion product by gaining its real reputation. Denim has started to reflect a clothing philosophy on its own. There is no other type of clothing in the world that is accepted by people of all nations and age groups. The yarn used in denim fabric production has a very important place in terms of wide product range and meeting the expected quality.
The most important feature of denim is that it is a tough and durable fabric obtained by frequent weaving with high twisted strong threads. In the classical sense, a denim fabric warp is dyed with indigo dyestuff, the weft is undyed (ecru) and produced using cotton fibers 2/1 Z (2 top 1 bottom or 2 full 1 empty right-handed) or 3/1 Z (3 upper 1 lower or It is produced in a 3 full empty right-handed twill weaving construction with warp density. It is a fabric structure with low rubbing fastness, which is dominated by the color of the warp thread in the appearance of the fabric, because the warp threads are dense on the surface of the fabric, both in terms of texture and density.
Denim fabrics, whose general features can be listed in this way, have started to come out of the framework of known production methods or conventional dye chemical application processes, thanks to the developing and growing fashion trend and innovative processes. They can now be produced not only from cotton fibers, but also with many different synthetic fiber blends. In addition, dyeing the wefts with various dyestuffs besides the warps completely changes the general appearance of the classic denim fabric. It is possible to multiply the examples that can be given in this way. This shows that denim fabrics also change their physical properties and go beyond the known denim fabric draft.
In denim fabric production, the yarns produced by one of the various spinning systems to be used to form the weft of the fabric are sent directly to the weaving preparation room, and the warp yarns are sent to the warp dyeing department to form the warp. Threads to be used as warp threads in denim fabric production are dyed with indigo dyestuffs, which give denim its characteristic feature, unlike weft threads. Warp threads used in denim fabric production today can be dyed not only with indigo dyestuff, but also combined with sulfur and some cube dyestuffs. It can be in the form of "top" and "bottom" painting, which comes from the words "top" and "bottom" in English. For example, it can be in the form of bottom sulfur-top indigo, that is, indigo on sulfur first, or bottom indigo-top sulfur, that is, sulfur dyeing on indigo at the bottom. Today, warp dyeing can be performed in two different forms with three different techniques. In the open width dyeing and loop dyeing methods, the warp threads are dyed wrapped around the warp beam, while in the rope dyeing method, the dyeing process takes place after the thread bobbins are transferred to the rope winding machine and the rope form is given.
Rope Dyeing Method
In the rope dyeing technique, 300-400 warp threads are drawn from the creel and wound in the form of ropes in lengths of 10.000 - 15.000 m with the help of rope winding machines.
This process is the first step of the rope dyeing method. Then, 12-36 of these ropes are exposed to 5 or even 6 passages of indigo dye in sequence. each passage; It consists of the immersion part where the material can take the dyestuff while passing, followed by the squeezing process and then the air passage to ensure the oxidation of the dyestuff. The warp yarns absorb most of the indigo dyestuff that they can take in the first dye bath. In subsequent dye baths, only a small amount of dyestuff penetrates the yarn. Darker colors can be obtained by increasing the number of boats and the concentration in the boats. The oxidation time is usually 1 minute. If it is taken below 1 minute, the dyestuff cannot be oxidized, if the oxidation time is kept long, the color may be very dark. After the last air passage, dyestuff and chemical residues are washed in washing trays. Neutralization with citric acid and then drying is done in the last vessel. After the rope winding and rope dyeing processes, the warp yarns are prepared for sizing. The sizing process is done after it is brought from the rope form to a single warp beam form. For this reason, the ropes prepared before the sizing process come to the rope opening section to be wound on the warp beam. Rope ends are placed exactly on the combs in front of the machine with a system called cross. The ropes in the buckets are passed through the rollers at a certain distance from the machine. The purpose of this process is to ensure the parallelism of the yarns that have passed through too many rollers and mixed with each other in the dyeing process. In the rope opening section, broken and missing ends are completed and a smooth warp beam is prepared. The indigo dyeing technique, which has the highest dyeing quality, is expressed as the rope dyeing technique.
Open Width Painting Method
In this dyeing method, beams coming from serial warping are first dyed and then sized in a machine called "slasher". Slasher machine is an alternative machine to rope dyeing, which aims to minimize the number of processes to be applied for the denim dyeing process, in which the warp threads wound on the beams in the serial warp machine are dyed and sized. In this system, 350-400 threads of 50.000 m length are wound on the warp beams and 12-16 of these warp beams are placed in front of the line. Then, all of the yarns in the warp beams are subjected to dyeing, drying, sizing and re-drying processes, respectively. All these process steps are carried out on the same machine line and the process is completed by wrapping all the warp threads on a single warp beam at the end. Since the dyeing process is not in the form of a rope, the warp yarns are made ready for weaving in a single operation by wrapping the warp yarns on the weaving beam by sizing in the last part of the machine, without the need for rope winding and unwinding processes.
Loop Painting Method
This dyeing method is also carried out in an open width form. Open-width warp threads are held by the inlet roller and transferred to the prewash bath. After the prewash, the yarns proceed to the dyeing trough. After the yarns reaching the dyeing vat are treated with indigo, they reach the warp beams over the indigo trough instead of the afterwash trough. Just after this part, it passes under the beams and reaches the indigo dyeing trough again. The dyeing method is called loop dyeing because this path it has covered reminds of a loop. In this dyeing, there is a single bath instead of many dye baths. The desired color is to dip the threads 4-10 times into the impregnation vessel called "Twin Pad" in this technique and oxidize with air while passing under the beams after each boat dive. However, since it is a single boat, it is not possible to dye the yarn with a wide variety of dyestuffs. Therefore, it is not a very flexible method. After the yarns are sufficiently dyed, they are wrapped in warp beams after being subjected to post-washing and drying processes. Then sizing is carried out.
With the methods mentioned above, the warp threads are made ready for weaving and the weaving process is started. Denim fabrics can be produced in hook, shuttle and air jet weaving machines. Generally, warp density twill textures such as 2/1 or 3/1 Z weaving construction are preferred. The weight of denim fabrics is usually us is expressed as. 1 ounce is 28,35 g. In this case, the equivalent of 1 oz/yd2 is approximately 33,91 g/m2. They are produced in sufficient density and weight with the necessary yarns in accordance with the area where the fabrics will be used (shirts, skirts, trousers, jackets, men's/women's clothing or summer/winter etc.). Since it is a type of fabric with a tight structure, the preferred weaving machines should be suitable for heavy working conditions.
Finishing Processes in Denim Fabric Production
Some finishing processes are applied to make the raw fabrics ready for sale. A classic denim fabric finishing is no different from any woven fabric finishing. Respectively brushing, burning, washing, finishing, drying and sanforization are processed. In the brushing process, the fabric passes between the cylindrical brushes. Meanwhile, dust, fly, foreign matter and threads on the fabric are cleaned by suction with air suction. Then, the hairs on the fabric surface, which are lifted into the air after brushing, are quickly passed under the flame used in the burning machine, and the fibers on the surface are removed. Thus, the pre-treatment processes that give the denim fabric a smooth and shiny appearance are completed.
The fabric is washed in this process by passing it through a water trough. After the incineration process, pre-treatment processes such as mercerization and bleaching can optionally be continued. Then, the fabrics are taken to stenters with a finishing trough in front of them. In the stenter machine, firstly, the fabrics are processed in the finishing vat according to the desired properties. softness, fullness, waterproofing, resin coating etc. substances that provide properties can be given. After removing the excess finishing on the fabric with the printing rollers, the curvatures in the fabric wefts are corrected with the mahlo device at the entrance of the stenter machine by the right-to-left movements of the tension rollers. When the denim fabric is sewn, the weft slope is adjusted in this way so that the legs of the jeans do not turn after washing. Since the fabric texture is in twill, this process is an important process and if the slope is not given properly, a trotting error may occur. mahlo After the assembly, the fabric comes to the section where the drying drums of the machine are located. During drying, steam is given out from inside the drum cylinder. This given steam passes through the fabric. The purpose here is to adjust the desired moisture content in the fabric. If the fabric is transported by the needle chain system at the machine entrance, the longitudinal shrinkage can also be positively affected by giving an advance, that is, pre-feeding.
The stenter is an important finishing machine in which the fabrics are both dried and provided with aspect-length dimensional stability. After the stenter machine, the fabrics are made to be non-shrinkable. to the sanforization process is taken. In the sanforizing machine, the tension that will be suffered in the next stages due to the tensions and fiber properties in the fabric is taken to the maximum. In this way, the fabric is put into the size it will take after many washings. In fact, in the sanforizing process, weft yarns are brought closer together by mechanical means. At the entrance of the machine, the fabric is passed through the opening roller to prevent folded and wrinkled entry into the machine. According to the quality of the fabric, water or steam is sprayed to moisten the fabric, soften the cracks and shrink from the width. With the help of the leg rotation adjustment cylinder, the desired leg rotation is given to the fabric and the weft slopes are corrected. The fabric is passed over the surface between the heated steel roller and the rubber band, and at a certain temperature and pressure, shrinkage is given in the warp direction. Then, the fabric is dried with the help of a felted roller, the ironing effect is applied to the fabric and the given shrinkage is stabilized. After the felt, the fabric passes through the cooling drums and is wrapped in the dock.
Finishing Processes Applied to the Finished Denim Fabric Today, the use of finished fabrics in this form is very low. Only when a durable and hard fabric such as workwear is desired, they can be converted into clothing in this way. In order to make denim products different and to remove the hard attitude on the fabric, they started to undergo dry and wet finishing processes after the garments and sewing processes were completed and turned into clothes or as finished fabrics.
While the dry-applied finishing processes are various abrasion methods applied by mechanical means, the wet-applied finishing processes are the processes that are applied using various chemicals and give different effects. Dry applied processes; scraping, sandblasting, manual damage, tagging, laser burning (laser), resin (resin), ironing-creases and flat press), printing (print) can be sorted.
Processes applied as age; desizing – pre-washing (desizing), grinding (stonewash), enzyme wash (enzyme wash), bleaching (bleaching), dyeing (tinting – overdyeing), softening (softening), rinsing (rinse), washing with plastic balls (rubber balls) can be sorted.
It is possible to multiply the given examples. These processes can also be used in combination.
Enzyme and stone washing processes, which are widely used in these processes, come to the fore. Before processes such as enzyme and stone washing, the sizing agents that form a slippery film layer on the warp threads must be removed. Sizing agents, which contribute to strength while reducing friction, increase efficiency in weaving. However, the film layer formed can cause problems in terms of washing processes. Therefore, it must be removed. The process, which takes about 20 minutes, is a process that does not discolor the fabric itself, using wetting-based or softening chemicals. The structure of the sizing material used determines how the process will be applied. Generally, when using water-soluble sizing agent, it is washed by adding wetting agent. For water-insoluble sizing agents, the sizing is first rendered water-soluble by enzymes.
Stonewashing is the process of dyeing fabrics in an aqueous medium by utilizing the low rubbing fastness of indigo dyestuff. pumice stone It is processed in industrial washing machines for periods ranging from 30 minutes to 1,5 hours with natural stones called natural stones. Denim products are washed with pumice stones until the desired color is obtained. Pumice stone has an abrasive effect on the fabric and prevents the paint from sticking to the fabric again. At the end of this washing, the fabric gets old and used air. In addition, the effects gained are particularly effective on puckers and seams. With grinding, the handle of denim products becomes softer. While the colors of denim products change with the processing time, the color becomes lighter as the time increases. However, the use of stone; This can cause problems such as excessive wear of the machines, blockages in the drainage lines, excessive wear of the washed products and the appearance of broken traces, the need for new areas for the storage of stones, the need for a lot of labor to clean the waste water and remove the dust from the finished pants.
The enzymes most commonly used in denim washing are amylase, lactase and cellulase enzymes. While amylase enzymes are used for desizing, laccase and cellulase enzymes are used instead of pumice stone to lighten the color of denim fabrics and give them a different look. However, cellulase enzymes are mostly used because of the back-staining problems of laccase enzymes. In fact, most of the enzymatic treatments with cellulase are used to remove heavy chemicals from cellulosic fibers or to achieve new finishing effects. There are two types of cellulase enzymes on the market. These are acidic cellulase and neutral cellulase. Biopolishing is carried out with acidic cellulases to remove the fiber ends protruding from the fabric surface. Effects on the surface of the product after the biopolishing process; reduction in pilling tendency, minimum hairiness on the product surface, a soft handle and drape.
Neutral cellulase enzymes are used to give denim products a surface effect and a new finishing effect. Neutral enzymes are preferred because of less back dyeing and less strength loss in the denim industry. Since it is more sensitive to pH, a safer washing is achieved. Since acidic cellulases are more aggressive, they negatively affect tear strength. The purpose of enzyme washing is to obtain clothes with the desired color effect but with less wear. Thus, the life of the denim product can be longer than washing with stones. With the enzyme washing method, the amount of pumice stone used in denim grinding, which has a long history, has decreased. Today, there are three ways to achieve the grinding effect. The first classical way is washing with pumice stones. The second is washing with neutral cellulase enzymes only. The third is the washing method in which pumice stone and enzymes are used together.. Achieving the desired etching effect; It can be done by adjusting the machine type, liquor ratio, fabric amount, stone amount and enzyme amount. Processing time can be reduced by using more cellulase enzymes
- Using hand tools
Posted by %AM, 08% 346% 2022 10%:%Dec in Weaving Read 350 times
SAFE AND CORRECT HAND TOOL USE RULES
1-Make sure that the size of the wrench corresponds with the size of the nut/bolt.
2-Do not use screwdrivers instead of chisels or crowbars.
3-Make sure that the size and type of the screwdriver and the size and type of the screw match each other.
4-Use the control pen as intended, do not use it as a general purpose screwdriver.
5-Do not use products such as pliers-side chisels-T Allen as a hammer, and do not hit the handle and jaw parts.
6-Do not cut hard steel wires with pliers or thin scissors.
7-Do not use the hammer on materials harder than its own hardness and do not work with the corner parts of the hammer.
8-Do not attach an extension arm to any hand tool to gain more force.
9- Pay attention to the direction of rotation of the wrench, especially in wrenches and pipe wrenches. In such products, the movable jaw should not be loaded.
10-Do not use pipe wrenches with worn threads.
11-Use a pipe wrench suitable for the diameter of the material.
12-Do not use socket wrenches with air gun. Prefer sockets specially produced for air guns.
13-Be careful not to wear out the ends of the ring collets.
14-Use hand tools for their intended purpose.
15-Do not apply chemical processes, sharpening and welding processes to hand tools. Do not modify the shape of the instruments.
16-Do not use worn and faulty hand tools.
17- When moving the wheeled repair cabinets from one place to another, make sure that the drawers are closed and that the cabinet is locked.
18- During operation, make sure that all the drawers of the wheeled repair cabinets are not open at the same time. Otherwise, the balance distribution of the cabinet will be disturbed and it may be overturned.
19-After using hand tools, make sure to keep them clean and well maintained.
20- Be sure to use personal protection equipment suitable for your working conditions.
REQUIREMENTS FOR USING HAND TOOLS
1. Make sure that the hand tool you will use is suitable for the work you are going to do.
2. Hand tools; If it has a stem, make sure it is from a knotless tree, with rounded edges, without splinters, straight, and of the appropriate size.
3. If the handles of the hand tools are loose, tighten them before use.
4. Use the appropriate wrench for tightening or loosening the nut. Do not use pliers or similar tools.
5. Do not extend normal lever wrenches by threading tubing or the like.
6. Do not use keys as hammers.
7. Secure the work being worked on to the table.
8. Do not carry hand tools in pockets, use a tool bag.
9. Do not apply excessive pressure or force to any tool.
10. When working with hand tools, use protective materials such as glasses, apron and gloves when necessary.
11. Be careful not to get your fingers, hands or clothes caught when using portable tools whose cutting edge rotates at high speed.
12. Do not leave tools without taking necessary precautions against falls from overhead.
13. Follow special instructions when using electric, hydraulic, pneumatic and all other hand tools.
14. Keep hand tools such as axes, cutters, and cleavers always sharp, make sure that their handles are inserted into the tool tightly and securely, and keep them in suitable sheaths, hangers and guards in case of wear.
15. In the case of pens, chisels (handled chisels), punches and similar tools, pencil tips, chisel blades and punch noses will always be sharp and appropriate for the job to be done, and have suitable shields, screens or similar guards when using them.
16. When you are not using levers and similar tools, do not leave them on the floor or on the bench and leave them upright, leave them lying down.
17. Files and rasps should have sturdy handles with metal collars or some other kind of handle. Do not use these tools without a handle.
18. Do not use files and rasps for chest opening, removing nails or hitting a hard object, do not hit them with hammers or similar tools, do not make tools such as chisels, pencils and staples from old files.
19. On the handles of the knives, if necessary, make hilt guards made of fiber, leather or stainless steel, put finger grips or shields.
20. Round the ends of the blades used for cutting rubber properly. 21. Place the jacks firmly and upright on the ground while the load is being lifted. After the loads are lifted to the desired height, do not work under or above these loads unless the jacks are fed with durable and suitable wedges and take the necessary precautions for lowering the loads with a jack.
22. When cutting taut wire, springs, and similar wires with pliers, wire shears and grippers, properly locate one of the cut ends of the wire.
23. Hand tools to be used in places where sparks will be dangerous should be made of materials that will not cause sparks. Do not use non-qualified tools in these locations.
24. Hammers, sledgehammers, pencils, chisels, staples and similar tools should be made of high quality steel in accordance with the standards. Correct their broken or burr head by grinding or filing.
25. Quenching or sharpening of hand tools, printing and repair work should be done by qualified workers. Properly protect their pointed or sharp ends when not in use.
26. Do not keep hand tools in the middle of floors, stairs, passages or any place where workers can use them as passages, and make suitable cabinets, hanging tables or shelves with skirts at least 2 centimeters high.
Posted by %PM, 13% 812% 2022 21%:%Nov in Weaving Read 722 times
Upholstery fabricsAs in all product groups in the textile sector, it has changed and developed over time depending on customer requests/demands and fashion trends.
For this reason, the use of fancy yarns has become widespread over time and chenille yarns have had an important share in the production of upholstery fabrics due to many different reasons such as having a velvet-like appearance when woven and being produced economically.
Upholstery fabrics; Considering the place of use, they are textile products with low draping, more thickness compared to other textile products, higher weight and high fastness values.
As with all textile products, upholstery fabrics are expected to preserve their initial state as much as possible against the external effects it is exposed to. Because; It is desired that upholstery fabrics have high abrasion resistance and accordingly, no color changes in the washed or wiped parts (having high friction fastness value).
In addition to all these, since upholstery fabrics are used in the furniture industry, they are required to have a low cast, that is, a full handle, as they need to be easily shaped and retain their form.
Upholstery fabrics are widely used in the furniture and automotive industry.
In addition to its high wear resistance, of upholstery fabrics It is desired that it has a high staining resistance and an easy-care feature. During the use of upholstery fabrics, staining is usually caused by water. For this reason, staining resistance is increased by fabric production using hydrophobic fibers in upholstery fabrics and by creating hydrophobic surfaces with different finishing techniques (water, dirt, oil repellent finishes).
It is desired that the fabrics used in the upholstery industry have high abrasion resistance. One of the factors affecting the abrasion resistance of fabrics is the property of the yarn used in production.
Upholstery fabrics should be woven in a certain warp and weft density, taking into account the weaving limit. Since low weft and warp density will adversely affect the sewing shear strength of the fabric, the weft and warp density values should be high in upholstery fabrics, which is related to yarn count, type, yarn twist, etc.
Upholstery fabrics are classified in 11818 groups in the standard TS 14465 EN 7;
1- Plain Textured Fabric: The fabrics produced in different patterns by the different movements of the frames in the weaving machines with the weft and warp threads intersecting with each other at an angle of 90° are called plain textured fabrics.
2-Knitted Fabric: It is obtained by connecting the yarns fed from the creel with the help of circular or flat knitting machines, forming a loop structure.
3-Full Fabric: In addition to the weft and warp ground yarns in the plain textured fabric, the fabrics that contain a third yarn called pile yarn are called pile fabric. Pile fabrics can be produced in special 3-thread weaving machines, as well as in classical weaving machines with yarns that have pile structure in the yarn structure, such as chenille yarn.
4-Non-Woven Fabric: Textile surfaces produced by binding together the fibers that are too short and thin to be included in the yarn structure with known yarn production methods, by mechanical, thermal or chemical methods are called nonwoven fabric/surface.
5-Tufting Fabric: They are textile products created by giving a pile surface with the help of a needle to the surface fed in the form of cheesecloth. The appearance of tufted surfaces is likened to grass. Tufted fabrics are divided into two as velor and loop surface.
6-Flocked Fabric: The textile surfaces created using flocked yarn weaving or knitting technique are called flocked fabrics. It is known that the abrasion resistance properties of flock yarns are better than the abrasion resistance properties of chenille yarn. Textile surfaces created with flocked yarn are widely used in automotive and seat upholstery.
7- Raised Fabric: Raised fabrics are textile surfaces obtained by subjecting the raising process, which is the mechanical finishing process of flat woven textile products. With the raising process, a pile layer is formed by pulling the fibers onto the fabric surface. The raising process; It occurs when the fabric comes into contact with the rotating layer with the needles on a cylinder and the needles bring the fibers in the fabric structure to the fabric surface.
Upholstery fabrics; It is produced in classical and modern weaving machines and velvet weaving machines. Velvet fabrics are produced with 2 yarns, different from the classical 3-thread weaving. Two of these yarns are weft and warp yarns, as in classical weaving, and the third yarn is the pile yarn that forms the pile structure of the velvet fabric.
Velvet fabrics; It can be classified under two main headings in terms of production technique: weft velvets, which are formed by connecting the pile yarn with the fabric in the direction of the weft yarn, and warp velvets, which are formed by connecting the pile yarn with the fabric in the warp direction.
Velvet fabrics are also produced using jacquard velvet weaving machines and different colored pile yarns.
Upholstery fabrics produced from chenille yarn; Chenille yarn is called false velvet because of its appearance resulting from its pile structure..
Upholstery fabrics produced from chenille yarn, instead of using an extra pile yarn as in velvet fabrics; It is produced by incorporating chenille yarn, which is used as weft yarn, into the fabric structure. Since the use of chenille yarn as a warp yarn is not suitable, pile yarns cannot be placed in the warp direction, as in velvet fabric. The most preferred weaving machines for weaving chenille yarns; They are machines with shuttles and hooks. The most preferred of these two machine types is hook weaving machines. Weaving of chenille yarns is done with an auxiliary weft yarn. The raw material of chenille yarns, which is generally preferred in the upholstery sector; cotton, polyester, acrylic, viscose, polypropylene and mixtures of these raw materials.
- Herringbone Twill Weave
Posted by %PM, 17% 557% 2022 15%:%Feb in Pattern Read 1000 times
Herringbone twill weaves are twill weaves in which the twill diagonal changes direction after half of the weave pattern is drawn as NULL opposite FULL and FULL opposite NULL. Herringbone weaves are used in weaving fabrics for jackets, skirts, overcoats, suits and overcoats. Herringbone Twill Weaves; There are two types of herringbone Twill Weaves in the Warp Direction and Herringbone Twill Weaves in the Weft Direction.
Herringbone weave in the warp direction;
In the herringbone twill weave drawing in the warp direction, the main weave is drawn. After the last warp, EMPTY is written against FILES in the last warp, FULL is written against EMPTY. In the WARP DIRECTION, if the twill weave, which is the basis of the FISH-back Twill weave, is RIGHT, the second part is drawn LEFT. In herringbone twill weaves in the warp direction, the WARP WIRE NUMBER in the report is twice the base weave. In herringbone twill weaves in the warp direction, the NUMBER OF WEFT WIRE in the report; It is as much as the number of wefts in the twill knitting pattern.
Herringbone weave in weft direction
In the drawing of herringbone twill weave in the weft direction, the main weave is drawn. After the last weft, EMPTY is written opposite the FULL ones in the last weft, and FULL is written against the EMPTY. In the WEFT DIRECTION, if the Twill weave, which forms the basis of the HERRINGBONE TWILY, is RIGHT, the second part is drawn LEFT. In herringbone twill weaves in the WEFT direction, the NUMBER OF WEFT WIRE in the report is twice the base weave. NUMBER OF WARP WIRES in the report in herringbone twill weaves in the WEFT direction; It is equal to the number of warps in the twill weave pattern. Well; If the pattern of the TWILY KNITTING, which is the basis of the HERRINGBREAK TWILN weaving in the WEFT direction, consists of 4 WARP AND 4 WEFT yarns; Knitting pattern of HERBIRTI TWILL weave in the WEFT direction; It consists of 4 warp and 8 weft threads.
- Machine Drafting
Posted by %PM, 08% 661% 2022 17%:%Feb in Weaving Read 811 times
Carding machines are machines that can draw in lamellas, forces and card at the same time.
Strength section: The process of passing the warp threads in the warp beam on the weaving loom or in a separate place from the strengths in accordance with the drawing-in report is called drawing-in.
This process is not done for fabric types whose draw-in pattern will not change, because the yarns of the other warp are tied one by one before the warp ends. If the drawing-in report is to be changed, the warp threads are usually drawn in a separate place on the weaving loom. The important thing here is to do the drawing in very carefully by adhering to the order specified in the drawing plan. Otherwise, since a row skip will disrupt the knitting structure, it will cause fabric defect, which is very difficult to compensate. The aim of drawing-in in weaving circles is to pass the warp threads through the strengths one by one according to the drawing-in plan. This process is done according to the drawing-in plan according to the weave of the fabric to be woven.
Powers are grouped in two magazine paths. After the powers are transferred onto the conveyor belt, the separation device separates the powers one by one. This then brings the forces into the starting position. Before drawing in, the comb and its strength are centered by optical centering. Developed forces are taken to the desired strength frame or power bearing bar, depending on the situation. The thrusters push the forces towards the frame or the power rods according to the drive report.
Yarn section: The yarns are separated from the warp layer stretched on the frame one by one using a separation unit and presented to the drawing-in hook. This hook returns after taking the yarn through the comb, the power and the lamella eye. After drawing-in through the lamella, power and comb, the yarn is released from the hook and held by the absorbent nozzle, the yarn sensor checks whether the yarn is drawn in correctly.
Lamel section: After the warp is attached to the weaving machine, lamellar stringing is performed in order to control the ends of the warp threads one by one during the weaving process. Lamellar is a wire or metal narrow and short warp element that is hung on each warp wire during warp preparation or weaving. The warp tension must be well adjusted in order for the lamella assembly to function well. Lamels have open or closed types. Closed lamellas are mostly used in warps drawn with automatic drawing-in machine. The open lamellas are stacked after they are placed on the warp weaving machine. The lamellae are arranged side by side in 4-12 rows. 4–6–8 row lamellas are the most commonly used in businesses. The ordinal numbers above this are used in silk weaving. If a warp thread breaks, the lamella attached to it falls down onto the lamella bars and stops the machine. When the lamellas fall down, they prevent the movement of the bars, also called lamella saws, and cause the machine to stop. Automatic lamella setting machines are generally used after warp drawing-in, that is, for open lamellas. There is a condition that the warp must be taken 1 to 1 diagonally. There are batteries that can be easily changed according to various lamella widths.
When the lamella is missing or the thread is not separated, the machine stops automatically and the signal lamp indicates the error. These machines can lay lamella on 8000 threads per hour. The coverslip group is prepared in the coverslip magazine. The coverslip separator separates the coverslips which are then held by the coverslip turner and brought into the drawing position. After the yarns are drawn, the lamellas are taken to the lamella slides. The desired lamella is pushed into the saw and lined up.
Reed section: Removal from the card is made according to the signs showing how many warp threads will pass through a tooth specified in the drawing-in report. The card is mounted on the card transport unit, which transports the card during carding. Optical comb monitoring and control controls the carding in accordance with the card thickness and the desired number of teeth. The comb blade enters between the teeth, opening the teeth quite wide, thus allowing the drawing hook and thread to pass unhindered.
It is the process of passing the warp threads passed through the reed teeth in the numbers specified in the drawing plan. The number of warp threads passed through each reed tooth depends on the width of the fabric and the warp density. The number of threads that will pass through the reed tooth and the reed number, that is, the tooth density in the reed, are selected depending on the warp density. This process is done by a single person with a small crochet-like tool, as well as in automatic or semi-automatic drawing-in machines.
Control cabinet: This cabinet houses the electrical control of the system and the central power supply that provides all the voltage necessary for operation. The control system, which has a hierarchical structure, communicates with motors and progressive digitizers through processor modules. It also communicates with solenoid valves and sensors through distribution circuits.
Operator console: The drawing-in machine is controlled and programmed with a keyboard located on the operator console. The screen shows the requested information in the language of that country in text and partly in graphic form. The status of the machine and the stages of the drawing-in process can be seen at any time. Programming the drawing report and its parameters is also performed on the operator console. The operator console also provides statistical data on machine operation and maintenance information. If necessary, the machine can be stopped immediately with the emergency stop button. There is a host computer and a floppy drive located under the console's cover.
Classic cardboard drawing-in machines are also used in enterprises as drawing-in machines. For this type of drawing-in machines, there are dobby cardboards used in shedding systems in weaving machines. The task of these cardboards is to determine which frame will have the warp thread on the drawing-in machine by processing the knitting of the fabric to be woven on the endless cardboard.
The drawing-in cardboard to be prepared according to the weave of the fabric to be woven is mounted in the cardboard slot of the mechanical drawing-in machine. With the action taken in line with this report, the force passed through the warp thread is added to the appropriate frame with the help of needles. There is no computer-aided work in the drawing-in process to be performed on mechanical drawing-in machines. Generally, the majority of transactions are carried out by working personnel. The mechanical nature of the drawing-in machine causes a loss of time compared to modern drawing-in machines.
Drawing in a Drawing Machine
Modern drawing-in machines are manufactured in such a way that they can draw in lamellas, forces and card at the same time. The warp remains in the drawing-in carriage throughout the drawing-in process. It is fixed from above and below with the help of clamps. After the process is completed, the drawing-in car is driven into the workbench and connected to the drawing-in machine. There is an electronic screen on the machine where all processes are followed during the drawing-in process. As a normal drawing-in principle in the machine, a warp wire is passed through each power eye. However, if a different number of warp wires will be passed through the power eye on the edges, this instruction must be entered into the machine by the worker.
A flexible awl is used for the process of passing the lamellar and strength eyes of the warps. Yarns, lamellas and power are taken by the holders one by one, they are made ready for the process and their drawing is done. The drawing plans can be given to the machine electronically by transfer diskettes or by the central transfer network. This information is scheduled and maintained by the control terminal. After the drawing-in process is completed, the drawing-in machine leaves the system and the warps remain in the drawing-in car to be placed on the weaving machine.
After the drawing-in process is completed, the warp beam, frames, reed and lamellas are transported by the drawing-in car and placed in the weaving machine. This system can also be used for disassembly and transportation of weaving machines.
Points to be Considered During the Operation of the Drawing Machine
Undesirable errors may occur due to various reasons during the drawing process. These are the errors such as cross error, lamellar misalignment skipping error, drawing-in error, card-in-drawn error and comb scar. These errors are generally encountered in the manual drawing-in process. Considering these errors in the drawing-in process with the machine, it will be ensured that quality products can be produced as a result of more precise work. In mechanical drawing-in machines, it is imperative that the drawing-in element constantly monitors the power of the drawing-in and the card drawing-in process and solves the errors instantly. The main controls to be made on the fully automatic drawing-in machine are listed below:
1- Buttonhole perception adjustment control,
2-Control of the lamellas,
4-Control of the drawing needle
5-Control of the weaving reed,
6-Warp ends draft control,
7-Report repeat control