What is Fiber Fusion?

Fiber Fusion is 2 days of fiber, education and fun!  Whether you are new to the world of natural fibers or are an experienced fiber aficionado – Fiber Fusion has something for you!

There will be fabulous fleeces – alpaca, wool, mohair, llama and angora – at our fleece shows and sales, as well as free demonstrations throughout the weekend, a wide variety of classes, over 60 fiber-related vendors, a live fiber animal exhibit, a fiber arts contest, people’s choice photo contest, a spin-in and much more!

Carbon Fiber | Characteristics/Properties of Carbon Fibers | Classification of Carbon Fiber | Application/Uses of Carbon Fibers

Carbon Fiber:

 

Weave of Carbon fiber

Carbon fiber is a high-tensile fiber or whisker made by heating rayon or polyacrylonitrile fibers or petroleum residues to appropriate temperatures. Fibers may be 7 to 8 microns in diameter and are more that 90% carbonized.This fibers are the stiffest and strongest reinforcing fibers for polymer composites, the most used after glass fibers. Made of pure carbon in form of graphite, they have low density and a negative coefficient of longitudinal thermal expansion.
Carbon fibers are very expensive and can give galvanic corrosion in contact with metals. They are generally used together with epoxy, where high strength and stiffness are required, i.e. race cars, automotive and space applications, sport equipment.

Depending on the orientation of the fiber, the carbon fiber composite can be stronger in a certain direction or equally strong in all directions. A small piece can withstand an impact of many tons and still deform minimally. The complex interwoven nature of the fiber makes it very difficult to break.

Characteristics/Properties of Carbon Fibers 

1. Physical strength, specific toughness, light weight.
2. Good vibration damping, strength, and toughness.
3. High dimensional stability, low coefficient of thermal expansion, and low abrasion.
4. Electrical conductivity.
5. Biological inertness and x-ray permeability.
6. Fatigue resistance, self-lubrication, high damping.
7. Electromagnetic properties.
8. Chemical inertness, high corrosion resistance.

Classification of Carbon Fiber:
Based on modulus, strength, and final heat treatment temperature, carbon fibers can be classified into the following categories:

1. Based on carbon fiber properties,
2. Based on precursor fiber materials,
3. Based on final heat treatment temperature,

1. Based on carbon fiber properties, carbon fibers can be grouped into:

• Ultra-high-modulus, type UHM (modulus >450Gpa)
• High-modulus, type HM (modulus between 350-450Gpa)
• Intermediate-modulus, type IM (modulus between 200-350Gpa)
• Low modulus and high-tensile, type HT (modulus 3.0Gpa)
• Super high-tensile, type SHT (tensile strength > 4.5Gpa)

2. Based on precursor fiber materials, carbon fibers are classified into:

• PAN-based carbon fibers
• Pitch-based carbon fibers
• Mesophase pitch-based carbon fibers
• Isotropic pitch-based carbon fibers
• Rayon-based carbon fibers
• Gas-phase-grown carbon fibers

3. Based on final heat treatment temperature, carbon fibers are classified into: 

• High-heat-treatment carbon fibers (HTT), where final heat treatment temperature should be above 2000°C and can be associated with high-modulus type fiber.
• Intermediate-heat-treatment carbon fibers (IHT), where final heat treatment temperature should be around or above 1500°C and can be associated with high-strength type fiber.
• Low-heat-treatment carbon fibers, where final heat treatment temperatures not greater than 1000°C. These are low modulus and low strength materials.

Application/Uses of Carbon Fiber
The two main applications of carbon fibers are in specialized technology, which includes aerospace and nuclear engineering, and in general engineering and transportation, which includes engineering components such as bearings, gears, cams, fan blades and automobile bodies. Recently, some new applications of carbon fibers have been found. Such as rehabilitation of a bridge in building and construction industry. Others include: decoration in automotive, marine, general aviation interiors, general entertainment and musical instruments and after-market transportation products. Conductivity in electronics technology provides additional new application.

Application Carbon Fiber are given as Shortly:

• Aerospace, road and marine transport, sporting goods.
• Missiles, aircraft brakes, aerospace antenna and support structure, large telescopes, optical benches, waveguides for stable high-frequency (GHz) precision measurement frames.
• Audio equipment, loudspeakers for Hi-fi equipment, pickup arms, robot arms.
• Automobile hoods, novel tooling, casings and bases for electronic equipments, EMI and RF shielding, brushes.
• Medical applications in prostheses, surgery and x-ray equipment, implants, tendon/ligament repair.
• Textile machinery, genera engineering.
• Chemical industry; nuclear field; valves, seals, and pump components in process plants.
• Large generator retaining rings, radiological equipment.

Carbon fibre is sometimes used in conjunction with fiberglass because of their similar manufacturing processes, an example of this would be the Corvette ZO6 where the front end is carbon fibre and the rear is fibreglass. Carbon fiber is however, far stronger and lighter than fiberglass.

Carbon fibre can be found in a wide range of performance vehicles including sports cars, superbikes, pedal bikes (where they are used to make frames), powerboats and it is often used in the tuning and customising industry where attractive woven panels are left unpainted to ‘show off’ the material.

Preparation of weaving machines

To obtain satisfactory weaving performance, it is essential to have not only a correct yarn preparation, but also an efficient organization which permits to have warps available at the right moment, thus avoiding any dead time with style or beam change. All these prerequisites aim at ensuring to the weaving mills a sufficient flexibility and at permitting them to cope promptly with a variable market demand.

Currently several weaving mills have installed weaving machines which enable to perform the quick style change (QSC), leading to a considerable reduction of the waiting time of the machine.

The following chart presents the possible alternatives for the preparation of the weaving machine:

Changing style means producing a new fabric style, weaver’s beam changing means going on weaving the same fabric style just replacing the empty beam with a full beam of same type. Drawing-in consists of threading the warp yarns through the drop wires, the healds and the reed (fig.1). Depending on the styles of the produced fabrics and on the company’s size, this operation can be carried out manually, by drawing-in female workers operating in pairs (a time consuming activity which requires also skill and care), or by using automatic drawing-in machines.

Fig. 1− Drawing-in:

Fig. 2 shows one of the most established heald drawing-in machines. The drawing-in begins by placing the weaver’s beam, the harness and the row of healds on the proper anchor brackets, then the drawing-in program is typed in on the computer and the machine is started. A sort of long needle picks up in sequence the threads and inserts them with only one movement into the drop wires, the healds and the reed dents, which are selected each time and lined up to that purpose. The computer controls the different functions and supervises them electronically, ensuring the exact execution of the operation and interrupting it in case of defects. The machine can be used with the usual types of healds, drop wires and reeds and can process a wide range of yarn types and counts, from silk yarns to coarse glass fibre yarns. The drawing-in speed can in optimum conditions exceed 6,000 threads/hour.

Fig 2.: Heddle drawing-in machine:

Fig. 30 presents another automatic drawing-in machine which carries out same functions as previous machine, however without needing the weaver’s beam. In fact it is fed by a common cotton twine which it inserts among the various elements of the warp stop motion, of the harness and of the reed according to the program set up on the computer and under its control and supervision. At the end of the drawing-in, the drawn-in devices are moved on the frame of a knotting station in which an automatic warp tying-in machine joins the drawing-in threads together with the threads of the beam. This operation can be made also on board the loom.

Fig 3:– Automatic drawing-in machine (Staubli KK / Korea Branch):

This machine offers the advantage of working always under optimum operating conditions (use of same yarn), independently of the quality of the warp to be prepared and in advance in respect to warping, therefore with higher flexibility. The drawing-in rate can reach 3600 threads/hour. Fig.4  shows a harness and a reed with already drawn-in threads, ready to be brought to the knotting station.

Fig. 4:–  A harness and a reed with drawn-in threads ready to be moved to the knotting station:

The piecing-up of the warp yarns (Fig. 5) permits to the weaving mills which are in a position to use it (not many mills at the moment) to simplify and speed up considerably the loom starting operations in case of warps which were drawn-in or tied-up outside the weaving machine. The warp threads are laid into a uniform layer by the brush roller of the piecing-up machine and successively pieced-up between two plastic sheets respectively about 5 cm and 140 cm wide, both covering the whole warp width.

The plastic sheet can be inserted into the weaving machine simply and quickly, avoiding to group the threads together into bundles; the threads are then pieced-up on the tying cloth of the take-up roller.

Fig. 5 − Piecing-up:

If a new drawing-in operation is not necessary (this expensive operation is avoided whenever possible) because no style change is needed, the warp is taken from the beam store and brought directly to the weaving room, where it is knotted on board the loom to the warp prepared with the knotting machine.

As an alternative to the usual knotting on board the loom, the knotting outside the loom or stationary knotting of a new warp with an already drawn-in warp can be carried out in the preparation department. The devices bearing the threads of the old warps are taken from the weaving machine and the knotting can be started in the preparation room under better conditions, leaving the weaving machine free for rapid cleaning and maintenance operations.

The stationary knotting, in particular, takes place in following stages:

• Taking out of the loom the prepared beam with the harness
• Transport of the beam into the weaving preparation department
• Fastening of the heald frames and of the reed on the proper frame
• Knotting
• Passing of the knots by proper drawing
• Warp piecing-up
• Temporary maintenance of the new warp with the harness
• Transport of the new warp inclusive of harness with proper carriage
• Loading of the weaving machine and start of the weaving process using plastic sheet (fig.7)
• Weaving

Fig. 6 − A knotting machine in operation on a warp with colour sequence, tensioned on the proper frame:

Fig. 7 − Harness loading in the weaving machine:

The automatic knotting machines can process a wide range of yarn types and counts at highly reliable and rapid operating conditions (up to 600 knots/minute), with mechanical or electronic control on double knots and on the sequence of warp patterns in case of multi-coloured warps. Fig. 6 shows a knotting machine in operation on a warp with colour  equence, tensioned on the proper frame.

Different Types of Yarn Spinning System

Spinning:

The present participle of the verb ‘to spin’ used verbally, adjectivally, or as a noun, meaning process or the processes used in the production of yarns or filaments.The term may apply to: (i) The drafting and, where appropriate, the insertion of twist in natural or staple man-made fibres to form a yarn;
(ii) The extrusion of filaments by spiders or silkworms; or
(iii) The production of filaments from glass, metals, fibre-forming polymers or ceramics.

Ring spinning

In the spinning of man-made filaments, fibre-forming substances in the plastic or molten state, or in solution, are forced through the holes of a spinneret or die at a controlled rate. There are five general methods of spinning man-made filaments i.e. dispersion spinning, dry spinning, melt spinning, reaction spinning, and wet spinning, but combinations of these methods may be used.

In the bast and leaf-fiber industries, the terms ‘wet spinning’ and ‘dry spinning’ refer to the spinning of fibres into yarns in the wet state and in the dry state respectively.

Open-end Spinning;

Break Spinning:
A spinning system in which sliver feed stock is highly drafted, ideally to individual fibre state, and thus creates an open end or break in the fibre flow. The fibres are subsequently assembled on the end of a rotating yarn and twisted in. Various techniques are available for collecting and twisting the fibres into a yarn, the most noteworthy being rotor spinning and friction spinning.Rotor Spinning:
A method of open-end spinning which uses a rotor (a high-speed centrifuge) to collect individual fibres into a yarn is known as Rotor spinning. The fibers on entering a rapidly rotating rotor are distributed around its circumference and temporarily held there by centrifugal force. The yarn is withdrawn from the rotor wall and, because of the rotation, twist is generated.

Friction Spinning:
A method of open-end spinning which uses the external surface of two rotating rollers to collect and twist individual fibres into a yarn is known as Friction spinning. At least one of the rollers is perforated so that air can be drawn through its surface to facilitate fibre collection. The twisting occurs near the nip of the rollers and, because of the relatively large difference between the yam and roller diameters, high yarn rotational speeds are achieved by the friction between the roller surface and the yarns.

Air-jet Spinning:
A system of staple-fibre spinning which utilizes air to apply the twisting couple to the yarn during its formation is known as Air-jet spinning. The air is blown through small holes arranged tangentially to the yarn surface and this causes the yarn to rotate. The majority of systems using this technique produce fasciated yarns, but by using two air jets operating in opposing twist directions it is possible to produce yarns with more controlled properties but of more complex structure.

Centrifugal Spinning:
A method of man-made fiber production in which the molten or dissolved polymer is thrown centrifugally in fibre form from the edge of a surface rotating at high speed. The term is also used to describe a method of yarn formation involving a rotating cylindrical container, in which, the yarn passes down a central guide tube and is then carried by centrifugal force to the inside of a rotating cylindrical container.

Dispersion Spinning:
A process in which the polymers that tend to an infusible, insoluble, and generally intractable character (e.g., polytetrafluoroethylene) are dispersed as fine particles in a carrier such as sodium alginate or sodium xanthate solutions is known as Dispersion spinning. These permit extrusion into fibers, after which the dispersed polymer is caused to coalesce by a heating process, the carrier being removed either by heating or by a dissolving process.

Draw-Spinning:
A process for spinning partially or highly oriented filaments in which the orientation is introduced prior to the first forwarding or collecting device.

Dry Spinning (man-made fiber production):
The spinning process involving conversion of a dissolved polymer into filaments by extrusion and evaporation of the solvent from the extrudate is known as Dry spinning.

Flash Spinning:
A modification of the accepted dry-spinning method in which a solution of a polymer is extruded at a temperature well above the boiling point of the solvent such that on emerging from the spinneret evaporation occurs so rapidly that the individual filaments are disrupted into a highly fibrillar form.

Flyer Spinning:
A spinning system in which yarn passes through a revolving flyer leg guide on to the package is known as Flyer spinning. The yarn is wound-on by making the flyer and spinning package rotate at slightly different speeds.

Melt Spinning (man-made fiber production):
The spinning process involving conversion of a molten polymer into filaments by extrusion and subsequent cooling of the extrude is known as Melt spinning.

Reaction Spinning (man-made-fiber production):
A process in which polymerization is achieved during the extrusion of reactants through a spinneret system.

Ring Spinning:
A spinning system in which twist is inserted in a yarn by using a revolving traveller is known as Ring spinning. The yarn is wound on since the rotational speed of the package is greater than that of the traveller.

Wet Spinning (man-made-fiber production):
The spinning process involving conversion of a dissolved polymer into filaments by extrusion into a coagulating liquid is known as Wet spinning. The extrusion may be directly into the coagulating liquid or through a small air-gap. In the latter case it may be known as dry-jet wet spinning or air-gap wet spinning.

August 31, 2013

Airlaid Web Formation Technique

Posted in Fiber, Hemp, Spinning ¶ Leave a comment

PRINCIPLE OF WEB FORMATION IN A SIMPLE AIR LAYING PROCESS:

RAW MATERIAL: 

• Natural or man-made textile fibre (cut length >25 mm)
• Short cut fibres (generally <25 mm)
• Wood pulp (1.5–6 mm)

Air laid fabric compared with carding technology has these features: 

• The fibers are oriented randomly on the fabric surface – isotropic structure.
• Voluminious webs can be produced
• The range of the area weight is wider (15 – 250 g/m2) but the mass uniformity of light air laid (up to 30 g/m2) is bad.
• Wide variety of processable fibers

AIR LAID – PRODUCTION PROBLEMS: 

• Low level of opening fiber material by lickerin roller Thus is suitable to use pre-opened fibers or combine air laid with card machine – Random card machine.

• Variable structures of web in width of layer due to irregular air flow close to walls of duct . This problem requires high quality design of duct.

• Possible entangling of fibers in air stream. This problem can be reduced by increasing the ratio air/fibers which nevertheless means decrease in performance and increase of energy consumption due to high volume of flowing air.

The relation between air flow and performance of device shows the importance of fiber length and fiber diameter. QA is air flow, K is device constant, P is performance of device (kg/hour), L is lenght of fiber staple (m) and D is fiber fineness (dtex).

QA = K.P.L2/D

Thus is suitable to use short fibers for this technology.

Random cards – combination of air laid and carding technology:

A major objective of this combination is isotropic textile fabric (random orientation of fibers) with good mass uniformity of light fabrics and with high production speed.

• The first part – card machine opens perfectly fibrous material so single fibers are as a output.
• The second part – air laid system uses the centrifugal force to strip the fibers off a roller and. put them down on an air controlled scrim belt.

Main variations of random cards I. Airlaid function of random card:

1) Random roller between main cylinder and doffer, which rotate in the opposite direction of the main cylinder.

MAIN VARIATIONS OF RANDOM CARDS:

Main variations of random cards II:

2) Centrifugal force of mean cylinder strips the fibers off.

AIR LAID AND RANDOM CARDS: USED FIBERS: 
Synthetic fibres, viscose, cotton and blends thereof; natural fibres such as flax, hemp, sisal etc.; Reclaimed textile waste and shoddy, cellulose pulp 1.7 – 2000dtex. Max. 120 mm staple length

FEEDING SYSTEM OF RANDO WEBBER:

RANDO-WEBBER SYSTEMS WITH PERFORATED SCREEN:

RANDO-WEBBER SYSTEMS WITH CYLINDRICAL CONDENSERS:

Rando–webber:

• Relatively narrow widths up to about two metres
• Webs of 10– 3000 g/m 2
• Virgin or recycled fibres
• Filtration, home furnishings, automotive fabrics, insulation and some medical specialities

RANDOM CARD K12 OF DR. E. FEHRER:

HIGH-PRODUCTION RANDOM CARD K21 OF DR. E. FEHRER:

• K12 is more particularly suited to coarse fibres (10–110 dtex), Basic weight range 20– 2000 g/m 2
• K21 is more particularly suited to synthetic and viscose rayon fibers of (1.7–3.3 dtex), Basic weight range 10–100 g/m 2

SCHEMATIC VIEW OF THE DOA AIRLAYING SYSTEM:

SCHEMATIC VIEW OF THE AIR LAYING SYSTEM:

CHICOPEE AIRLAYING SYSTEM:

• Air velocity ( 140 m/s)
• Surface speed of the cylinder ( 20–60 m/s)
• Staple fibres ranging from 13–75 mm

SPINNBAU AIRLAYING SYSTEM:

THIBEAU HYBRID CARD AIRLAYING MACHINE:

Thibeau hybrid system: 

• Typical MD/CD ratio of 1.2–1.5:1
• Production rate of 200–260 kg/h/m
• Web weights of 35–200 g/m 2
• Fibre types cotton, viscose rayon, PET, PP, PA
• Fibre length of 10–40 mm.

“TURBO-UNIT”

TURBO-CARD RC 2-6 TR:

Turbo-Unit and Turbo-Card: 

• The turbo-unit TU is either fed by pre-carded webs via a feed plate intake or may be combined with a random card.
• The turbo-roll is equipped with carding segments.
• Aerodynamical web-forming by centrifugal force, doffer fan and suction conveyor
• Lower to medium fibre fineness range
• Staple length: approx. 10 – 80 mm
• Web weight: approx. 25 – 450 g/m 2
• Throughput depending on fibre fineness and fibre type: up to approx. 400 kg/h/m of working width
• Working widths: up to 4.000 mm
• Web speed: approx. 20 – 120 m/min

WEB FORMING MACHINE 008-0445 OF LAROCHE S.A.:

Laroche System: 

• Web weight ranges from 300 to 3000 g/m 2
• Production speed of up to 10–15 m/min
• Fibre length should be in the range 20–75 mm
• Cotton, man-made, glass fibres
• Hemp, flax, sisal, coconut
• Bed covers, mats, upholstery and insulation material, carrier material for carpets, industrial and geotextiles as well as furniture textiles

GENERAL PROPERTIES OF AIRLAID FABRICS: 

• HIGH ISOTROPICITY
• HIGH LOFT (IF REQUIRED)
• HIGH POROSITY (95–>99%)
• HIGH ABSORBENCY AND WICKING RATE
• SOFT HANDLE
• ADEQUATE TENSILE STRENGTH
• GOOD RESILIENCY (COMPRESSION RECOVERY)
• HIGH THERMAL RESISTANCE.

Air laid and random cards: end products:

• Chemical bonding: napkins, table cloths and wipes
• Thermal bonding: nappies (different components, i.e., acquisition layer, distribution layer and absorption core), feminine hygiene/incontinence products and insulation
• Spunlacing: wet and dry wipes for domestic and industrial applications medical textiles (including disposable gowns, curtains, wound-care dressings, bed sheets), filtration media
• Needle punching: interlinings and shoe linings, wadding, medical and hygiene products, geotextiles and roofing felts, insulation felts, automotive components, filters, wipes

Combination of unidirectional and cross directional web:

CROSSLAPPER WITH HORIZONTAL LAYING DEVICE:

Tasks of the web-laying machine:

• Increasing the web mass
• Increasing the web width
• Determining the web strength in the length and cross directions
• Improving the end product quality

LAP DRAFTER VSTG:

WORKING WIDTH UP TO 7.000 MM. INDIVIDUAL SERVO-DRIVES FOR 4 DRAFTING ZONES WITH INFINITELY VARIABLE DRAFTS. ONLY LITTLE CHANGES OF BATT WEIGHT REGULARITY BY FIBRE RE-ORIENTATION INCREASE STRENGTH IN MD.

MERITS AND LIMITATIONS OF CARD – CROSS LAPPING AND AIR LAYING:

August 31, 2013

3D Weaving Manufacturing Process of 3D

Posted in Weaving ¶ Leave a comment

3D-Weaving:

3D-Weaving is a complete new concept in case of weaving. The first method of 3D woven fabric denotes 3 Dimensional fabrics, that is length, width and breadth. In 3 Dimensional fabrics, the thickness is an important criterion. Ordinary fabrics also have length, width and breadth, but in the 3 Dimensional fabrics, the thickness is much more than ordinary fabric. The thickness is achieved by forming multiplayer using multi series of warp and multi series of weft, which are intersecting at regular 90o angle as in usual cloth weaving principle.

It cannot be performed with existing traditional methods and machines. It interlaces a multiple layer warp with multiple horizontal wefts and multiple vertical wefts producing directly shell, solid and tubular types of fully interlaced 3D fabrics with countless cross-sectional profiles.First demonstrated in 1997, Dual-Directional (D-D) Shedding System is indispensable for performing 3D-weaving. This path breaking development has advanced the technology of weaving to a new dimension for the first time in its more than 27000 years of history.