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Showing posts with label KNOWLEDGE. Show all posts
Showing posts with label KNOWLEDGE. Show all posts

Wednesday, 26 October 2011

Warp Knitting | Tricot Machines (Karl Mayer) at Glance

HKS 2
Two guide bars tricot machine with high performance from Karl Mayer for universal application, from light tulles to heavy raised velour .This model is also suitable for very low stitch densities and coarse gauges as well.

Below are some of applications that can be produced in the HKS 2 tricot machine.
  • Mosquito nets.
  • All kind of tulle fabrics.
  • Sport wear articles.
  • Shoe Fabrics.
  • Ground fabrics for printing / advertising media.
  • Coating substrates.
  • Laminating backings.
HKS 2-3 / HKS 2-3 E
High-performance tricot machines with two guide bars from Karl Mayer to produce plain rigid  fabrics and elastic fabric as well by fitting the elastic device (tube deviation) for the second guide bar as a replacement tension bar which is used to produce un-elastic fabric,The letter (E) on HKS 2-3 E signify that machine equipped with Elastic device to produce elastic fabrics.

Tuesday, 24 August 2010

Warp Knitting | Caculation of Residual Yarn sheet on Warp Beam


In some cases on warp knitting fabric production practically ,we need to cut and replace the warp beam before the warp beams are finish and some yarn still remain wound up on the warp beams.The remain yarn sheet /residual yarn sheet on warp beam will be keep for next production order,for example due  a sudden change an order of fabric article or during the warping process warped yarn to much in the length or just for make a fabric samples or due another reason,whatever…

In this case we need to tape a yarn sheet on the warp beam,cut them  off and remove,however  we need  also to calculate  how many meters or kilo grams a yarn sheet remain on the warp beam for future used.Following are the formula to calculate the remain yarn sheet on warp beam for Warp Knitting.

First of all we need to know and to determine the current winding or the actual winding on warp beam,as follows ;

Wednesday, 14 July 2010

Warp Knitting | Calculation of Yarn run-in (mm/rack)

The relationships between fabric parameters and yarn run-in (yarn consumption) is an extremely important factor for production planning.This data allows the knitter to estimate his yarn requirements,predict  his production rate.
The values needed to determine the yarn run-in :
Lapping,Gauge  E (needles/inch) ,course per cm (CPC),needle thickness  (d).
Calculation :
  • Head of the loop = πd /2.2
d = needle thickness
  • Legs of the loop = 2 x S
S = 10 mm : course per cm (cpc)

image
  • a =  number of needle loops
  • b =  number of needle gaps crossed by the sinker loop
  • c =  number of sinker loops in the same wale
T = 25,4 mm : E (gauge)

image 

Yarn run-in (mm/rack) *= 480 [a ( πd /2.2  + 2S) +bT + cT ]
notice : * The calculated values are as approximate values
Example 1 :
closed 1x1
  • E = 28
  • CPC = 20
  • d = 0,5 mm
  • Lapping =  1 0 / 1 2 //   | a = 1 | b = 1 | c = 0 (per course).
Yarn run-in (mm/rack) = 480 ( 0,7 mm + 1 mm +0,9 mm) = 1250 mm/rack

Example 2 :
open pillar

Sunday, 11 July 2010

Warp Knitting | Warp Length Required to Knit a Certain Fabric Length

warp beam
Following formula is to calculate the length of warp beam (yarn length) in order to produce certain fabric length.
To produce a length of fabric ( Lf-meters) ,the number of racks the warp knitting machine has to knit is:
rack =( Lf x CPC x 100) : 480
The length of warp in meters which required for each guide bars is :
meters = ( Lf x CPC x 100 x run-in) : 480     | run-in units are in meters/480 courses|

Tuesday, 13 October 2009

Warp Knitting | Stitch Forming Process on Raschel Machines

285° – knock over position
The compound needles and slides are at their lowest position (knocking-over position).
The knock-over comb bar moves back and rests just in front of the stitch comb bar. In so doing, the next to last loop slips from the needles. The last loop lies in the head of the needle and is pulled through the preceding loop when it is cast off.




 

345° – holding down
The knock-over comb bar moves further in the direction of the rear reversal point. The compound needles rise, the slides remain in their lowest position. The stitch comb bar holds the fabric down together with the fabric take-down. The last-laid loop slip onto the shands of the needles.




 


0° – rear reversal point
The slides rise but do not come out of the groove in the compound needles. The
knock-over comb bar is at the rearmost point.






 
40° – swing-in
Before the compound needles swing into the pattern bar of the last shogging course the under-lapping shog of the guide bars in completed. The knock-over comb bar, compound and slide bars move forward (in the photograph the compound needle is just swinging into the last shogging course of the pattern bars; on this type of machine the guide bars and stitch comb are fixed).


 


 105° – overlapping shog of the ground guide bars
The knock-over comb, compound needle and slide bars swing out of the stitch
comb bar into the forward reversal position (ejection position). As they move forward the compound needles pass the pattern bars and ground guide bars. The yarns now lie in the gaps between the needles. Once the needles have passed the foremost guide bar L 1(GB 1), the overlapping shog begins. The knock-over comb, compound needle and slide bars begin their movement backwards and as they pass through guide bar L 1(GB 1) the yarns laid in the underlapping slip into the hooks of the needles.


190° – closing of the compound needles
The knock-over comb, compound needle and slide bars move further back.
After the swinging through of the second shogging course the compound needles
begin to sink. The slides remain in their upper position until the needles are closed.




220° – start of the underlapping
After the compound needles are closed they move down together with the direction
of the knock-over edge. Now the underlapping of the guide bars can begin.
As the compound needles move further back the old loops slip from the shanks onto the slides. As the needles pass the knock-over edge the newly laid-in yarns in the needles heads are pulled through the old loops. When the backwards movement of the compound needles with the slide bar has been completed the latter are in the
knocking-over position (285°). The loops whick slip over the heads of the needles as a result of this are pulled by the take down over the top edge of the knock-over
sinker. Depending on the take down and yarn tension the cast-off loops are pulled
together in their final form and size.

Wednesday, 30 September 2009

Warp Knitting | Elastane Safety System (ESS device)

The ESS device prevents the rebounding (re-jumping) of yarn ends in case of yarn breakages
on warp knitting machines processing elastane yarns.



In keeping with its concept of "accurate feeding of delicate yarns", Karl Mayer Textilmaschinenfabrik GmbH has recently optimized its two-bar tricot machines by developing a special tension bar for processing fine-count elastane yarns more efficiently with the name Elastane-Security System (ESS).

The demand for super light as well as opaque and mouldable underwear fabrics, produced in finer machine gauges, is continuing to rise. The market share of fine-count elastane yarns in the 11 - 14 dtex range is also continuing to rise.

An easily accessible tubular guide, which is driven by the yarn, is currently used as standard for feeding the elastane yarn to the knitting point. This system guarantees a uniform yarn feed. A prerequisite for this is that the yarn tension between the warp beam and the guide causes the yarns to adhere at the tube. However, as the yarn count decreases, the maximum yarn tension that can be achieved also decreases. As a guideline, this should be roughly 1 gram per 10 dtex of yarn. For example, an elastane yarn of 44 dtex can be loaded with four grams, and a yarn of 11 dtex with just one gram.

In order to achieve these low yarn tension levels at fine counts during processing, a modified tubular guide belonging to the new ESS is actively controlled via its own EBA drive. The rubber-coated surface, the precision grinding of the tubular guide, and an additional pressure roller guarantee the non-slip transfer of the peripheral speed to the yarns (Fig. 1). The control functions are also carried out by the EBA computer, which is extended to three positions on the two-bar machines.

Monday, 14 September 2009

Basic Stitch Constructions in Warp Knitting | Single Face Fabric

The basic stitch constructions describe the various lapping, their designations have partly been taken from weaving,however, without any common features from the point of view of the lapping technique.
Basic stitch constructions worked as one-bar constructions are without much importance, because optical, elastic and stability properties do not meet the needs of a textile fabric.
All basic stitch constructions can be worked open or closed.

The following stitch constructions are described:
    Basic binding combination of single-face fabrics

    Fabrics with combined bindings are fabrics which are produced with at least two guide bars.
    Bindings are combined with each other to improve the properties of the fabrics (e.g. strength, elasticity, stretch, appearance, etc.) thus increasing their service value. The properties are mainly influenced by the following aspects:
    1.  yarn parts in horizontal direction (e.g. under-laps, inlays)
    2.  yarn parts in vertical direction (e.g. fillers, floats)
    3.  thickness of the yarn
    4. lapping direction of the guide bars to each other (equal- or counter-lapped)




    Monday, 7 September 2009

    Warp Knitting Elements

    The kind of knitting elements depends of the respective warp knitting machine type.Here with the knitting elements on tricot warp knitting machine and raschel warp knitting machine.The knitting elements mounted on its bar.

    1. Knitting elements on tricot warp knitting machine






    2. Knitting elements on raschel warp knitting machine


     

    3.Knitting elements on double needle raschel warp knitting machine.
    On Karl Mayer double needle bar raschel machines there used latch needle for working needle instead of compound needle.




    4. Knitting elements on stitch bonding warp knitting machine,Malimo type


    Friday, 4 September 2009

    Warp Knitting|Chain link Profile|Oldies but Goldies

    1. Profile chain links for N and E pattern drives

    The profile N and E chain links are always produced as new parts, in conformity with the specific order and can, therefore, be supplied with the new designation already starting from 01.01.2004. Due to the fact that these chain links are used at high machine speeds, they are subject to the same regulations as pattern discs. Therefore, a more extensive la-belling is necessary, which, however, is fully in conformity with the designation of the pat-tern discs. Due to the reduced space required, only six different details should be applied to a profile chain in the future. The machine type and the degree, for example, will no longer appear on profile chains for tricot machines in the future. Fig. 1 shows the prescribed designation of profile chain links starting from 01.01.2004. Apart from the guide bar position, all the other data will appear at least once per pattern repeat on each chain link. The guide bar position should only appear in case of restrictions to certain positions, for high-speed machines.

    A -Chain link height with new continuous numbering system starting at 0,1,2 etc.,
    will show only one number. The labelling will depend on the number of chain links
    per stitch course (tempi). For the lapping 10/12// the labelling of the first six chain
    links is done – as standard -for three chain links per stitch course (3 tempi) in the
    following sequence: 1-0-0-1-2-2 and in case of four chain links (i.e. the first eight
    chain links): 1-0-0-0-1-2-2-2. Only in special cases, for designating a special grind
    ing, for example, will the chain links be described differently.

    This means that from January 2004 onwards, the chain link height always corresponds to the current gauge, for which this shog movement of the guide bar had been optimised, even if the machine is not fully needled. Please see in this re-spect the pattern disc description in our Information Service No. 26/2003.

    B -Serial number of the chain link within the entire chain. This number represents the beginning of the requested lapping, enabling a quick and reliable new assembly of the chain after an undesired falling asunder of the chain.

    C -Gauge designation only in E or F for which this chain link had been produced (E corresponds to needles per inch and F corresponds to needles per 25 mm), thus, replacing the term „fine“ and/or ER. As far as standard machines are concerned, the gauge designation on the chain link is always identical with the specified machine gauge. In case of some Raschel machines, equipped with shog levers on the pattern drive, a second pattern drum and not fully set needle bars, it might happen that the pattern chain gauge deviates from the machine gauge. In this respect please see the pat-tern disc description in our Information Service No. 26/2003.

    D -The number of knitting motion (Gang) corresponds to the initial knitting motion of the machine for which the curve of this profile chain had been developed, so that it can differ from the current knitting motion (Gang) of customer's machine type. In order to ensure that in the future the customers of tricot machines can assign the supplied pattern chains to the various machine types, please find in Table 1 the currently used numbers of knitting motion (Gang) and the respective previously stamped ma-chine types.

    E -Indication of the applicable guide bar position(s), if the disc cannot be used for all positions of the relevant machine; due to lack of space, however, without the word „only“, e.g. GB2

    F -Number of stitch cycles as ratio. In case of chain links this number describes how many chain links are used per stitch cycle, e.g. 16:1 means 16 stitch cycles per revolution of an N pattern drum (48 chain links per circumference), replacing the former designation 3 tempi (3 chain links per stitch cycle);16:1 for an E pattern drum (16 chain links per circumference) means that only one chain link is used per stitch cycle (1 tempi)

    2. Plain and polished (ground) chain links for N pattern drives

    Recently these chain link types had already been labelled with the current numbering sys-tem 0,1,2 etc., the gauge numbering, however, had been done in reverse order, e.g. as 28

    E.
    In the future these chain links will continue to be labelled with the chain link height 0,1,2, thegauge, however, will get the new designation: e.g. E 28.The mix of new and old chain links within a new chain at customer's factory can be donewithout any problems; what is different with new chain links is only the way of specifying thegauge.

    3. Plain and polished (ground) E, H, and S chain links for E pattern drives and special pattern drives

    Today, large quantities of these non-profiled chain links (which can be easily combined) are still on stock at customers’ and manufacturers’ companies and can be used for an almost unlimited period of time. Nowadays, the use and production of these chain links is mainly restricted to the current machinery programme of Karl Mayer Wujin (China). In view of the high re-employment rate of the old chain links, it would be most dangerous to mix these chain links with newly produced chain links having another designation. Besides, the change-over process would take several years. Therefore, we have decided in the Karl Mayer Group not to change the designation of these chain link types, but to supply them with the previous identification, as long as they are ordered by customers.

    This new way of designating the chain links ensures a standardisation of the labelling of all chain link types, thus, making their daily use much easier. Besides, the specification of the most important features is identical to that of the pattern discs, being continuously applica-ble for all kinds of pattern systems. All the relevant data consist of numbers (digits) or the same English terms used world-wide. All the other data previously existing on chain links, are either cancelled or replaced. Further information, however, could be added on the chain links for special applications.

    In the first six months of the next year, an information sheet regarding the changed labelling of chain links will be added to every consignment of profiled pattern chains for machines and/or spare parts.

    Fig. 1: Designation of profiled N and E chain links


    Table 1: Survey on knitting motions and types  for tricot machines

    Nylon and Polyester Characteristics | Warp Knitting

    Almost warp knitting fabric used Polyester and Nylon fiber for the raw material,following is the characteristics of Polyester and Nylon Fiber.

    Polyester Fiber
    Basic Principles of Polyester Fiber Production — The most common polyester for fiber purposes is poly (ethylene terephthalate), or simply PET. This is also the polymer used for many soft drink bottles and it is becoming increasingly common to recycle them after use by remelting the PET and extruding it as fiber. This saves valuable petroleum raw materials, reduces energy consumption, and eliminates solid waste sent to landfills.

    PET is made by reacting ethylene glycol with either terephthalic acid or its methyl ester in the presence of an antimony catalyst. The reaction is carried out at high temperature and vacuum to achieve the high molecular weights need to form useful fibers. PET is melt spun. For a detailed production flowchart, go here.

    Polyester Fiber Characteristics

    o Strong
    o Resistant to stretching and shrinking
    o Resistant to most chemicals
    o Quick drying
    o Crisp and resilient when wet or dry
    o Wrinkle resistant
    o Mildew resistant
    o Abrasion resistant
    o Retains heat-set pleats and crease
    o Easily washed

    Some Major Polyester Fiber Uses

    * Apparel: Every form of clothing
    * Home Furnishings: Carpets, curtains, draperies, sheets and pillow cases, wall coverings, and upholstery
    * Other Uses: hoses, power belting, ropes and nets, thread, tire cord, auto upholstery, sails, floppy disk liners, and fiberfill for various products including pillows and furniture

    General Polyester Fiber Care Tips

    o Most items made from polyester can be machine washed and dried. Use warm water and add a fabric softener to the final rinse cycle. Machine dry at a low temperature and remove articles as soon as the tumbling cycle is completed.
    o If ironing is desired, use a moderately warm iron.
    o Most items made from polyester can be dry-cleaned.

    Nylon Fiber
    Basic Principles of Nylon Fiber Production — The term nylon refers to a family of polymers called linear polyamides. There are two common methods of making nylon for fiber applications. In one approach, molecules with an acid (COOH) group on each end are reacted with molecules containing amine (NH2) groups on each end. The resulting nylon is named on the basis of the number of carbon atoms separating the two acid groups and the two amines. Thus nylon 6,6 which is widely used for fibers is made from adipic acid and hexamethylene diamine. The two compounds form a salt, known as nylon salt, an exact 1:1 ratio of acid to base. This salt is then dried and heated under vacuum to eliminate water and form the polymer.

    In another approach, a compound containing an amine at one end and an acid at the other is polymerized to form a chain with repeating units of (-NH-[CH2]n-CO-)x. If n=5, the nylon is referred to as nylon 6, another common form of this polymer. The commercial production of nylon 6 begins with caprolactam uses a ring-opening polymerization. For a detailed production flowchart, go here.

    In both cases the polyamide is melt spun and drawn after cooling to give the desired properties for each intended use. Production of nylon industrial and carpet fibers begins with an aqueous solution of monomers and proceeds continuously through polymerization, spinning, drawing, or draw-texturing.

    Nylon Characteristics

    o Exceptionally strong
    o Elastic
    o Abrasion resistant
    o Lustrous
    o Easy to wash
    o Resistant to damage from oil and many chemicals
    o Can be precolored or dyed in wide range of colors
    o Resilient
    o Low in moisture absorbency
    o Filament yarns provide smooth, soft, long-lasting fabrics
    o Spun yarns lend fabrics light weight and warmth

    Some Major Nylon Fiber Uses

    * Apparel: Blouses, dresses, foundation garments, hosiery, lingerie, underwear, raincoats, ski apparel, windbreakers, swimwear, and cycle wear
    * Home Furnishings: Bedspreads, carpets, curtains, upholstery
    * Industrial and Other Uses: Tire cord, hoses, conveyer and seat belts, parachutes, racket strings, ropes and nets, sleeping bags, tarpaulins, tents, thread, monofilament fishing line, dental floss

    General Nylon Fiber Care Tips

    o Most items made from nylon can be machine washed and tumble dried at low temperatures. Use warm water and add a fabric softener to the final rinse cycle.
    o Remove articles from dryer as soon as tumbling cycle is completed.
    o If ironing is required, use warm iron. 


     Nylon 6,6 and Nylon 6 are the most versatile commercial nylon products in the market having a vast range of uses depending upon the need. Both the products are used for engineering applications though Nylon 6,6 is more used for its ductility and tensile strength. Nylon-6,6 which is also known as Polyamide 6,6.is the semi-crystalline polyamide commonly used in fiber applications such as carpeting, clothing, and tire cords. Nylon 6 which is also known as Poly-caprolactum has many individual uses. The numerical nomenclature for nylon is derived from the number of carbon atoms in the diamine and dibasic acid monomers used to manufacture it. The ratio of carbon atoms is what gives each nylon type its unique property characteristics.
    Nylon 6 is used more for products like Bristles for toothbrushes, sutures for surgery, manufacture of hosiery, knitted garments. Also recently there had been more products developed using Nylon 6 which includes large variety of threads, ropes, filaments, nets, and tire cords.
    Nylon 6,6 has a tighter molecular structure than nylon 6 due to a higher level of hydrogen bonding and maximum alignment between molecular chains, creating a tighter structure that better resists crushing, matting and stain penetration. Nylon 6 does not have this level of internal bonding, resulting in a more open structure. Nylon 6,6 gives carpet the unique balance of strength, elasticity and durability it needs to survive in commercial installations.
    The stiffness of nylon 6/6 can be improved up to 10 times. The use of internal lubricants improves on the already excellent wear resistance and friction properties on nylon 6/6. Its versatility allows it to be used in almost any application that requires high physical strength, ductility, heat resistance and chemical resistance.

    Wednesday, 2 September 2009

    Winding Calculation for Warp Beam on Warp Knitting

    Windings, warp length:
     
    mm / meter                                                                   inch / yard
    windings =     warp length (m) x 2000                                            windings =       warp length (yd) x 72
                                       (Ul + UA)*                                                                                          (Ul + UA)**
    warp length (m) = (Ul + UA)* x windings                                    warp length (yd) = (Ul + UA)** x  windings
                                               2000                                                                                                      72
    *m = meter                                                                                          yd = yard
    *Ul = inner circumference in mm                                                   **UI = inner circumference in inch
    *UA = outer circumference in mm                                                  **UA = outer circumference in inch
    Actual windings
    actual windings                           (UA actual ‑ Ul)* x  full windings                                 *Ul = inner circumference in mm
                                                                            (UA full ‑ Ul)*                                               *UA = outter circumference in mm
    Maximum yarn feed ‑ FZ:
    FZ (mm/Rack) = 3000 x Ul* x 480
                                      nH x i
     
    Explanation of symbols:
    m = meter
    2000 = refers to Ul/UA and conversion from meter to millimeter
    Ul=  inner circumference in millimeter
    UA= outer circumference in millimeter
    3000=max. speed of beam motor
    480 = rack
    nH = speed of main shaft reduction ratio of the beam motor: warp beam
    72=refers to Ul/UA and conversion from yard to inch


    No. Work steps Procedure Example
    I U1 is known 617 min
    2 Measure Ua 900 min
    3 Program computer for Enter UI: Ua-value Inputs:
    corresponding beam Ua: measured Ui: 900 MM
    Enter Wdg (windings) (see Ua: 900 min
    following work step) Wdg: 5 0
    4 Detect thickness of winding Wind off 50 windings and measure Results:
    layers. Ua again. 50 Wdg wound off
    Note: Ua old 900 min
    For this purpose, wind-off The more windings have been Ua new: 898 min
    beam supervised. wound off, the more precise the
    layer thickness calculation will
    be
    5 Calculate thickness of formula : 900 - 898 = 2 min
    winding layers (layer layer thicknes = (UA old - UA new) 2*winding 2 / 50 = 0,04 min
    thickness). 0,04  / 2 = 0,02 min
    Layer thickenss: 0,02
    mm
    6 Calculate windings formula : 898 - 617 = 281
    Winding = (UA new - UI ) / 2*layer thicknes 281 / 2 = 140,5
    140,5 / 0,02 = 7025
    Windings: 7025
    7 Enter new beam data UI: 617 min
    Ua: 898 min
    Wdg: 7025
    FZ: upon request
     

    Heksatex