Document 6460860
Transcription
Document 6460860
Hosiery technology Radko Kovar, Irena Lenfeldova, Martina Syrovatkova KTT, Technical University of Liberec, Halkova 6, 461 17 Liberec, cz Introduction: For centuries, the production of hosiery was the main concern of the knitting industry. The prototype machines for warp, circular, flat and fully-fashioned knitting were all originally conceived for knitting hosiery. Nowadays, however, hosiery production is centred almost exclusively on the use of small-diameter circular machines. In single cylinder and finegauge hosiery particularly, much of the latest development is centred in Italy. Brief content (modules): 1. Principles of hosiery technology 2. Production of stockings and tights (pantyhose) 3. Production of socks and knee socks 4. Single-cylinder machines 5. Double cylinder machines 6. Machines programming 7. Finalization of products 8. Structure and properties of products 9. Supplementary information 1. Principles of hosiery technology: Content (chapters): 1.1. Classification of hosiery products 1.2. Scheme of hosiery products 1.3. Scheme of hosiery knitting 1.4. Materials used in hosiery products 1.5. Welts 1.6. Shaping of heels and toes 1.7. Shaping of legs 1.8. Used knitted structures and designs 1.9. Closing of toes 1.10. Standardization of hosiery products 1.1. Classification of hosiery products ¾The term “Hosiery products” is used for clothes, covering manly lower extremities (legs and foots) ¾From the point of view of fabric “fines” there are: ¾Fine products, usually made of multifilament yarns on knitting machines with 24 – 40 needles per 25.4 mm (fine women stocking and tights) ¾Course products, usually made of spun yarns on knitting machines with 5 – 24 needles per 25.4 mm (socks, knee socks, course pantyhose) Types of hosiery products: I. According to Type and Size ¾ Stockings, which are designed to fit the leg up to or above the knee and may or may not be self-supporting ¾ Tights (panty hose), particularly in fine gauge. They may have a body section of the same knitted structure and the legs and an inserted gusset and elastic waist-band. They are usually sewn together from 2 longer stockings. ¾ Three-quarter Hose. This term was originally applied to hose of knee length and the definition still holds good although in Boys’ and Girls’ ¾ hose a turnover top is often used. The term ¾ sock is rarely used now but formerly referred to children’s sock having a fashioned leg and rib top. Types of hosiery products: I. According to Type and Size ¾ Men’s half-hose. This is the trade term for men’s socks. A distinctive feature is that the upper portion or “top” is of a ribbed character in order to fit closely to the leg. Usually are in two leglength ranges (7 - 9 and 11 - 15 inches, 18 - 23 and 28 – 38 cm) ¾ Socks. This term is applied to children, women’s and men’s knitted footwear having a short leg and ribbed top. Long ago it has also been used for a foot covering with ankle and turnover top. Presently the inturned top usually makes top of the socks. ¾ Footies. Very short cushioned foot sock. Top reaches to the anklebone ¾ Footlets. Covers only toe, foot ant heel ¾ Bootees and Infantees. Soft, fluffy knitted foot coverings for infants. Footwear knitted to the shape of the foot usually in a fancy rib or purl stitch for children of pre-walking ages Types of hosiery products: II. According to Yarns and Gauge ¾ Knitted footwear may be manufactured form all kinds and counts of yarns but whereas the material is frequently mentioned the count is rarely stated. An indication of the relative fineness is given by the gauge, which is expressed in one of two ways: ¾ Number of wales in hose, i.e., number of needles in machine ¾ Gauge of straight-bar machine on which the hose leg is made Types of hosiery products: III. According to Process of Manufacture ¾ Three types of hosiery machines, in order of their increasing complexity and needle bed arrangement, are: ¾ Single cylinder, ¾ Cylinder and dial (they are often considered as singled cylinder machines if dial is not able to knit wales of stitches) ¾ Double cylinder Ladies’ fine-gauge seamless hose and tights are knitted in plain structure on single-cylinder machines with holding-down sinkers Types of hosiery products: III. According to Process of Manufacture ¾ Ladies’ fine-gauge seamless hose and tights are knitted in plain structure on single-cylinder machines with holding-down sinkers. ¾ Men’s, ladies’ and children’s socks and half-hose in rib or purl (links-links) structure are knitted on doublecylinder machines with reciprocated heel and toe that has been closed by linking. Can be an anklet as well as an over-the-calf length. A typical machine specification would be 4-inch diameter, 168 needles. Types of hosiery products: III. According to Process of Manufacture ¾ Sports and casual socks (A broad hosiery term used to describe all women's socks and any men's socks with the exception of dress, athletic, and work styles.) in a plain base structure are now usually knitted on single-cylinder machines with holding-down sinkers. ¾ More formal simple rib socks may be knitted on cylinder and dial rib machines termed ‘true-rib’ machines. Types of hosiery products: III. According to Process of Manufacture Other possibilities: ¾ Fully-fashioned, produced on a straight bar frames and shaped by change of working needles. ¾ Fashioned Seamless, shaped by increasing or decreasing of the number of wales on a flat or circular machine; in some cases ordinary seamless hose shaped by gradually reducing the stitch length have been marked “fashioned”. ¾ Seamless hose are shoes possessing tubular legs and feet and seamless heel and toe pouches. ¾ Tailored hoses are cut from narrow or wide tubular fabric or warp knitted fabrics. Types of hosiery products: IV. According to Stitch, or Design and Colour ¾ Plain half-hose are those with drop-stitch or accordion stitch are sometimes used. ¾ Fancy Plated hose – where the pattern or design is obtained by using two threads, one or other of which appears on the face. ¾ Plush structures ¾ Laid-in structures (all in different modifications) ¾ Plane double-faced structures ¾ Ribbed hose are usually named after the character of the rib-stitch used, e.g., 1 x 1 ribbed hose or 2 x 1 ribbed hose ¾ Jacquard Hose – the term jacquard is loosely applied to mean fancy design in colour Machines used: ¾Majority of hosiery products is produced on small-diameter automatic circular knitting machines Machines used: ¾Another used technologies are mainly ¾Warp knitting ¾Weft knitting on flat machines. Example: 1.2. Scheme of hosiery products ¾Majority of hosiery products differs mainly in product length. The shortest are footlets, the longest tights (pants). ¾Some products uses only inner part of the long product (knee-guard etc.) ¾Main types of hosiery products are: ¾Footlets (covers only toe, foot ant heel) ¾Socks of different lengths ¾Half hoses (reach under or above the knee) ¾Stockings ¾Tights (usually sewn from 2 longer stockings). 1.3. Scheme of hosiery knitting ¾Originally (before and after the second world war) fine stockings were knitted on straight bar frames (products with seams). ¾Now great majority of hosiery seamless products comes from circular knitting machines of small diameter (mostly between 3.5 and 5.0 “E or 76.2 and 147 mm). ¾Production on flat knitting machines or warp knitting machines is as well possible. 1.3. Scheme of hosiery knitting ¾Single cylinder machines prevail, although they are able to create only single side structure and problems with fast and extensible welt and with border curling must be solved. ¾Double cylinder machines are able to knit double side fabric, but several disadvantages cut their production down. They are not available in fine gauges. The scheme of single cylinder machine: 1. Latch knitting needles in cylinder bed 2. Sinkers 3. Cylinder cams 4. Sinkers ring cams More in module 2. The scheme of double cylinder machine: 1. Double-sided knitting needles 2. Sinkers 3. Upper cylinder sliders 4. Lower cylinder sliders Other mechanisms of machines: Knitting mechanism is completed mainly by: ¾ Yarn supply system (creel, tensioners and feeders, guides) ¾ Fabric take-of (often combination of pneumatic and mechanic systems) ¾ Machine drive (to enable reciprocated heel and toe both rotation and oscillatory movement of the bed is necessary) ¾ Machine control (computer, control drum…) ¾ Other parts (checking of yarn, needles, fabric, frame, electrical installation etc.) 1.4. Materials used in hosiery products ¾All usual textile yarns could be used, produced both from staple and continuous fibers (spun yarns, monofilament, multifilament) ¾Usually fine hosiery products prefers continuous fibers and course products staple spun yarns ¾Yarn linear density needs to correspond with the machine gauge g, usually defined as number of knitting needles per 25.4 mm (one English inch) ¾Roughly yarn diameter could be somewhere around l/5 of needle pitch (25.4/g) or lower Mostly used materials for fine products: a) Polyamide multifilament ¾ Low extensibility ¾ High extensibility ¾ Wide range of linear density (from 1.5 to 8 tex) b) Elastomeric materials (polyurethane), usually only 3 – 12 % of product mass c) Not so often another materials (cotton, polyester etc.) ¾ In one hosiery product usually several materials is used (till 6 different yarns) Mostly used materials for course products: a) Spun yarns of cotton type (cotton, viscous striz, blends) b) Spun yarns of wool type (wool, acrylic, viscous, polyester, blends) c) Multifilament, often textured (polyamide, polypropylene etc.) d) Elastomeric yarns (covered rubber, polyurethane), used ¾ In welt only ¾ In all product (excellent elasticity) Mostly used materials for course products: Combination of materials may bring better properties and user comfort. Examples: ¾ Polypropylene inside and cotton outside keeps the skin dry but allows sweat to evaporate. ¾ Plating of spun yarns and multifilament increase product durability. 1.5. Welts ¾Quality welt should meet next demands: ¾To be fast (upper border ready for use) ¾No or low curling ¾Suitable stretchability ¾Double cylinder machines may produce doublefaced (rib) structure that is ideal for welts. ¾Single cylinder machines are able to knit singlefaced structure only. Mostly used types of welts: a) Rib welt (1x1 rib structure) with fast border (starting courses), great stretchability, often with elastic inlayed yarn. b) Inturned (tubular) welt formed by transfer of kinks of the yarn in some of initial course again on knitting needles after knitting double length of final welt. 1.6. Shaping of heels and toes ¾Heels and toes could be knitted as: ¾ Reciprocated, knitted on reverse movement of the needle bed and creating “3-D” pouch on about one half of the product. ¾Rotary producing only tubular fabric. Examples of heels ¾Reciprocated a) 3-D pouch on about one half of the product. b) Part above the pouch could be reinforced. ¾Rotary c) Producing only tubular fabric with inserted additional courses on about one half of the perimeter. d) Only reinforced and shaped by thermal setting later. Examples of toes ¾ Reciprocated a) Knitted in the same way as reciprocated heel but sawn together later. b) Similar toe with inserted a group of rotation courses. ¾ Rotary c) Only reinforced tubular part is finalized by sewing. The seem may be led from left to right side or from above down. 1.7. Shaping of legs ¾The number of needle in circular needle bed is done. This fact limits changes of product diameter. Basic and generally used possibility is change of stitches length. ¾The change of the yarn consumption is connected with the change of wales and courses density and so as well with fabric diameter. 1.8. Used knitted structures and designs ¾Mostly used single-faced structures (from single bed machines): ¾Plane structures ¾Plated structures ¾Plush structures ¾Laid-in structures All in different modifications 1.8. Used knitted structures and designs ¾Mostly used double-faced structures (from double bed machines): ¾Plane double-faced structures ¾Rib structures ¾Purl structures etc. in different modifications and designs ¾Heels, foots and toes are knitted in plane singlefaced structure. The reason is relatively flat surface and low thickness and so better comfort of user. 1.9. Closing of toes ¾Product of circular machine is ended by tubular open part and before usage the toe need to be closed. Next two possibilities are important: ¾Closing the toes by sewing or linking on product finalization. ¾Closing the toes when knitting on circular machine. There are several used principles. 1.10. Standardization of hosiery products ¾Some chosen ISO standards: ¾ISO 5971:1981 Size designation of clothes – pantyhose ¾ISO 5971 (CSN 805044): Marking of sizes of hosiery tights ¾ISO 7070 (CSN 805045): Marking of sizes of hosiery products ¾ISO 8117:2003: Textile machinery - Knitting machines - Nominal diameters of circular machines 1.10. Standardization of hosiery products ¾ In Czech Republic next standards are relevant: ¾ CSN 804159: Elastic medical tights and compressive products ¾ CSN 805801: Standard stockings, half-hoses, …, classification ¾ CSN 805802 EN 13770: Measuring of resistance of hosiery products in abrasion ¾ CSN 805810: Fine stockings, half-hoses, socks and footlets ¾ CSN 805841: Course tights, regulation and classification ¾ CSN 800863: Measuring of weight of knitted products ¾ CSN 800864: Measuring of dimensions and appearance of hosiery products