Aug 25, 2012
The production of upholstery fabrics on KARL MAYER’s three-bar HKS and DS machines – efficient, high-quality and all available from a single supplier
KARL MAYER’s three-bar high-speed tricot machines are more flexible than virtually any other warp knitting machine range and sells well all over the world. These all-round machines have found a growing market in Turkey in particular. Home textiles manufacturers especially are interested in the HKS 3-M (P) and HKS 3-1. Warp knitting companies as well as traditional weaving firms depend on the efficiency and production capabilities of three-bar tricot machines and are expanding their operations using KARL MAYER’s machines. This boom has been fuelled by a government decision on 24 March 2011 to remove additional customs duties relating to the importation of warp-knitted textiles into Turkey. The ruling came into force shortly afterwards on 22 July. It did not apply to textiles originating in the EU. Warp-knitted textiles are mainly produced inside Turkey, and some are processed within a company group. KARL MAYER delivered roughly 100 three-bar high-speed tricot machines to Turkey last year. Some of these machines were sent to manufacturers of marquisette fabrics. This lightweight, transparent fabric has become a firm favourite on the market as a high-quality embroidery ground in particular. However, the vast majority of tricot machines are used to produce velour fabric for covering upholstered furniture. There are three different ways of producing these fluffy cover textiles on the three-bar HKS machines. The first method involves producing a typical loop-pile fabric from polyester filament yarns and then cutting the loops during the shearing process. This is the easiest method of producing velour textiles using the HKS 3-M P. Ground guide bar GB 1 works the tricot construction of the ground, while GB 2 produces the pile loops using a pillar stitch or counter notation tricot construction. The velour layer of the finished textile has high degree of orientation so that it is relatively flat. In the second production method, the velvety surface of the fabric is not produced by pile loops but by an underlap. The relatively long stretches of yarn, which are not tied in, are either cut open, emerised or raised. The raising process in particular requires a great deal of skill and experience, since as many of the filaments as possible have to be cut cleanly. Otherwise, the fabric could have a felted appearance and the quality would be decreased. An HKS 3-M machine is used if this second method is used to produce the velour. In this case, GB 1 works the underlap. GB 2 and GB 3 produce the ground from polyester filament yarns and work a plain next to a counter notation tricot construction. A soft fabric is produced, which has a high dimensional stability, i.e. a low elongation. Microfibre yarns are often used in this process to enhance the soft feel and the silky, velvety appearance. The third method for producing velour involves using elastane. This stretch yarn produces a fabric having a specific stretch which, when contracted, forces the underlap to the surface. The loops produced are similar to the loops on a pile sinker fabric and can then be cut open. The HKS 3-M or HKS 3-1 are the most suitable machines for this application. Whereas GB 3 of each high-performance tricot machine processes the elastane in a tricot construction, GB 2 works a counter notation tricot construction using polyester filament yarns. GB 1 produces the underlap in an even notation in relation to GB 2 – also using polyester filament yarns. After the shearing process, the finished stretch velour textile is laminated to a firm raised fabric produced on a 2-bar tricot machine. This two-layered construction minimises the stretch required during the process. A stable, velvety fabric is produced with a fluffy layer, which is superior to that produced using the pile sinker technique. Depending on which process is used, there are fine differences in the fabric characteristics and these will decide which is the most suitable process to use. Another factor here is the equipment already available in the plant. For example, if a manufacturer already has the shearing equipment available, then the pile sinker process or the stretch velour technique are the most suitable. KARL MAYER’s product developers are always on hand to give expert help with choosing the best production strategy. For example, in April, the warp knitting expert, Markus Otte, travelled through Turkey to help home textiles manufacturers with a number of technical issues, to discuss the design possibilities offered by warp-knitted velour, and to learn more about trends and developments there. “Development trends are mainly focusing on the structure,” explained Markus Otte. He says that many companies are using thermal embossing machines to create high/low sculptured effects on single-shade fabrics.