Leading warp knitting machine builder Karl Mayer has unveiled its new RD 7/2-12 EL double needle bar raschel machine here at ShanghaiTex. The machine is the German company's latest offering in the spacer fabric field and is suitable for the production of 3D knitted spacer fabrics for shoes, linings, orthopaedic bandages and supports, mattress covers, automotive interiors and furniture applications.

The newcomer to Karl Mayer's RD product range, the RD 7/2-12 EL is available in gauges of E 18, 22 and 24 (needles per inch) and operates at a working width of 138 inches (3505mm). The machine is based on the same principles as the RD 6 /1-12 but has one guide bar more than its six-bar sister machine, enabling it to produce a wider range of patterns.

Spacer fabrics of variable thickness

The RD 7/2-12 EL has two needle bars equipped with latch needles, two moveable knock-over stitch comb bars and seven ground guide bars. GB4 and GB5 are stitch forming on both needle bars and optionally GB3, GB4 and GB5 can be stitch forming on both needle bars.

The 2-12 in the RD 7/2-12 EL's name refers to the range of spacer fabrics which can be produced, i.e.  Fabrics of 2-12mm thickness, which can be achieved via the moveable stitch comb bars. EL refers to the electronic control of the machine's seven electronic guide bar drives.

"The RD 7/2-12 EL has been developed over the last six months and the seventh guide bar has been requested by Karl Mayer's customers who wanted greater patterning possibilities, especially in China and Korea where demand is strong," said Karl Mayer China's Chief of Sales Armin Alber.

KAMCOS

The RD 7/2-12 EL is equipped with Karl Mayer's KAMCOS  (Karl Mayer Command System) with Motion Control and Multi Speed for electronic control of basic functions and Pattern Control for electronic control of the ground guide bars.

In terms of warp beam support the machine is equipped with 6 free standing warp beam positions for sectional beams with a flange diameter of 32 inches (812mm). For each warp beam position the RD 7/2-12 EL is fitted with one electronically controlled yarn let-off drive, driven by geared motor which is controlled via the machine's Motion Control.

Fabric take-up is via a 4 roller system with electronic drive and batching is via a free standing batching device with friction drive, having a maximum batch diameter of 50 inches (1270mm).

Electronic guide bar movement control

According to Karl Mayer, a new level of flexibility has been achieved by incorporating the EL guide bar movement control, which is available as an optional configuration and with Multispeed system.

Karl Mayer says it is possible to produce many new variations by superimposing constructions having different colours and densities in the cover faces of 3D products to produce three-dimensional optical effects.

The lengthwise repeat on the RD 7/2012 EL is said to be virtually unlimited and the possibility of adjusting the distance between the knock-over comb bars between 2 and 12 mm also offers an additional advantage in the version equipped with electronic guide bar control.

Manufacturers of shoe fabrics are said to be particularly interested in the extended patterning possibilities of the RD 7/2-12, as well as its high level of efficiency. The machine was producing a polyester patterned shoe fabric at ShanghaiTex in gauge E22 at a set thickness of 6mm on a 138 inch knitting width.  The machine was able to run at a maximum speed of 425 rpm or 850 courses per minute and at a stitch density of 16 courses/cm it yields 23 kg of finished fabric per hour.