According to leading warp knitting machine builder Karl Mayer, warp-knitted spacer fabrics are functional, versatile materials, whose appearance is increasingly setting the scene in their various end-use sectors. 

The company reports that thinner spacer fabrics are used in shoes, padded harnesses, jackets, backpacks, sports protectors and for the side borders of mattresses and car seats – or in other words, in those segments of the market that are particularly influenced by fashion trends.

Since last year, Karl Mayer has been offering a wider selection of new designs and styles, as well as a greater range of functions via its new RD 7/2-12 EL raschel machine.

The latest addition to the company’s range of double needle bar raschel machines was unveiled for the first time at ShanghaiTex in June 2011. With gauges of E 18, 22 and 24, a working width of 138 inches and a maximum knockover comb bar spacing of 12 mm, the new machine is said to be already generating considerable interest among manufacturers.

It has the same basic construction as the RD 6/1-12, but the RD 7/2-12 has an extra guide bar for use in patterning. Up to four of the seven available guide bars can be used to produce each of the cover faces, and up to three can be used to work the pile spacer layer.

Karl Mayer explains that thanks to its EL facility for controlling the guide bars and its Multispeed function, the potential of the new RD model can be fully realised. For example, different styles of high-quality net constructions having unlimited repeat lengths can be produced efficiently, without any problems, the company says. The specific nature of the construction also means that physical characteristics, such as the elasticity or air permeability, can also be adjusted to suit the particular end-use.

Karl Mayer’s product developers have been continuously working on a large number of pattern creations to show just what types of design the machine can achieve. Some of the latest examples are presented below.

Patterns produced on an RD 7/2-12 EL, E 22, 138 inch machine

The set described here is made up of four patterns and was produced by working with customers taking part in a course at the Karl Mayer Academy. The spacer fabrics were produced using five guide bars only but feature a completely new and unconventional design. 

Pattern no. 1 (below) was worked with a distance of 6 mm between the knockover comb bars. Whereas the lower side of the spacer textile has a uniform, filet construction, the upper side features dense segments alternating with comparatively narrow stripes having a loose, open-work pattern.

The striped pattern was produced by uniformly threading-in all the guide bars - 2 in, 2 out - and can be produced with a repeat length of 48 stitches only by the EL version. Lengths of about 4 m are needed when using pattern warps.

Pattern no. 2 (below) has the same textile construction on both sides. The pattern looks as if it has been produced using four ground guide bars, but was actually worked with just two ground guide bars. The standard lapping includes a short repeat and was worked only by the threading-in arrangement.

The arrangement was 2 in, 2 out for producing the lengthwise-running segments consisting of a filet pattern and an adjacent dense area, and 1 in, 1 out to work the dense stripes lying in-between. The dimensions of the segments can be adjusted by varying the threading-in width.

Pattern no. 3 (below) was produced using the same threading-in arrangement as pattern two. The longitudinal striped pattern on one of the sides was worked from a net ground with smooth areas running through it as produced on spacer fabric no. 2.

The other side features a modified form of the pattern shown in fabric no. 1. The dense ground, through which narrow, open-meshed crosswise stripes run, is also covered by longitudinal segments having a dense surface. The dense structure is replaced by a filigree micro-mesh construction at the crossing points with the vertical strands of the net. The large-repeat, lattice-like structure of the pattern is the result of the threading-in arrangement and the EL drive.

Climate-controlling zones and optical effects as well as ready-made edges and fabric borders can be produced by varying the pore shape and the size and the location of the net strands.

The construction of pattern no. 4 (below) is based on the previous version. It was produced using the same threading-in arrangement. On one side, it has the same lattice-like pattern construction of the pattern but with the larger repeat consisting of a thin, horizontal net and dense lengthwise stripes – a theme that is also carried on into the design of the opposite side.

The mesh structure of this design, however, is more airy and has rectangular holes and raised lengthwise ribs. This pattern can also be produced with a repeat length of 86 stitches and can only be worked using the EL control facility.

Ideas for patterning with all the guide bars

Completely new optical effects can be produced by using the whole range of guide bars available, especially if coloured yarns are used. The coloured yarns can be used in an even or counter notation lapping and some can be incorporated adjacent to or on top of each other in the surfaces. The result is an interplay of colours that creates virtual three-dimensional and shot effects. The pores of the mesh structures can also be filled-in in this way with bright colours if required.

The coloured patterns can also be interrupted sequentially on one side and continued through to the other side. This interplay between the surfaces emphasizes the optical 3D characteristics of the fabric.

Interesting coloured effects with different depths of shade can also be created by using brightly coloured pile yarns that shimmer through onto the cover faces. Actual three-dimensional effects can be produced by integrating pile-free zones using the EL control facility.

Another type of design can be produced by modifying the width of the holes in the net and filet patterns in the cover faces by means of distorting.

The simulated images shown in Figs. 5 to 11 give an idea of the patterning capabilities of the RD 7/2-12 EL. In the virtually simulated spacer textiles, the filet structures of the cover faces were each worked by two ground guide bars, and the pile layer was worked by one ground guide bar. The remaining two ground guide bars carried out the actual patterning process.