The ultra fine gauge single jersey machine trend is led by European machine builders with most of the Asian manufacturers following in their wake. Machine models produced with and without sinkers with gauges up to 60/62 needles per inch are now the norm.
Machine builders have undergone a major rethink regarding knitting head design, knitting actions, knitting elements and tighter engineering tolerances. Finer gauges highlight fabric defects all the more, which are either caused by knitting elements, mechanical tolerances or loop formation methods.
All prominent machine builders experienced these challenges in the past. The elimination of fabric defects has prompted some machine manufacturers to redesign knitting heads, both with sinkers and without in order to overcome them. These new developments have also led to improved machine speeds without compromising fabric quality and performance. The advent of ultra fine gauge machines has also forced yarn spinners to improve the quality of their fine yarn counts and minimise the variances which hitherto would not be seen in coarser gauge fabrics.
The Santoni flagship in its ultra fine large diameter range is the Atlas single jersey model. The Atlas HS model has been designed without loop forming sinker elements. This machine has, however, retained the fabric web holding capacity in the form of holding down jacks; this idea has been patented by Santoni.
The holding down jacks come into play as the cylinder needles are cammed upwards and thus holding down the fabric. As the cylinder needles descend, the jacks are rendered out of action and are not involved in the stitch formation process as the needles reach knock-over point at the top of the precision ground cylinder.
Removing sinkers from the loop formation process eliminates any loop distortions caused by sinker manufacture variance and also movement of the sinkers themselves. Stitch formation is also less prone to yarn breakages that can occur during the “robbing back” syndrome from adjacent knitted loops.
The result is that the knitted loops are compact and smaller than those made on conventional sinker machines. Another advantage of the Atlas model is the avoidance of sinker marks on the fabric which tend to increase as the machine gauge becomes finer on conventional models.
On traditional sinker machines, loops tend to be longer as the yarn is dragged over the sinkers, but because the Atlas knitting action has no sinkers, the shorter stitch length gives compact loops and therefore better fabric density, appearance and handle. It also goes some way to eliminating spirality by reducing the loop twist factor due to compactness of the stitches. The greater fabric density also allows finer yarns to be used when certain fabric weights are required, instead of using coarser bulkier yarns which compromise fabric properties.
Higher fabric density also reduces the residual shrinkage factor present in all weft knitted fabrics. Using the holding down jack system also permits the machine to operate with a reduced fabric takedown, rendering a better and more uniform fabric quality. The holding down jack system allows an easy knitting restart after a fabric press-off.
The Atlas HS has improved cam profiles, taking into consideration angle of impact of the needle butts and needle acceleration at the point of stitch knock over. These studies have led to fewer needles being active in the stitch formation process with a subsequent reduction in stresses as the yarn is fed to needles.
The cam profile also allows the machine to keep the full complement of knit feeds. The improved camming, absence of the sinker ring and related friction together with an in-built air cooling system on the cylinder, enables the machine to perform at a higher operating speed, e.g. a 30in diameter machine can run at 45rpm (conventional gauges).
The Atlas HS model is available in 30in, 32in and 34in diameter and in gauges from 40 n.p.i. up to 62 n.p.i. All models have approximately 2.9 feeds per diametrical inch. The machine is equipped with two cam tracks and can be supplied in open width format or with a traditional tubular frame.
Cam boxes are made from Ergal, an extremely light aluminium alloy that has very good heat dissipation properties which avoids dimensional changes during production cycles. Yarn carriers are made from black Zirconium allowing greater visibility when using elastomeric yarns.
Mayer & Cie has several ultra fine gauge machine models in single jersey which are versatile and give a high performance. The MV 4-3.2 II is Mayer & Cie’s top of the range model for ultra fine gauge fabrics. This machine has a newly designed knitting head.
The new knitting head developments also reduce fluffing, increasing quality and performance. The machine also has individual adjustable sinker cam boxes; double sinker guidance with revised sinker design, which halves the wear and tear factor and ensures a uniform fabric appearance; fewer faults; lower costs and a higher productivity.
This is the result of three years of studies and trials aimed at overcoming horizontal and vertical fabric defects associated with ultra fine gauge machines. Mayer & Cie has more than 5,000 machines in the field in daily use already, which proves the track record of this particular model. The machine is equipped with one, two three or four needle tracks depending on customer requirements. The camming incorporates three needle positions with four types of needle, and various kits can be supplied for different fabric production capabilities.
The stitch cams are diagonally set, giving a clean loop knock-over even for lightweight knits. The diagonal cam system also eliminates the need to reset the yarn feeders. The machine also has a collective central stitch mechanism for making rapid quality adjustments. Machine diameters vary from 26in up to 48in and machines are available in gauges from 12 n.p.i. up to 60 n.p.i. The machine is supplied with short needles for single jersey production and holding down sinkers.
The cam box sections are made from Perunal, a high tech material used in the aerospace industry. This material has outstanding dimensional stability at different temperatures, reducing wear and heat dissipation. Perunal does not oxidise and is substantially harder than conventional materials used for cam box manufacture. Other features of the MV4 – 3.2 II fine gauge machines include a temperature controller, which keeps the machine operating temperature within the range of 33C to 40C.
The temperature controller can also be used to heat up machines after a weekend shutdown using a timer. The machines are then ready to run on the first production shift at the correct temperature.
Other features of the machine include the Coni++ positive feeding system equipped with ceramic pins in the capstan cages to avoid wear and tear. Mayer & Cie also has its own cylinder production within the same group. The machine is available in open width frame format with facilities for producing fabric rolls of up to 600mm and can be supplied with a fabric folding device for use with tubular frames.
In response to market demand and by working closely with several of Europe’s leading fabric producers, Monarch launched its first range of high definition (HD) fine gauge single and double jersey models in 2010.
Because of the positive reaction to this range, Monarch has now developed and introduced additional models, each incorporating the latest technology to ensure maximum productivity and cost efficiency. By pushing forward the barriers of technology, Monarch has provided its customers with the opportunity to create high performance, super lightweight fabrics with and without power stretch and with unique comfort and handle aesthetics, together with a design potential not previously possible.
Customers can now choose from a wide variety of models including the OD4-VSEC7CS single jersey electronic jacquard machine produced in 34in diameter, 44 gauge with 84 feeds and a speed factor of up to 550. Also available is model OD4- VXC3.2, a 30in diameter, 60 gauge, 96 feed machine for the production of super fine basic single jersey structures, with a speed factor of up to 900.
There are some signs indicating a growing demand for fine gauge striped fabrics. The multi-feed single jersey electronic jacquard model SEC-4BFY6 is fitted with F-type 6-colour stripers at each feeder to maximise productivity. Available in 26, 30 and 34in with 30, 42 and 48 feeds respectively, and in gauges up to 36 n.p.i., this model offers 3-needle selection based on SS actuators, whilst the cylinder cams are semi-closed for positive 3- position knit, tuck and welt control.
Designers have the opportunity to create new ranges of fine gauge 6- colour stripers with single jersey electronic jacquard designs or as 6- colour stripes incorporating 3-position structure patterns.
Initially, designers were, by the careful selection of yarns such as polyamide and cotton, in combination with elastomeric yarns, specifically engineering fabric weights, appearance, handle, drape, stretch and power performance, targeting lingerie, intimate apparel, sportswear and men’s underwear. However, Monarch’s design team has been working very closely with customers to develop the second generation of HD fine gauge fabrics for such diverse end-uses as automotive and household textiles as well as apparel.
The Terrot ultra fine gauge single jersey range comprises the S296-1 and S296-2. These two models have been re-engineered giving refined needle and sinker movements during the stitch forming process. They are produced in diameters from 26in to 44in and in gauges up to 54 n.p.i. and have fourcylinder needle tracks. The machines can be supplied in open width format for fabric rolls of up to 800mm with doffing device and 1050mm without doffing device.
The ultra fine contribution from Orizio comes in the form of the JPF and JPA models. These models are produced in 30in diameter and in gauges from 40 up to 52 n.p.i. The JPF has 1.6 feeds per diametrical inch and the JPA has two feeds.
The ultra fine gauge BSM 3.0 model from the Beck group is produced in diameters from 14in up to 42in and in gauges up to 62 n.p.i. The machine has 2.5 feeds per diametrical inch and operates at a peripheral speed of 1.4m/sec. The machine comes with all standard accessories and can be supplied in open width format.