Customer support is key

Customer service is a priority at Graf’s and professional support for our customers is not just an empty phrase but a promise. This Graf fulfills, from the initial evaluation of the clothings to the installation up to the ?end of life‘ of its products. The esteemed customers can count on proven experts that are at their service on-site as well as in the head office in Rapperswil (CH).

Detailed information on the raw material processed and the intended yarn count are the key parameters in the selection of the correct clothings for the components of a card. While the eventual yarn count can be considered quite easily in the specification in this early stage of the spinning process since it just depends on the fibre length and the carding fineness (eventually the density), the raw material is far more difficult to handle. For cotton and/or man-made fibers Graf differentiates between a total of 25 different processes, each with 2 to 3 production rates and for each process defines a number of different clothing combinations for the main cylinder, doffer, licker-in and flats. These specifications are optimized for the more than 200 types of cards and their characteristics. For rollers with larger diameteres, for example, metallic card clothings with a more aggressive working angle are installed and, depending on the operating speed or the throughput respectively, different densities and tooth shapes are chosen. Not only the wire geometry or the choice of alloy are at the centre of this consideration, but always the interaction of the individual clothings and customer’s machinery, too. Graf, for decades, has gained experience and has optimized its clothing combinations, in some cases specifically for individual types of cards and card makers; resulting in the availability of around 1’500 different clothings to perfectly meet all conceivable requirements of the customers’.

The trash content in the cotton can be compensated to a certain degree by the choice of the clothings, e.g. with more sturdy flat clothings. However there are physical limits resulting in the confrontation with a classical problem of optimization. A lower rate of waste extraction in the blow room increases the material yield and economic efficiency – but also the trash content in the subsequent processes. This causes damage, and the premature wear of the clothings on the card results in lower quality, decreased revenue and an increase in maintenance costs. Graf provides its customers with support in accurately matching the settings in the blow room, mote knives etc. to ensure production in an optimal operating point –economically as well as technically.

Picture 1: Excessive contamination of flat clothing with subsequent damage due to wrong settings in the blow room

Following the selection of the best possible clothing combination, a professional installation and maintenance is decisive for the clothings to perform to their full potential. Graf continuously strives to convey the correct use of its products to its clientele and the quality-assurance laboratory at the head office in Rapperswil provides an indispensable contribution in determining the action required. Most of the defects reported and problems encountered by customers are consequential damage resulting from incorrect handling of material and equipment – which basically is easy to prevent provided the critical points are known and observed.

Common error patterns are illustrated in the picture spread. Horizontal storage or wrong positioning of coil when mounting damages the tooth points of the clothing and renders it unusable from the start (picture 2and3). The periodic markings at the wire base are clearly visible, caused by contact with the tooth points. Quite frequent damage symptons are shown in picture 4-5: a crash of the flat clothings with the cylinder. As a result of the increasing production speeds and working widths of thecards the permissible machinery parameters and tolerances become closer, and as such also the margin for inaccuracies and faults.