An investigation into the effect of licker-in design on carding performance
Carding is one of the most important preparatory processes in the short-staple spinning of yarn from a raw material such as cotton. The main purpose of carding is to individualise fibres thoroughly so that they can be spun into yarns. Therefore, the quality of the yarns spun and the quality of fabrics produced from them is largely determined by the effectiveness of the carding process. The design of the licker-in zone determines the degree of pre-opening, and so plays a major role in determining the carding efficiency. This work investigates and evaluates the influence and effectiveness of licker-in design in determining the quality of carded yarns and the fibre configurations in yarn with the two licker-in designs in use today, viz. the single and triple licker-in designs. Two Indian cotton fibre varieties with widely differing characteristics were processed on a commercial high-production card using the single and triple licker-in systems. The quality of yarns spun revealed that licker-in design indeed has a bearing on fibre, yarn and fabric quality. Test results show that whilst the triple licker-in system demonstrated a relative improvement in the yarn quality when processing the medium staple cotton of average fineness, the single licker-in was observed to be more suitable for the longer and finer variety. The analysis of the fibre configuration in yarns indicates that licker-in designs as well as the processing parameters such as licker-in speed and carding rate have an influence on the fibre configuration. Yarns spun using the material processed through the triple licker-in showed more disorder than those of the single licker-in. Finally, an investigation into the fibre opening at the licker-in using high-speed video photography indicates that the degree of opening and the fibre orientation on the licker-in surface before fibre transfer to the main carding cylinder is different between the two licker-in systems. The degree of opening and fibre orientation were also found to depend on the cotton variety, the production rate and licker-in parameters such as speed.