Machinery manufacturer Loepfe says the process of clearing core yarns, is a challenge for the clothing manufacturers, as stretch fabrics become more popular in clothing industry. They are used in sports fashion and in day-to-day garments as well.

Loepfe, manufactures sensors and monitoring equipment for yarn spinning and fabric weaving processes and offers optical yarn clearers, such as the Zenit+ which offer reliability and assist companies in yarn clearing and eliminates yarn faults during winding. Garment made of elastic yarns offer better comfort, better fit, and retain their shapes. Core yarns consist of at least two different components. Core yarns are used for woven and knitted stretch fabrics.

A staple fibre, such as cotton, is spun around an elasthane filament, during production. Loepfe reports that today, duo-core yarns made of three components, are used for high quality denim. These pose a challenge for the spinning and winding process. The structure of core yarns is a challenge, the manufacturer states. The so-called strip-back, for one, is a fault. Because of a slippage between the inner elasthane filament and the staple fibre the core is not completely covered with the cotton fibres. During dyeing, these faults can become visible in the end product, as elasthane and cotton have different characteristics.

Zenit+, which is the yarn clearer from Loepfe, has the optional LabPack, and is designed to identify these faults reliably. Manufactures use an optical method to identify thin and thick faults during winding and even dark foreign fibres can be detected with this optical method. An additional triboelectric sensor detects synthetic foreign matter, for example, polypropylene originating from packaging material.