Doubling

Doubling 

the process by which several uniformly drawn threads are combined and then wound in parallel on a bobbin without twisting. Doubling is an auxiliary process in textile production, used to prepare thread for processing on twisters. In doubling, the thread is also cleaned of lint and waste, and the weak and overly thick sections are removed. The thread is cross wound on a cylindrical bobbin, which makes further processing easier.

Doubling is carried out on a doubler. The thread is wound off feed packages, the number of which equals the number of threads to be doubled, and passes over a guide rod. It then passes through a control and cleaning device, which consists of a tension device and two metal plates or blades that form a slit. The width of the slit selected depends on the nominal diameter of the thread; thus, thick sections of thread do not pass through the slit and break the thread. The tension applied causes the thread to break at weak points. The winding speed reaches 500 m/min.

In the production of twisted silk and chemical filaments, doubling is often accompanied by twisting and is carried out on a doubling-and-twisting frame. Spinning-and-twisting frames have been developed that combine the processes of spinning, doubling, twisting, and winding.

V. V. ZHOKHOVSKII