Seven-channel alternating drawing twist wrap coated ring ingot fancy yarn forming device and method

The invention provides a seven-channel alternating drawing twist wrap coated ring ingot fancy yarn forming device and method. The yarn forming device comprises a first channel, a second channel, a third channel, a fourth channel, a fifth channel, a fifth channel, a sixth channel and a seventh channel. First twisting points and second twisting points are arranged on the channels; first, second, third, fourth, fifth and sixth component yarns are inter-twisted and wrapped through the first twisting points to form a fancy yarn main body; the seventh component yarn wraps and twists the fancy yarn main body to form the fancy yarn through the second twisting points. The device spins the fancy yarn in one step. By regulating the speed of feeding the decorative yarn and the core yarn synergically into the twisting points, the linear density and the blending ratio of the decorative yarn, the twisting degree of the core yarn and switching of the corn yarn and the decorative yarn and the like, online changes of colors an