This is done by a three-dimensional knitting machine.

这是由三维针织机完成的。

Then, yarns are sent to the mill, where huge circular knitting machines weave them into sheets of rough grayish fabric treated with heat and chemicals until they turn soft and white.

然后，纱线被送到工厂，在那里巨大的圆形针织机将它们编织成粗糙的灰色织物片，这些织物经过热处理和化学处理，直到它们变得柔软和白色。

Knitting machines are not difficult in the sense that they only do a very small number of things. But coordinating those things to happen at the right time at the right speed etc is hard to think about.

想要针织机少量生产是不难的。但要在正确的时间以适当的速度协调这些事情发生，就不容易了。