Method and apparatus for making nonwoven fabric of crimped synthetic fibers

A method of making a nonwoven fabric of crimped synthetic filaments, the method comprising the steps of:

• spinning the synthetic filaments;
• depositing the spun filaments on a conveyor at a deposition location as a nonwoven web;
• drawing main suction air down through the web and the conveyor at a main suction-air speed at the deposition location;
• prebonding the deposited nonwoven web with a hot-air knife constituting a first hot-air bonding device downstream in a travel direction of the conveyor from the deposition location by blowing first hot air down at the web on the conveyor at a first hot-air speed smaller than the main suction-air speed and simultaneously drawing air down through the conveyor and web beneath the first hot-air bonding device at a first suction-air speed smaller than the main suction-air speed and equal to or greater than the first hot-air speed;
• drawing second suction air down through the web and conveyor between the deposition location and the hot-air knife at a second suction-air speed smaller than the main suction-air speed and greater than the first suction-air speed;
• and
• bonding the deposited nonwoven web on the conveyor with a second hot-air bonding device downstream of the hot-air knife by blowing second hot air down at the deposited nonwoven web on the conveyor at a second hot-air speed that is less than the first hot-air speed.