Method for making a fiber fleece

A method of making a nonwoven spun-bond or melt-blown fabric, the method comprising the steps of:

• extruding thermoplastic filaments from a spinneret in a travel direction;
• receiving and cooling the spun filaments downstream in the direction from the spinneret with a cooler;
• stretching the cooled filaments downstream in the direction of the cooler with a stretcher;
• depositing the stretched and cooled filaments on a conveyor to form thereon a nonwoven web;
• determining respective different reference parameters for the spinneret, cooler, stretcher, and/or conveyor representing normal trouble-free operation thereof;
• generating respective input parameters different from one another and from the respective reference parameters with respective sensors at the spinneret, cooler, stretcher, and/or conveyor during operation of the system;
• evaluating the input parameters and generating respective different output parameters representing the evaluation;
• comparing the output parameters with the respective reference parameters and, when the comparison reveals a deviation of at least one of the output parameters from the respective reference parameter, generating an alarm signal;
• compacting the nonwoven web with a calender of a compacter, the reference or output parameters being from the group comprised of:
• firmness of the nonwoven web in a machine direction, firmness of the nonwoven web transverse to the machine direction, stretchability of the nonwoven web in the machine direction, stretchability of the nonwoven web transverse to the machine direction, and nonwoven web thickness, the input parameters being selected from the group comprised of:
• process air pressure, process air temperature, process air volumetric flow rate, speed of at least one calender roll, calender temperature of at least one calender roll, calender engraving, speed of the mesh conveyor belt, and melt flow index of the plastic used for the filaments;
• and
• using a mesh conveyor belt as the conveyor, the reference or output parameters being selected from the group comprised of:
• screen belt wear, particularly screen belt attrition and screen belt clogging, the input parameters being from the group comprised of:
• process air volumetric flow rate of the process air suctioned through the screen belt, process air speed of the process air suctioned through the screen belt, screen belt speed, process air temperature, and monomer volumetric flow rate.

A method of making a nonwoven spun-bond fabric, the method comprising the steps of:

• extruding thermoplastic filaments from a spinneret in a travel direction;
• passing the extruded filaments through a cooling chamber;
• introducing process air into the cooling chamber from at least one air-supply compartment with a blower and thereby cooling the filaments in the chamber;
• extracting monomers between the spinneret and the cooling chamber;
• stretching the cooled filaments downstream in the direction of the cooler with a stretcher;
• passing the stretched filaments through a diffusor;
• receiving the filaments from the diffuser and depositing them on a conveyor to form thereon a nonwoven web;
• determining a single reference parameter s for the spinneret, cooler, stretcher, and/or conveyor representing normal trouble-free operation thereof;
• selecting input parameters different from one another and from the reference parameter from the group comprising melt temperature, monomer-flow rate, process-air temperature, blower speed, width of a downstream end of the stretcher, and position of walls of the diffuser;
• evaluating the input parameters and generating a single output parameter representing the evaluation, the reference parameters or the output parameter being cooling-chamber pressure;
• comparing the output parameter with the reference parameter and, when the comparison reveals a deviation of the output parameter from the reference parameter, generating an alarm signal.