Ultrasonic Thermofixing
Compared with conventional processes, ultrasonic thermofixing (UST) grants a far lower energy consumption, far smaller machines and an important reduction of the quantity of material inside the machine.
SONOTRONIC projected the highly developed ultrasonic technology on a new range of application, developing an effective procedure for thermic processing of narrow fabrics. The decisive innovation lies in the fact that the heat which is needed for thermofixing is generated directly inside the material by the ultrasonic effect.
Therefore the generator transforms the line voltage in high frequency voltage which is transferred to the ultrasonic converter. The converter converts the incoming voltage into mechanical oscillations of the same frequency which is lead into the material via the booster and the sonotrode (welding tool). These oscillations are brought into the material in vertical direction and under pressure where they are absorbed generating interfacial and molecular friction. The result is a local temperature rise of the material (ex: PA, PES, PP, cotton, aramid, dyneema®, glass silk, nonwoven as also blended textiles).
In our patented ultrasonic thermofixing process, the material is continuously pulled through the gap between the anvil (which is designed to exert an adjustable pressure) and the sonotrode. This is how the ultrasonic oscillation generates the requested temperature directly inside the material. The ultrasonic oscillation generates also a calandering effect inside the material. The transport of the material is done by speed-adapted drives, located before and after the ultrasonic units. If necessary, it is possible to use these drives to generate a traction tension, in order to maintain a constant shrinking or stretching of the material.
Schematic representation of an ultrasonic thermofixing machine
- Intake
mechanism with stretching device
Driven material intake with integrated stretching device which is adaptable to the material's characteristics.
Takeover of the material from a dyeing or from a finishing machine or simply from a cardboard box. - Two,
four, six or even more ultrasonic units with 20 or 35 kHz (the quantity
and the frequency depends from the needed processing intensity) generate
the necessary temperature inside the material.
It is possible to influence the material's width by using a special anvil technology. - Heating-up
chamber
Depending from the particular application: An adapted supply of electrically generated heat in order to maintain temperature constant inside the material for a certain period of time. - Outlet
mechanism with stretching device.
Driven material outlet with integrated stretching device which is adaptable to the material's characteristics.
Transfer of the material to a further cooling down device (depending from the specific application), to an inspecting installation, to a coiling station or to an edging installation. - Controller
Controlling of the installation.
Storing and retrieving of product data and of application linked parameters.
The patented ultrasonic thermofixing process distinguishes itself in particular through its high flexibility: The maximum temperature and the maximum speed are quickly attained thanks to the direct character of ultrasounds. So stopping and starting of the machine is possible at any time. The long heating-up phases with their high energy costs belong to the past. The total energy saving effect lies at up to 90% in confront with conventional installations, because ultrasonic oscillations have a very direct effect on the material: The necessary heat is generated in a split second.
The big advantage is that only a few meters of material are inside the ultrasonic thermofixing machine during the thermofixing process, what affects a respectively compact size of the machine. Therefore ultrasonic thermofixing makes possible an easy processing of smaller batches of material. The respective product parameters can be stored in the controller and can be retrieved at any time.
Infrared picture of a sonotrode and a belt during the ultrasonic thermofixing process |
