High-quality processing of thermo-plastic material - LiSEC TPA

Thermo-plastic spacers have fought for their place on the market and won. The advantages of this ‚warm edge‘ are familiar
both to construction contractors and manufacturers. LiSEC now offers a concept that takes the entire manufacturing
process into consideration.
The core: LiSEC TPA
The core of the concept is formed by a newly developed system called TPA, which stands for ‚thermo-plastic applicator‘. This
involves a fully-automatic system for applying thermo-plastic spacers directly on the glass sheet. „During the development of this
system, three things were very important to us,“ explains Alexander Kronsteiner, head of product management. „First of all, we
recognised from the start that this could never be an independent system, but rather that the direct application of thermo-plastic
spacer materials would require a well thought-out production process in advance. Secondly, the stability of the system is very
important to us, and finally, we enable a visually undetectable sealing, a nearly ‚endless‘ application of the spacer.“
No stress
The TPA system has been designed so that the system and the material are preserved during the complete process, during which
the material is only pressed. Large-volume containers and gliding pistons are used, and absolutely no toothed wheel pumps that
are subject to wear and tear are present, which roll the spacer material through the system according to the shearing principle.
A heating plate warms the material, and then it is held in an intermediate store, from where it is processed. The highly-precise
and self-regulating dosing via rotary valve reduces stress significantly. Planned dosing quantities and the spacer material that is
actually applied are constantly measured and electronically readjusted if required. Kronsteiner: „This approach offers two advantages:
On the one hand, we control the material quantity with low-maintenance conveyor systems, while on the other hand, this
enables us to offer a self-adjusting option for regulating the material quantity, using electronics that are free of wear and tear,
which means operator independence with constantly perfect quality even if the viscosity changes.“
Uninterrupted production is possible even in case of a drum change, which ultimately also means less stress for technicians and
ensures a stable process. The applicator head is designed in such a way that it is able to be accessed quickly and easily for service
work.
Hardly visible
The LiSEC TPA system enables sealing during the application of thermo-plastic spacer material that is hardly visible when integrated
and that also ensures that the spacer is applied absolutely diffusion-tight. Kronsteiner: „In a dedicated step, the spacer
material is pressed carefully into a mould chamber at the sealing position. The result is really unique, and in terms of the resulting
look and process safety, it can‘t be compared with conventional solutions.“
Line principle
In order to make this approach perfect in reality, LiSEC offers the solution as a line concept. This is most suitable for process steps
like assembly, gas filling, and pressing, which have special requirements during application of the thermo-plastic material. In this
case, LiSEC‘s patented system plays a special role, whereby the gas is filled without swirling from below and without the need
for bending the glass sheet. “The line principle goes back to the subject of logistics; even in this case, insulating glass elements
produced using thermo-plastic spacers require special treatment,“ adds Kronsteiner. In spite of soft spacers, the insulating glass
element should remain inherently stable until the sealing material has hardened. The logistics solution offered by LiSEC consists
of an automatic unloading station and a special insulating glass buffer. „Only in this way the resulting quality can be permanently
ensured during application,“ concludes Kronsteiner.