Production Process
Polysterene
EPS (Sintered Expanded Polystyrene) is a material produced from styrene, a monomer derived from petroleum, but also found in foods such as wheat, strawberries, meat and coffee; polystyrene is obtained through the polymerization of styrene. Before being expanded, the polystyrene is in glassy granule form (beads) with sizes ranging from 0.3 to 2.8 mm.
Pre-expansion
Pre-expansion is the physical-chemical process that leads to the formation of the polystyrene beads by heating the polystyrene without using CFCs. The beads are then treated with water vapour at temperatures above 90°C to allow the pentane in the beads to expand, causing an increase in their initial volume by up to 20-25 times and forming an internal closed cell structure that holds air and gives the product its excellent thermal insulation properties.
Sintering (Moulding)
During the “sintering” (moulding) process, the expanded polystyrene beads are welded and compressed. The expanded and dried beads are injected into a mould and are again subjected to vapour that causes a further swelling. This process completely closes the interstices between the beads that when welded together create a homogeneous block of foam. After cooling, these blocks are left to cure before final cutting into slabs.
Cutting and Shaping
The blocks are cut and shaped by a CNC hot-wire, high-precision cutter which is programmed by the operator according to specific job requirements.
Unrolling and straightening of metal wire
The welding machine systems of NXT Panels feed the longitudinal wire through an automatic towing machine system, which picks directly from the 20 loading bobbins that ensure that wires are straight.
Stitching the Sandwich Panel
The panel assembly and welding machine are the core of the entire production line; in this phase, the “sandwich” is made of two or four electro-welded meshes and one or two EPS panels, according to the type of panel to be produced.
Welding and Cutting Mesh:
The NXT automatic welding machine produces galvanized flat steel meshes made up of 20 longitudinal wires and cross wires at variable pitch. The meshes are automatically produced to size then lifted by an automatic device and stacked on a steel pallet ready for transfer to a panel machine.
