The cutting process is a smelt process. Here cut a hot thin wire the Styrofoam. This wire is heating till 300°C and so it can cut the different foams. This is a touchless process, so it is not necessary to clamp the Styrofoam blocks ore sheets. Only the wire is clamp.
Picture III.11: The hot wire cut the foam
The wire is heat up because the resistance. Here is to observe that the resistance is dependent on different quantities. These are the length, the diameter, the voltage and the amperage. Because safety reasons the voltage have to limited, the maximal value is 40V. This limited the length.
How you can see in the picture 3.1-1, the cutting split is little, but this is dependent on the wire diameter. So the cutting split is 0.7 mm if you use a wire with a diameter of 0.1mm and when you work with a wire of 0.4 mm so the cutting split is 2mm.
The optimal temperature for cutting is 300°C, these was determined trough experiments, because Styrofoam has not a fixed melt temperature. If the wire is 300°C hot then the wire become black. If the temperature is too high, then the wire starts to glow. A higher cutting temperature can’t increase raise the feet, only the cutting split will be bigger, the cut will be inexact and the risk that the material can catch fire is higher.
After the cut wire is 300°C hot, you can begin with cutting. Then the material is moved fore- and backwards by a table ore by pushing per hand or the feed is the gravity. But this is different from machine to machine. In front of the Styrofoam, the hot wire melts it and a split arises. Styrofoam begins to shrink at circa 100°C. It smelt not in drops like other plastic but also shrink at the smelt places. So the foam is cut, without that you can see at the cutting split and that the foam is combine join together.