Many foundries – especially in large casting – face a problem: up from a certain neck diameter size of the risers used, the residues that remain on the riser can only be knocked off and removed under great effort.
The reason: due to the high thermal load, conventional crusher cores tend to be severely distorted in risers with a module size of more than 5.0 cm in the hand-moulded area.
As a result, large, cauliflower-like structures form at the neck of the riser. This unwanted sintering usually cannot be solved simply by knocking off the remains of the riser, as there is no process-reliable breaking edge. This increases the scrap rate.
In addition, the use of “heavy calibres” when knocking off the risers harbors the risk of excessive mechanical stress on the component. Also breaking in the remains of the riser – which significantly increases the cleaning effort. To solve thes problems, GTP Schäfer developed NETCore ®
NETCore® are crushing cores that are used together with highly exothermic THERMO risers® or cylindrically reduced ECO-ISO fiber risers.
The breaker core material is characterised by a high resistance to penetration and distortion. Furthermore, it disintegrates. Both factors ensure the formation of a clean breaking edge.
A refractory mesh fabric is incorporated into the sinter-free crusher core. This ensures a targeted material weakening. With the result that the riser neck or gate in the area of the mesh is weakened to around 80% of the cross-section. At this predetermined breaking point, you can remove the rest of the riser quickly, safely and without great effort.
“The head feeders could be removed with just a few blows with a hammer and some even fell off in the emptying process. In the case of the internal side feeders, the gentle use of a hydraulic scraper enabled a process-reliable removal of the remainder of the feeder with a significant reduction in the risk of rejects.” Gerd Lorenz, Production Manager HEGER GUSS
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