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Exothermic or insulating risers are open or closed cavities within a casting mould, which are filled simultaneously, along with the casting, with liquid metal. In order to prevent the final piece from shrinking, risers should be designed in such a way that the solidification module is larger than that of the junction to the cast piece. Due to the larger solidification module, the riser keeps the metal contained inside longer in a liquid state, thus providing time to balance the volume deficit in the solidification phase of the piece. In this way, the final point of solidification occurs within the riser and the sealing of the cast piece is ensured.
THERMO-risers are thick-walled risers which enable feed metal utilization of up to 60-70%. The properties of the solid riser wall range from highly exothermic to highly insulating, according to the intended application. The optimized material properties and the adapted volume enable substantial improvements in output and economic efficiency. A modulus range between 0.8 cm and around 8 cm can be covered with risers from this product segment.
In order to cover this broad modulus range, our formulations are tailored to the different geometries concerned. This enables modulus-specific factors such as firing temperature, ignition, burn-off and heating time to be optimized. The particularly robust design of the THERMO-risers means that they are equally suitable for use in hand molding shops or in automatic high-pressure molding lines. Fixed pins or spring-loaded pins can be used, according to the underlying conditions and the application concerned.
The sintering tendency of the riser rests allows them to be separated from the remaining molding sand virtually in their entirety in the course of the shake-out process. In addition to the broad selection of different riser geometries, a choice of different qualities is also available.
POINT risers® are thick-walled risers which enable feed metal utilization of up to 60-70%. They have been developed especially for demanding applications in modern high-pressure molding lines. The properties of the solid riser wall range from highly exothermic to highly insulating, according to the intended application. The optimized material properties and the adapted volume enable substantial improvements in output and economic efficiency.
The self-centering inner contour ensures fast charging of the pattern plate with risers in sync with the molding plant. The small neck of the riser only requires the area of the metal connection channel between casting and riser. In contrast to risers with a breaker core, this enables absolutely accurate positioning of the riser. These risers can thus be used on the smallest items, such as cams or fins.
During pouring of the molding sand into the molding box, the POINT risers® are initially held up by a pin. As the molding sand is compacted, the riser is moved in the direction of the pattern, thus compacting the molding sand between riser and pattern. The casting contour under the riser is produced by the molding sand which is molded between riser and casting in the form of a breaker core. The neatly formed casting contour is only interrupted by the small metal riser neck.