Why Use Feeder Sleeves? During the condensation process, if the volume reduced cannot be replenished, some holes will be formed in the casting. The large and concentrated ones are called shrinkage pores, and the small and scattered ones are called shrinkage porosity.
A common process measure to prevent shrinkage cavities and shrinkage porosity is to control the solidification sequence of the castings, so that the castings can achieve “sequential solidification”. The feeder sleeve is a cavity in the mold for storing molten metal. During the process of metal cooling and solidification, the molten metal is replenished to prevent the formation of shrinkage cavities and shrinkage porosity. At the same time, it also has the functions of slag collection and exhaust gas. Traditionally, the metal entity cast by the feeder sleeve is also called the exothermic riser sleeve.
① Above or beside the hot section.
②Try to set up subsidies or cold iron in the highest and thickest parts of the castings and the lower part of the hot junction.
③ It should not be located in the most important and stress-bearing part of the casting.
④Do not choose the place where the casting stress is concentrated, the shrinkage barrier to the casting should be reduced, and cracks should be avoided.
⑤ Try to use one riser to feed several hot joints or castings at the same time.
⑥The riser is arranged on the processing surface, which can save the casting finishing time and has a good appearance.
⑦ For the risers of different heights, use cold iron to separate the feeding range of each riser.
The above is the selection principle of the position of the riser. Would you like to learn more about packing sleeves? Welcome to consult at [email protected].