Permanent molds are produced from alloys such as steel or cast iron that can retain its structure at the casting temperature of aluminum. If it is necessary to use cores to produce the parts that are desired to come out empty, again steel or sand cores can be used, depending on the mold design and the ease with which the part comes out of the mold after casting. In the case of using sand cores, it should be noted that this casting method is mentioned as semi-permanent mold casting in some sources.
Errors can be seen in the casting of parts with a section thinner than 4 mm in permanent molds. It should be known that it shows superior properties compared to the sand casting method in terms of mechanical properties. It is generally given as 0.8% as shrinkage.