After determining the geometric characteristics, modulus and other parameters of sand castings, the feeding system can be designed. The following principles should be referred to in the design:
(1) The feeding system should solidify later than the feeding part of sand mold casting, so as to establish a good feeding channel.
(2) When the density requirement of sand castings is high, the feeding system shall be set with reference to its effective feeding distance.
(3) The feeding system shall store sufficient liquid metal for feeding the solid shrinkage and liquid shrinkage of sand castings during solidification and mold expansion during pouring.
(4) The feeding system shall be set at the upper part or side of the hot joint of sand casting, and multiple hot joints shall be fed at the same time as far as possible.
(5) The feeding system shall be designed on the processing surface as far as possible to reduce the amount of cleaning in the later stage.
(6) When designing the feeding system, try to avoid the parts with large load on the sand casting, so as to prevent the coarse grain from affecting the mechanical properties and reduce the service life of the sand casting.
(7) Under the condition of meeting the feeding requirements of sand casting, the volume of feeding system should be designed as small as possible, and the structure should be designed as simple as possible to facilitate modeling.