Parting surface refers to the surface on which two half molds contact each other. The selection of parting surface has a great influence on the precision, production cost and productivity of castings. The following principles should be paid attention to when selecting parting surface:

1.Place the whole casting or its main processing surface and reference surface in the same sand box as far as possible;

2.Reduce the number of parting surfaces as much as possible;

3.Try to choose plane type;

4.The parting surface shall be selected at the maximum projection surface of the casting;

5.Use as little sand core as possible;

6.Avoid flash on the non machined surface of the casting as much as possible;

7.Reduce the height of sand box as much as possible;

8.The selection of parting surface of stressed parts shall not weaken the structural strength of castings;

9.It is beneficial to lower core, checking and closing.

There are three maximum sections of the support table parts, which can be divided into axial and radial types. Radial parting has two parting surfaces, a and B under the upper and lower flanges. It needs to use three boxes for modeling, with complex technology, a large number of sand boxes and prone to errors such as wrong boxes, and low production efficiency. The axial parting is a parting surface, which is divided into two boxes on the vertical axis of the part. It is easy to start, lower core and check mold, and the parting surface is the same as the parting surface, so axial parting is selected.