Design of sand core for parts casting

The design of sand core is very important in the casting process, which directly affects the dimensional accuracy of castings and the interrelated dimensions.

1.Coating thickness

The corresponding coating thickness shall be determined according to the specific conditions and coating types of each manufacturer. Increase the thickness of coating layer in mold design.

2.Clearance between cores

According to the size and structure of the core head, the reasonable core head clearance should be selected. It is generally controlled between 0.1-0.5mm. The gap between the upper core head and the lower core head is large.

3.Core inclination

For the convenience of closing the box, the core head of the sand core shall be designed with draft angle. Generally, the inclination of upper core head is large and that of lower core head is small.

4.Special positioning core head

For the circular core head with direction requirements, notch positioning must be designed to ensure the internal shape and direction of the product is accurate.

5.Pressure ring design

In order to ensure that the sand mold can tightly press the sand core, a circle of semicircle concave groove is often designed on the top surface of the upper pattern core. After molding, a convex annular sand is formed on the upper pattern core. After closing the box, the sand core can be tightly pressed, and the core head is positioned firmly.

6.Anti pressure ring design

At the root of the pattern near the horizontal core head, a raised ring is designed, with a height of 0.5-1mm and a width of 5-10mm. After molding, the corresponding parts form a concave annular gap. When the core is lower and the box is closed, it can prevent the sand mold from collapsing, so it can prevent the sand falling defects.

7.Design of sand squeezing groove

A convex ring is designed at the edge of the core head of the lower pattern, with a depth of about 2-5mm. After molding, a ring groove is formed in the sand mold to store individual scattered sand particles.