(1) Determination of parting surface

Mold parting surface refers to the joint surface between mold members. The quality of parting surface affects the dimensional accuracy, cost productivity of castings to a great extent. The following principles should be considered when selecting parting surface:

1. In order to ensure the casting accuracy, the mechanical casting factory shall place all most of the castings in the lower sand box as far as possible.

2. Try to put the processing positioning surface main processing surface of the casting in the same sand box to reduce the dimensional deviation of processing positioning.

3. Try to reduce the number of parting surface to simplify the molding operation improve the mold precision.

4. Machining of mechanical casting. In order to facilitate box closing sand core inspection, the basic sand core shall be located in the lower mold as far as possible.

5. The mechanical casting shall be customized with flat parting surface as far as possible to reduce the workload of casting pattern other process equipment.

6. The parting surface shall be selected at the section of the casting to facilitate mold lifting.

7. The parting surface shall be consistent with the pouring position as far as possible, so as to avoid inaccurate casting size caused by turning over the box.

The structure of tee pipe casting is completely symmetrical, its symmetrical surface can be selected as parting surface, which only ensures that the parting surface is on the large curved surface of the pipe fitting, but also facilitates the lamination of the die; at the same time, only one kind of foaming is needed for the completely symmetrical the same parting, so as to greatly improve the production efficiency reduce the labor level.

(2) Stripping angle of EPC

The outstanding advantage of EPC process is dry sand molding, no need to lift, lower core, close box other processes, no need to design the demoulding angle, but in the process of making EPS pattern, there is a certain friction resistance between Yo the mold the pattern, 0.5 ° demoulding angle should be considered in the mold design.

Negative number of typing

For dry sand mold, surface drying mold large size wet sand mold, the parting surface is generally smooth due to baking, finishing other reasons, the upper lower contact surfaces are strict. In order to prevent fire during pouring, asbestos rope mud strip should be padded between the parting surfaces before closing the box, so that the size of the casting is increased obviously at the parting surface. In order to ensure the casting size, it is called negative parting number to subtract the corresponding size the pattern in order to offset the increased size of the casting in the proposed process. The negative number of tee is considered because it is a wet type a small casting.