Bedded In Method Of Mold Casting And Its Process

If the upper surface of the casting is not flat or must be smoother than the rough surfaces produced by open-sand molds, a solid pattern can also be molded by using a technique known as "bedded In", in which a sand cover or cope is necessary.

In bedded-In method, the pattern is pressed or hammered down to bed it into the sand of the foundry floor or in a drag partially filled with sand to form the mold cavity. To ensure that the sand is properly compacted, careful ramming of the sand close to the pattern is necessary. As a check , the pattern can be drawn and the mold cavity surface tested for soft spots. All soft spots should be filled in with extra sand and the pattern again pressed downward until properly rammed mold cavity is obtained.

After the joint has been smoothed , and parting sand spread , a cope is placed over the pattern. The cope is rammed up, runners and risers cut , and the cope box lifted, leaving the solid pattern in the floor or in the drag as the case may be. The pattern is drawn out, and the surfaces of both parts of the mold finished and the cope box replaced in its correct position to complete the mold.

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Mechinopedia For Mechanical Engineers

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