Procedure of Making a Mould of Simple Block

Write down the complete procedure (step by step) of making a mould of simple block.

Procedure of Making a Mould of Simple Block

Procedure of Making a Mould of Simple Block

1. Place the pattern on a wooden turnover board. Later, place a molding box on the board.

2. Fill the molding sand with a hand-shovel around the pattern Press the sand evenly with a rammer.

3. Pour more sand till it covers the pattern and then ram It properly. The number of intermediate ramming stages will depend upon the depth through, which the sand is to be tilled.

4. Add more sand so as to rais-e the level by nearly 4 cm. over the molding box edges. Then use a fiat or butt rammer for producing a flat surface of well-pressed sand extending about 6 mm. above the box.

5. Remove this extending layer of sand with the help of a stickle bar.

6. Sprinkle a little amount of “parting sand on the face of the sand box. Use a venting rod to prick deep through the sand as to provide a number of venting holes in the sand to allow undesired gases.

7. Now lift up the box from turnover board. Invert the box and place it again on the board. Use a trowel to smoothen sand surface and to make it in line with the pattern face. Sprinikle a little amount of parting sand on the face of molding box except the pattern.

8. Place another molding box on the first on and clamp the two boxes together. Insert two tapered rods (gate pin and raiser rod) A and B in the sand of the lower bow. Then pour sand in the upper box and ram it. The sand surrounding these two rods is properly rammed to keep them standing in vertical position level the top surface of the sand with a smoother. Vent with a venting rod. After that take out the two rods A and B resulting in the formation of two holes, one (pouring spree) of them is for molten metal that will be poured in the mold and the other (riser hole) will be left for escaping the ga.es or any slag in suspension with the liquid metal. Enlarge the metal receiving end of the pouring sprue with the help of a gate knife. Remove the clamp and pick up the upper box. Turn it ever and place it on the floor, Brush off all parting sand and damp up the pattern edges with a swab .

10. Drive a pattern lifer in the pattern, loosen the pattern in the sand by lateral rapping and take it out from there. Make necessary channel connection for the flow of molten metal from the bottom of pouring sprue to the mold cavity and then to the riser hole. Mend the mold with the help of trowel, cleaner or sleeker as per conditions of the breakage in mold.

11. Use a hand blower to clean sand or dirt from mold cavity. Apply some refractory blacking to the mold faces which come in contact with molten metal. Carefully place the top box over the lower one and clamp the two boxes together. A sectional view of this state is shown in Figure. Put some weight resting on the upper box walls so that during the process of casting, due to the pressure of metal, the upper box sand may not disturb its position. Weight should cause no hindrance to the vents.

12. Now pour molten metal is the mold through the pouring sprue and see that it fills the mold and then comes up to the top of riser hole. Allow the contents of the boxes to cool. After that take out the casting from the sand. It will have a shape nearly similar to that shown in Figure. Remove surplus metal of sprue and riser with the help of a chisel and hammer. Grind roughly if so desired.