To make a green sand mould of half bearing block.

Experiment No. : 03

Aim: –

To make a green sand mould of half bearing block.

Materials Required: –

Moulding Box.

Diagram: –

Procedures: –

1. Initially a suitable size of molding box for creating suitable wall thickness is selected for a two piece pattern. Sufficient care, should be taken in such that the molding box must adjust mold cavity, riser and the gating system.
2. Next, place the drag portion of the pattern with the pattern with the parting surface down on the bottom (ram-up) board.
3. The facing sand is then sprinkled carefully all around the pattern so that the pattern does not stick with molding sand during withdrawn of the pattern.
4. The drag is then filled with loose prepared molding sand and ramming of the molding sand is done uniformly in the molding box around the pattern, fill the molding sand once again and then perform ramming, Repeat the process three four times.
5. the excess amount of sand is then removed using strike off bar to bring molding sand at the same level of the molding flask height to complete. the drag.
6. The drag is then rolled over and the parting is sprinkled over on the top of the drag.
7. Now, the cope, pattern is placed on the drag pattern (such that the proper dimensioning is not disturbed) and alignment is done using dowel pins.
8. The cope (flask) is placed over the rammed drag and parting sand is sprinkled all around cope, pattern.
9. Sprue and riser pins are placed in vertically position at suitable locations using support of molding sound. It will help to form suitable sized cavities for pouring molten metal.
10. Strike off the excess sand from the top of the cope.
11. Remove sprue and riser pins and create, vent holes in the cope with vent wire.
12. Sprinkle parting sand over the top of the surface and roll over cope on the bottom board.
13. Rap and remove both the cope and drag pattern and repair the mold suitably if needed and dressing is applied.
14. The gats is then cut connecting the lower base of sprue basin with rummer and then the mold cavity.
15. Apply mold coating with a swab.
16. The cores in the mold, as needed for half bearing block and close the mold by inverting cope over drag.
17. The cope is then clamped with drag and the mold is ready for pouring.

Safety and Precautions: –

1. Ramming of filled sand should be proper and uniform through out the surface of drag and cope.
2. Place the pattern in the drag properly.
3. Make the gats properly with broadening at the gats point.
4. The cope and drag should fit properly.
5. Take out the pattern carefully causing minimum damage.
6. Molten metal should be poured into the mould cavity carefully to avoid any kind of accident.
7. Do hot touch the casting immediately after taking out of the sand mold.