General information. Work execution order

Practice work #3

Technology of (one-shot) pattern production in two flasks

Aim: Acquaint students with manually made (one-shot) pattern in two flasks

Equipment and instrument: two flasks, split pattern, molding board, gating system pattern, needle, dry sand, gauze sieve or separator, sand blend (sand).

General information

One-shot patterns production is a complicated operation and it demands attention and care from worker (working man). All the component parts of operation should be carried out in series with the observance of corresponding requirements. It is obligatory should be remembered about application of sand parting(separation)layer on the half-mold surface, otherwise all previous work will be useless. Also, mold parts should be carefully taken out in order not to destroy the pattern.

Work execution order

1. Molding board is placed on the worktable.

2. Mold lower half (that without tenons) is lied on the molding board the opening area downward.

3. Mold is covered with flask so that mold is located in the centre of flask.

4. Molding plate is strewed with fine dry sand, and mold is coated (covered) with facing mixture layer and is swaged around the mold.

5. Flask is filled with backing sand and rammed. Unwanted sand is cleansed by a ruler level with the flask.

6. Canals to the mold are pricked in the pattern by a long needle, for the improvement of mold gas permeability, as it is shown in fig. б.

7. Made half-mold with molding board (plate) is rotated at 180˚.

8. Upper half of mold is installed on its lower half.

9. Lower half-mold is covered with the upper flask, joining them together with the help of pins.

10. Elements of gating system patterns are adjusted, and joint face(parting face, parting) is strewed with dry parting sand (fig. в).

11. Upper flask is filled with facing sand and then with backing sand, they are rammed, and gas flues(gas dusts, gas-escape channels) are pricked (fig. г). Elements of gating system patterns are taken out.

12. Upper half-mold is removed from lower one and also is rotated at 180˚ opening area upwards.

13. Sand blend(sand) is moistened over the mold circuit, molds are loosened slightly right and left, and with the help of a draw screw they are taken away of the pattern.

14. Disturbed mold parts are updated and smoothed(flattened) by appropriate tool(instrument).

15. Final operation is the stowing of a kernel (if it exists), mold assembling and flasks fastening.

The mold is ready for casting of metal in it (fig. e).

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