1. List all casting methods with high precision You know.

1. Odlewnictwo ciśnieniowe -die casting

2. Odlewnictwo odśrodkowe – centrifugal casting

3. Odlewanie skorupowe – shell mold casting

4. Odlewanie kokilowe - permanent mold casting

5. Metoda pełnej formy - lost foam process

6. Metoda Shaw’a – the Shaw process

7. Metoda wytapianych modeli – investment casting

8. Metoda Mario di Maio – investment casting plaster

2. Write everything You know about making a pattern (what is it, materials, technological requirements, …)

Pattern is a replica of the object to be cast, used to prepare the mold into which molten material will be poured during the casting process.

Patterns may be made of: wood, metal, plastics, clay, gypsum, wax (lost wax method), polystyrene (lost foam process).

Patterns are made to: exact standards of construction, so that they can last for a reasonable length of time, according to the quality grade of the pattern being built, and so that they will repeatably provide a dimensionally acceptable casting.

The pattern needs to incorporate suitable allowances for shrinkage (contraction allowances). Their exact values depend on the alloy being cast and the exact casting method being used.

Draft allowance -To avoid leading edges from breaking off, when the pattern is removed from mold, on the pattern is provided a taper. It facilitates easy removal of the pattern from the mold, and reduce damage to edges. The taper angle provided is called the Draft angle.

Distortion allowance - During cooling of the mold, stresses developed in the solid metal may induce distortions in the cast. This is more evident when the mold is thinner in width as compared to its length. This can be eliminated by initially distorting the pattern in the opposite direction.

3. Lost foam process – a diagram

4. Investment casting plaster – characteristic of Mario di Maio method

1. Pattern and sprue system are made by injection of special wax into a metal or pattern (Figure 1 - wax tree)

2. Mould mass – special plaster used to produce castings of the lower melting temperature metals (e. g. aluminum alloys).

3. Making a mould – in one step (pouring a plaster into a special cylindrical flask with

4. process is generally used for small castings (e. g. jewellery).

5. high production rates.

6. high dimensional accuracy and consistency.

7. Extremely good surface finish obtained (little or no machining is necessary).

8. complex shapes can be cast.

9. Minimum shot blast and grinding needed

10. Environmentally good

11. Specialised equipment needed

5. Advantages and disadvantages of Mario do Maio casting method

Advantages:

Can form complex shapes and fine details

High strength parts

Very good surface finish and accuracy

Little need for secondary machining

High production rate

Disadvantages:

High labor cost

High tooling cost

Long lead time possible

Limited material options (only low melting point)