From Smithells Metals Reference Book, Eighth Edition

26.1 Casting Techniques [1]

TABLE 26.1: TECHNIQUES USING AN EXPENDABLE MOULD AND PATTERN

Investment casting

Full mould

Equivalent terminology

Lost wax casting Precision casting

Cavity-less casting Lost foam

Pattern material

Foamed polystyrene or polyurethane

Foamed poly

Wax, thermoplastics, frozen mercury

Mould material

Silica base ceramic

Slurry + stucco

Silica sand

Full mould

Binder

Ethyl silicate

Magnesium or aluminium phosphate

Usually Na 2SiO 3 or resin (Furane)

Lost foam unbounded

Size range (kg)

Up to 4.5 except frozen Hg for which up to 45

Up to 5 000 in iron

Scope

Complex shapes and fine detail

One-off castings, e.g. jigs and press tools, complex shapes

Alloys cast

High temp Steel Cu base Al base alloys

iron and aluminium castings

Surface finish (CLA)

25 25 125 50 85 50 125

60 250

Minimum section for length

25 mm

1.5 1.0 1.5 12

150 mm

1.5 1.5 1.5 12

Dimensional tolerancet [ ] mm

25 mm

0.13 0.13 0.13 0.6

0.20

150 mm

0.38 0.25 0.18 2.5

0.61

Labour cost per kg

High

Low

Equipment cost per kg

High

Low

Mould material cost

High

Polystyrene pattern approximate cost one third that of wood. Low for unbonded. For other see Table 26.2.

[ ]The following additional tolerances should be added if dimension chosen crosses parting line:

Sand

0.38

Permanent

0.38

Centrifugal

0.25

for a 25mm casting.

Shell

0.25

Plaster

0.25

Shaw

0.10 to 0.15

TABLE 26.2: TECHNIQUES USING AN EXPENDABLE MOULD

Ceramic mould casting

Plaster mould casting

Copyright Elsevier Inc. 2004 under license agreement with Books24x7

Products & Services
Ingots and Casting Stock
Ingots and casting stock are metal and alloy product forms designed for foundry work, die casting, investment casting, and other metal casting applications.
Metal Castings and Cast Stock
Castings and cast stock are metals, alloys, polymers and other materials that are cast into bar, rod, angle, channel, tee, or other shapes.
Foundry Equipment and Supplies
Foundry equipment and foundry supplies used in die casting, investment casting and other metal casting operations.
Zinc and Zinc Alloys
Zinc and zinc alloys are non-ferrous alloys that are used widely in the production of die cast components.

Topics of Interest

27.1 Physical and Mechanical Properties of Engineering Ceramics Intensive development of ceramic materials has increased the availability of well-characterised engineering ceramics capable of use...

12.1 Castings The casting of metals and alloys is an important branch of the metal-working industry. Castings allow parts to be made at a rapid pace with controlled accuracy. Castings replace parts...

12.1 CASTINGS The casting of metals and alloys is an important branch of the metalworking industry and of prime importance to the electromechanical design engineer. Castings allow parts to be made at...

OVERVIEW Aluminium is one of the most versatile of the common foundry metals and the ratio of cast to wrought aluminium alloy products is increasing primarily because of the larger amounts of...

2.1 Introduction In the rotational moulding industry, the vast majority of moulds are made from metal - usually sheet steel, nickel or cast aluminium. The moulds are relatively thin, shell-like...

Product Announcements
Simalex Manufacturing Co. Ltd.
M&P Manufacturing USA, Inc.
Momentum Industries, LLC