Example 1 Cadmium Plating of Valve Bodies and Baffle Plates in Still Tanks

Valve bodies and baffle plates are typical of many parts that are plated in still tanks (see Table 5). To cadmium plate the production quantities of these parts given in Table 5, the equipment required is:

Equipment

Specification

Plating tank (1440 L, or 380 gal)

2.7 by 0.76 by 0.76 m (9 by 2 1by 2± ft)

Other tanks (420 L, or 110 gal)

0.91 by 0.76 by 0.76 m (3 by 2 -2-by 2± ft)

Power rectifier (600 A)

1.5 to 6 V

Dimensions of rectifier

0.76 by 0.91 by 2.1 m (2-2 by 3 by 7 ft)

Total floor space of equipment and access area

2.0 by 4.6 m (61 by 15 ft)

Number of racks

15

Other tanks include a cleaning tank, an acid pickle tank, a hot-water rinse tank, and three cold-water rinse tanks. Table 5 Equipment requirements for cadmium plating of valve bodies and baffle plates in still tanks

Production requirements

Valve body

Baffle plate

Weight per piece

1.1 kg (2-1 lb)

0.2 kg (0.5 lb)

Pieces plated per hour

210

175

Area plated per hour

6.5 m2 (70 ft2)

11.1 m2 (120 ft2)

Minimum thickness

8 ^m (320 ^in.)

4 ^m (160 ^in.)

Barrel plating may be used for parts up to 100 mm (4 in.) long and 50 mm (2 in.) thick. Parts such as machine bolts, nuts, and washers are ideal for barrel plating. Conversely, intricate shapes, such as ornaments and complex castings of brittle metals with small sections that fracture easily, should not be barrel plated; the tumbling action may damage these parts, and variation in plating thickness and appearance may result. Intricate designs incorporating recessed or shielded areas may present problems in plating coverage, luster, and appearance. Barrel plating is not applicable for parts requiring heavy plate. Usually, 8 to 13 ^m (320 to 520 ^in.) is the maximum thickness of plate applied.

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