CASE STUDY OF A LARGE RATCHET WRENCH - Essay Example

In terms of shape, it is a flat tapering part in the lower end and has an expanded closed head-end with precise dimensions. Head-end requires to be sufficiently hard to resist wear during use. The material specifications, product size and weight of the handle are important factors in the selection of the right combination of materials and production process. a. Fabrication & machining method: The head-end and the long arm can be fabricated as separate parts. The head-end itself can be made in two halves using press machines, to be assembled and welded to form the final shape.

The arm part can be produced by gas cutting or on profile cutting machine and welded to the base of the head-end. The finished assembly is then annealed, machined on shaping machines to the required profiles and hand-finished by grinding for obtaining smooth finish. The completed component is then sent for heat treatment and chrome plating. This process is elaborate and time consuming and is not suitable for production in large numbers. It can not also be used for non-weldable materials. However, when small quantities are to be produced this method is economical since investment in casting and forging facilities and special tooling can be avoided. b. Casting: The part can be produced by the simple process of sand casting when the required volumes of production are not too high.

Castings are easy to produce since technology is well established. Investment costs are not high and the same facilities can be used for any number of differently shaped castings of different materials. c. Forging: This method is most suitable and is common for producing large numbers of very high quality pieces. Recurring expenses on costly dies is one consideration. On the other hand, we can get uniformly high quality product that requires little finishing. Considering the yield strength and elongation specifications given, we can use alloy carbon steel materials for all the three processes.

Alloy carbon