Process selection and sequencing, Mechanical Engineering

Process Selection and Sequencing

In this, some factors, which have an influence in all processes, are discussed. The factors include size, shape complexity, tolerances and production volume.

After product consideration, selection of sequence of process is greatly influenced by the characteristics of the manufacturing processes. Hence a brief treatment of various manufacturing process right from casting to welding are discussed.

In all casting processes, a metal or alloy is melted, poured into a mold, allowed to solidify and the part thus produced is released from the mold. Very broadly, casting processes fall into two groups: expendable-mold and permanent-mold processes. Choice of process and mold material is greatly influenced by the melting point of the alloy.

All plastic deformation processes exploit the ability of metals and alloys to change shape by plastic flow. The ability to deform without fracture is highly variable. Bulk deformation processes impose material flow in all directions, and the ability to deform is expressed as workability; in sheet metal working processes deformation is essentially two-dimensional, and limits of deformation are referred to as formability. It is important to recognize that the limits of plastic deformation are the outputs of a system and these are greatly affected by the stress state prevailing in the process.

Powder processing involves a sequence of operations. The powder is produced by various techniques: reduction of an oxide, thermal decomposition, electrolysis, hydrometallurgy, or breaking up (atomizing) a melt. Particle size is controlled during powder production or by comminution; size fractions are separated by sizing. After cleaning (and possibly annealing), alloying elements and lubricants are added by blending. There are several process routes to arrive at finished parts.

Parts produced by casting, deformation, and powder processing techniques frequently require some metal removal to create the final shape, meet tolerances, or obtain the requisite surface finish. Machining may also be an economical alternative to create the shaper from a semi fabricated product such as bar or plate. Metal may be removed by chip formation or by less conventional, noncutting techniques.

A good manufacturing sequence is always determined by selecting suitable terminal points. Hence such a sequence must begin and end with part prints. Before formulating any process plan, the process engineer find out what is wanted in the final product. At the end of manufacturing sequence, the process engineer must again make reference to the part print to determine by comparison whether or not the final product can meet all design specifications.

Posted Date: 12/24/2012 4:24:09 AM | Location : United States







Related Discussions:- Process selection and sequencing, Assignment Help, Ask Question on Process selection and sequencing, Get Answer, Expert's Help, Process selection and sequencing Discussions

Write discussion on Process selection and sequencing
Your posts are moderated
Related Questions
Leakage flux : The flux that links the coil only partially passes through the core does not link the coil as the moving or rotating device is called leakage flux.

What is Data Unification To optimize the UPR data structures, during design we study the semantics of each data type of the supported CAD systems and identify data types that a

(a) Describe that internal energy is property of the system. (b) one kg of air at 1 bar and 300k is compressed adiabatically till its pressure becomes 5 times the original press

Kineti c (Dynamic) Friction: When applied force exceeds limiting friction the body starts moving over the other body and the friction of resistance experienced by the body a

Q. Corrosion in Steam Condensate System? Carbon dioxide and oxygen, either acting alone or in combination, account for the majority of steel corrosion problems in the condensat

FLUX SHIELDED ARC WELDING This process is popularly known as Submerged Arc Welding (SAW).This is a fully mechanised welding process. The electrode is a continuous metallic sol

What is melting point of aluminium?

If Engine Does Not Start at Cranking Speed Causes of Problem Remedy Incorrect electrode gap of spark plug Fouled spar

A load of 1.9 MN is applied on a short concrete column 300mm x 300mm. The column is reinforced with four steel bars of 10mm diameter, one in each corner. Evaluate the stresses in t

Q. Design evacuation systems for plant? The plant will have designated Muster areas where personnel can go during an emergency and be accounted for and from which they can then