Category: Mechanical Working Of Metals, Sheet Metal Work, And Powder Metallurgy

Powder metallurgy is a process of making components from metallic powders. Initially, it was used to replace castings for metals which were difficult to melt because of high melting point. The development of technique made it possible to produce a product economically, and today it occupies an important place in the field of metallurgical process.… Continue reading INTRODUCTION OF POWDER METALLURGY

Roll forming is a process by which a metal strip is progressively bent as it passes through a series of forming rolls (Figure 21.28). Figure 21.28 Eight-roll Sequence for the Roll Forming of a Box Channel

The parts having circular cross-section can be made by spinning from thin sheet metal. The principle of metal spinning is that a heated circular blank of sheet metal is lightly held against a chuck by the pressure of a freely rotating pad on the lathe tail stock. A rounded stick or roller is pressed against… Continue reading Hot Spinning

The number of draws is based on the ratio of height and diameter of the cup as given in Table 21.1.   Table 21.1 Number of Draws in Deep Drawing where h, depth of cup; d, shell diameter; D, blank diameter. Both the factors limit the reduction percentage; top limit for the first draw is in between 45 and 48%… Continue reading Number of Draws

If D is the blank diameter in mm, r is the corner radius (in mm), h is the height of the shell as shown in Figure 21.26. Then for thin shells whose wall thickness is t and bottom thickness is T, If wall thickness t is not equal to bottom thickness T which is also the blank thickness. Since, volume before and after drawing is equal. Therefore, . To find… Continue reading Blank Diameter

Deep drawing or drawing is defined as process for the making of cup-shaped parts from flat sheet metal blanks. The blank is first heated to provide necessary plasticity for working. The heated blank is then placed in position over the die or cavity. The punch descends and pushes the metal through the die to form… Continue reading Deep Drawing

In a stretch forming operation, a sheet metal is stretched to yield point in tension and then wrapped over and around the form block (die). This method has the advantage over other forming methods that spring back is either greatly reduced or completely eliminated, since direct bending stress is never introduced. All the plastic deformations… Continue reading Stretch Forming

This is the forming process which causes the sheet metal to undergo the desired shape by bending without failure (Figure 21.24). Figure 21.24 Bending

Punching is a process of producing hole in a flat sheet while blanking is a process of cutting out an intricate shape from the sheet which is known as blank (Figure 21.23). The main difference between punching and blanking is that the main ambition in punching is to hole but in blanking is to cut… Continue reading Punching and Blanking