Figure 2 14 a shows the process of stretch forming of sheet.
Low levels of friction sheet metal forming.
Mishra in friction stir processing for enhanced low temperature formability 2014 sheet metal forming is quite common for making shaped components from soda cans to automotive car bodies.
For the original drawing of the blank 50 reduction is rarely used during industrial manufacturing practice.
It is customary to refer to a material below the thickness of 6 35 mm as a sheet and thicker materials as plate.
For example emmens 6 has found that friction in sheet forming is a function of a variable which is very similar to ss although he places a somewhat different interpretation on its significance.
The ends of sheet are pulled while a die is pressed against the sheet surface.
First redraw is commonly performed at.
The initial reduction is usually 35 to 45.
The amount of forming of the sheet metal that can be accomplished on the first redraw is less than on the original draw.
The sheet metal forming parts will collide with the surrounding objects in the process of raw material inventory manufacturing and shipping.
There are two reasons behind this defect.
The sheet is plastically deformed to the curved form of the die.
This high resistance compels the sheet metal to stretch more than required producing a high amount of thinning and in some cases huge amount of splits as shown in figure 4.
Metal flow is retarded forces and power are increased.
Low die angle surface area is large which.
In most metal forming processes friction is undesirable.
Sheet metal forming to make cup shaped box shaped or other complex curved hollow shaped parts.
Figure 2 14 b illustrates forming of tubular work piece with the help of hydraulic pressure and an axial force.
Conversely when the amount of lubrication applied on the sheet is very low the resistance to motion is very high.
If the interface friction between the strip and rolls is low the neutral section will advance towards exit side and hence the forward slip will also will be low.
At the micro scopic level friction is due to adhesion between contacting as perities 1 2 the ploughing effect between asperities 1 2 and the appearance of hydrodynamic friction stresses 3 4.
In case of rolling the forward slip is an indicator of the friction or effectiveness of lubricant.
Today the simulation of sheet metal forming 5 6 has become essential in the automotive industry for the automotive sheet metal product design die developments die construction and production.