WIRE DRAWING: DRAWING Typical drawing processes: 1.Single draft drawing 2.Tandem Drawing - Cold working improves the mechanical properties - Intermediate annealing is required to restore ductility if subsequent drawing is required - Wire from drawing machines, while arranged in tandem, is coiled in a drum (run by motors) up to a sufficient length before it reenters into the subsequent die. - Sometimes it involves dipping the wire inside a lubricant bath before the next stage

# PRESS TOOL WORK # FORMING ** Possibly the cheapest and fastest way of manufacturing various components ** We could not have even thought of having mechanical toys to automobiles, household vessels to aerospace parts, or aircraft bodies etc at such low cost.  Operations carried out by press tools are mostly on Sheet Metals  Sheets are rolled products, which have thickness less than 6mm or large surface area to thickness ratio  Sheet metal forming involves predominantly tensile, shear or combination of forces and stretching or shrinking the sheet metal blanks.  Hydraulic or mechanical presses called stamping presses are used for the forming process  Die – punch combination is used for the process to impart the desired shape to the blank.

# PRESS TOOL WORK # FORMING SHEARING: a primary discussion…. A process of cutting off of sheets using a die and punch, applying shear stress along the thickness of the sheet. A die and punch or a pair of blades are used. Shearing happens by severe plastic deformation locally followed by fracture propagating deeper into the thickness of the blank. The clearance between the die and punch is an important parameter which decides the shape of the sheared edge.  Clearance can vary between 2% and 8% of the sheet thickness.  For harder materials and larger sheet thickness, larger clearance are required

# PRESS TOOL WORK # FORMING SHEARING: how it works? Shearing begins with formation of cracks on both sides of the blank, which propagates with application of shear force. The fracture progresses downwards with the movement of upper shear and finally results in separation from parent strip Shearing a blank involves plastic deformation due to shear stress. Therefore, the force required for shearing is theoretically equal to the shear strength of blank material

# PRESS TOOL WORK # FORMING SHEARING: operations PARTING Separating a part from the remaining sheet, by punching away the material between parts. It signifies that scrap is removed between the two pieces to part them.

# PRESS TOOL WORK # FORMING SHEARING: operations BLANKING It is a kind of shearing operation, carried out along a closed contour. The desirable part in this operation is the metal inside the sheared contour, called blank. Example: Making of circular blanks out of sheets for subsequent deep drawing of cups.

# PRESS TOOL WORK # FORMING SHEARING: operations PIERCING The typical operation, in which a cylindrical punch pierces a hole into the sheet. Sometimes called Punching Identical to Blanking, only the punched out portion which is coming out through die is scrap. Normally Blanking follows a piercing operation

# PRESS TOOL WORK # FORMING SHEARING: operations NOTCHING Punching the edge of a sheet, forming a notch in the shape of a portion of the punch. It usually removes a small portion from edge or side of a sheet.

# PRESS TOOL WORK # FORMING DRAWING: …. what is that? - It is a cold drawing operation - A process of making utensils, pressure vessels, gas cylinders, cans, shells, kitchen sinks, etc from blanks - Similar to Blanking except that the punch and die are provided with the necessary rounding at the corners to allow smooth flow of metal during drawing & to avoid shearing - One of the widely used sheet metal forming operations. - Cupping and Deep Drawing are two operations

# PRESS TOOL WORK # FORMING DRAWING: …. how does it take place? - A sheet metal called blank is placed on a die cavity, held in position using a holding plate or holding ring and pressed against the die cavity using a solid punch. - The punch slowly descends on the blank and forces it to take the CUP shape formed by the end of the punch. - During drawing of sheet into the die, there is thickening of the sheet up to 12%. - The radial clearance therefore is equal to the sheet thickness plus the thickening of sheet. Deep drawn manufacturing.mp4

# PRESS TOOL WORK # FORMING DRAWING: deep drawing

# PRESS TOOL WORK # FORMING SPINING: - Spinning may be either hot or cold - In both cases, the metal is forced to flow over a rotating shape / mandrel by pressure of a blunt tool - The amount of pressure of the blunt spinning tool against the disc controls the generated heat, which helps in forming processes. - Spun parts may have diameter as large as 6 m - Blank diameter is larger than the diameter of finished part Spinning a Brass Lamp Top.mp4