1. Processes used to form metallic materials
Chapter 14 part 2
Processes used to form metallic materials

2. Upsetting AKA cold forming or cold heading
Thickens or bulges the workpiece while shortening it by compression
Combination of forging and extrusion
Fastest process
High volume production of nails, bolts and rivets
Cold forms a head on the end of a metal rod by compressing it’s length in a die cavity

3. Consists of a die block and a punch
Punch pushes precut stock through a hole
Ejector pin in hole pushes part out when finished

4. Cold Forming Advantages
Higher production rates
Little or no scrap
Close tolerances
Good surface finish
Increased part strength

5. Stamping Considered inexpensive and easy to make parts Cold forming
Set of matched molds in a press
Stock is shaped under pressure under one stroke from the stamping press
Chipless process
Highly used in the automotive industry

6. Stamping presses can also be used to:
Punch
Notch
Pierce
Trim

7. Embossing Produces raised areas on a flat sheet of metal
Dog tags, id plates, license plates
One side has raised printing, other side has indentation
Uses 2 part matched die

8. Drawing Stretching and compressing to make a shape Several types
Kitchen sinks, pans, car fenders
Several types

9. Deep Drawing
Female die pressed into sheet stock
Stock stretches over male die or punch

10. Mating dies must match perfectly
Stretch-draw Forming
Mating dies must match perfectly
Dies are expensive
Would also have an upper die

11. Marforming
Uses a thick rubber pad, metal retainer and a forming block
Begins when upper platen holding the rubber pad moves down against the holding punch

12. Hydroforming
Uses hydraulic fluid in place of rubber pad
Workpiece is positioned on bottom die block
Pressure chamber is lowered
Punch is forced upward
Pressure increases in the fluid chamber forcing workpiece around the punch

13. High speed process
Parts as large as 25” dia and 12” deep
Steel 3/8” thick
Aluminum 1” thick

14. Expanding Increase the diameter of tubular parts
Punch travels down into the part, pushing it against the sidewalls of the die
Parts to be expanded 30% or less of the diameter of the workpiece can be done in one stroke
More than 30% needs several strokes

15. Bulging Similar to expanding Make bellows or musical instruments
Tube is placed inside a die (shaped like final part)
Bulging punch is lowered into tube (rubber)
Punch is compressed forcing material against the die
Die has to be opened to get part out

16. Necking Reduce the diameter of the end of a tubular part
CO2 cartridge
Increased tensile strength in reduced area

17. Nosing Used to partially close the end of a tube
Can also taper or round an end of the tube
Similar to rotary swaging

18. Electromagnetic Forming
Uses magnetic forces
Magnetic coil creates a magnetic field that is passed through the workpiece
The magnetic fields oppose each other
This pushes the workpiece against a die
Usually on round parts
Can be used inside or outside
Also used to join tubular parts

19. Contouring Magnetic force used to shape flat parts
Coil looks like electric stove burner
Coil is placed against a sheet
Magnetic force pushes the sheet against a die
Can not be used for complex shapes
Pressure is constant, can’t have high pressure in one area and low in another
Doesn’t work with holes in the part (interferes with magnetic flow)

20. Peen Forming
Bombarding the surface of a part with small spheres called shot
Shot made from:
Cast steel
Glass
Ceramic particles
Blasting creates overlapping indentations creating higher compression strength
Peened areas will not crack
Increases product life
Engine valve springs

21. Explosive Forming
Uses a female die, large water tank and an explosive charge
Die, stock and charge are placed in water
Air is removed from the die
Charge is detonated, shock waves force stock into the die
Size is only limited by the water tank

22. HERF (high-energy-rate forming)
Variation of explosive forming
Uses spark-generated shock wave

23. Spinning Stretching sheet stock over a spinning mold
Cold or hot worked