Question

UIZ ECC209 1.pdf Meet - mkh-mjvb-bkc X ownloads/QUIZ%20ECC209%201.pdf What are the characteristics that distinguish bulk deformation processes from sheet metal processes? Answer.. 2. Extrusion is a fundamental shaping process. Describe it. Answer.. 3. Why is the term press working often used for sheet metal processes? Answer. 4. Indicate some of the advantages of cold working relative to warm and hot working. Answer. Multiple Choice Quiz 5. Which of the following are bulk deformation processes (more than one)? (a) bending, (b) deep drawing, (c) extrusion, (d) forging, and (c) rolling. Answer Which of the following is typical of the work geometry in sheet metal processes? (a) high volume-to-area ratio, or (b) low volume-lo-area ratio. Answer. 7. Hot working of metals refers to which one of the following temperature regions relative Cho

Answer 1

1Q...BULK DEFORMATION::

Bulk deformation is the metal forming operation where a significant change in shape occurs via plastic deformation in metallic parts..

SHEET METAL PROCESS::

Sheet metal is the metal formed by different process on a thin, flat sheet pieces. It can be cut and bent into a variety of shapes.

Different processes or operations like punching, blanking, deep drawing, bending, etc....

The main characteristics difference between  BULK DEFORMATION and SHEET METAL is

1.. In bulk deformation, the work parts have a low area to volume ratio whereas, in sheet metal forming, the area to volume ratio is very high.

2.. In bulk deformation the initial shape of work piece can be billet, rod, slab etc.. Whereas in sheet metal it is sheet only

​​​​​​2Q...EXTRUSION::

Metal Extrusion is a metal forming manufacturing process in which a cylindrical billet inside a closed cavity is forced to flow through a die of a desired cross section. These fixed cross sectional profile extruded parts are called EXTRUDATES and pushed out using either a mechanical or hydraulic press.

Metal extrusion can divided into following types

• Direct Extrusion
• Indirect Extrusion
• Hydrostatic Extrusion
• Lateral or Vertical Extrusion
• Hot extrusion
• Cold Extrusion
• Impact Extrusion

Able to create complex cross sections and will be uniform over the entire length of the extrudates.

What ever the deformation takes place in extrusion is 100% permanent plastic deformation and therefore spring back action is 0(zero).

3Q...PRESS WORKING::

Press working may be defined as, a manufacturing process by which various components are made from sheet metal. This process is also termed as cold stamping. The machine used for press working is called a press.

Press tools are commonly used in hydraulic, pneumatic, and mechanical presses to produce the sheet metal components in large volumes. Generally press tools are categorized by the types of operation performed using the tool, such as blanking, piercing, bending, forming, forging, trimming etc.

4Q...ADVANTAGES OF COLD WORKING OVER HOT WORKING::

1. Friction involved in cold working (0.1 to 0.2) is less than hot working (0.6 to 0.7)..

2. The dimensional accuracy and surface finish produced in cold working are excellent compared to hot working..

3. Strength and hardness increases in cold working, but decreases in hot working.

5Q....BULK DEFORMATION PROCESSES FROM THE FOLOWING ARE::

Rolling, Forging, Extrusion. . ..

6Q... SHEET METAL WORK GEOMETRY OF THE FOLLOWING IS::

Area to volume ratio is high.. ie LOW VOLUME TO AREA ratio..

7Q.. HOT WORKING OF METAL REFERS TO TEMPERATURE::

Temperature above (or) greater than RECRYSTALLISATION Temperatures.

Recrystallisation temperature is defined as temperature which is 1/3rd of melting point temperature.

8Q.. ADVANTAGES OF HOT WORKING OVER COLD WORKING ARE::

: lesser deformation forces are required.

: less overall energy is required.

: due less strength and hardness more significant change in shapes are possible.

: Mechanical properties like Malleability and Ductility increases.