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Flashcards in Sheet Metalworking Review Questions Deck (18)
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1

Identify three basic types of sheetmetalworking operations

  • cutting
  • bending
  • shearing

2

In conventional sheet metalworking operation, (a)what is the name of the tooling and (b) what is the name of the machine tool used in the oepration

(a) punch and die

(b) stamping press

3

In blanking of a circular sheet-metal part, is the clearance applied to the punch diameter or the die diameter

blank diameter = die diameter

 

punch diameter smaller by twice the clearance

4

What is the difference between a cutoff operation and a parting operation

cutoff

shearing operation in which blanks are separated from a sheet metal strip by cutting two opposite sides of the part in sequence from a sheet metal strip

 

parting

cutting a sheet metal strip by a punch with two cutting edges that match the opposite sides of the blank

5

what is the difference between a notching and seminothcing operation

NOTCHING

cutting out a portion of metal from the side of the sheet/strip

 

SEMINOTCHING

removing a potion of metal from the interior of the sheet

6

Describe each of the two types of sheet metal-bending operations: V-bending and edge bending

V-Bending

sheet metal is bent between a V-shaped punch and die

 

Edge Bending

involves cantilever loading of the sheet metal

7

For what is the bend alloawnce intended to compnesate

stretching of the metal that occurs in a bending operation when the bend radius is small relative to stock thickness

8

WHat is spring back in sheet metal bending

increase in included angle of the bent part relative to the included angle of the forming tool after the tool is removed

 

tendency of metal to partially return to its original state after a bend. 

9

Define drawing in the context of sheet metal working

sheet metalworking operation used to make cup-shaped, box-shaped, complex-curved, and concave parts

10

what are some of the simple measures used to assess the feasibility of a proposed cup-drawing operation

  • drawing ratio
    Dr = D/Dp
  • reduction
  • thickness to diameter ratio

11

Distinguish between redrawing and reverse drawing

Redrawing

If shape requiring drawing is too severe, complete forming of the part may require multiple drawing steps, redrwing is that second step

 

Reverse drawing

drawn part is positioned face down on the die so that the second drawing operation produces a new configuration.

12

What are some possible defects in drawn sheet-metal parts

  • wrinkling in flanges
  • wrinkling in walls
  • tearing
  • earing
  • surface scratches

13

What is embossing

forming operation used to create indentations in the sheet, such as raised lettering or strengthening ribs

 

some strecthing and thinning of metal involved

14

what is strecth forming

simultaneously strecthing and bending the sheet-metal work part to achieve shape change

15

what are two basic catagories of structural frames used in stamping presses

straight sided frame presses

 

gap frame presses

16

What is the Guerin process

uses a thick rubber pad to form sheet metal over a positive form block

17

what are the relative advantages and disadvantages of mechanical presses versus hydraulic presses in sheet metal working

Faster

 

Not limited to deep drawing and other operations involving load-stroke characteristics

18

difference between roll bending and roll forming

roll bending

operation in which usually large sheet-metal or plate-metal parts are formed into curved sections by means of rolls

 

roll forming

continous bending process in which opposing rolls are used to produce long sections of formed shapes from coil or strip