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HW10 DFA and Sheet Metal Work
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Terms in this set (10)
Which question is important in determining the theoretical minimum number of parts?
Does the part move every time and only when another part moves?
If the theoretical minimum number of parts for this geared water pump is three and the total assembly time 116 seconds, what is its assembly efficiency?
e = (3*NM)/TM
7.7586%
Which Design Principle revolutionized the photocopy industry?
5 - incorporate "self-assembly" or minimize the need for adjustments
In a sheet metal stamping operation, the scrap part cut out is referred to as a:
slug
If the blanking force in a sheet metal operation increases significantly, then the clearance may need to be:
increased
If a stamping operation witnesses an increase in burr size, what can be done to correct this (select all correct answers)?
Decrease the clearance
Use a harder material
Under-bending a part ensures that any spring back in the metal will allow it achieve the desired shape.
False (It's called overbending)
- Stamping of holes should have diameters greater than the thickness of the metal, except for hard alloys like stainless steel, which can accommodate smaller holes.
- Holes should be separated by at least the thickness of the metal. (F, 2T)
- What is preferred are holes separated from the edge and each other by twice the metal thickness. (F, 1T)
- Bending very near a stamped pattern creates distortions, but this can be eliminated by removing the material near the pattern that is included in the bend radius.
- Stamping of holes should have diameters greater than the thickness of the metal, except for hard alloys like stainless steel, which can accommodate smaller holes.
- Bending very near a stamped pattern creates distortions, but this can be eliminated by removing the material near the pattern that is included in the bend radius.
You are setting up a progressive 2-die stamping operation to make washers with an inner diameter of 26 mm26 mm, an outer diameter of 39 mm39 mm, and a thickness of 3 mm3 mm. The material has an ultimate tensile strength of 400 MPa 400 MPa, and clearance allowance of 0.050.05 and a shear strength of 201 MPa201 MPa.
What is the die opening diameter for the punching operation (mm) to make the ID? If both the ID and OD are cut simultaneously, what is the force (kN) needed for this operation?
clearance = allowance * thickness
die opening 1 = inner diameter + (2*clearance)
die opening 2 = outer diameter
force = shear force
thickness
(die1 +die 2) * pi
To make the angle bracket shown below, what is the required starting length of sheet metal, assuming L1 is 29 mm29 mm, the corner radius is 10 mm10 mm, and the thickness is 4 mm 4 mm?
(hint: the answer is always less than 2 * L1)
Ab = 2
pi
[alpha/360]
[R + (Kb
t)]
Kb = .5 when r > 2t
Length = Ab + [2*(L-R)]
;