Example 2

Figure 10 shows an example of power brake, given by Mascle and Hong (2008).

The material list is given in Table 5. We use website

http://www.fastener-world.com.tw/giga to define which parts are fasteners and which

parts are components. In this example, single-component selective disassembly for

component 17 is shown.

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Figure 10. Exploded view of power brake [16] .

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Table 5. Components and fasteners lists of power brake in figure 10 [16] .

Fig. and

Index No.

Component (C)

or Fastener (f)

Nomenclature Units per

Assy.

1 C Housing 1

2 f Stud 1/4” 10

3 f Nut 10

4 f Washer 10

5 C Cover 1

6 C Gasket 1

7 f Washer 2

8 C Seat 2

9 f Spring 2

10 f Ball ¹/4” Dia. 2

11 f Spring 2

12 f Pin 2

13 f Spacer 1¹/2 Dia. 2

14 C Packing - Neoprene 2

15 f Nut 1 1/8 2

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16 f Pin 3/8” Dia. 2

17 C Piston 2

18 C Packing - neoprene 8

19 f Spacer 1 1/8” 2

20 f Nut 7/8” 14 NF 2

21 f Capnut 2

22 f Washer 2

23 f Nut 10 – 32 NF 2

24 f Screw 1 – 32 NF 2

25 C Link 2

26 f Shaft 5/8” Nickel Steel 2

27 f Shaft 9/11” Dia. Nickel Steel 2

28 C Lever - Assembly 1

29 f Nut 5/16 2

30 f Screw 3/8 Dia. 5/16 2

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Figure 11. (continued)

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Figure 11. (continued)

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Figure 11. Illustrate the DC, MC, DF, and MF of power brake.

Using the developed method, here component 17 is chosen as a target component.

Component 17 is input to the Func_Component() function. From the DC of the target

component 17, we can see that it requires disassemble some fasteners before component

17 can be disassembled. Thus, function Func_Remove_Fastener() is called. If fastener

11 is firstly chosen, it can be removed along +y or –y directions. From MF11, we know

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that , before disassembling 11, 8 needs to be disassembled along the +y direction or 12

needs to be disassembled along the -y direction. However, 12 cannot be selected,

because 12 is a parent component of 11. Therefore, the next part to be chosen is

component 8, and Func_Remove_Component() is called.

Inside of Func_Remove_Component(), Func_Component() is calledCheck the DC

of 8, there are three fasteners, 2, 7, and 11 require to be disassembled. Thus,

Func_Remove_Fastener() is called. However, since 11 is a parent part of 8, 11 will not

to be considered here. If 2 is selected to remove, check DF and MF of 2. We found that

2 cannot be removed unless 4 is removed first. Thus, Func_Remove_Fastener() is called

again. However, before 4 can be removed, 3 needs to be removed first. Thus,

Func_Remove_Fastener() is called again. Finally, fastener 3 can be removed from the

+y direction. After that, fasteners 4, and 2 can be removed and the incomplete

disassembly sequence (3-4-2) is stored in the Sequence_Stack, and we need to go back

to select fastener 7 to disassemble.

Check the DF and MF of 7, there are parts 8 and 9 which have to be disassembled

before 7. However, since 8 is a parent component of 7, we cannot choose 8 to

disassemble. Therefore, the next part to be chosen is fastener 9, and function

Func_Remove_Fastener() is called. Check the DF and MF of 9, we found that fastener

10 needs to be disassembled before 9. Thus, Func_Remove_Fastener() is called.

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However, 10 cannot be disassembled along +y direction before part 5 is disassembled.

Thus, function Func_Remove_Component() is called, and inside of which, function

Func_Component is called. Check the DC of 5, we found that component 5 has no

fasteners attached to it. The parameters in the +y direction in DC and MC of component

5 both are 0. Thus, component 5 can be disassembled along the +y direction. Therefore,

disassemble 5, 10, 9 and 7 and store the incomplete disassembly sequence (5-10-9-7) in

the Sequence_Stack and go back to check the DC and MC of 8.

Now, we need to check the DC and MC of component 8. We found that component

6 needs to be disassembled first so that function Func_Remove_Component() is called,

and inside of which, function Func_Component() is called. Since at this moment, all

parts blocking the motion of component 6 have been removed, component 6 can be

removed along the +y direction. After component 6 is disassembled, component 8 and

fastener 11 can be disassembled afterward, and the incomplete disassembly sequence

(6-8-11) is stored in the Sequence_Stack. Now, fasteners 12 and 13 need to be

disassembled in the +y direction. If we select 12 as the next part to be disassembled.

Check the DF and MF of 12, since 11 has been removed, 12 can be removed along the

+y direction. The incomplete disassembly sequence (12) is stored in the

Sequence_Stack. Follow the same process, fastener 13 can also be removed directly

along the +y direction. The incomplete disassembly sequence (13) is stored in the

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Sequence_Stack. Finally, check the DC and MC of 17, we found that fasteners 16 and

15 need to be removed. Check DF and MF of 16, we found that 16 can be removed in

the -x direction. The incomplete sequence (16) is stored in the Sequence_Stack. After

that, check DF and MF of 15, since 16 has been removed and 17 is a parent of 15, 15 is

not considered here.

After that, all the fasteners of 17 have been checked, and +x, -x, +z, -z are all 0 in

DC17 so that they are possible disassembly directions for component 17. However,

according to Rule 6, component 17 is blocked by 1, 14, 15 in both directions of the x

principal axis and is blocked by 1, 14, 15 in both directions of the principal z axis, so

both x and z axis are not considered as the disassembly directions. Therefore, the

possible disassembly directions will be +y and –y. If we choose the –y direction,

fastener 15 needs to be removed, and component 17 needs to be removed before 15.

However, since 17 is a parent of 15, we will not consider the –y direction. Now, we

chose +y direction as the next disassembly direction, so component 14 needs to be

removed. Function Func_Remove_Component() is called, and inside of which, function

Func_Component() is called. Check the DC and MC of 14, we found that 14 can be

removed in the +y direction. The incomplete sequence (14-17) is stored in the

Sequence_Stack. After that, we found a selective disassembly sequence planning for

disassembling component 17: 3, 4, 2, 5, 10, 9, 7, 6, 8, 11, 12, 13, 16, 14 and 17. The

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complete disassembly sequence can be shown in Figure 12.

Figure 12. Disassembly sequence for example 2.

There are fifteen parts to be disassembled and one reorientation, 13 to 16 and 16 to

14. In equation 1, Cost Value = w1*Time + w2*Reorientation + w3*Parts. The cost value

= 0 + 2+ 15 = 17. The time parameter used here is the same as Mascle and Hong (2008).

To compare with the results by Mascle and Hong, we set w1 to be “0” to ignore the time

parameter, and w2 and w3 are “1”. The cost value of the results by Mascle and Hong is

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also 0 + 2 + 15 = 17. However, the results by Mascle and Hong (2008) needs to remove

fastener 2 first. From Figure 10, we can see that fastener 2 cannot be removed unless

fasteners 3 and 4 are removed first. Therefore, our method can provide a better solution.

Table 6. The selective disassembly sequence planning of power brake by Mascle and

Hong (2008) [16] .

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