Page 395 - Design for Six Sigma a Roadmap for Product Development

364 Chapter Ten

Figure 10.5 DFMA optimum design (Huang 1996).

TABLE 10.3 DFMA Worksheet for Optimum Design
Theoretical Assembly Assembly cost,
Item Number part count time, s U.S. cents
Base 1 1 3.5 2.9
Motor subassembly 1 1 4.5 3.8
Motor screw 2 0 12.0 10.0
Sensor subassembly 1 1 8.5 7.1
Setscrew 1 0 8.5 7.1
Thread leads — — 5.0 4.2
Plastic cover 1 1 4.0 3.3
Totals 7 4 46.0 38.4

a. Total actual assembly time T 1 46 s from the DFMA database.
b. Theoretical number of parts is 4 with an average of 3 s assembly time.
Then, the total theoretical assembly time T 2 12 s.
c. Calculate the datum assembly design 1 efficiency using

T 2
1
100%
T 1
12

100%
46
26.087% (10.2)

6. Calculate the parts cost savings as shown in Table 10.4. The saving
$35.44 $21.73 $13.71 in parts cost with a new fixed cover cost of $5000.