DFMA as Applied to the Swingline 747 Desktop ... - University of Utah

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Redesigned Anvil: Upper Arm: Cost for progressive die = $7050 Cycle time = 0.6 sec Processing cost per part = Cp = 0.91 cents Cost for progressive die = $22,220 Cycle time = 0.67 sec Processing cost per part = Cp = 1.4 cents Redesigned Upper Arm: Cost for progressive die = $22,060 Cycle time = 0.67 sec Processing cost per part = Cp = 1.4 cents Unmodified parts: Upper leaf spring: Cost for progressive die = $9760.00 Cycle time = 0.6 sec Processing cost per part = Cp = 0.91 cents Bottom Staple Guide: End Cap: Cost for progressive die = $9130.00 Cycle time = 0.6 sec Processing cost per part = Cp = 0.91 cents Cost for progressive die = $5250.00 Cycle time = 0.6 sec Processing cost per part = Cp = 0.91 cents DFMA as Applied to the Swingline ® 747 Desktop Stapler 24
2.5 Assembly Paradigms DFMA as Applied to the Swingline ® 747 Desktop Stapler When designing for assembly, there are many varied considerations. As has been the precedent, a brief discussion of the DFMA paradigms will be followed by application of relevant paradigms to the Swingline ® 747 classic stapler. The object of design for assembly is to provide the designers a tool for effective assembly considerations, to guide the designers to simplicity, to provide information from experienced engineers early in the process that will help less experienced designers, and to establish a database of assembly times and cost factors. Most of the following information is taken from Product DFMA, 2 nd ed., hereafter referred to as PDFMA, by Boothroyd, Dewhurst, and Knight. While there are tools and equations to be used for both manual and automated (robotic, high-speed) assembly, the focus will remain on manual assembly since it is most pertinent to the case at hand. Briefly, the main advantage for automation is the reduced errors in assembly that lead to quality issues. The authors state, “…it is becoming widely accepted that faulty assembly steps, rather than defective components, are more often the reason for production quality problems.” For more information on automated assembly, the interested reader is referred to the text. For manual assembly, there are several issues to be considered. 2.5a Assembly Times and Efficiency Assembly efficiency, also known as the DFA index, is vital to proper assembly design. Two main factors that influence efficiency are the number of parts and the ease of handling, inserting, and fastening those parts. To calculate the efficiency, Ema, the following equation is given: Ema = Nminta/tma where Nmin is the theoretical minimum number of parts, ta is the basic assembly time for one part, which is about 3 s, and tma is the estimated time to complete the assembly of the entire product. There are three time systems that can be used to estimate assembly times. One of these, MOST, is used for very large parts which cannot be carried by workers. A lifting device must be employed. Since this is beyond the scope of the example, it is not discussed here. The other two systems, methods time measurement (MTM) and work 25
Page 1 and 2: DFMA as Applied to the Swingline ®
Page 3 and 4: Appendix A: Material Selection Anal
Page 5 and 6: 28. Base……..………………
Page 7 and 8: 1 Introduction DFMA as Applied to t
Page 9 and 10: 2. Release Clip Fig 2 Release Clip
Page 11 and 12: 7. Spacer Fig 10 Spacer DFMA as App
Page 13 and 14: 14. End Cap Fig 17 End Cap DFMA as
Page 15 and 16: σu σy σ Woods Metals DFMA as App
Page 19 and 20: 2.4a Sheet Metal Analyses DFMA as A
Page 21 and 22: Pp = 112 mm = 11.2 cm, Np = 2 DFMA
Page 23 and 24: Where Cid = 2565 + 2720 + 3390 + 25
Page 25 and 26: Scrap percent: Plan area = 71.3 cm
Page 27 and 28: = 35.233 DFMA as Applied to the Swi
Page 29: Fbendung = 1.92 KN DFMA as Applied
Page 35: 2.5g Assembly Layout DFMA as Applie
Page 40 and 41: NOTE: The best and the worst materi
Page 42 and 43: Stainless steel 0 Aluminum alloy 24
Page 44 and 45: Analysis Run for Strongest Beam and
Page 46 and 47: Alloy steel 54 Stainless steel 30 A
Page 48 and 49: Malleable iron 26 Mild steel 7 Allo
Page 56 and 57: Step 2 The 2 nd step as seen in the
Page 58: 1. www.swingline.com References 2.

DFMA as Applied to the Swingline 747 Desktop ... - University of Utah

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