Hinge & Swivel Mechanism Design Cost Analysis
OBJECTIVE
The design objective is to redesign the hinge and swivel mechanism of a Bose QC 25 headphones for a production volume of 100,000 units.
DESIGN
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The hinge & swivel mechanism is 6 components including the bolt.
1. Hinge Swivel Arm
2. Hinge and Swivel Joint
3. Back Panel
4. Bottom Panel
5. M2 Bolt
6. Top Panel
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The hinge and swivel motion allows for compact storage of the headphone
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The original production volume was 1 million units. Now, the redesign is set for 100,000 units.
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Material selection requirements are resistant to general user wear and tear, corrosion-resistant, lightweight, and cheap.
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Plastic components were made out of polypropylene and metal components were made out of aluminum
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Processing selection requirements are cheap, repetitive, and aesthetic.
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Injection molding is used for polypropylene and aluminum is used for cold chamber die casting
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Design for Manufacturing: Fillets, a uniform thickness, and a draft was added for injection molding and die casting.
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Design for Assembly: Snap fits and lips were used to reduce components and decrease assembly time
Material Selection & DFM + DFA
RESULTS
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The red boxes highlight potential errors in the design and cost analysis where there were high prices. For example, the mold for the bottom panel costs a lot because the snap fits would require more side pulls and increase the geometric complexity of the mold.
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Reducing the production size from 1 million to 100,000 units will increase the cost of the overall design. However, the applied DFM saved 10% of the cost while the applied DFA saved 15% of the cost.