Herman Miller Foam Alternative

Group 4 Shira Bergman • Brian Della Mora

Boning Qu • Teresa Vasievich

Overview1. Who is Herman Miller?2. Prioritization of Factors 3. Polyurethane: Gold Standard4. How Foam Works5. Our Solution6. The Program7. Shortcomings

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1. Who is Herman Miller?

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Herman Miller: The Customer● Ultimate consumer customization● Suppliers contact Herman Miller● All outsourced designers● Six R&D teams involved in materials search

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Herman Miller: Value Chain

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2. Prioritization of Factors

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Performance Properties

Manufacturing

Monetary Costs

Environmental Impact

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Prioritization: Performance PropertiesMatch or outperform polyurethane

● Foam properties of ‘Gold Standard’○ Elastic modulus○ Plateau stress○ Densification stress

● Comfort properties of ‘Gold Standard’

○ Foamed solution feels like PUR (IFD)

○ Diverse applications (i.e., arm pads, couches)

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Prioritization: Environmental Impacts● Manufacturing

○ Reduce use of harmful chemicals○ Consider impacts of ‘natural’ solutions

● Usage○ Chemically inert

● End-of-life management○ Recyclable○ Reusable

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Prioritization: Manufacturing & Monetary CostsManufacturing● HM does not manufacture furniture components● Target customer widened to manufacturing companies● HM has leverage to obtain any material

Monetary Costs● Cost increase must not exceed 20%● Few foamed alternatives

○ No raw materials comparison○ Initiation costs not accounted for

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3. Polyurethane: Gold Standard

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Polyurethane Foam● Polyurethane Foams

○ Open-cell ○ Two main ingredients

■ Isocyanates and polyols

● Flame Retardant Additives

Glass Transition

(K)

Density (g/cm3)

Elastic Modulus

(MPa)

Plateau Stress (MPa)

IFD (lbs-force)

Polyurethane Foam 290-300 0.016 0.34 0.003-0.004 ~3.1

500 μm

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4. How Foam Works

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Foaming Process

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How Foams Work● Material Properties of Solid

○ Young’s Modulus○ Resin Density

● Microscopic Properties of Foam○ Relative Density○ Cell Size○ Cell Density

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How Foams Work● In-Plane Compression

○ Linear elasticity○ Plateau○ Indentation Force Deflection○ Densification

● Governing Equations

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stress/strain at IFD

How Foams Work - Darcy’s Law● Air flow through foam

○ Permeability of medium○ Dynamic viscosity of fluid (air)

● Governs recovery time

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5. Our Solution

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Program to Predict Foam● Inputs

○ Resin options■ Non-isocyanate involved■ Thermoplastic elastomer■ Resin density■ Resin elastic modulus

○ Relative density

● Outputs○ Stress-strain curve○ Recovery time○ IFD

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Factors Affecting Foam● Relative Density

○ Stress in each region

● Transition Points○ Strain at buckling○ Length of plateau

● Darcy’s Law○ Air velocity○ Recovery time

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Our Solution - Assumptions

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● Considered○ Physical blowing agents○ Resin properties○ Uniform cell size

● Overlooked○ Chemical blowing agents○ Foam additives○ Post-foaming processes

ShortcomingsInaccuracy of Program● Lack of accurate foaming conditions● Lack of calibrated constants for each material

Problems with Solution● Environmental problems unresolved● ‘Ideal’ resin unknown

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Questions?

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Referenceshttps://ir.library.oregonstate.edu/xmlui/bitstream/handle/1957/2487/FPL_2031ocr.pdf;jsessionid=8D30129A19AA18B020122730E7BF353E?sequence=1

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