Thermoplastic Material Selection for Performance, Cost, and Feel
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Transcript of Thermoplastic Material Selection for Performance, Cost, and Feel
Eric R. Larson, P.E. Owner / Chief Engineer Art of Mass Production
Selecting Thermoplastic Materials for Performance, Cost, and Feel
Agenda
! Overview of Thermoplastics ! Material Selection Criteria
! Performance ! Cost ! Feel
! Bicycles - Key Requirements ! Recommended Palette of Materials
© 2016 Eric R. Larson, all rights reserved
My Background
! Born in Detroit
! B.S.E. (Aerospace)
! LearFan
© 2016 Eric R. Larson, all rights reserved
Intro to Thermoplastics
! Commodity Plastics ! PE, PP, EPS
! Engineering Plastics ! ABS, acetal, nylon, PC
© 2016 Eric R. Larson, all rights reserved
Intro to Thermoplastics
! Application Engineer ! acetal, nylon, PBT
© 2016 Eric R. Larson, all rights reserved
Consulting Engineer
! 20+ years
© 2016 Eric R. Larson, all rights reserved
Plastics Primer
! Polymer Chemistry ! unique language ! chemistry + physics
! Polymer Molecules ! carbon based (organic) ! primarily synthetic (man-made) ! NOT base elements
! Categorization ! Characterization
© 2016 Eric R. Larson, all rights reserved
Polymer Chemistry
! Polymerization ! marriage of the monomers ! divorce of the monomers
! The Mer Family ! polymers ! homo-polymers ! co-polymers ! ter-polymers
© 2016 Eric R. Larson, all rights reserved
Categorization
! Traditional Polymers
! Aromatic Polymers ! Kevlar = an aramid
! Fluorinated Polymers ! PE => PTFE
© 2016 Eric R. Larson, all rights reserved
Characterization - Property Data
“The designer who has access to standard data sheet values only must use them cautiously as a source of design information. Many of the tests reported on the sheets come under the jurisdiction of the American Society for Testing and Materials (ASTM), and the properties are intended to characterize a material, not necessarily to provide design information.”
© 2016 Eric R. Larson, all rights reserved
- Engineered Materials Handbook, Volume 2, Engineering Plastics. ASM International
(formerly known as the American Society for Materials)
Material Selection Based on Performance
! Mechanical Performance ! Strength, Stiffness, Toughness
! Electrical Performance
! Environmental Effects
! The Effects of Time ! durability, reliability
© 2016 Eric R. Larson, all rights reserved
Material Selection Based on Performance
! Strength the ability to withstand an applied force
! Stiffness the ability to withstand bending
! Toughness the ability to withstand sudden impact
© 2016 Eric R. Larson, all rights reserved
Toughness
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Toughness
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Performance Killers
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Material Selection Based on Performance
! Avoid Data Sheets
! Find Good Data
! Design Modules
© 2016 Eric R. Larson, all rights reserved
Material Selection Based on Cost
© 2016 Eric R. Larson, all rights reserved
Why Use Plastic?
corrosion resistance!
molded-in color!
reduced weight!
molded-in features!
global availability!
design freedom!
net shape manufacturing !
energy efficient!
accurate and repeatable !
environmentally benign!
part consolidation!
lower part costs!
end-use performance!
99% of the time - we make something out of plastic because it is a cost effective manufacturing method
ease of use and re-use !
Material Selection Based on Cost
part cost = material cost + processing cost where
material costs = material mass x material cost per part per part per unit mass
and
processing costs = molding cost + handling cost +
finishing cost + assembly cost + packaging cost, etc.
© 2016 Eric R. Larson, all rights reserved
Material Selection Based on Cost
part cost = material cost + processing cost where
material costs = material mass x material cost per part per part per unit mass
and
material mass = ƒ(design)
material cost = ƒ(resin pricing, supply chain, etc)
© 2016 Eric R. Larson, all rights reserved
Material Selection Based on Cost
part cost = material cost + processing cost where
total processing cost = molding cost + handling cost +
finishing cost + assembly cost + packaging cost, etc.
and processn cost = processn rate x cycle timen
© 2016 Eric R. Larson, all rights reserved
Material Selection Based on Cost
Molding Cost = machine rate x cycle time where
machine rate = ƒ(machine size, age, location, etc)
and machine size = ƒ(part size, geometry, cavitation,
required shot size, tonnage) cycle time = ƒ(part design, mold design, material
used, wall thickness)
© 2016 Eric R. Larson, all rights reserved
Material Selection Based on Cost
© 2016 Eric R. Larson, all rights reserved
Understanding Cost is Your Job
© 2016 Eric R. Larson, all rights reserved
Material Selection Based on Feel
! A Methodology
© 2016 Eric R. Larson, all rights reserved
Material Selection Based on Feel
! verbto have perception, especially by touch or by any nerves of sensation (other than those of sight, hearing, taste, and smell) to be aware of something that affects you (physically, psychologically, emotionally) to be aware of by instinct or inference
! nouna quality of an object that is perceived by feeling or touching: the soft feel of a feathera sensation of something, or a vague mental impression or feeling: the feel of winter; a feeling of sadness in the airintuitive knowledge or native ability or acquired sensitivity: a feel for the game
© 2016 Eric R. Larson, all rights reserved
Material Selection Based on Feel
© 2016 Eric R. Larson, all rights reserved
thermoplastic materials offer unique opportunities to influence human response
Material Selection Based on Feel
Material Selection Based on Feel
© 2016 Eric R. Larson, all rights reserved
Material Selection Based on Feel
© 2016 Eric R. Larson, all rights reserved
Material Selection Based on Feel
Good Feel = ƒ ( design, material, application, wow factor)
where
WOW = overall utility x (huh)n product cost
and
huh = ∑ ( function, cool factor, funkiness . . .)
n = ƒ (what?)
© 2016 Eric R. Larson, all rights reserved
Material Selection Based on Feel
Xtl < Xjr < Xtm where
X = the “feel” factor we are trying to determine
and Xtl = too little X
Xtm = too much XXjr = just right X
© 2016 Eric R. Larson, all rights reserved
credit: Robert Southeyc. 1837
Material Selection Based on Feel
Management Commitment
The Feel Team
Develop a Process
© 2016 Eric R. Larson, all rights reserved
resources: people, equipment, time
those with a knack for “feel”curious, inquisitive comfortable with ambiguity people skills
goals, milestones, deadlinesa Decision Maker
Key Requirements for Bicycles
! Mechanical Performance ! Safety ! Durability
! Moderate Chemical Resistance
! Moderate Temperature Requirements
! Cost Cost Cost
© 2016 Eric R. Larson, all rights reserved
Key Manufacturing Processes
! Machining ! Prototyping ! Short Run Production
! Injection Molding
! Blow Molding
! Thermoforming / Pressure Forming
© 2016 Eric R. Larson, all rights reserved
Recommended Material Palette
! Good ! ABS ! PP, PE
! Better ! acetal ! nylon
! Best ! glass reinforced nylon ! semi-aromatic nylon ! toughened nylon
© 2016 Eric R. Larson, all rights reserved
! Custom Compounds ! tougheners, lubricants ! structural reinforcement
! Special Applications ! PTFE, Aramid, PPA ! TP elastomers
! New Developments ! long glass fiber (LGF) ! TP composites ! alloys / blends
Long Fiber Thermoplastics
Material Selection Methods
! Based on Data
! Based on Experience
! Based on Familiarity
! Based on Feel
! Based on Other
© 2016 Eric R. Larson, all rights reserved
Resources
! Professional Societies ! SPE / ASME / SAMPE ! IAPD
! Trade Publications ! Plastics Engineering ! Plastics Today ! Plastics Technology
! Resin Suppliers / Distributors ! Compounders
© 2016 Eric R. Larson, all rights reserved
www . art of mass production . com
619-269-0184
info @ art of mass production . com
Contact Info