Intro to Life Cycle Energy

Assessment of a Product

1

Mat’l

Prod

Mfg. Use EOL

Oct 15, 2018 2.810

Manufacturing of a Product

2

Mat’l

Prod

Mfg. Use EOL

Oct 15, 2018 2.810

Major Energy & Mat’l Flows

Mining

&

Mat’ls

MfgProcess

Energy InputsEnergy Inputs

Material

Inputs

Product

Waste Materials Waste Materials

Material

Inputs

Oct 15, 2018 2.810 3

Em

bodie

d E

nerg

y in M

ate

rials

fro

m K

alp

akjia

n

Oct 15, 2018 2.810 4

Gold ~ 250 GJ/kg

Ashby 20095Oct 15, 2018 2.810

Gold ~ 250 GJ/kg

Ashby 20096

Mat’l GJ/kg

Ag 2

Pd 35-50

Au ~70

Pt ~117

Oct 15, 2018 2.810

7

See extra slides at end

Nominal Mfg Process Rates

Vary by more than 8 orders

Oct 15, 2018 2.810

8

See extra slides at end

Oct 15, 2018 2.810

Junk and Cote 2012

9.4E-03 kg/hr,1.8 to 2.3 E+08 J/kg

Corman 2014

1.2 to 1.8 E-02 kg/hr, 4.1E+07 J/kg to 2.9 E+08

J/kg

EPRI 2014

2.2E-02 kg/hr, 2.8 to 4.0 E+08J/kg

EPRI 2014 , BAAM,

10.0 kg/hr, 4.0E+06 J/kg

Telenko et al. 2011,

2.6E-02 kg/hr, 5.0E+08 J/kgBaumers et al. 2011,

4.1E-01 kg/hr, 2.0E+08 J/kgKellens et al. 2011,

4.1E-02 kg/hr, 1.3E+08 J/kg

Morrow et al. 2005,

3.6E-03kg/hr, 7.7E+09 J/kg

Baumers et al. 2010 ,

1.3E-01 kg/hr, 6.1E+07 J/kg

EPRI 2014,

8.9E-02 kg/hr, 1.1E+08 J/kg

Faludi et al. 2017 Full bed,

1.1E-02 kg/hr, 5.7E+08 J/kg

Faludi et al 2017 Single bed,

4.0E-02 kg/hr,1.2E+09 J/kg

Baumers et al. 2010 Full bed,

5.6E-02 kg/hr,1.1E+08 J/kg

Baumers et al. 2010 Single bed,

4.0E-02 kg/hr, 1.4E+08 J/kg

EPRI 2014

Binder jetting, 6.5E-03 kg/hr, 8.3E+07 J/kg

1.E+05

1.E+06

1.E+07

1.E+08

1.E+09

1.E+10

1.E+11

1.E+12

1.E+13

1.E+14

1.E+15

1.E-06 1.E-05 1.E-04 1.E-03 1.E-02 1.E-01 1.E+00 1.E+01 1.E+02 1.E+03 1.E+04 1.E+05 1.E+06

Ele

ctr

icit

y R

equ

irem

ents

[J/

kg]

Process Rate [kg/hr]

cupola Electric Induction Melting Injection Molding

Machining Finish Machining CVD

Sputtering Grinding Waterjet

Wire EDM Drill EDM Oxidation (Semiconductor)

Material Extrusion: FDM Material Extrusion: BAAM Powder bed fusion: Polymer, laser

Directed energy deposition: DMD Powder bed fusion: Metal, eletron beam Powder bed fusion: Metal, laser

Binder jetting

50 kW 5 kW

500 W

Measured 3D Printing

energy intensity (J/kg)

Vs Print rate (kg/hr) for AM

(metals in red,

plastics in blue)

overlaid on conventional

manufacturing processes.

(Gutowski et al 2017 JIE)

BAAM technology

Oct 15, 2018 2.810 9

Scrap rates from Kalpakjian

Oct 15, 2018 2.810 10

Two Examples

Machining of an aluminum bracket:

(part mass = 444g,

starting block = 9cmX12cmX30cm

= 3240cm3 x2.7g/cm3 = 8748g

waste = 8304g)

Injection molding of a PET container

(hot runner, little waste, part = 67g,

High volume so ignore tooling)

Oct 15, 2018 2.810 11

Machining of an aluminum

bracket (*ref Ashby)Primary Aluminum: ~200MJ/kg*

~ 12kg CO2/kg*

Secondary Aluminum: ~25MJ/kg*

~ 2kg CO2/kg*

Scrap = Waste/Starting Block = 8304/8748 = 95%

Buy/Fly = Starting Block/Part = 8748/444 = 20

Oct 15, 2018 2.810 12

Machining of an aluminum

bracket

• 200MJ/kg X block (8.75 kg) = 1750 MJ

• 3MJelect/kg X 3grid = 9MJ/kg X scrap (8.3

kg) = 75 MJ

• Embodied energy in the material

dominates 1750MJ + 75MJ = 1825 MJ• Ref: gal of gasoline 115MJ,

World annual average: 65GJ/capOct 15, 2018 2.810 13

Injection molding of a PET

container (ref Ashby*)

Primary PET: ~85MJ/kg*

~ 4kg CO2/kg*

Secondary PET:~40MJ/kg*

~ 2.3 kgCO2/kg*

Injection Molding from pellets, hot runner =

(3MJextrusion/kg + 3MJ injection molding/kg) X 3 = 18MJ/kg

Little scrap, again materials dominate 5.7 + 1.2 = 6.9MJ

Oct 15, 2018 2.810 14

These are rough estimates,

better estimates require more

details…but you get the idea.

• What if the aluminum scrap was

recycled?

• What if the aluminum part was cast, or

AM?

• What if the plastic part was made by

FDM?

Oct 15, 2018 2.810 15

Extra slides

• Boundaries for analysis

• Sample values for the production of

polymers

• Compounding

• Hydraulic Vs electric machines

• Driers

• Recycling

Oct 15, 2018 2.810 16

17Oct 15, 2018 2.810

Polymer ProductionLargest Player in the Injection Molding LCI

What is a polymer:

How much energy does it take to make 1 kg of polymer = a lot !!!

Values are in MJ per kg of polymer produced. Thiriez ‘0618Oct 15, 2018 2.810

Compounding - extrusion

• An extruder is used to mix additives with a polymer base, to

bestow the polymer with the required characteristics.

• Similar to an injection molding machine, but without a mold

and continuous production.

• Thus it has a similar energy consumption profile.

Environmentally Unfriendly Additives:

•Fluorinated blowing agents (GHG’s)

•Phalates (some toxic to human

liver, kidney and testicles)

•Organotin stabilizers (toxic and

damage marine wildlife)

19Oct 15, 2018 2.810

Injection Molding Process

Source:

http://cache.husky.ca/pdf/br

ochures/br-hylectric03a.pdf

Machine types: Hydraulic, electric, hydro-electric

20Oct 15, 2018 2.810

All-electric vs. hybrid

The hydraulic plot would be even higher than the hybrid curve

Source: [Thiriez]

21Oct 15, 2018 2.810

For Hydraulics and Hybrids as throughput

increases, SEC → k.

Enthalpy value to melt plastics is just 0.1 to 0.7 MJ/kg !!!

Does not account for the electric grid. Source: [Thiriez]

22Oct 15, 2018 2.810

All-electrics have very low fixed energy costs (small

idling power). SEC is constant as throughput

increases.

Source: [Thiriez]23Oct 15, 2018 2.810

Driers• Used to dry internal moisture in hygroscopic polymers and external

moisture in non-hygroscopic ones.

• It is done before extruding and injection molding.

Source: [Thiriez]

Same as24Oct 15, 2018 2.810

Do Polymers get recycled?

Ref Ashby 200925Oct 15, 2018 2.810

The printer goes in the hopper…

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And comes out….

27Oct 15, 2018 2.810