Environmentally Conscious Process Planning

1. Environmentally Conscious Process Planning Prepared by Felipe Román

2. Last Week… Today • Last lectures • Some ECDM assessment tools… • For processes: process mapping I/O assessment • For facilities & regions: EnviroFacts & TRI Explorer • Today • Begin considering environmental concerns during the product development process… particularly in the process planning stage

3. Learning Objectives • Know what is process planning and how it fits in the product development process • Understand how to carry out environmentally conscious process planning • Learn how to quantitatively assess manufacturing environmental loads

4. Focus: Manufacturing Life Cycle Stage Why manufacturing?...

5. Product Development

6. Environmentally Conscious Manufacturing Strategies • Good housekeeping • Training and supervision • Waste handling • Material substitution / elimination / addition • In-process recycling • Process modification • Process Planning • Part / product modification Source: http://www.fotosearch.com/ICL154/bim_139/ Adapted from (Sutherland and Gunter, 2001) and (Skerlos 2005).

7. Figure from Feng and Song, 2000 Process Planning Process planning is the set of product development activities that determines how a part will be manufactured given product and production specifications. • Also known as… • Process engineering • Manufacturing engineering • Process design • Process routing • Resources • Machines • Auxiliary equipments • Cutting tools • Cutting fluids

8. Manufacturing Processes • Metal Casting • Bulk Deformation / Forming • Sheet Metal Forming • Material Removal • Traditional Machining • Precision Machining • Deburring • Advanced Machining • Surface Preparation • Cleaning • Hardening • Electro-plating • Painting • Joining and Fastening / Assembly • Polymer Processing • Rapid Prototyping Source: http://divisions.asme.org/med/enewsletter/2003july/meTCreportWeb_files/image002.gif. More information can be found at http://erc.engin.umich.edu/.

9. Some Auxiliary Equipment (Supporting) • Air compressors • Coolant systems • Water softeners • Water Recirculation • Material/waste handling • Chillers • Boilers • Piping system

10. Some Auxiliary Equipment (Pollution Control) • Oil/dust mist collectors • Incinerators / oxidizers • Wastewater treatment • Gondolas & roll offs • Chip centrifuges / Chip wringers • Briquetting machines Source: http://www.nationalconveyors.com/metal_chip_only/metal_chip_processing/chipwringers6.html Source: http://www.ars-inc.com/industrial.htm

11. Environmentally Conscious Process Planning • For traditional machining (turning)… • Process selection • Resource selection • Machine selection • Auxiliary equipment selection • Cutting fluid selection • Cutting tool selection • Process parameter, operational sequence selection

12. Turning Process - Lathe Source: http://www.efunda.com/processes/machining/turn.cfm

13. Turning Categories

14. Mass & Energy Balances * Mass & energy balances are your friend… Mass balance equation for an open system: CV Energy balance equation for an open system:

15. Machine-Level Assessment Elec. = f (x1,x2,x3) • Identify process-related environmental Inputs/Outputs (I/Os) • Quantify I/Os • Electricity (kWh) • Coolant (gals) • Wet chips (lbs) • Used coolant (gals) • Oil mist (mg/m3) • Identify mathematical relationship / function for I/Os Mist = f (y1,y2,y3,…)

16. Some Machine-Level Models • Electricity (kWh/yr) • Coolant (gals/yr) • Wet chips (lbs/yr) • Used coolant (gals/yr) • Oil mist (mg/m3)

17. Operational-Level Assessment Coolant = f (w1,w2,…) Energy = f (z1,z2,…)

18. Some Operational-Level Models For straight turning operations… • Cutting energy (kWh) • Cutting force • Machining time • Coolant lost from machined part (gals) • Density of cutting fluid • Surface tension of cutting fluid • Cross-sectional area of workpiece • Oil mist generated from straight turning (mg/m3)

19. Different Cleaning Processes

20. Direct consumption Closed-loop consumption Aqueous Cleaning Processes Source: http://www.acme-fab.com/html_640/PROD_Monorail-washer.html Source: http://www.karcher.ca/CCE/HD%20-%20HDS%20Web%20Pages/Features/PowerNozzle%20Spray%20Others.jpg

21. Aqueous Cleaning Inputs/Outputs • Can you think of mathematical models for estimating these inputs/outputs for a closed-loop system?

22. Generic Process Map of an Aqueous System Add chemicals and electricity to wastewater treatment

23. Summary Main Points • Showed how to estimate environmental loads of straight turning operation • Similar approach should be applicable to other manufacturing processes (e.g., milling, cleaning, etc.) • By estimating environmental loads & impacts a process engineer can (quantitatively) tradeoff cost, quality and productivity objectives and make better process planning decisions

24. References • Sutherland, J.W. and Gunter, K.L., 2001, "Environmental Attributes of Manufacturing Processes," in Handbook of Environmentally Conscious Manufacturing, C.N. Madu, Kluwer Academic Publishers, pp. 293-316. • Skerlos, S.J., 2005, "Prevention of Metalworking Fluid Pollution: Environmentally Conscious Manufacturing at the Machine Tool, under peer review for textbook," in Handbook of Environmentally Conscious Mechanical Design - Volume 2: Environmentally Conscious Manufacturing, John Wiley & Sons.