Simulating the Impacts of Remanufacturing

Richard Farr and Niels Lohse

International Conference on RemanufacturingICoR 2011, 27–29 July 2011

University of Strathclyde, Glasgow

capacify.wordpress.com

Use of Enterprise Simulation to Assess the Impacts of Remanufacturing Operations

Content

The remanufacturing conundrumWhy simulate?Model construction and operationSelected resultsOngoing workConclusions and questions


The remanufacturing conundrum

“Stochastic product returns, imbalances in return and demand rates, and the unknown condition of returned products”

– Guide (2000)

how?


Wikner & Tang (2008), “A structural framework for closed-loop supply chains”

Closed loop?


Closed loop?

Can a product such as a toner cartridge be made to serve again and again?


The remanufacturing conundrum

Many people would agree that remanufacturing seems like the right thing to do... but do we really know what to expect?

Impact upon primary manufacturing operationsCapacity requirementsLogistic consequencesCosts as well as savingsSources of risk


Why simulate?

Improve our understanding of the operations within a system.Don’t disrupt the operations of a business while going through this learning process.Reduce risk, since we can experiment with a system before we build the real thing......and before we build thousands of products!Attempt to optimise whole system settings.


Model architecture

Make and ship

Use

End of Life

Install


Model Construction

Rockwell Automation’s discrete event simulation software ‘Arena’

Visual model uses variables held in an Excel spreadsheet, detailing the demand pattern, usage pattern, return rates, etc.


Model Construction


Cyclicuse phase


Application of the model

1. Casing2. Shaft3. Windings, brushes4. Packaging

A simplified product: electric motor with four ‘composite components’: sets of items that behave or are handled in the same way


Application of the model

Composite components are represented parametrically within the model


Static Simulation

Mathematical analysis might tell you approximately how many components you can expect to get back, but it won’t tell you anything about the timing of such flows.(Still useful for model validation)

Lost

Returned

Cannibalize

Refurbish

Remarket

Remanufacture

Recycle


Static Simulation

The timing of flows is significant because sufficient capacity must be in place to perform remanufacturing – and sufficient demand must exist for the product to be sold again.

Lost

Returned

Cannibalize

Refurbish

Timely

Untimely

Remarket

Remanufacture

Recyclecapacify.wordpress.com

Model characteristics

Allows exploration of multiple variables: Quality of new componentsLife expectancy of products…

Accident rate, and vulnerabilitiesWear rates, and longevityContract / business modelCustomer behaviour

Condition of returned productsLikelihood of return


Model characteristics

All possibilities (‘decide modules’) within the model are expressed parametrically.If you can edit a spreadsheet, you can ‘drive’ this simulation.


Basic Scenario

Quantity

Month



Shorter product redesign cycle

Quantity

Month

Reduce volume demand period to two years

No time for significant remanufacturing activity


Increased accident rate

Make and ship

Use

Dispose / EOL

Install


Less durable product

Quantity

Month

Increased risk of accidental damage to 5% per month

More remanufacturing, starting earlier


Product retirements

Quantity

Month

Retirements beginning at 24 months (then 5% per month)

Earlier returns


More product retirements

Quantity

Month

Retirements beginning at 12 months (then 12% per month)

Slump


Expanded model with component reuse

Component 3 is reused in a second product type

Extended reuse of components

Qu anti ty

Month

Component 3 reused in a second product type


Is it necessarily a good thing to be doing lots of remanufacturing?

Product not robust enough?Product not being provided under the right kind of contract?Customers not continuing to use the product for as long as we might hope?

Need to understand the whole system, not just the level of remanufacturing.

Contentiousissues


Does the original manufacturing system work well when demand is variable, as a result of recirculated material?Are you able to store all the material that comes back?Will you end up paying to dispose of unwanted EOL products that you get back?Is your remanufacturing division going to be in direct competition with another part of the company?

Remanufacturing problems


Investigate the overall utility delivered to society.Associate environmental impact (carbon footprint, or eco-points) with each outcome.This requires that we examine the need for utility – not the monthly demand for the product.Contractual arrangements should match the needs of the market, not just the needs of the remanufacturer.

Ongoing work


Utility viewpoint – maximising the total benefit derived from the resources that are expended.

Ongoing work

Month

Products supplied

Total products in service


Remanufacturing can introduce tremendous complexity.It’s relatively easy to do a little, but hard to do a lot. (A bit like renewable energy in this regard.)There will be some nasty surprises for the ill-prepared.

Conclusions


Further reading

Further information from me can be found on Capacify, the Sustainable Supply Chain blog

http://capacify.wordpress.com

@Capacified

http://capacify.wordpress.com/

References:

Guide, V.D.R. (2000) Production planning and control for remanufacturing: industry practice and research needs, Journal of Operations Management, Vol. 18, No. 4, June 2000, pp. 467–483

Wikner, J. & Tang, O. (2008), A structural framework for closed-loop supply chains, International Journal of Logistics Management, Vol. 19, No. 3, pp. 344–366

Acknowledgement:

Thanks to Brother Industries UK staff in Ruabon, Wales, for sharing so much of their knowledge about remanufacturing practices.

The paper that accompanied this presentation was:

Farr, R and Lohse N (2011) Use of Enterprise Simulation to Assess the Impacts of Remanufacturing Operations, in the Proceedings of the International Conference on Remanufacturing, ICoR 2011, 27–29 July 2011, University of Strathclyde, Glasgow, UK

Available from: http://eprints.nottingham.ac.uk/3255/

Endnotes


http://eprints.nottingham.ac.uk/3255/

Engineering

Simulating the Impacts of Remanufacturing