7.1 What makes cleaning a costly operation in remanufacturing?
J.R.Gamage1, W.L.Ijomah1, J.Windmill2
1 Department of Design, Manufacture and Engineering Management, University of Strathclyde, UK
2 Department of Electronic and Electrical Engineering, University of Strathclyde, UK
Abstract
Product remanufacturing is a widely accepted product reuse strategy in most industries due to its unique
advantage of retaining a greater portion of added value in the initial manufacturing stage. Remanufacturing
involves a sequence of operations including disassembly, cleaning, inspection, parts replacement, re-
assembly and testing. Previous research has shown that the cost of cleaning is only second to the cost of
parts replacement. The objective of this study is to illustrate the significance of the cleaning operation in
automotive remanufacturing and to identify the factors influencing the cost of the cleaning process. Case
studies on four UK remanufacturers, three automotive and one copier, were carried out. Seven key factors
causing high cleaning costs were identified and categorised under two dimensions. These are the technical
nature of the products and processes of cleaning and the business nature of the remanufacturer.
Keywords:
Automotive Industry; Cleaning; Remanufacturing
1 INTRODUCTION
Open loop supply chains were common in the early days of
the manufacturing industry and even today it is the same for
some industries and products. The continued extraction of
natural resources and increasing adverse effects on the
environment is pushing the society towards more sustainable
way of manufacturing. In the context of sustainable
manufacturing more attention is being paid to closing the
manufacturing loop by developing methods to reuse products.
One such method is remanufacturing while others are repair,
recondition, repurpose and recycle. Product remanufacturing
is a widely accepted sustainable product reuse strategy [1] in
most industries due to its unique advantage of retaining a
greater portion of added value during the initial manufacturing
stages[2][3] and has developed to a faster growing business
than some traditional industries [4].
Remanufacturing is quite an old concept for high value
products and the term ‘remanufacturing’ has been used in
literature with various meanings sometimes creating an
ambiguity. In 1983 Lund[5] in his book on the experiences of
United States’ remanufacturing industry comprehensively
defines remanufacturing “as an industrial process in which
worn-out products are restored to like-new condition through
a series of industrial processes in a factory environment, a
discarded product is completely disassembled, useable parts
are cleaned, refurbished, and put into inventory. Then the
new product is reassembled from the old and, where
necessary, new parts to produce a fully equivalent and
sometimes superior in performance and expected lifetime to
the original new product”. Since then many research has
been conducted on this subject in variety of industries
contributing some improvements and simplifications to the
definition and concepts of remanufacturing. For the purpose
of this paper the definition published by the British Standards
Institute is used. BS 8887-220:2010 - Design for manufacture,
assembly, disassembly and end-of-life processing (MADE)
and BS 8887-2 Design for manufacture, assembly,
disassembly and end-of-life processing (MADE) Part 2: Terms
and definitions, defines remanufacturing as ‘returning a used
product to at least its original performance with a warranty
that is equivalent to or better than that of the newly
manufactured product’[6][7].
The remanufacturing process consists of several important
steps (Please refer to Figure 1). Firstly the used product,
which is known as the ‘Core’, is received at the
remanufacturing facility. Then the product is fully
disassembled in to part level and then each part is cleaned.
For example in automotive gearbox remanufacturing, the
parts would be gear box housing, all internal gears, shafts,
bearings, connecting bolts and nuts, couplings and shifter
mechanisms. The main purpose of cleaning is to facilitate
inspection and damage correction, and thus make the parts to
like new in condition. The process of cleaning requires one or
multiple processes including both manual and machine
operations. The correct extent of cleaning is cleaning the
product up to like- new condition. However, it is difficult to
measure the level of cleaning irrespectively as there is no
standard yardstick available. In practice it is mostly done by
visual inspection and then determining which is good enough
by experience of the workers. This also causes a difference in
cleaning efforts and hence costs for each remanufacturer.
The cleaned parts are then inspected for their quality and
performance. Parts which fail the expected standard are
either scrapped or sent for component remanufacture.
Scrapped parts are replaced with new or remanufactured
parts. Some critical parts which have limited operational life
such as bearings are replaced with new parts irrespective of
their condition to ensure the required quality and hence the
required guarantee. Rebuilding of the product is then carried
out by assembling the parts together according the original
G. Seliger (Ed.), Proceedings of the 11th Global Conference on Sustainable Manufacturing - Innovative Solutions
ISBN 978-3-7983-2609-5 © Universitätsverlag der TU Berlin 2013
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J.R.Gamage, W.L.Ijomah, J.Windmill
equipment manufacturers (OEM) specification. As the last
step of remanufacturing the assembled product is subjected
to an operational performance test which is similar to that
used to test a new product during initial manufacture. In the
event of using remanufactured components, the component
should also be tested individually according to OEM
standards before assembly to ensure successful component
remanufacture.
Almost all the remanufacturing steps discussed above are
highly labour intensive and time consuming unlike the
operations in initial manufacturing which may use automation.
This can make remanufacturing a costly operation so that
sometimes it is not worth opting for remanufacture instead of
the other end-of-life processes. Compared to the other steps
of remanufacturing cleaning accounts for a considerable
portion of the cost of automotive remanufacturing [8]. It is of
paramount importance that the costs of product recovery
activities are limited to make them economically viable and
hence sustainable. Therefore this research aims at
investigating factors for higher costs in the cleaning process
of automotive remanufacturing and suggests ways in which
these costs could be reduced.
Figure 1: General process of Remanufacturing
2 LITERATURE REVIEW
Literature is enriched with a range of research on various
aspects of remanufacturing in a variety of industries. It is
stated that remanufactured products consumes about 50% to
80%less energy to produce when compared with a new
product manufacture but with the comparable quality level [9].
Further there could be production cost savings from 20% to
80% compared with conventional manufacturing making
remanufacturing a financially sound operation [2][9]. A study
on environmental savings through remanufacturing of
compressors has shown that the amount of greenhouse gas
emission of remanufactured product is around 90% less than
the manufacturing new compressor and it is 50% cheaper
[10].
When it comes to automobile industry, it is estimated that 8-9
million vehicles are discarded every year in the European
Union of which a major proportion is recycled meaning that
an average value of 75% by weight of a vehicle is being
recycled [11]. The above volume is comprised of the
components that are discarded during remanufacture and
components that are not considered for remanufacture. The
large quantities discarded and high residual values of
automobiles encourage reuse strategies to be followed.
Hence it is important to develop cost effective strategies in
remanufacturing. It has been found that the cost of cleaning
seconds only to new parts replacement within reassembly
operation in a survey undertaken in US automotive
remanufacturing sector [8].
A study on the Swedish remanufacturing industry focusing on
automotive and household appliances [12] has indicated that
cleaning and damage correction steps are the most critical
steps in the remanufacturing process. The cost for cleaning
is largely from labour cost component among other capital
and overhead costs. This is because there are few automated
or machine assisted processes for cleaning. Other costs arise
from consumables like chemical detergents and other factory
overheads like electricity to operate cleaning machinery. So
the time spent on cleaning is vital in controlling the cleaning
costs involved. An assessment on US remanufacturing
practices [13] indicates that cleaning accounts for the major
portion of total remanufacturing processing time with an
average of 20% spent on cleaning operation. One more
reason for these excessive cleaning time is the requirement
of multiple processing within the cleaning operation [4]. A
study on energy intensities in diesel engine component
manufacture in US[14] states cleaning remains a dominant
energy consumer for remanufacturing of all of the engine
components.
3 METHODOLOGY
A comprehensive literature survey on product
remanufacturing was undertaken to figure out the issues of
remanufacturing. The nature of the research objectives
demands multiple case study approach as discussed in [15].
Four remanufacturing companies in the United Kingdom were
chosen out of which three were in the automotive
remanufacturing industry and the other in office equipment,
(the photo copier) remanufacturing industry. Senior technical
managers and operational level staff were interviewed onsite.
Direct observations and company documents were used to
understand the remanufacturing process in general and the
importance and procedures of cleaning in particular.
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What makes cleaning a costly operation in remanufacturing?
4 CASE STUDIES
The entire process of remanufacturing from gate-to-gate was
studied during case study visits. A comparison of case
companies with regard to industry sector, category of
remanufacturing, volume of operation and nature of cleaning
operation is presented in Table 1. Automotive transmission
and engine components (such as gear wheels, shafts,
couplings, valve bodies, torque converters, pistons, cylinder
blocks, etc) require different degrees of cleaning and often
done by different machine aids. Machine aided cleaning used
in the case companies were, spray cleaning, baking, chemical
bath agitating, shot blasting, and vibration grits cleaning.
Manual washing, which is the most common, may still be
required even after one stage machine aided cleaning.
Table 1 : Comparison of case companies
COMPANY A
COMPANY B
COMPANY C
COMPANY D
Sector
Automotive
Automotive
Automotive
Copier
Nature of business
Both automatic and
manual transmission
remanufacturing
Manual transmission
and engine
remanufacturing
diesel engines and
transmissions,
cylinder heads
Photo copier
remanufacturing and
after sales services
Category
Independent
remanufacturer
Contract
remanufacture
OEM
Independent catering
for limited brands
Company size
(employees)
25 approx.
SME
75 approx.
SME
300 approx.
15 approx.
SME
Average
production
(approx.)
600 units/year
15,000 units/year
Complex
400 units/year
Nature of cleaning
operation
Machine and manual
Uses aqueous based
detergents and
degreasers
Varity of machines
and manual
Uses aqueous based
detergents and
degreasers
Varity of machines
(Ex. vibration) and
manual cleaning
Only Manual cleaning
Uses aqueous based
detergents
Company A, uses a spray cleaner machine and manual
cleaning of automobile transmissions parts. After cleaning
they spray paints the gearbox cases in bringing those to like
new condition. Whereas company B uses only cleaning
techniques in bringing the gearbox casings to like-new
condition. These include the spray machine wash and then
shot blasting to get the natural aluminium outlook without
painting it. For other inside components they use dipped
cleaning with kerosene and aqueous detergents, vibration
grits cleaning and manual cleaning. Company B spends 40%
of its total remanufacturing time for cleaning operation during
manual transmission cleaning. This has been largely
contributed by the manual cleaning operation. Company C
also uses manual cleaning and variety of machine cleaning
techniques. It was mentioned that consumables of cleaning
alone accounts for 10% from the total cost of remanufacturing
in company C.
A study on automotive parts remanufacturing [8] reveals five
main reasons for cleaning difficulties; namely the size of
parts/orifices, environmental regulations, excess debris,
material type and corrosion. These were enquired and
confirmed by the case studies A, B and C. Additionally two
new important factors were also found. These are the output
form of the remanufactured product and the approaches to
cleaning by individual remanufacturer. The attention to
cleaning is higher in component remanufacture than whole
unit remanufacture. For example during whole engine
remanufacture versus piston remanufacture, there is much
higher effort is needed for the later. This is because the
customer is comparing the remanufactured component
(piston) with its new counterpart. However during whole
engine remanufacturing the attention/effort needed to clean
the same piston would be much lesser. Some
remanufacturers use finishing operations, like painting, to
bring products to like new condition thus reducing the efforts
of cleaning. These kinds of alternative approaches to cleaning
by some remanufacturers may reduce the costs incurred for
cleaning.
Attention for cleaning was comparatively low in company A,
medium in Company B and high in company C. This may be
due to the fact that OEMs and contract remanufacturers are
much more concern about the brand value of products.
Further they have to incur higher costs when complying with
environmental regulations than for small scale independent
remanufacturers who outsource the waste disposal. The use
of technology also increases from company A to C as
company wealth, volume and complexity of operation
increases. Furthermore company C has to put an extra effort
for cleaning as their output form of products includes
remanufactured spare parts other than whole units. In
contrast, company D, which is in the copier industry has a
relatively lower extent of cleaning which requires only manual
cleaning with aqueous detergents as it does not contain large
amounts of debris and they use a final painting operation.
Further copiers have fewer parts, less intricate components
and simpler joining methods compared to automotive parts.
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J.R.Gamage, W.L.Ijomah, J.Windmill
5 FINDINGS
Seven factors were identified which make cleaning costlier
(please refer left most column in Figure 2). Out of which first
five was mentioned in literature and also confirmed through
the case studies. New two factors, output form and
approaches to cleaning, were revealed through case studies.
These seven factors can be categorised to two main
dimensions. The first is the technical difficulty due to physical
characteristics of the product and/or process which makes
cleaning process more complex. This demands extended
labour and machine hours adding up to the cost of cleaning.
The first four factors in the list (Figure 2) belong to this
category. The second dimension is the factors arising from
the nature of the business of the remanufacturer.
Characteristics like company scale, volume and variety of
operation, output form and internal standards coupled with
the brand image are concerned under business nature. The
last three factors in the list could be categorised under
second dimension. The costs associated with cleaning
consumables, overheads and compliance to cleaning waste
disposal regulations may increase due to the factors under
second dimension.
Figure 2 shows the relative costs incurred for cleaning in each
of the case studies. The circles represent automotive
remanufacturers and square represents the copier
remanufacturer. The relative size of object shows the size of
the organisation in terms of employees and volume of
operation. The figure is not to scale but represents a fair
enough picture based on the information gained during the
case studies. The x - axis represents the factors which make
cleaning costlier and the y - axis represents the cost of
cleaning as a proportion of total remanufacturing cost in each
company.
FACTOR
Part complexity (shape, size)
Low
High
Excessive debris
Low
High
Material type
Easy (ex. Ferrous)
Difficult (ex. Aluminum)
Corrosion
Low
High
Environmental regulations
Low applicability
High applicability
Output form
Whole units (ex. Complete
transmission or engine)
Part level
(ex. Crank shaft, piston)
Approaches to cleaning
(due to brand consciousness and
internal standards)
Simple
Complex
Figure 2 : Cost of cleaning vs factors affecting cleaning
Effort/cost of cleaning operation
(As a proportion of total remanufacturing
effort/cost)
A
B
C
D
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What makes cleaning a costly operation in remanufacturing?
It could be concluded that both dimensions equally contribute
to the cost of cleaning. It is important to identify what are the
factors that mostly affect in a given context and address them
to bring down the cost of cleaning during remanufacture.
Individual companies need to set their own targets in cleaning
operations and invest accordingly in gaining a cost
advantage.
6 SUMMARY
The factors making higher cleaning efforts have been
identified. Those factors affect every remanufacturer
depending on the nature of their operation and type of the
products. The findings of previous research have been
confirmed and some new factors were also identified. The
research emphasises the significance of the cleaning
operation as a high cost contributor for remanufacturing.
Higher cost of remanufactured products may hinder their
competitiveness in the market place which affects sustainable
manufacturing. The authors believe that this knowledge would
encourage product designers to consider more about the
aspect of cleaning during the product design stage (Design
for Cleaning) thus assisting them to design more sustainable
and environmentally friendly products.
7 ACKNOWLEDGMENTS
Authors extend their sincere gratitude to all participating
companies in the UK remanufacturing sector for facilitating
observation visits and thanks for the interviewees at all levels
for sharing their valuable experience.
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