Prioritizing ‘Design for Recyclability’ guidelines,
bridging the gap between recyclers and product developers
Harm Peters1, Marten Toxopeus1, Juan Jauregui-Becker1, Mark-Olof Dirksen2
1 Laboratory of Design, Production and Management, Faculty of Engineering Technology,
University of Twente, Enschede, The Netherlands
2 Innovation Domestic Appliances, Consumer Lifestyle,
Royal Philips Electronics, The Netherlands
Recycling has proven to be an end of life method that gives rise to a more efficient usage of materials. However, most
products are not designed with recycling as an end of life scenario in mind. In order to improve this situation, this paper
presents a Design For eXcellence (DFX) method for recyclability, resulting in a practical tool for product engineers. The
tool enables an assessment of the concept at an early stage, as decisions not data are the input for the tool. This
provides information and feedback when it is most needed. The method is based on ongoing research aiming at closing
the loop of the material streams. This Design for Recyclability (DFR) method focuses on small domestic appliances
recycled in Europe and incorporates potential future legislation. The Design for Recyclability method has three main
components, namely: a set of design guidelines, a recycling performance evaluation method, and prioritized
improvement suggestions. The DFR guidelines are to be used during the concept and embodiment design phases by
indicating how to improve the recyclability of new products. The performance evaluation method allows engineers to
obtain an indication of the recyclability of a concept or product whereby comparisons can be made and improvements
quantatively measured. Furthermore, the method has been implemented into an accessible computer application. The
software supports the three steps of the method. This flexible and dynamic approach offers the possibility to assess
product concepts or existing products on recyclability in the early stages of the product creation process. Experts from
both Van Gansewinkel, a large recycler in the Netherlands and from Royal Philips Consumer Electronics were actively
involved in the development of both the method and the tool. Preliminary testing of the tool by assessment of products
available on the market, yields promising results.
Design; recyclability; recycling; tool
With increased environmental awareness and depleting resources,
efficient recycling of products becomes more of an imperative
requirement for both society and producers.
Most products available nowadays in the market are not designed
with the end of life scenario of recycling in mind. In order to change
this current situation, companies have to adopt new design
paradigms where the ability to recycle a product is taken into
consideration from the start of product conceptualization. In this
context, this paper presents a Design For eXcellence method,
focusing on maximizing a product’s recyclability. Recyclability is
here defined as; the affordance a product has for recovering as
much components and materials as possible (quantity) with the
highest possible purity (quality) by the least amount of effort (ease)
with existing recycling technologies.
The ‘ability’ part of Design for Recyclability is a performance
indicator . The performance indicator expresses how well the
product can be recycled. Design for Recyclability enables engineers
in obtaining an indicator score of the recycling performance after
applying the method, while the currently widely used term, Design
for Recycling, purely focuses on method and directions.
The development of Design for Recyclability methods has currently
taken more importance, especially in Best in Class industries, as a
way to standardize and popularize the implementation of such
approaches within companies.
Actually, various publications describe design for
recycling/recyclability guidelines [2-9]. Most of them are very
general and do not provide concrete steps, actions or solutions. For
example, they propose to ‘minimize material diversity’, without
stating which materials to avoid or are of preference. Often
guidelines concern ‘recycling’ in general and not a specific industrial
recycling process, containing various guidelines for manual
disassembly, automated disassembly, and dismantling. Most sets of
guidelines described are a combination of different recycling
processes. This may be the desired approach when a product is
intended to be recycled by different recycling processes.
Alternatively, designing a product by focusing on a specific likely
recycling process can result in fewer compromises and minimising
the guidelines required to be considered, thus making applying the
guidelines easier. At present the most specific information is
outlined in the VDI 2243 guideline, providing a checklist, practical
hints, and examples .
Additionally a model linked to CAD to assess the recyclability of a
product is reported . The model evaluates a specific product for
which design choices are already made. On the other hand the
purpose of the guidelines is to support engineers in making these
design choices at the front end of the design process, before the
product is developed.
19th CIRP International Conference on Life Cycle Engineering, Berkeley, 2012
Design for Recycling guidelines have been around for two decades,
yet closed-loop recycling is still more of an exception than standard
practice. It is assumed that general design guidelines are not
sufficient to achieve (improved) closed-loop recycling or that the
guidelines are simply not applied.
Therefore, this paper describes a DFX methodology capable of
providing engineers with clear and complete Design for
Recyclability guidelines, as well as the possibility to assess a
product to obtain an indication of its recyclability performance.
Section 2 describes the theoretical basis for developing a DFX
methodology. Section 3 presents the application of the DFX
methodology. Weighting factors of the different strategies are
applied to enable a product recyclability assessment. Weighting
factors for the strategies also prioritize the strategies and thereby
enable engineers to select the most important strategies to optimize
design towards better recyclable small domestic appliances. In
section 4 the tool to support engineers in developing better
recyclable products is presented. Section 5 presents the preliminary
results to validate the Impact Assessment Method (IAM). The
conclusion is stated in section 6.
This section explains the approach used for developing the DFX
methodology. First, Section 2.1. describes the design process steps
that require to be supported by a Design for eXellence
methodology. Secondly, Section 2.2. explains the steps that were
followed in developing the method.
2.1 The Design process
A widely accepted generic model of the design process is shown in
Figure 1 . According to this, candidate solutions are generated
in a creation process. Then they are analyzed to calculate its
performance and evaluated to assess whether the design is to be
adjusted (path 1), rejected (path 2) or accepted (path 3). Therefore,
the four basic processes that need to be supported in a DFX
methodology are; Creation, Analysis, Evaluation and Adjustment.
Furthermore, and as described in , the types of information
content present in a design process can be classified into three,
categories, namely; embodiment, scenario and performance.
• Embodiment regards the set of parameters describing the
design object, like its topology and its properties.
• Scenario is related to the set of entities describing the
flow of energy, mass or information the embodiment is
• Performance determines how the embodiment behaves
within a certain (group of) scenarios.
Figure 1: The design process 
Figure 2: The analysis and the creation process
From here it follows that an analysis technique allows the
quantification and qualification of the performance of an
embodiment undergoing a given scenario, as shown in Figure 2. On
the other hand, creation is the process of specifying embodiment
parameters such that it meets certain performance values for a
given scenario. In this sense, design rules have an inverted effect to
analysis, since scenario and/or performances help defining the
From the previous discussion, it can be concluded that the DFX
methodology should have a clear description of the following:
1. Types of embodiment, scenario and performance
variables involved in the method.
2. An analysis method for calculating the designs
3. A set of design rules to assist the generation of
4. A set of evaluation criteria for judging the performance
values obtained in an analysis process.
5. A set of adjustment rules for improving previously
obtained candidate solutions.
The resulting Design for Recyclability method presented in this
paper was developed taking this into consideration.
2.2 The DFX methodology
A Design for eXcellence methodology is developed to generate
design guidelines that support product developers to focus on a
single variable; X. The Design for eXcellence methodology was
utilized to develop the Design for Recyclability method, and
consisted out of the following steps:
• Goal definition: defining the application of the DFX
method, defining the subject of study, determining the
depth of study.
• Subject definition: knowing the initiatives, determining
experts to interview, knowing the process (X),
determining aspects of attention.
• User operability: determining how the target group should
use the DFX method.
• DFX model making: choosing and making the model.
• Evaluation: testing and revising the model, determining
• Model revision: revising the model according to the
outcome of the evaluation.
The DFX methodology is a systematic step wise approach with
associated actions to generate Design for X guidelines.
3 THE DFX METHOD: DESIGN FOR RECYCLABILITY
The development of the method here presented is commissioned
by Philips Royal Electronics. Boundary conditions of the tool were
determined for small domestic appliances, to be recycled in Europe,
utilizing shredding recycling systems. The tool is created with
1 2 3
Content of guidelines and strategies
Chemical experts (Royal Philips Electronics)
Legislation expert (Royal Philips Electronics)
Material expert (Royal Philips Electronics)
Sustainability experts (Royal Philips Electronics)
Recycling company experts (Van Gansewinkel Group)
Formulation of guidelines and strategies Design experts (University of Twente)
Psychology expert (University of Twente)
Creation of Impact Assessment Method (IAM)
IAM expert (University of Twente)
Decision making expert (University of Twente)
Multi criteria analysis expert (University of Twente)
Prioritizing WF’s of Impact Assessment Method (IAM) Recycling company experts (Van Gansewinkel Group,
Knowledge management Knowledge management expert (University of Twente)
Feedback on use of tool
Systems architect (Royal Philips Electronics)
Product architect (Royal Philips Electronics)
Development engineers (Royal Philips Electronics)
Design engineers (University of Twente)
Table 1: Conducted expert interviews.
ambitious guidelines, intending that products designed with these
guidelines are effectively recyclable nowadays, as well as in the
coming years. The foreseeable recycling processes and candidate
future legislation are taken into account during development. This
ensures that the materials are valid for the coming years. This is
necessary as Product Life Cycles (PLC’s) experience a delay that
can take up to a decade or longer, from being produced to actually
reaching the disposal and recycling stage. Only considering
Europe, there are over 1000 recycling companies. The origin of the
waste these companies recycle varies: packaging,
building/construction, agriculture, automotive electrical/electronic
and other markets. Of the 57 Waste Electrical and Electronic
Equipment (WEEE) recycling companies 56 use ‘size reduction’ as
a recycling technology . It is assumed the size reduction
technology is shredding, indicating that shredding can be regarded
as the common European WEEE recycling process.
Figure 3: Practical execution of DFX methodology
A literature study was performed to form a starting basis of the
guidelines already available, followed by a patent study to obtain
insight into the technologies that could potentially lead towards an
improved future recycling process. Subsequently observational
visits and studies are performed to the recycling facilities to provide
the link between theory and the important firsthand experience.
During these stages many expert interviews were conducted to gain
further necessary practical insight. These experts were involved to
ensure the right knowledge on each different topic is included, table
1. The practical execution of the DFX methodology is visualized in
3.1 Variables and parameters
First 6 consequences to be prevented are defined. The
consequences apply to the output of the recycling process. The
recycler wants to prevent these consequences in order to maximize
the quality and quantity of the output material stream. Following
this, 5 types of materials or components are defined which cause
these consequences. Finally the strategies prevent the product
design from containing these types of materials or components.
Therefore it follows that the:
• Scenario variables: are the strategies.
• Embodiment variables: are materials and connections.
• Performance: are the consequences.
3.2 Creation support
Literature on Eco-design [2-9] provides general guidelines for
designing products with increased recyclability. However
experience indicates that engineers prefer more specific directions
in order to know how to design better recyclable products.
Therefore, the method in this paper approaches design support on
two levels, namely, higher level guidelines, and a more specific
strategy level. The guideline level consists of 7 guidelines which
describe a general objective. The strategies, which are grouped by
guidelines, describe in specific terms the actions and decisions
required to achieve the objective of the guideline they are coupled
to. Special attention has been paid to the formulation of the
strategies to avoid misinterpretation. An example of a guideline is:
Guideline; Minimize material diversity.
And an example of a strategy to achieve this guideline is:
Strategy; Do not use polymer blends. Blends like PS-ABS cannot
be separated into PS and ABS. Use mono materials instead of
blends. Pure materials are supremely recyclable (if the material is
As the example shows, the guideline describes an objective, while a
strategy describes a way to achieve this objective. A total of 7
guidelines and 39 strategies were developed. Confidentiality
prohibits describing all of them.
3.3 Analysis Method
The performance indicator that measures the degree of recyclability
of a product is here defined as Product Recyclability Indicator (PRI).
Its lowest value is 0% recyclability efficiency, which represents a
product when best suitable for energy recovery. Whilst its highest
value is 100% recyclability efficiency, which represents that the
product meets all the objectives stated in the guidelines. In order to
develop an analysis method that can be used to calculate the PRI,
each strategy has been provided with a weighting factor that
describes its importance in making the product recyclable. The PRI
is calculated by adding all of the weighting factors attributed to each
of the strategies that have been used during the design of the
product. The values of the weighting factors are based on concrete
input extracted from the recycling industry. The transformation of
weighting factors to recyclability efficiency has been regarded as
the Impact Assessment Method (IAM).
Multiple versions of the IAM are created and tested, resulting in a
workable and refined IAM. The final IAM version consists of a
structure of 6 consequences, 5 types of materials or components,
and 39 strategies. The analytical hierarchy process tree of IAM is
displayed in figure 4. Weighting factors of the variables and
parameters were obtained accordingly:
Consequences: Three large recyclers in Europe used Multi Criteria
Analysis (MCA) to provide the consequences with weighting factors
(WF). This is used to obtain the relative importance of prevention of
each consequence based on daily practice. This empirical input
strengthens the reliability of the IAM.
Materials and components: An MCA is used to identify the extent of
severity each type of material or component causes the
consequence. This is the most uncertain part of the IAM as it is
based on the intuition and experience of a relevant expert.
However, the expert should be familiar with both the recycling
process and product development. The MCA is therefore an
approximation of reality based on the opinion of this expert. The WF
of the consequences and the WF of how severe each material or
component causes the consequence is put in a sub criteria analysis
to generate WFs of the different types of materials or components.
Strategies: WFs of how well each strategy prevents a type of
material or component from being used are obtained by an MCA.
The MCA input is based on logical thinking and is a reflection of
reality. A sub criteria analysis of the two previously mentioned
weighting factors provide WFs for the strategies. Figure 5 visualizes
how the different weighting factors of the strategies are obtained.
5 Types of material
causing a certain
39 Strategies to
type of materials
A well recyclable product
Toxic waste Toxic
Figure 4: Analytical network process tree
WF Consequence WF how severe the type of material or
component causes the consequence
WF of type of material
WF of type of material
WF how well the strategy prevents the
type of material or component
Figure 5: Impact Assessment Method to calculate static weighting factors
Figure 6: Impact Assessment Method to calculate WF for next best strategies
Unfortunately the usual static weighting factors are not sufficient
because when conditions change, different strategies increase in
importance and thus their weighting factors should increase as well.
For example when toxic substances are not used there is no need
to enable removal. Inversely when toxic substances are used,
enabling removal of these toxic substances or components gets a
higher priority. The solution is to apply dynamic weighting factors.
Superior strategies are assigned WFs by the earlier mentioned IAM.
Inferior strategies are assigned a fraction of the superior strategy
when this superior strategy is not met. Four parameters are
determined which cause a strategy to be strictly superior:
1. Increased probability of occurrence of a consequence
2. Increased severity of the consequence possible
3. Increased effort required to prevent a consequence
4. Increased wear caused to prevent a consequence
Each inferior strategy is compared to its superior strategy
employing these parameters. The parameters are assigned five
grades ranging from 0.1 to 1. When the inferior strategy scores
equal on a certain parameter, a 1 is assigned. When the inferior
strategy scores worse a lower value is assigned. Multiplying the
WFs of the parameters results in the Next Best Factor (NBF). The
inferior strategy is assigned the WF of the superior strategy
multiplied with the NBF. Note: this only occurs when the superior
strategy is not complied with. Figure 6 shows how the weighting
factors of next best strategies are calculated to enable dynamic
weighting factors. Evaluation criteria
The user of the method indicates which strategies the concept or
product complies with to assess its recyclability. The Product
Recyclability Indicator score is the sum of the weighting factors of
the strategies complied with. This efficiency performance is
indicated as a percentage. Whether the result is good or bad
depends on the criteria of the company or user. Philips marks a
score of <50% as bad, 50 – 75% as average, and ≥75% as good.
3.4 Improvement suggestions
The method also provides improvement suggestions when an
assessment is performed. Here the method selects and displays the
top five strategies of priority not yet complied with. These strategies
are most significant to further improve the recyclability of the
product. In addition, when completed by the user, the tool indicates
why those strategies were not complied with and who made that
3.5 The analysis method applied
Product developers can use the analysis method by following these
• Set a recyclability performance indicator objective.
• Select which strategies to comply with to achieve the
• Generate a concept product design complying with those
• Assess the concept product design on recyclability.
• When the objective score is not achieved developers
should take into account the improvement suggestions.
4 THE TOOL
The tool is created including (1) the Design for Recyclability
guidelines and strategies, (2) the dynamic weighting factors of the
strategies and (3) the ability to assess a concept or product on
recyclability. The benefit of combining these three aspects into a
single tool is; clustered knowledge, ease of use, and the ability to
perform a relatively quick assessment of products recyclability.
Additionally the tool offers improvement suggestions for the
assessed product, comprising of the top five strategies with highest
priority. Optionally the user can declare why a certain strategy is not
complied with and who decided so. This consolidation of
information is helpful for possible future redesign or when a similar
product will be designed. With the top five improvement
suggestions the reason for non compliance as well as the
responsible decision maker is clearly indicated.
To conduct an assessment the user indicates which strategies the
product complies with. This set up means the input of the IAM are
the design process decisions. The input of decisions enables not
only the assessment of products but also concepts. Information and
feedback on how to improve the product design is required at an
early stage of the product design process when major decisions
have yet to be made. Information and feedback at an early stage
enables the developers to improve the design before large
investments are made. For a Life Cycle Analysis, product data is
required, including details such as the exact amount of a certain
material. This data is not available at an early stage of product
design. The tool enables an assessment of the concept at an early
stage because decisions not data are the input for the tool. This
provides information and feedback when it is most needed.
5 METHOD VALIDATION EXPERIMENTS
Different types of small domestic appliances are assessed to
evaluate the validity of the weighting factors in the tool and the
product recyclability indicator score. The sustainability expert of
Philips set a recyclability performance indicator score for each of
the assessed existing products prior to tool assessment. This
expected recyclability indicator is solely based on expertise and
experience. The results of the assessment are compared to these
expectations. In the case where the tool would show a totally
different recyclability indicator, contradicting the expert’s
expectation, the IAM is considered incorrect and requires
improvement. Four different types of small domestic appliances are
assessed so far. The preliminary results are promising, showing
that the results from the assessments align closely with the expert
expectations. Some results are displayed in figure 7. The expert
consistently sets the expected recyclability score 12 to 16% higher
than the results from the tool. There are no large deviations from
the expert’s expectations. The preliminary conclusion from the
WF Severity of
NBF (next best factor) WF Superior strategy WF added to the next
Philips experts is that the model is usable and that first indications
are that the tool functions accordingly.
Explanation for the consistently higher indicator score of the expert
could be; 1) The tool takes candidate future legislation into account
whereas the expert does not, 2) the tool takes other aspects into
account compared to the expert, 3) the relative importance of the
strategies differ for recycler and product developer.
5.2 Expert opinion
Following these experiments the expert’s opinion of the tool was
gauged. The new developed tool will enhance the awareness and
innovation with respect to the recyclability of electronic products.
The tool is a bridge between product designers and recyclers of
WEEE waste in Europe as it is a complex dynamic tool, however
this is hidden behind a clear user interface, and provides a simple
interpretable output. For the first time Philips can review products
on recyclability and then use this knowledge to improve closed loop
product recycling chains. First product assessments meet the
expectations and this new supportive product development tool
could lead to new product designs in the future at Philips.
6 CONCLUSION AND RECOMMENDATION
Practical input is utilized in a theoretical model (the tool), to
generate practical output. A tool is created to support engineers in
developing improved recyclable products. The tool contains all
aspects of a complete DFX method. The tool enables an
assessment of both concept and existing products to obtain an
indication of the recyclability of the product. The preliminary tests of
the method yield promising results, meeting expert expectations.
A study should be conducted of how to optimize the IAM. More
recyclers can provide input for the IAM to increase reliability of the
IAM. Additionally it is recommended to extend the geographical
validity of the tool to the United States. It is expected only minor
adjustments are required to make the tool valid for products
recycled in the US. The method is evaluated by assessing different
types of small domestic appliances. It is recommended to evaluate
the method by assessing a greater variety of small domestic
7 FUTURE WORK
Future work will continue on improved product designs to contribute
to closed loop WEEE recycling. Philips will continue the
implementation and improvement these kinds of sustainability tools
to reach their EcoVision5 targets by 2015.
The authors especially would like to thank Piet de Meer from
recycler Van Gansewinkel Group and Erica Purvis from Royal
Philips Electronics for their cooperation on this project.
 Huang, G. Q. (1996). Design for X - concurrent engineering
imperatives. London: Chapman & Hall.
 Bârsan, L., & Bârsan, A. (2009). Some Aspects Concerning
the Design for Recycling and Waste Minimisation.
Proceedings of the 2nd International Conference on
Environmental and Geological Science and Engineering, (pp.
 BECO Groep. (2004). Eindrapport, inzet van recyclaat.
Rotterdam: BECO Groep BV.
 Kriwet, A., Zussman, E., & Seliger, G. (1995). Systematic
Integration of Design-for-Recycling into Product Design.
International Journal of Production Electronics , 15-22.
 Luttropp, C., & Lagerstedt, J. (2006). EcoDesign and The Ten
Golden Rules: generic advice for merging environmental
aspects into product development. Journal of Cleaner
Production , 1396-1408.
 Remich, N. (1991). First Recyclable Appliance. Appliance
 Rifer, W., Katz, J., Omelchuck, J., & Salazar, V. (2007).
Conceptualizing an Optimal Electronic Product Design and
End-of-Life Management System. Electronics & the
Environment, Proceedings of the 2007 IEEE International
Symposium on, (pp. 159-163). Orlando.
 Tabone, M. D., Cregg, J. J., Beckman, E. J., & Landis, A. E.
(2010). Sustainability Metrics: Life Cycle Assessment and
Green Design in Polymers. Environmental Science &
Technology , 8264-8269.
 Xing, K., Abhary, K., & Luong, L. (2003). IREDA: An
integrated methodology for product recyclability and end-of-
life design. The Journal of Sustainable Product Design , 149-
 VDI 2243. (2002). VDI 2243 - Recycling-oriented product
development. Düsseldorf: Verein Deutscher Ingenieure.
 van Schaik, A., & Reuter, M. A. (2010). Dynamic modelling of
E-waste recycling system performance based on product
design. Minerals Engineering , 192-210.
 W. O. Schotborgh, F. G. M. Kokkeler, H. Tragter, and Fjam
van Houten. A bottom-up approach for automated synthesis
tools in the engineering design process. Proceedings of
International Design Conference 2006, pp. 349-356,
 Jauregui-Becker J.M, Tragter H, and F.J.A.M. van Houten,
Structure and models of artifactual routine design problems
for computational synthesis. CIRP Journal of Manufacturing
Science and Technology, 2009. 1(3):120-125.
 Applied Market Information Lfd. (2006). AMI’s guide to the
plastic recycling industry in Europe. ISBN 1 904188419 1, 2
edition. Great Britain.