1. Design for Disassembly (DfD) Reduce, Recycle, Reuse
by: Jesse Miller

2. Agenda DfD Defined Why use DfD? How do you implement DfD?
Workplace examples of DfD
Is it easy to disassemble your product?
Reading list

3. Design for Disassembly (DfD) Defined
A process by which a product and its parts can be easily:
Reused
Re-manufactured
Refurbished or
Recycled
There is a great deal of information on DfD that goes into much more depth than the scope of this presentation will allow. Some of the concepts that we will not be able to cover include disassembly operations and the economic model for disassembly. Both these topics would require a much more in depth and lengthy discussion on the subject. For information on disassembly operations and the economic model for disassembly see

4. DfD Breakdown There are two levels of strategy in DfD
Product Disassembly
Material Disassembly
When levels of strategy is used, it means that for some products it may be more work than necessary to break it down according to material disassembly, and therefore more costly. Use what is best suited to your situation. If you cannot melt down parts or return them to their original form without incurring unnecessary costs, then stick to product disassembly.

5. Product Disassembly
Breaking a product down for reuse into its recognizable components
Disassembling a computer in order to reuse switches, boards, circuits, etc
The process of product disassembly is mostly used because a product is defective, but the majority of components can still be re-used.
To facilitate disassembly, consider the following:
How recyclable are the parts used in production
* By choosing materials that have a proven history of durability to recycling, the product components will last longer
Connection and fastener design
* Products that are easier to take apart are more likely to be recycled more often
Ref: Dowie-Bhamra, T., 1996: Design for disassembly, Co-design: the interdisciplinary journal of design and contextual studies, No. 5-6.

6. Material Disassembly
Breaking down a product in order to reuse materials instead of individual components
Using the plastic in a computer for the outer shell of another computer, i.e. melting it down
Though this process is somewhat more expensive considering the equipment necessary to reach this level of disassembly, there are third parties who are willing to help in this process for a fee. Breaking a product down to the fourth level may not always be the best alternative for products who have exceeded their life cycle. The best way to compare the different alternatives is through ABC or a project cost analysis. Organizations will vary depending on goals and core competiencies.

7. DfD Illustration

8. The first three levels can be classified as product disassembly
The fourth level can be classified as material disassembly.

9. Why use DfD? Reduce Costs Facilitate maintenance and repair
Facilitate part/component re-use, i.e. recovering materials
Products made under DfD will be easier to repair because it will be easier to get to the problem while disassembling the product
Having the ability to re-use undamaged parts while recycling products will greatly decrease production costs

10. Why use DfD? Reduce Waste Disposal Assist material recycling
By not having 100% new construction, product components with no defects can be put back into production.

11. Why use DfD? Increase Product Quality
Assist product testing and failure-mode/end-of-life analysis
The ease of disassembly lends itself to the testing of individual parts for quality and durability. By being able to test the individual components, instead of the whole product, quality can be enhanced starting with the weakest piece. As time goes on, the whole product will become better and the company will spend less on production because of the recyclability of the components.

12. How do you implement DfD?
Parts Connection
Use joints, snaps, or screws instead of welding, soldering or glue
Using joints or snaps in assembly will make it easier to disassemble the product, and re-use or recycle the individual components. This is easier because not only will it take less time to take the product apart, but the parts will be re-useable. If the parts were welded or glued together there would more than likely be damage to the part upon disassembly.

13. How do you implement DfD?
Parts Standardization
The product can be disassembled with minimal work and use minimal tools, i.e. the same size screw throughout the whole product

14. How do you implement DfD?
Parts Placement
Put parts that are likely to wear out at the same time near each other so they can be easily replaced simultaneously
If the parts that are more than likely going to need replacing first are in the same place, then when the product comes in for repairs, less money will be spend on repairs because the technicians will be able to repair more products in a given time period. Also, placing the parts in the same place will help with ease of replacement. If a technician doesn’t have to go around other parts in order to repair the broken one, the whole process time is decreased.

15. Workplace Examples of DfD:
“BMW's 1991 Z1 Roadster, whose plastic side panels come apart like the halves of a walnut shell, is an example of a car designed for disassembly. One of the lessons learned, is that glue or solder in bumpers should be replaced with fasteners so that the bumpers can come apart more easily and the materials can be recycled…Now BMW uses variations of polyurethane, foam, and rubber so the panel can be recycled. The portion of a car recycled is 80% by weight and BMW is aiming for 95%.”

16. Workplace Examples of DfD:
HP products are designed to be recycled. Recycling design features include:
Modular design to allow components to be removed, upgraded or replaced
Eliminating glues and adhesives, for example, by using snap-in features
Marking plastic parts weighing more than 25g according to ISO international standards, to speed up materials identification during recycling
This information was gathered from:
This web site explains in further detail the ISO international standards:

17. Workplace Examples of DfD:
HP Continued:
Reducing the number and types of materials used
Using single plastic polymers
Using molded-in colors and finishes instead of paint, coatings or plating
Relying on modular designs for ease of disassembly of dissimilar recyclable materials

18. Workplace Examples of DfD:
GE Plastics is involved in numerous consumer recycling efforts, from making tea kettles that are easy to disassemble and recycle to turning old plastic computer housings into roof tiles for restaurants. It's trying to put that kind of ingenuity to work for automakers not only in DfD, but also in design for serviceability (DfS). Greg Jones, GE Plastic's manager of design development, currently sees more OEM interest in DfS than DfD, but he sees them as being closely related.

19. Is it easy to disassemble your product?
When using the checklist, you may want to apply a weighting scale; doing so will help you see your most important parts of the disassembly process and interpret your weak and strong areas.

20. Evaluate ease of disassembly:
What are the additional operations required for disassembly?
fracturing
drilling
ungluing
heating
lubricating
– article entitled “A product/component disassembly checklist”

21. Evaluate ease of disassembly:
What are the bonding and fastening methods of parts and components?
insert molding
cohesion
adhesion
mechanical fastening
friction fitting
By knowing what exatly it will take to take the product apart, the process can be completed in less time, but if the process is simple and disassembly requires minimum effort, then it will be much easier to handle a greater volume when recycling or repairing parts.

22. Evaluate ease of disassembly:
What are the tools required for disassembly?
special tool
simple tool
by hand
If a product only requires disassembly by hand, i.e. like a lego, there are minimal costs involved with that kind of disassembly, but if the product is more complex, like a computer, there are a variety of tools needed, some specialized and some simple tools.

23. Evaluate ease of disassembly:
What is the level of difficulty for disassembly?
technician needed
assistant needed
deformation required
hold-down required
difficult access
difficult to view
When taking into consideration the level of difficulty for disassembly, it is important to think about who will be doing the disassembly. If a technician is needed then there is a cost incurred in the process, if an assistant to the technician needed there is a cost on top of that. If taking apart a product requires any deformation of the product that will reduce the amount of materials that can be reused, and therefore will cause an increase in disassembly costs.

24. Summary
With the growing world demand for manufactured goods, and the decreasing availability of landfill space, recycling is becoming more of a necessity than a good idea. By making it possible to re-use product parts, companies can decrease their production costs, decrease refuse and landfill materials, and increase their quality management. A company that can recycle and re-use their own parts is not only ahead of the game of the future, which will eventually require compliance with DfD, DfS, and other green design initiatives, but that company is also at an advantage compared to others in their industry who have not considered such changes.

25. Readings
S. Thomas Foster, Managing Quality (Prentice Hall 2001)
Beitz W. (1993) Designing for ease of recycling, Journal of Engineering Design, 4(1).
Boothroyd G. and Alting L. (1992) Design for assembly and disassembly, Annals of CIRP, 41(2).
Dewhurst P. (1993) Design for disassembly, Boothroyd Dewhurst Inc..
Dowie-Bhamra, T., 1996: Design for disassembly, Co-design: the interdisciplinary journal of design and contextual studies, No. 5-6.
Jackson, T., 1996: Material Concerns. Pollution, Profit and Quality of Life. Routledge, London, p78
endoflife.html
Information in the presentation was gathered using the above sources and any other sources listed throughout.
By reading and consulting the above sources, a company will be able to get a general idea of effective implementation and understanding of DfD.