Disassembly, Step by Step

It’s not too difficult to design more easily disas­sembled products when it’s part of the initial phase of the design specification and goals. However, once engineering, design, and pro­duction are already decided, it’s nearly impos­sible to redesign for easy disassembly.

To whatever extent possible, designers and developers can increase the likelihood of their products being recycled by using the following techniques.

Pure-material parts: These are parts made from only one material that doesn’t need to be separated. For most products, it’s unlikely that the whole product can be made from the same material, but if a product’s parts are at least uni-material, then each can be recycled easily.

Fewer parts: Where possible and applicable, reducing the number of parts can reduce the time and cost of disassembly and also affect the overall environmental impact by potentially reducing the amount of materials used.

Have you ever tried to assemble a piece of furniture or tried to repair an electronic product only to find that there were many different fasteners used throughout the product?

Batteries and other electronics that are easy to remove: These components are often the most hazardous in terms of toxic chemicals, and they should be separated from the rest of the waste stream as early as possible. Ide­ally, they should be recycled separately, which isn’t possible if users can’t pull them out of the product easily.

Standardized fasteners: Have you ever tried to assemble a piece of furniture or tried to repair an electronic product only to find that there were many different fasteners used throughout the product? It sometimes feels like each bolt or screw has a unique length, size, and head configuration, needing a unique tool to deal with each. While this is often a deter­rent on the part of the manufacturer to prevent users from repairing their own products, it also increases the complexity (and likelihood to mistakes) in terms of assembly and repair for the manufacturer, too. This is just one of the many other benefits that standardization can create.

Accessible fasteners: Anyone who has ever tried to change the oil filter on a typical small car, or a fuse in just about any car, knows the pain involved when parts aren’t easily acces­sible. There’s no reason why this is the case except that their developers simply didn’t con­sider putting these parts in more accessible places. The same is true of fasteners. Even if you’ve standardized and reduced the number of fasteners in a product, if you don’t make them accessible, the parts will likely not be separated or recycled. Making any metal fasteners mag­netic can both ease disassembly and increase the likelihood that the fasteners themselves will be recovered for reuse or recycling.

Anyone who has ever tried to change the oil filter on a typical small car, or a fuse in just about any car, knows the pain involved when parts aren’t easily accessible.

Standardized components: Standardization can make components easier to replace and repair. It can help products be more easily used and understood, as well as upgraded. Most electronics would not be possible without a vast number of standards for everything from hard drive sizes to file formats to transistor con­nectors and power outlets. Modular compo­nents can extend this technique to make prod­ucts more easily understood, used, serviced, repaired, and ultimately recycled.

No fasteners: Sometimes, cases and compo­nents can be designed to clip together without the need for fasteners like screws. For example, many mobile phone cases (like those for the

Nokia 6200) do this to allow a plethora of third-party custom case designs. The Macin­tosh IIcx and IIci family excelled in this re­spect as well. Hard drives, fans, power supply, motherboard, and other components simply snapped into place with plastic tabs molded into the case itself. These bent just enough to allow them to be held aside for the components to be removed. Parts can be glued or bonded, but only where they are recyclable together because they are identical materials.

Part material labels: No matter how the parts are assembled or how easily disassembled, if the materials for each aren’t immediately identifiable, they won’t be recycled. Recyclers can’t take many chances in contaminating their material streams. If they don’t know that the part is a specific type of plastic or alloy of aluminium, for example, they won’t throw it in the right bin. Instead, they’ll usually divert it to the trash or to the shredder (where it may get contaminated even more, requiring it to be further downcycled). Each part should be clearly marked with an internationally under­stood label or icon declaring what it is. If some parts are just too tiny (like screws), they should all be made of the same material (so someone could safely assume that they’re all the same material). If a part is made from an unexpected material or a material that looks like something else, this is even more critical. Metals that use alloys (like aluminum cases) should also be labeled by the alloy. It’s not enough to just say “glass” or “aluminum” if it’s a special kind that shouldn’t be mixed with others.

No matter how the parts are assem­bled or how easily disassembled, if the materials for each aren’t immediately identifiable, they won’t be recycled.

There are several commonly understood la­bels and indicators for just these purposes (see Figure 12.2). For example, the most commonly occurring plastics use a series of seven num­bers within a recycling symbol (how’s that for clear?). This system, though less common, extends to glass, metals, batteries, and other materials (see Table 12.1).

/V /V /V /V /V /V /V

£20 £20 £20 £20 £20 £20 £20

PET HDPE PVC PELD PP PS OTHER

fr /V

£20 £20 £10 £10 £10 £20 £10

LEAD alkaline NiiCD NiMH Li SO(Z) CZ

/V А /V

£20 £20 £20

PAP PAP PAP

/ /V

£20 £20

FE ALU

/V /V /V /V

£20 £20 £20 £20

FOR FOR TEX TEX

/V /V /V /V /V /V /V /V

£10 £20 £20 £20 £20 £20 £20 £20

GL GL GL GL GL GL GL GL /V /V

CD CD

GL GL

FIGURE 12.2. http://www. flickr. com/photos/rosenfeldmedia/3264806511 You are probably familiar with a few of these material indicators, but the system is quite extensive.

TABLE 12.1

RECYCLING SYMBOL KEY

Plastics

#1 PET

Polyethylene terephthalate

#2 PEHD or HDPE

High-density polyethylene

#3 PVC

Polyvinyl chloride

#4 PELD or LDPE

Low-density polyethylene

#5 PP

Polypropylene

#6 PS

Polystyrene

#7 O(ther)

All other plastics

#9 or #ABS

Acrylonitrile Butadiene Styrene: monitor/TV cases, cof­fee makers, cell phones, most computer plastic

Batteries

#8 Lead

Lead-acid battery

#9 or #19 Alkaline

Alkaline battery

#10 NiCD

Nickel-cadmium battery

#11 NiMH

Nickel metal hydride battery

#12 Li

Lithium battery

#13 SO(Z)

Silver-oxide battery

#14 CZ

Zinc-carbon battery

Paper

#20 C PAP (PCB)

Cardboard

#21 PAP

Other paper, mixed paper (magazines, mail)

#22 PAP

Paper

#23 PBD (PPB)

Paperboard: greeting cards, frozen food boxes, book cov­ers

Metals

#40 FE

Steel

#41 ALU

Aluminium

Organic Materials

#50 FOR

Wood

#51 FOR

Cork (bottle toppers, place mats, construction material)

#60 COT

Cotton

#61 TEX

Jute

#62-69 TEX

Other textiles

RECYCLING SYMBOL KEY (CONTINUED)

Glass

#70 GLS

Mixed glass container/multi-part container

#71 GLS

Clear glass

#72 GLS

Green glass

#73 GLS

Dark sort glass

#74 GLS

Light sort glass

#75 GLS

Light leaded glass (televisions, high-end electronics dis­play glass)

#76 GLS

Leaded glass (older televisions, ashtrays, older beverage holders)

#77 GLS

Copper mixed/copper backed glass (electronics, LCD display heads, clocks/watches)

#78 GLS

Silver mixed/silver backed glass (mirrors, formal table settings)

#79 GLS

Gold mixed/gold backed glass (computer glass, formal table settings)

Of course, these need to be easy to find and read. Often, the label is molded right into the part (requiring no paint or applique), but these can be difficult to read if they aren’t molded deep enough to cast a reasonable shadow. If the label can’t be molded into the material itself (clothing would be an example), a label needs to be affixed in a convenient and clear way.

Indicate separation points: It’s much easier (and faster, making it less costly) to separate parts if the edges are clearly indicated. This can be done by a change in color, texture, or finish, pronounced groove, or instructions (whether molded into the parts or applied later). It works for adjacent parts of similar or different materi­als.

Indicate disassembly sequence: Both for repairability and recycling, indicating the proper sequence to disassemble complex parts will increase the likelihood that products are repaired or recycled correctly and completely. For example, large Xerox office copiers have extremely complex mechanisms. Even a simple procedure, like clearing a paper jam, can be a nightmare to fix. For decades, these copiers have used colored parts and numbers to indi­cate which components to check first, how to open them correctly, and how to reset them to work properly again.

Reduce use of paint: Paint can often contam­inate materials streams that flow through facto­ries and recycling centers, requiring them to be diverted into separate substreams or discarded completely. This is because it contaminates the

purity of the materials used so that they can’t be effectively recycled. So, the less used, the better. The same goes for ink. This isn’t always possible, of course.

All of the previous techniques make it easier to separate parts and disassemble products, and they do so by minimizing the time required. This further reduces the costs associated with recycling since time is often the most expensive component of disassembly—or assembly, for that matter.

Finally, to truly develop products for easy disassembly, designing them from the begin­ning to be assembled and disassembled easily is the best approach. It is during the concep­tual phases or product and service develop­ment that wholly new approaches can result in break-through ideas that eliminate parts, affect manufacturing costs, specify materials in dif­ferent ways, and conceive of challenges in new ways.

CHAPTER 13