DES 40A-03 Winter '18
March 15, 2018
Materials in a Fitbit
In today's digital age, technological products can be seen in each and every part of our lives. Among these products are smart, fitness watches such as the Fitbit. This watch helps track our activity, exercise, sleep, weight and overall health. But despite these benefits of the smart watch, it has various issues relating to the materials used in it. Observing the material use in a Fitbit, it is seen that this watch causes damage not only to the environment but also to customers by causing rashes on their wrists. However, after looking at the raw materials used at every stage of its life-cycle, we can see that the company is taking action against their defective products. They are modifying their materials used, in an attempt to make their products more user and environmentally friendly.
The Fitbit consists of various components which make up this useful product. Weighing about 25.8 grams, the Fitbit Charge 2 has a slim design which makes it blend in with athletic clothing as well as every day wear. Though its weight and compact design don't show much material use, a lot of work goes into the making of a Fitbit. Most of the material used is derived from naturally occurring minerals in the Earth. It uses all kinds of metals such as iron ore, silicon, nickel, carbon, nitrogen, and manganese. All of these minerals are either locally mined or transported from other countries to the place of manufacture.
Fitbit, being one of the most popular athletic watch companies, has a variety of watches manufactured to measure different areas of health. Their watches are also one of the most liked among the public. When it comes to manufacturing, Fitbit gets their watches assembled by the P. O. S. Manufacturing Company of Beijing, China. Their transport is by plane or by sea, both requiring either fossil fuels or crude oil as fuel. The Fitbit Charge 2 consists of a few different parts including the belt, OLED screen, belt buckle, and the electric system; all of them are composed with one common material called Silicon. Most of all, the belt is completely derived from silicon. Throughout the manufacture process of the belt it can be seen, that these materials are actually extremely safe and environmentally friendly.
The Fitbit belt is made of a silicone elastomer which is a type of chemically manufactured rubber. The base material of this elastomer is silicon. Silicon is the second most abundant element in the earth's crust and the eighth most common element in the world. Nearly 30 percent of the weight of the earth's crust can be attributed to silicon. It can be found in silicon oxides (silica) or silicate materials. The name silica is given to a group of minerals composed solely of silicon and oxygen, including silica sand, quartz, rock crystal, amethyst, agate, flint, jasper and opal. It also occurs in feldspar, mica and sandstone. Silicon is majorly mined in China, followed, after a large gap, by Russia, United States, Norway, France, Brazil, South Africa, Spain, Bhutan, and Iceland.
Silicon can be obtained from silica sand using the industrial method of heating it with coke, which is a form of coal. This heating is done in a furnace and silica is converted to pure silicon. Afterwards, this pure silicon is chemically reacted with methyl chloride (CH3Cl) over a copper containing substance, which acts as a catalyst (one which speeds up the reaction). This forms dimethyldichlorosilane ([CH3]2Si[Cl]2), a complex compound. By reacting this compound with water (H2O), the chlorine atoms (Cl) are replaced by hydroxyl (OH) groups. The resultant unstable compound called silanol ([CH3]2Si[OH]2), polymerizes or combines to form a structure containing a large number of similar chemical units bonded together. It polymerizes in a condensation reaction, in which the single-unit molecules linking together form polydimethylsiloxane (C2H6OSi)n with an associated loss of water. This compound is called an elastomer derived from silicon. It is considered to be a 100 percent safe ingredient by the Cosmetics Database and the FDA approves it as a safe food additive as well.
Some advantages of silicone elastomers include extreme temperature resistance, environmental resistance to ozone, UV and general weather like rain, snow, sleet and frost. It is also resistant to compression at high temperatures and even when exposed to flames, the elastomer reduces to a non-conducting ash, which is safe for children as well. The main feature of silicone elastomers is their physiological inertness meaning it is tasteless, odorless, non-toxic, and resistant to bacteria and fungi, making the material extremely safe and healthy for humans. It also has a long life or no expiration date. However, silicone is prone to swelling if in contact with oil for a certain period of time. Hence, it is advised to not wear the band too tight. The band can be maintained by using a soap-free cleanser, rubbing alcohol, or a little bit of water to clean it. While the device is water resistant, it is not good for skin to wear a wet band for long periods of time.
Silicone elastomers can also be reused and recycled by shredding, preparing into molds, and addition of fresh silicon. This creates a wide range of rubber-based products used in all types of daily instruments. Popular uses of recycled silicone rubber include baking utensils, food storage, household electronic products, personal care products, clothing and footwear, arts and crafts, mold-making, children's toys, building and hardware, and lubricants. In short, silicone elastomers are completely safe for any kind of daily use, including athletic watch bands.
The next major component of this watch is its belt buckle. Numerous amounts of complaints have been received by Fitbit about their customers experiencing discomfort and rashes on their wrists. This discomfort has been found to be an allergic reaction to the materials within the belt buckle. According to several reviews, people are more affected by the buckle than the band and Fitbit has confirmed that the buckle contains traces of a certain element which can react with our skin.
The belt buckle is a metal called surgical-grade stainless steel. Being surgical-grade, this metal is commonly used for medical purposes such as biomedical implants. It is made up of basic elements like iron ore, chromium, silicon, nickel, carbon, nitrogen, and manganese. These elements are combined to form an alloy, which is a metal made by combining two or more metallic elements to give greater strength or resistance to corrosion. Surgical-grade steel is the most common metal used for body jewelry. It is safe for skin since it has a low amount of carbon. However, like most other stainless steel, it contains about 8-10.5 percent of nickel, which makes it unsuitable for people with nickel allergies. Fitbit has confirmed that their steel also contains traces of nickel, causing rashes on the wrists of people having allergies. At the same time, surgical grade steel is also considered to be the best grade to use when allergic reactions are concerned. Thus, Fitbit is not entirely at fault.
Stainless steel production has increased substantially, almost doubled in the last 10 years. Therefore, stainless steel needs to be recycled and is an essential way of preserving raw materials. Stainless steel in particular is a type of steel which has chromium and nickel to prevent it from rust, corrosion, and the environment. It is also known as inox steel, short for inoxidable, meaning it does not oxidize or react with oxygen in the air. Since many of the stainless-steel types look similar, they are required to be separated before recycling. Using a variety of methods, like electric currents, high pressure, magnets, and liquid baths, this metal is separated from other metals. Then, it is melted, and shaped into slabs, ingots, or rolled into sheets of metal to be reused. The good thing about stainless steel is that it is 100 percent recyclable, so it does not have any waste products or does not lose anything during recycling.
Some of the main advantages of stainless steel includes its resistance to high temperatures and its strength. This makes it ideal for environments which have extreme conditions, both chemical and physical. For example, stainless steel is used in the automotive industry and in construction. Its resistance to corrosion and its flexibility have also made it a common material for household appliances and kitchen ware. Therefore, stainless steel is a suitable material to use for the buckle production.
Then comes the main system of the watch, including electric components and the screen. Similar to other glass-based screens, the Fitbit screen is made of a common polycarbonate material. A polycarbonate is a naturally transparent type of plastic. Although they are commercially made and are available in various colors, the raw material allows for the internal transmission of light or the movement of all kinds of light through a material.
The starting material of this polycarbonate is Bisphenol A, which is an organic synthetic compound with the chemical formula (CH3)2C2. It is produced commercially by the acid catalyzed condensation of phenol (C6H5OH) and acetone (C3H6O, rubbing alcohol), under mild conditions of temperature and pressure. Since they are organic compounds, the starting element of each of them is carbon. Phosgene (COCl2¬) is a highly toxic gas that has been used as a warfare agent before. It can be formed when chlorinated hydrocarbons, which are substances containing chlorine, hydrogen, and carbon, are exposed to high temperatures. It is generally produced from a reaction of carbon monoxide and chlorine gas in the presence of activated charcoal. The final polycarbonate is made by reacting bisphenol A with sodium hydroxide (NaOH) to get the sodium salt of bisphenol A. This sodium salt is then reacted with phosgene to get a polycarbonate.
An optical-grade polycarbonate is optically clear, providing total luminous transmittance, and a very low haze factor. The high impact strength makes it resistant to repeated blows, shattering, and spalling. However, they are still easily scratched so, they need to be handled with care. Thus, a polycarbonate screen is a good choice for devices requiring low distortion but with optimal visual quality. These polymers are used to produce a variety of materials and are particularly useful when impact resistance and/or transparency are a requirement for the product, for example bullet-proof glass. Polycarbonates are commonly used for plastic lenses in eyewear, in medical devices, automotive components, protective gear, greenhouses, CDs, DVDs, Blu-rays, and exterior lighting fixtures. It also has good resistance to heat and can be combined with heat retardant materials without significant material degradation.
Polycarbonates are so strong that they are resistant to impact, they generally end up at landfills. This can cause danger as these plastics also emit some amounts of Bisphenol A (BPA). However, they are still fully recyclable and re-produced in an eco-friendly manner since they are made from natural resources. The usual process includes sorting, shredding, washing with ethanol and then turning the substance into a granulate, ready for manufacturers to use again. Another way is by chemical recycling. The Polycarbonate is made to react with phenol in the presence of a catalyst to form BPA monomers. After purification, both of these monomers are used to produce the polymer (polycarbonate). They are the reused in the manufacture of plastic profiles, which have high color ability and gloss finish, imitating metal and gloss.
The most important part of the Fitbit is its functioning system. This system contains various parts, all containing elements like sand, copper, tin, silver, palladium, hard gold, aluminum, silica, and iron ore. Major elements include enclosure, diagonal monochrome OLED screen, MCU (microcontroller), USB type A to charger port, Barometric pressure sensor, Bluetooth, temperature compensated crystal oscillator (tcxo), and amplifier. All of these components are commonly used in the electronics industry.
An electrical enclosure is a cabinet for electrical equipment to mount switches, knobs and displays, and to prevent electrical shock to equipment users. They are generally made from rigid plastics and metals, particularly stainless steel, carbon steel, and aluminum. Steel cabinets may be painted or galvanized (coated with a protective layer of zinc) to provide further protection from the atmosphere. It is an important part of the product and is primarily for the safety of people who handle the product.
An organic light emitting diode (OLED) is a flat light emitting technology, made by placing a series of organic thin films between two conductors. When an electric current is applied to this, a bright light is emitted. OLED screens are based on emissive display which do not require any backlight. As a result, they are thinner and more efficient than LCD displays which do require a backlight. The OLED consists of many layers, out of which the conductive layer is made of polymer called polyaniline. The emissive layer (emits the light) is made of polyfluorene. This whole part emits the electromagnetic waves which make the Fitbit screen light up.
The microcontroller in the system is a computer present in a single integrated circuit which is dedicated to performing one task and execute one specific application. It contains memory, programmable input/output peripherals as well as a processor. Its power management is generally done by the device BQ25120YFP by Texas Instruments. Microcontrollers are mostly used in automatically controlled electronic devices such as cellphones, cameras, microwaves ovens, washing machines, etc. It is mainly made out of copper, aluminum and alloys like steel, and tin. In short, a microcontroller is the 'brain' of a system.
A USB port is a standard connection interface for personal computers and consumer electronic devices. It stands for Universal Serial Bus and allows devices to be connected to each other and transfer digital data over the USB cables. They can also supply electric power across cables to the device. It has two different pins: one being a USB port and the other being a charger port. This is the function that the USB type A port has in a Fitbit: it charges the device. The ports can be made of a variety of materials including copper alloy (brass), stainless steel, tin, gold plated alloys, and very rarely flame-retardant plastic. Basically, they are made of different types of metallic substances.
A barometric pressure sensor, also commonly known as the barometric air pressure sensor (BAP), is a type of engine management sensor. It is commonly found in vehicles and is responsible for measuring the atmospheric pressure of the environment that the vehicle is travelling in. These devices have a sensing element and respond to force applied to this area by a fluid pressure. In the Charge 2, this has the function of measuring the weather, heart rate, and overall health while doing exercise. These sensors are made of silicon. Since silicon offers great elasticity, repeatability, small temperature dependence and superior long-term stability, the use of a single crystal silicon is suitable for this component.
Bluetooth is a standard for the short-range wireless interconnection of devices like mobile phones, computers, TVs, smart watches, etc. They are generally used to transfer data over a wireless connection. With a smart watch, a Bluetooth connection to your phone means the watch can help you place calls or send and receive messages through your phone. Fitbit trackers and watches use Bluetooth Low Energy (BLE) technology to sync with phones, tablets, and certain computers. It specifically uses STMicroelectronics BLUENRGCSP low-energy Bluetooth solution, in place of a formerly occupied Nordic Semiconductor. Through this, your health data can be transferred from the Fitbit watch onto your phone or other device.
The temperature compensated crystal oscillator (tcxo) is used for providing much higher levels of temperature stability than are possible with a normal crystal oscillator. With this, it is possible to considerably improve on the basic performance of the oscillator. It is generally made of a quartz crystal, including lithium niobate, langatate, and yttrium calcium oxoborate (ycob). The oscillator in a Fitbit is called SiTime SiT1532. This component makes the Fitbit resistant to a wide range of temperatures and atmospheres, including the heat from your skin during a workout.
Amplifiers are electronic devices which increase the amplitude of an electromagnetic wave, for sound reproduction. It is commonly used to amplify electric guitars and other musical instruments, as well as the voices coming from a hearing aid. An amplifier consists of N-P-N type of transistor, which conducts electric current in varying manners. The main elements in a transistor are semiconductors. Semiconductors are generally made of a poor conductor such as silicon and has impurities added to it. Metallic silicon, being used to manufacture steel, solar cells, and microchips, is a suitable element for this component. This amplifier generates sound in a Fitbit device.
As can be seen, most of the electrical components in a Fitbit Charge 2 consist of materials which are commonly used in other electronic devices as well. These materials are all non-toxic, majorly consisting of silicon. Since most of the Fitbit is made from the basic element Silicon, which is non-toxic and extremely safe for the environment as well, a Fitbit overall is a very sustainable product. However, many of these electronic elements are non-recyclable. Some equipment can be reused, depending on their status. In most cases, the components are destroyed by open burning and acid leaching, to recover valuable metals from it. However, the residues to these chemical reactions end up in a landfill. New strategies are being discussed and slowly implemented to make electronic equipment recycling more efficient and environment friendly.
In a nutshell, though many customers had complaints about materials used in a Fitbit, the above research proves that the materials used are actually quite sustainable and non-toxic. There are a few ways in which the Fitbit could improve, including the use of nickel. Instead of using stainless steel comprised of nickel, Fitbit can use a metal which is equally effective yet customer friendly. Though most of the information was possible to uncover about the manufacture process of a Fitbit, some areas of information were hard to find, such as materials within the electronic components and how they are manufactured. Nevertheless, the provided research tells a lot about the Fitbit's sustainability. While Fitbit is looking for ways towards making their products more environmentally friendly, the Charge 2 may still be considered a product which goes from the cradle to the grave. However, it is still undoubtedly one of the world's best fitness-tracker smart watches.
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Design 40 Project Essay
2 March 2018
An analysis on the Waste Emissions Produced Through the Production of a Fitbit Watch
Becoming a household brand in many countries, Fitbit and its popularity have skyrocketed since its founding in 2007 with about 22.3 million units sold (Gordon). Having models for all lifestyles, Fitbit has seemed to cater to the everyday lives of individuals ranging from students, to white collar workers, to athletes. Although the appeal of the Fitbit has been very successful in the market, questioning the environmental impact of its production still remains. In a watch that seems to do so many things; Fitbit’s small size in contrast to its waste emissions throughout its lifecycle are substantial and hazardous to both humans and the environment.
Beginning with the silicone rubber materials that are made to create the wristband, more specifically the shot injection molded polycarbonate silicone rubber wristband and the enclosing injection molded plastic are two main components that make up a significant portion of the watch and which also have many harmful emissions (Electronics 360 and SIMTEC). Beginning with the byproducts produced by burning fossil fuels to heat the process for rubber, benzene (according to EUK Online), is harmful to the atmosphere and can deteriorate bone marrow in humans proving that this is a very toxic emission that is produced in the process of creating silicone rubber. Additionally, petroleum being a main component in synthetic plastic produces 1,3-Butadiene which is not only a known human carcinogen but also deteriorates the Ozone (even when disposed of dunerground) (EUK Online).
Polymers are also an important factor in producing the specific type of silicone rubber needed for the wristband of the Fitbit (Electronics 360). Polymers which are large chains of a molecule bonded together (essential for flexible rubber) mainly consist of carbon and go through many complicated steps to be produced (Adiza). However, one of the most important processes is the production of fumed silica (a step needed to produce polymers). This process emits hydrochloric acid which is extremely harmful because its high acidity makes it very hard to dispose of and is very corrosive (EUK Online). After these products have been disposed of, the carbon in the polymers is released into the atmosphere when incinerated and adds to the rising carbon levels in the ozone layer.
However, one must remember that in using these gases to make synthetic rubber, there is also the refinement of the gas itself which also is harmful to the environment. hydrogen sulfide, can be released with the extraction of gas. Because hydrogen sulfide is heavier than air it collects in low lying places which makes the work environment dangerous to the people working in the area in addition to the fumes deteriorating our delicately balanced atmosphere.
Subsequently, Water hazards caused by hydraulic fracking that are used to drill for natural gas can create a water solution (called “produced water”) that contains toxins like toluene, xylene, ethylbenzene and benzene in addition to naturally occurring radioactive material (EUK Online). This “Produced Water” is found to have 1800x more picocuries of radium than what the EPA allows (EUK Online) which makes its disposal harmful to the environment because of its high concentration in toxins.
Another component of the Fitbit that is used in many other electronic devices with a rechargeable battery is a lithium polymer battery (Electronics 360). In order to create these batteries, one must first extract aluminium using the Bayer Process (Journal of Cleaner Production). According to the article by the Journal of Cleaner Production, firstly a bauxite slurry and a caustic soda liquor are used to digest the material surrounding the metal. The caustic soda liquor can either be reused for another digestive process but it is also disposed of. The Journal of Cleaner Production does not specify the way in which it is disposed of, however, considering its highly acidic properties, if it is not carefully neutralized or disposed of it can be very harmful to the ground in which it may be disposed in or the wildlife in the water it can be poured in. Additionally, the copper that is used in the lithium batteries in addition to some of the wires (sciencedirect.com) also goes through an entire process. This includes (according to sciencedirect.com) a smelting process that is needed to refine the copper which produces the waste product: sulfuric acid. Sulfuric acid is not only dangerous when in contact, but adds to the list of very destructive chemicals due to its high acidity that can break down materials from skin to metals. These destructive properties make this waste not only hard to dispose of safely, but can physically damage surrounding areas in which it is deposited. Another waste emission from refining copper ore is during the converting process. During converting, “slag treatment” is used as a step during this process that emits a waste called “slag tailing”. This term is used to describe the waste of ores that contains materials that can be used for concrete and roads (sciencedirect.com). Fortunately, this waste emission can be put to other uses which allows for the disposal to be both useful and possibly profitable.
Finally, Another portion of the Fitbit that has many components, including different metals, is the PCB board that is in the inside of the device (Electronics 360). This board is allows for the Fitbit to function through electronic signals in a small board that is more portable and efficient (Bizzo). However, because of the diverse raw materials needed, their processes to dispose of the materials and put them to other uses also creates a significant amount of waste materials that is normally ignored (Journal of Cleaner Production). Introduced by Waldir through Table 1 in the article, two methods are used to extract useful materials out of PCB boards: thermal and non thermal. In the thermal process, characteristics include not being able to obtain non-metallic materials and expensive equipment. However, the environmental impact is described in the tabe to create pollutants in the form of gases such as lead fumes and dioxins (Waldir). In contrast, the non thermal process of obtaining metals from PCB boards includes health risk to employees because of fiberglass dust in addition to producing phenolic resin and another large investment in equipment. This process is said to impact the environment because it produces acidic waste water and solid waste. This waste is described in Waldeyer's article in Table 2 includes substances such as arsenic, lead, mercury, and other harmful elements. The study in the article shows that the majority of the amount of metals in the solid waste greatly exceeds the amount permitted by the EPA. These metals can be concerning for many reasons, for instance, if not disposed of properly, mercury, lead, and arsenic, which are known human carcinogens, can contaminate soil, food, and water sources. With unsafe disposal, there is great potential for these waste products to end up into the environment and into our own bodies.
In essence, the Fitbit may seem like a simple, small, efficient product when looked at behind the glass window of your local store. The booming business of this product would prove to be an overall success. However, what the customer may not see on the surface of such a small watch, is the inversely proportional impact it has on the environment due to its waste emissions. With the invisibility of all these process to the consumer, it is easy to see why the elaborate process of extracting, using, and disposing the necessary materials for Fitbit is widely ignored. However, it is important to realize and understand the reality of the consequences associated with industry and consumerism on the environment and ultimately, our well being.
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Hok Him Tam
An Life Cycle Analysis on the Embodied Energy of a Fitbit Charge 2
When we want to know a little bit more about our health on a daily basis, Fitbit Charge 2 does it all for us. Fitbit company was founded in San Francisco in 2007 and it has developed series of watches regard health and fitness. Their standout features such as the heart rate and footsteps tracking to all sort of notification alerts are vital factors to be popular worldwide. From 2010 to 2015, Fitbit company had increased their income from 5 million to 1.8 billion U.S. dollars (Gordon). Fitbit then has gained attention ever since its success. Although Fitbit’s revenue appears to have incline potential in the future, its embodied energy used in production should highly be substantial as it develops further.
Before diving into the embodied energy consumption in each process, we have to know that different materials go into making different parts of a Fitbit charge 2. First, take a look at the outside view of the Fitbit, we have the wristband that’s made of silicone rubber and the remaining hard plastics and the screen is made of molded polycarbonate (Electronics 360). Second, if you take a look at the inside, which is the main PCB board, it includes an accelerometer, a Bluetooth chip, and a battery (Electronics 360). Especially the accelerometer and the Bluetooth chip, they are categorized as microchips that produced from the semiconductor industry, which silicone is their main raw material. Finally, just like any other electric companies, Fitbit company chose to use lithium battery as their energy source (Buchmann, 2017). A small watch that seems to provide such effective and meaningful analysis upon health and fitness; Fitbit’s embodied energy used in extracting raw materials, processing, transporting, and recycling cover a big portion during production.
Raw Material Acquisition
Beginning with the wristband of Fitbit, silicone rubber is the primary material to make the plastic rubber. In the process of making liquid silicone rubber, forming polymers, adding fumed silica, and blending have the most energy consumption. According to Enser (2017), the prime material for silicone rubber to be molded is the polymers and they are Vinyl and methyl siloxane groups that polymerized to form polydimethylsiloxane chains. As he describes, this process will change its almost watery starting components from the liquid to the thicker basic form of the liquid silicone rubber. Depends on the strength and flexibility of your product, there’s a lot of other properties that can also be added to the material as well. Since Fitbit Charge 2 is for sports purpose, the wristband has to be strong and flexible at the same time; therefore massive among of energy is used for adding fumed silica to reinforce the material. After when the material separates into two halves (the catalyst and crosslinker are added to separate halves), more energy goes into blending the separated materials together. The blending machine then turns on for around eight hours to complete forming liquid silicone rubber. Although Enser doesn’t specify the actual measurement of the energy used in these processes, silicone rubber is mass produced and it’s used in many industries as he explains. However, liquid silicone rubber can be stored for years without curing, more energy can be saved in the future of making silicone rubber if massively produce it at once.
Silicon is especially a critical raw material for components in the PCB board of the Fitbit charge 2, including accelerometer and Bluetooth chip (electronics360). In order to extract silicon, minors mine a material called Quartzite is found in only a few places in the world: Appalachian Mountains in North Carolina and Wisconsin in the US, Rift Valley in Africa, Australia, and some in Europe (Welland, 2009). He explains that the reason why quartzite is needed is that its plurality of silica can be well over 99 percent and they sell for $50,000 a ton. In Mitchell County, 1 out of 15 workers is a miner; until today, no one knows what they are doing inside the quartz plants because they are protected by security guards, gates, and cameras and no one from the mining companies is allowed to talk to outsiders (Nelson, 2009). We could estimate how much human energy consumption is put into mining workers in comparison with railroad workers back in 1912.
Embodied energy for polycarbonate and silicone rubber are primarily from machines and human power during production. Coincidentally, both use a similar molding process during manufacturing. In order to make a silicone rubber wristband and polycarbonate plastics, the manufacturing process requires liquid silicone rubber and polycarbonate to be ready to be molded. This process is known as the injection molding process. According to SIMTEC Silicone Parts, the liquid injection molding (LIM) process molds materials into a broad array of parts and products. In this case, the wristband and the plastics. First, labors and machines are probably involved to prepare two compound to release in a 1 to 1 ratio. Second, customize the automated injection-molding machine by justify the temperature, pressure, injection rate and cycle time. Again, human energy is involved in this process. Third, the machine heats the mold to the appropriate temperature and applies the appropriate clamping force for the injection machine to push the material into the mold and cavities. Forth, solidifying is done by the workers or the machine itself to open the mold for flashing. Finally, the workers take out the parts for post-molding: deflashing, post-curing, inspection, and packaging.
Embodied energy for polycarbonate in its manufacturing process is specifically manifest with data; hopefully, this information can help describe the embodied energy for silicone rubber since they go through the same process. In order to operate the machines, oil fuels and electricity cover the embodied energy. According to Boustead (2005), he did a report on the eco-profile of polycarbonate, table 1 and 2 explain the gross or cumulative energy to produce 1 kg of polycarbonate in terms of the types of primary fuel and primary fuels in specific. For fuel production and delivery energy, 10.63 MJ of electricity, 0.34 MJ oil fuels, 2.04 MJ other fuels, and total 13.1MJ is required. For energy content of the delivered fuel, 4.41MJ of electricity, 9.59 oil fuels, 48.66 MJ other fuels, and total 62.67 MJ is required. In total, it requires 75.68 Joules of energy to make 1 kg of polycarbonate. Not include energy use in transport and feedstock, the total energy use in production is distributed to machines.
Energy and fuels consumption used in chip manufacturing process is quite big to compare the actual size of the chip it produces. According to Williams, Ayres, and Heller, the 1993 MCC life cycle study reports that fabrication of semiconductor circuits on one 150-mm wafer requires 285 kWh of electricity, which corresponds to 1.6 kWh per square centimeter. In exchange, around 0.002 kg of chips, 1.2kg of fossil fuels are required in the manufacturing process, which is 600 times more fuels to make 1 chip Williams(2004). Unfortunately, manufacturers continue to use fossil fuels because it’s cheap.
Transportation and distribution are where Fitbit put together all the manufacture parts and when it delivered to consumers hands. Although Fitbit founded in San Francisco, California, it manufactures in China. Therefore, embodied the energy that uses to ship from China to the U.S. plays is substantial here. Unfortunately, information on how a Fitbit watch is ship obscure, however, the most common transportation that could possibly deliver a Fitbit is through airplanes, ships, and cargo trucks. According to Rivlin (2013), airplanes use between 12,000 and 14,000 BTUs per ton-mile (BTU is equivalent to 1.06 kilojoules), cargo ships use 350 BTUs per ton-mile, and an average for vehicles is around 1,800 to 2,500 BTUs per ton-mile. Although airplanes seem to use most energy compared to ships and vehicles, they use relatively fewer fossil fuels; instead, the most common type of fuel an airplane would use is Kerosene based fuel.
Use, Re-Use, and Maintenance
The energy source for Fitbit is Li-polymer battery and when it’s fully charged, it could last around 5-7 days. However, low battery life seems to be a common problem that consumers encounter. Fitbit company chose to use lithium battery just like any other electric companies because it offers slightly higher specific energy and can be made thinner than conventional Li-ion (Buchmann, 2017). However, as the battery is used, the voltage will drop lower and lower until it reaches the minimum which is around 3.0V. In other words, lithium batteries typically have a charge or discharge life cycle of 300 to 500 before they “die” (Nanalyze).
Material like polycarbonate is highly recycled even though it is so strong that it’s less resistant to impact. It’s fully recyclable and as it’s made from oil, so it provides an excellent yield for plastic recycling factories (Recycling Today). The usual process for recycling polycarbonate is to sort, shred and wash and then turn into a granulate ready for manufacturers to use again. Jeanette Garcia, Ph.D., research staff member, IBM Research – Almaden states, “While preventing these plastics from entering landfills, we simultaneously recycle the substance into a new type of plastic—safe and strong enough for purifying our water and producing medical equipment,” plastic materials like polycarbonate in production are formed chemically and made molded, however, they need to find a way to break them down into different byproducts or change its property to make a different type of plastic for different purposes. Therefore, research development on finding the effectiveness of ways to recycle this material is substantial in embodied energy.
Waste & management
Availability of waste depends on your distributors or who you bought it from. According to Best Buy, once they get the recycle products from consumers, the products are removed from stores, consolidated, and then delivered directly to one of our contracted recycling partners. However, the products cannot be determined whether it can be repaired, repurposed or recycled without the recyclers determine it. Ideally, Best Buy should have at least one recycle center in a city or at least in an area. Cargo truck could simply get the job done for transportation. Also, the non-recyclable part such as microchips will be destroyed in a shredder.
Fitbit is promoted as health-related sports product. Compare its energy use in all aspect of production to other giant companies like Apple is actually way less in terms of the size of the product. Also, I personally think that Fitbit has done a really good job on the data analysis on phone apps. That way, it saves the production process whole lots of energy to make more parts for internal data analysis. So, It only left human energy to figure out how to code the app. At the end, it’s hard to fully do research on every detail because most companies only want their consumers to see what they want them to see; therefore, I tried my best to find the close outside general sources about the energy used in extracting materials, manufacturing, transportation, waste, and so on. Nevertheless, Fitbit company itself is trying to be more ethics in the future, and the embodied energy throughout the life-cycle of Fitbit really manifest how much effort is put into it.
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