Metal Dents/ Bends, Glass Breaks/ Shatters, plastics used in phones are very impact resistant, strong for the real world. Why make phones out of fragile easy to totally break materials like aluminum & glass (iPhone 6,6S,7 & Plus Models) etc.
My current cell phone came from generous benevolent family like friends, a Galaxy Note 3 that once belonged to Alicia & Jaeson Long. Its a white model made mostly of plastic with a big glass phablet screen.
This GN3 was my main phone for about a year when I decided to try a Kyocera Brigadier, wooed by the "sizzle" of a "sapphire display" waterproof construction and the rugged Bear Grilles inspired & promoted design.
After about 8 months of use the Brigadiers sealed internal battery was loosing its charge more quickly despite my carefully keeping the battery between 30 & 80% charged to go easy on the battery. A quick trip to a local Verizon store about 60 days ago got me back in touch with my the GN3 and I have been using it ever since.
I keep the Galaxy Note 3 in a plastic bag in my lunch container, with thin cardboard & paper writing pad covering the screen inside the bag to protect the glass. I do not store my phone in my pocket to keep the RF from soaking into my tissues, stem cells & DNA for health & safety reasons. I similarly almost always make voice calls using the speak phone function, which allows the phone to use lower levels of RF to connect to the cell towers while also reducing the health hazards of soaking up cell signals during a phone call of CW RF wave propagation.
Smartphone Glass Breaks
I repair smartphones, mostly iPhones as part of my job, professionally. I like the Apple design of the iPhones, especially the iPhone SE. While the 6, 6S & plus version are the ones I most often repair, from a design perspective they are well engineered, but exceedingly fragile.
Long ago, I planned on making the original iPhone 5 my first smartphone, but was angry with Apple for the way they sealed the battery into my iPad 2. My first smartphone was a Galaxy Note 2 with an easily interchangable & large capacity battery. Before smartphone I was using LG feature phones up through the ENV3. Made mostly of plastic, theses phones were very rugged, small, easy to handle in one hand, and impact resistant when dropped.
I am resistant to recommending plastic as a material because of how it often ends up in the worlds oceans because of thoughtless people who throw recyclable materials into the trash, ocean: who litter and treat the world as though it were their personal trash basket. Between 1997 & 2007 Americans threw 20 million pounds of aluminum into trash dumps, thats enough aluminum to rebuild every commercial airline plane made up to the year 2007. I imagine that dumps will become resource mines in the future as a result of senseless trashing of perfectly recyclable materials.
CTO of Dewalt Tools
Plastics are electrical insulators or dielectric, and some advanced plastics approach the strength of metals, especially when they are reinforced with glass or carbon fibers.
Plastics have much higher elastic modulus properties than most metals, meaning they can be impacted or bent without lasting damage, in sharp contrast to stiff inelastic materials like aluminum when dent & bend in a very hard & expensive to repair if a repair is feasible. Think of the mostly Aluminum Tesla Model S in a car accident and look up what it costs to fix a model S.
Making the case of an electrical device out of plastics and polymersgreatly simplifies the interior power & electrical routing in contrast to complex conductive metal cases made of aluminum or magnesium alloys that have to be carefully isolated from the wiring & electrical contacts to avoid shorting. Many of the exploding self balancing scooters & electrical problems in the BMW i3 are the result of wire insulator being rubbed off where sharp conductive metal edges were rubbing the wires, design oversight thoughtlessness.
Mixed Materials / Multi Materials
Phone cases are almost always made of plastic & elastomeric polymers so that they can withstand drops while protecting the fragile metal & glass phones inside the case. Many screen protectors are made of high strength hard scratch resistant plastics with good optical clarity, as are most computer monitors, and most flat screen TV displays of LCD LED, OLED designs.
Plastic fibers and plastic polymer structures dominate the interior of most modern vehicles, while steel remains the only safety strong affordable metal for the body frame manufacturing stamping & welding. Mainstream automakers use a handful of different steel alloys and plastic polymers + synthetic fibers. To produce my Honda 14 CR-z ex., Honda Co. Jp. almost needed to stick to steel & plastic as materials to keep the costs down. One of the primary goals in the engineering of the CR-z was to produce an affordable hybrid fun car that younger people could actually buy.
Apple made the case of my aging & still functional iPod Touch 4 out of polished laser engraved steel. Around the same time aluminum became a huge thing as a material of the unibody construction designs that now dominate Apple product engineering circles, to such a great extend that the trashcan mac was engineering into a thermal dissipation corner that caused a 4+ redesign with a renewed focus on module designs emblematic of the older Mac Pro's!
Apple Aluminum Berserk
The trashcan Mac Pro, Macbooks, iMac, iPhone, and iPad, all making use of aluminum extensively in the case designs. Aluminums high thermal conductivity makes sense as the aluminum can soak away heat from the board components more efficiently than a case made of steel or plastic. In stationary computers, like the Mac Pro or iMac, aluminum makes really good sense from a thermal perspective. In fanless pocket computers like the iPhone, the over-use of thin aluminum case design philosophy gave rise to "bend gate", a phenomenon where many iPhone 6 users experienced catastrophic phone bending damage with minimal forces applied, forces that never damaged the mich stronger iPhone 5, 5C, 5S or 5SE. These smaller 4" boxy edge strong aluminum designs is far stronger than the thin curvy designs of the latest bigger iPhones.
Making a larger screen cell phone thinner means a loss of mechanical integrity. Think about a phone in the back pocket of someones pants, the kinds of loads that will be applied to the phones screen & case. To make matters worse, Apple has the screen glass floating as the top-most surface of iPhones, meaning any impact to the front face on a hard surface like tile or concrete will shatter the display glass. If you want your iPhone to hold up well over time, put it in a nice strong plastic or wood protective case. I understand the appeal of having a sleek small device that feels light, but in the real world you are likely to drop your phone. In the USA alone, people break phone screens once every 2 seconds!
Glass Front & Back ?
I look at the newer Samsung Galaxy S6 & S7 & S8, with the glass case front & back and scratch my head wondering why they would use glass as the back case material! Older Samsung phones were made mostly of impact resistant tough plastics! Older Samsung galaxy phones also had easily user replaceable batteries! It makes absolutely no sense to make the back of a phone out of glass. That sounds like the pipe dream of Dow Corning or another glass manufacturer, and I am sure it was! Plastics make impact resistant devices. Look at a Fluke Multi-meter for a good example! Most multi-meters are made of plastic because of the dielectric insulating nature of a plastic case design which is good for electrical safety!
Killing Case Makers with Rugged Phones ?
If Apple started making their iPhones rugged, I think the market for Otterbox's could rapidly disintegrate. Look at what happened to the stock price of Imagination Technologies when Apple recently announced in house GPU development for iPhone 8 onward.
Rugged Cases Highly Recommended
If you own a metal & glass phone, I highly recommend a rugged protective case. Screen breaks are a waster of time, can end up lodging glass bits into your sensitive finger tips. It easier to not break your screen than it is to waste time & money having it repaired. Similarly it is far easier to lose weight by eating less than it is to waste time & money trying to burn off the extra intake calories. Think about it! Screen protection & serving sizes.
Less is More!
To burn anything to the splendor & enjoyment of no one represent harm & waste that negatively effects everyone. Turn off lights that are not providing useful light to someones eyes for example! Turn your computer off or put it to sleep if you are going to walk away from it! You can get longer battery life out of your smartphone if you lock the screen as soon as you look away from it!