3D Printed Smartphone Case




Introduction: 3D Printed Smartphone Case

Hello everyone! After a long time of absence, I am finally back on my favorite How-to site, Instructables! With winter break coming up, everyone (including me) sort of has a "I don't care about anything anymore I just wanna do what I wanna do" attitude. Personally, I'm excited to get back into making things, playing video games, and watching random YouTube videos for hours on end.

One of the things I am NOT excited for is breaking yet another smartphone screen. I drop phones much too often and this is more of a problem nowadays then it was 5 years ago. Back when flip phones were prevalent, dropping a phone wasn't such a big deal; no significant damage would be done from a drop at shoulder height. However, now that flip phones have been outsmarted by smartphones, the dangers of such a drop should be realized. The touchscreens of smartphones are very prone to fracture, and I have had to get repairs done (which cost money, in case you didn't know :P) to fix broken screens in the past.

Now, I am determined to maintaining the integrity of my latest, unscathed smartphone BY ANY MEANS NECESSARY (jk). But anyways this is going to be my first project in a long time; it's kinda like my "reintroduction" to both 3D printing/CAD and Instructables, and also a comprehensive guide to all the people out there who want to learn some basic CAD or protect their phones (or both).

So, without further ado, let's get started.

NOTE: I don't know how to save captions/notes to pictures in this new editor, I can type them in, but they won't save...so I'll just have to type explanations for the pictures outside. It might be more confusing, but this new editor is confusing....sorry.


Picture 1: This is one of the flip phones I've used in the past for about 2 years. Besides the small crack and minor signs of wear, the phone is functional even though I have dropped it many times.

Picture 2: One of my smartphones...it lasted me 2 months before parts of the screen started turning black due to damaged LEDs from lots of drops; the screen was cracked before that though.

Picture 3: My latest smartphone. It has (surprisingly) not been damaged too bad yet, aside from the hardly visible wear on the front. I hope to keep it that way.

Step 1: What You'll Need (Materials and Tools)

The materials and tools used to create a custom 3D printed phone case are actually not that expensive or hard to get, the most expensive would be either the 3D printer or the phone itself, depending on what phone or printer you have. Everything else can be obtained from local stores, even though you probably already have most of the stuff at home.

Materials Needed:

  • Your phone, obviously
  • Headphone cable and phone charger cable, you'll need to measure the dimensions to accommodate these.
  • String, preferably some type of flat and ribbon-like (see picture)
  • Clear Tape, used to tape the string down

Tools Needed:

  • 3D Printer: I don't actually have a 3D Printer, but there is one at my school and they were nice enough to let me use it (Thanks school :P)
  • Dial or Digital Calipers: The most useful measuring tool (in my opinion); needed to measure phone dimensions and the distance of the buttons/ports relative to the edge and to each other.
  • Yardstick: Used to measure the length of the string and to determine the fillet radius (with the string). A longer ruler can be used in place of the yardstick, but the ruler length should be 15 inches or longer.
  • Some type of 3D modeling software/CAD: You can use Google Sketchup, Autodesk Inventor, SolidWorks, etc. I like to use Autodesk Inventor because that is the program I am most familiar with, but feel free to use what you like.
  • Sandpaper/Drill/Dremel (Optional): These are optional if you need to make minor changes to your print, or if you want to use the "Sand and Drill" method (more on this later).


Step 2: Choose Your Design

Now comes the part where you get to make a choice...a choice that will determine the fate of your phone. Do you want a case that closes in on your phone from the sides? Or one that pieces together around your phone like a puzzle? Maybe one that snaps together with one half on top and one on the bottom? Whatever your design is, there are 2 things to keep in mind. First, you need to remember that the plastics used in 3D printing are solid (not flexible), so you cannot make a case that is one piece, because that way you cannot fit the phone inside. Rather, you would need to print multiple pieces or halves that can be fit around the phone. The first idea I came up with for making a case was actually just a single piece of plastic that would fit around the phone. I was thinking about commercial phone cases at the time, which were usually made of a rubbery material that could be stretched over the phone. The second thing to think about is disassembly of the case if necessary. You may want to take the case off at some point in the future, so it would be a good idea to make your design have removable halves/pieces.

For my design, I chose a design with 2 halves. One half of it encloses the phone on all sides except the back, where it protrudes a bit; the protrusion allows for the other half, which acts like a plug, to snap in place. My original design was a friction fit design with pegs and holes, where 2 halves where pushed together from the sides, but then I did some research and found this site. It gave me the idea to use a snap fit design instead, which is very similar to the one in the picture, but with 4 connection points instead of 2.

Step 3: Measure and Take Notes!

This is probably the most important step in making a case specifically for your phone: taking very exact measurements of the phone. There are many important things to note when measuring and recording dimensions. First you'll need to decide a thickness for the case ( I chose 0.1 in.). Then measure the distance of everything relative to the edges and other parts of the phone. This should be recorded because you will need to know where to draw the openings for headphone output, charging port, buttons, etc. in the 3D modeling software. I personally took 2 pages of very specific notes; they are very messy though and most people would not understand it, but as long as you can understand your own notes it should be fine.

Also, now is the time to find the fillet radius for the rounded corners (unless your phone has pointed corners O.O) of your phone. To do this, you must first find the perimeter of the phone. Take the flat string, and tape it somewhere on the edge of the phone. Then, tightly "wrap" the string around the edges of the phone, using tape to hold it down if necessary. When you get back to the starting point, cut the string. Now measure the string, the length will be your perimeter. Now that you have the perimeter, you must find the length of the sides (length and width) just before the rounded corner of the phone (see picture). Measure the green and pink edges, and add the lengths together. In my case, my side lengths were approximately 4.060 and 2.030 in, so I did 4.060 + 4.060 + 2.030 + 2.030 = 12.18. You may have noticed that if you take the 4 corners (highlighted yellow) and pieced them together, you get a full circle! This is very useful, because now you can use the equation p = 2πr + n to solve for r, where p is the perimeter, 2πr is the circumference, and n is the sum of the edges. For me, r was about 0.337. The fillet radius will be needed later in the CAD work.

Another thing to point out are the cables, which should be measured and dimensioned where the plastic is, not where the metal is. This is because you want the opening to be big enough to fit the plastic part, or else the cables can't be plugged in with the case on.

Picture 1: Some detailed but messy notes...

Picture 2: More notes...do I have OCD?

Picture 3: Method of finding perimeter.

Picture 4: Phone outlined with pretty colors XD

Picture 5: Headphone and charging cables.

Step 4: Draw It Out!

With all the data and measurements, we can now proceed to model the case on your favorite CAD software. So the first thing that must be done is to outline the inside of the case, where the phone will actually sit. A good idea would be to take the actual exact dimensions of the phone, and "rounding it up" a bit. For example, if you have a measurement of 2.011 inches, you might want to round it up to 2.02 inches. This is because if you make the case the exact same dimensions as the phone, it may not fit in the case as well as you'd like. The exact length and width of my phone were 4.814 and 2.662 respectively, but I rounded them up to 4.820 and 2.670. Alternately, you could use the "Sand and Drill" method I mentioned earlier. The Sand and Drill method is when you intentionally make the dimensions smaller or same as that of the phone, then you sand and/or drill the plastic after you print it, to achieve a proper fit. This method may be preferred over the other method, because it can get a better fit; the other method may create a slightly larger/loose case. Anyways, back to the drawing. Now you will need to apply the fillet radius to the corners of the rectangle shaped box you made. Since I have a 0.337 fillet radius, that is what I used. After that, you can use your amazing CAD skills to draw out the rest of your phone case, but remember that the shape you just added the fillet radius to is the inside; you need to add your chosen case thickness to the OUTSIDE of it.

Picture 1: The outline of the inside, before fillets are added.

Picture 2: Same dimensions and all as picture 1, but with the 0.337 fillet radius added to corners.

Picture 3: Finished top half of my case, you can see the slots and holes on the sides, where the buttons and stuff come out.

Picture 4: Finished bottom half of my case, you can see the slot cut out for the camera, as well as the 4 "tongues" that lock in place when pressed into the top half.

Picture 5: The back of my phone, shows the camera location.

Step 5: Printing It Out!

Now you can export your model as an stl. file and 3D print it! After you print it, you may have some problems fitting the parts because you made them too small (accidental or on purpose) or the printer misprinted something. Either way, that's where the sandpaper comes in! If the case was designed too large, then you can learn from your mistakes and remake the model. For me, everything turned out fine, except the headphone cable hole was a little small so I slightly widened it with a drill. If you want to look at my model, I've included the stl. files on here if you want to download, maybe you have the same phone as me. Once again I would like to thank my school for letting me use their 3D printer...and their green filament!

I like this color :)

Picture 1: The top half of the printed case, with hooks to attach to the other half.

Picture 2: The bottom half, much more simple than the top half.

Picture 3: The phone enclosed in the case, top view.

Picture 4: The back of the phone in case; the camera is visible through the opening.

Step 6: Improvements?

Now that you've built the basic phone case, why not improve? You can add different shapes, textures, patterns...the possibilities are endless! (kinda) You could make one of those Pikachu phone cases, although it probably wouldn't be a good idea because you'd get jabbed in the leg by those solid (and pointy) ears. Although it is not possible to 3D print in multiple colors as of now, you could still paint the case after printing. I would also like to mention one of the mistakes that I made on my phone case; the casing itself was made a bit too thick! I chose a 0.1 inch thick case, and a problem I encountered was pressing the buttons through the case because the case itself was thicker than the buttons were tall. Luckily for me I have decently long nails, but for those people who don't have long nails, I wouldn't recommend making a case thicker than 0.075 in. But whatever you want to do with this is entirely up to you...so be creative! And also if you have any questions, feel free to ask in the comments.

Picture 1: Pikachu!

Picture 2: Coffee Phone Case :)

Picture 3: Bieber case...ewwww

P.S: I dropped my phone twice during the making of this phone case. I dropped it once while measuring it and again after I put the case on.

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