iPhone 7 Plus Slim Bumper Case

by ScottyMakesStuff, published

iPhone 7 Plus Slim Bumper Case by ScottyMakesStuff Aug 8, 2017


Today I’ve got something hot off the printer for all you iPhone 7 Plus owners out there. After designing a few iPhone 7 cases I had a number of requests to make the same cases for the iPhone 7 Plus. I've used the same minimalist look while still making it easily printable. It's designed to protrude slightly on the front and back to absorb any knocks, scratches and impacts... plus it let's your phone cool down much better than a full case will :)

############ UPDATE 2: #############
There's now two versions of this case. The original design and a newer version that is 0.2mm longer in length and width. The slightly more loose version is denoted with 02mm in the name. My personal preference is for the original design but YMMV.

Here's a link to a video showcasing the original iPhone 7 bumper but since it's essentually the same but smaller I thought it would be useful to see:-

In case you are after a case for the smaller iPhone 7 then you'll find them here:-

Fitting to your phone is easy, just put the end in first and then on a flat surface push down on the top until it snaps firmly on. An example of fitting is in the video at 2:40.

You can check out my other designs here:-

Print Settings

Printer Brand:



Prusa Mk2










Supports are needed as this should be printed with the rear of the case facing up just as the STL file appears. The reason it's not the other way around is that the detail on the back will likely be blemished by any supports.

I now mainly use Simplyfy3D to slice for three main reasons;-

  1. the supports come away beautifully and
  2. for items that rely on tight tolerances (like this case!) it prints the most accurate that I've used and
  3. You can specify different print settings in a print so for sections with detail you can reduce layer height and for uniform sections you can increase it and get great looking prints done fast!

I suggest printing with 4 perimeters and 25% infill as there's only a handful of grams of plastic in this so don't skimp.

I suggest printing this in an improved PLA (see below) or other filament that's strong and tough.

Beware: Not all PLA's are made equal.

Most of my prototypes and a good proportion of final prints are with an 'improved' PLA from Esun called PLA Plus (sometimes called pro) and it's tough and definitely not brittle and it's really cheap too. Some other moderately priced improved PLA's I've used are Filamentum, Prusa Brand & Colorfabb Economy PLA.

I haven't tried Hatchbox, Matterhackers, Taulman InPLA and Filaform Pro PLA but I hear some good things about them.

I also use a few better quality name brand PLA's for special one off jobs like phone cases and these are quite a bit better than the Esun though up to triple the price... though bare in mind this print in the pricey filament would still only cost a couple of bucks.

For the best looking prints with a fair bit better toughness than the Esun I use either Polymaker PolyMax PLA or ColorFabb PLA PHA. If excellent toughness and strength is a priority then the Polymaker PC Max polycarbonate is the one I'll always reach for and the finish is still good too.

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Scott, I have attempted this twice now with very similar results. See the photo I posed under "Made". My most recent settings:

Makerbot Replicator 5
20% infill
.1mm layer height
4 shells
18mm/s shell print speed
25mm/s first model layer speed (hoping it would adhere better, I might have gone the wrong direction, faster would likely be better)

Using Hatchbox black PLA

Hi JHawk, hmmm,.. that's a nice printer and Hatchbox PLA is well known for being suitable for printers without heated beds so with everything working well it should print the bumper quite well.
I'd say you likely have a few possible culprits and the following would be my suggested process to work it out;
The first is the print speed but although it is on the slow side I'd say it's probably not that as a slower speed should encourage first layer adhesion. Still, I'd be inclined to speed up those two by around 5mm/s. The picture shows your raft is nice and flat so adhesion from the bed is good so the adhesion of the part to the raft is definitely an issue. Rafts tend to be better for ABS. I'd be using a 10mm brim instead of a raft. This can be be easily pulled off and lightly sanded to remove any rough edges from the brim.
Now because your raft is holding well I suspect the part cooling fan is off for the first layer but best to check that.
So, without the raft, try the print it with the brim. I'm guessing that will fix it.
If that doesn't work then get back to me and we can go through some less likely culprits for increasing adhesion such as increasing filament temp, reducing cooling fan speed or even a smaller raft separation distance.

Makerbot Print software doesn't easily offer an option to use a brim, or at least not that I can find. I have however been looking into "Simplify 3D" for use in the future.

Since you have problems adding a brim I just made a special version of the case with a brim just so you can print it. It has "withEars" at the end of the name.

Simplify3D is my 'go to' as it does the best job of printing items with tight tolerances (like this case) plus it's supports come away very easily.

Whenever I'm having problems with a filament I always start by calibrating the filament... in fact, I should really do it whenever I've opened a spool of something I've never used before.

All the best with it!

Scotty, I printed another today with slightly quicker speeds, and without the raft. Worked flawlessly. When the bumper adheres to the build plate, it doesn't curl. However when I was putting this on it did crack a small piece off from the top left corner.

I might re-print it 1% larger. But either way, thank you for your help. Your design is great and the buttons are amazing.


Hi Brandon, good news that it printed well. Bad luck with the crack. My iphone case is made from Esun PLA+ and has been on and off well over a dozen times with no cracks. You might have some better luck with the version that has 0.2mm in the name as it has already had 0.4mm taken from the length and width. I've read that the hatchbox pla is meant to print very accurately but I can't vouch for whether it's an improved (toughened) pla like the Esun PLA+ that I use. I also read that Hatchbox have a pro version of PLA which should be less inclined to crack.

I printed this last night. I tried to put it on my phone this morning and the case just broke in half :(

Hey Jim, sorry to hear that. You probably did it right but just to be sure, the bottom of the phone needs to be slid in first and then the top snaps in second. I've done this a few times to my phone and the case is still completely intact. The video I added shows me doing it at @ 2:40. The next reason may be that your PLA might be a bit brittle. PLA takes on moisture in the air so drying it out might help or else try a different PLA you've had success with. Another issue might be over-extrusion giving you thicker walls - hence a tighter fit. You can adjust the extrusion multiplier for this... to get the correct multiplier I do a 1cm (0.9mm wall) hollow open top cube to test the wall thickness and then divide 0.9mm by the thickness to get the correct multiplier. Hope some of this has been helpful. If not post some more details and I'll try to figure it out for you? Scotty

Hi Scotty, my first post was rather blunt. I know how hard it is to design something, and have it fit well, so apologies if I was rude.

During my first installation, I did install it from the bottom, although I didn't notice you slipping in the volume adjustment side of the phone first, so I will try that. I took my PLA out of the vacuum packed bag about a week before doing this print, so I don't think that's the issue.

I am reprinting it right now and I'll let you know what happens...

That's fine Jim, I'm not offended at all, I appreciate any and all feedback! :)
I too well understand the frustration of a print not working out. Please let me know how it goes? The tolerances on this bumper is a very small fraction tighter than my iPhone 7 bumper. Being a bigger phone I wanted a snug fit as the bumper is minimal. I generally use a more expensive name brand tough PLA for my phone cases as the case only totals around 10 grams of plastic used. Some other PLA's out there still sold today still use the far less tough formulas. Even cheap Chinese PLA's can work well... I'm extremely happy with PLA Pro from Esun... tough enough for phone cases too! I'll do a reprint of the bumper to double check the print fitting and unfitting a few times to see if any weaknesses surface and re-post later today.

Ok, it finished re-printing. I got my phone into it. The portion of plastic in between the volume switch and the corner easement cracked, but not too noticeable. The case fits pretty tight. I'll use if for a day and report back.

Thanks for the feedback Jim. I just finished printing the bumper in Esun PLA pro... So it's no Hatchbox or Colorfabb. I put it on and off 5 times and it's still intact though your right that it's a tight fit. I've now got the fitting process down pat, I start by laying it flat and sliding in the bottom but after doing it 5 times I found it's easier to lift it up and with my thumbs on either side of the phone I first push the left side in slowly and then the right.
The tight fit still bothers me as I can now see some slight flexing under lengthwise tension at that point you mentioned. The first print didn't have any issues but to be safe I've decided to add a little bit of wiggle room to the designs. Thanks again for your help, I'll re-post when I've uploaded new designs.

Oh very cool! If you provide the designs, I am happy to try and reprint. Its a quick print, and even faster if you setup your print as you mention in the video and notes section

Something to this effect:
4 layer top/bottom
4 perimeters
5-25% infill

But I do believe those settings depend on your layer height.

Aug 9, 2017 - Modified Aug 9, 2017

Thanks Jim, I just re-uploaded an updated bumper case and the other 3 full cases for the iPhone 7 Plus. I've taken 0.1mm off the inside which equates to 0.2mm total length and width increase which should make all the difference. Let me know how you go with it? Cheers!

I just started the print. Thanks for correcting the obscure angle the model was in, made it that much easier to start the print. I'll let you know how it comes out.

Thanks Jim, there's so many variables that make a print come out differently from one printer / filament / slicer to the next and like a craw in my foot it bugged me so this morning I went and re-checked the calibration of my filament and slicer and it's printing 'spot on' - better than 1/10 th of a mm. I've refitted the case at least another dozen times with no damage to the bumper and re-examining the print fit makes me sure the tighter version is best for me. I'll be re-uploading the original (tighter) stl files with the newer (less tight) models with some explanation so people can choose for themselves. Anyway, hope your print went well. I guess I'll hear from you later.

The other print did finish. It fit, but the upper left corner broke. Still usable. Thanks for making both versions, I think it's good to have both versions, as both versions do fit my phone. I prefer the looser fit, but have been switching back and fourth between the two. Unfortunately both versions kinda bow out at the sides. I might try your dotty case as it might help prevent this while still providing some better cooling characteristics that my over priced leather case from Apple.

ok, from what you've said I'm pretty sure I can pinpoint the issue. Initially I thought it might have been the filament calibration but the fractures and bowing tells me another story. The bowing says to me it's a low strength PLA and the brittle failure also points to that too. I printed my bumper in a 'improved' PLA from Esun called PLA Plus (sometimes called pro) and it's really cheap too. I've put it through the wars refitting countless times since yesterday and it's still 100%. I also use a few quality name brand PLA's for special one off jobs and these are quite a bit better than the Esun though triple the price. For the best looking phone case prints with a fair bit better toughness than the Esun I use either Polymaker PolyMax PLA or ColorFabb PLA PHA. If excellent toughness and strength is a priority then the Polymaker PC Max polycarbonate is the one I'll always reach for and the finish is still quite good too.

But if you want to persist with your PLA then my suggestion is to print the dotty case which has been popular and there's been no problems come up.

Whatever you end up doing, thanks for your help so far and good luck with it!