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Improved! iPhone Gear Case with Geneva Mechanism

by QuentinT, published

Improved! iPhone Gear Case with Geneva Mechanism by QuentinT Mar 25, 2013

Description

You can now buy this case from my Shapeways shop here: shapeways.com/model/997471/iphone-gear-case-for-shapeways.html?li=modelEdit

For iPhone 4/4s

This is a version of the iPhone Gear Case that I completely designed and drew myself. It is much easier to print than the first case, as well as being stronger and a better fit. The areas beneath the buttons and sliders has been removed to make them easier to use, and a cutout has been made around the headphone port so bigger jacks will fit without having to remove the case. The edges of the case are also tall enough to prevent the screen from touching when placed face down. I added a bevel to the ledges that hold the case onto the phone that makes the case very easy to print without support.

Here's a video of the gears in action
youtube.com/watch?v=lWJ5edtyhjU
flickr.com/photos/quentint/8587604437/

I got the Geneva Mechanism idea from jessed, and used msruggles' solidworks gear generator to create the gear profiles.

Recent Comments

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i would make the gears different colors . or all the gears one color and the geneva gear another color. just an idea
i would make the gears different colors . or all the gears one color and the geneva gear another color. just an idea
I printed on a rep 2 with PLA.

Had to scale the shell and ridge to 107%
Scaled the Gears to 106% except the Geneva mechanism, which I scaled to 105%
Kept the pins at 100% but had to redesign them to lengthen the inner concentric extrusion that actually fits into the shell/ridge.

sanded, glue, and oiled everything down and it works, but does not spin as readily as the video posted. I actually prefer it not to spin as fast because I didnt want it to spin while I was just using my phone. Requires a little more force to move so I dont accidentally spin the gears in daily usage.

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Instructions

1. Print one of each part, except for the 3x2.75mm pin, of which you will need two.

Print the case shell and ridge with 0.1 mm layer height, no support, and single perimeters. There is a slight bevel on the ledges that hold the case onto the phone that make it printable with no support. The bevel will only work if layer heights are low enough though. You may want to scale the case up by 1% to account for shrinking.

Print the gears with taller layer heights and single perimeters, I used 0.25 mm.

Ideally, print the pins with a fan. lower layer heights work best for strength, but anything should work.

2. Glue the case ridge onto the back of the case shell, making sure it lines up well and the pins still fit. You can use acetone or super glue for this.

3. Sand the gear faces a little bit to make sure they can spin smoothly against the case.

4. Attach the gears by press fitting the pins into their corresponding holes. Look at the pictures for gear placement. After you are happy with the way the case functions, turn it over and put a dab of glue on each pin securing it to the case. I sprayed the gears with some CRC Heavy Duty Silicone, and it made the gears turn effortlessly.
i would make the gears different colors . or all the gears one color and the geneva gear another color. just an idea
i would make the gears different colors . or all the gears one color and the geneva gear another color. just an idea
I printed on a rep 2 with PLA.

Had to scale the shell and ridge to 107%
Scaled the Gears to 106% except the Geneva mechanism, which I scaled to 105%
Kept the pins at 100% but had to redesign them to lengthen the inner concentric extrusion that actually fits into the shell/ridge.

sanded, glue, and oiled everything down and it works, but does not spin as readily as the video posted. I actually prefer it not to spin as fast because I didnt want it to spin while I was just using my phone. Requires a little more force to move so I dont accidentally spin the gears in daily usage.
Question about the 1% scale up mentioned in your instructions. Is the purpose for fitting the phone or giving the gears some play?
58Soon to be leaving thingiverse because of Makerbot's behavior towards open source.Details: fabbaloo.com/blog/2014/5/25/has-makerbot-crossed-the-line-for-some-yes
Hi... Any possible chance of posting dxf or svg files from your 3D
program to this post for us poor laser cutter folk? This would be
cool to cut out. thanks
Love it, though i'm having a couple of issues.
1) The design seems to print backwards/flipped so that the cut outs for the volume and power buttons are on the wrong side.

2) .2mm resolution. Will that work or should I not waste my time?
I've printed his twice, the top left corner is never right - no pun intended. The iPhone won't snap down. Any help?
Is it possible that your hot end pushes on the free standing wall slightly while printing? It may be pushing the corner out further than intended. It's also possible that you need to very slightly shrink the case when you print. That top left corner will be the most obvious at showing dimensional errors in the print as far as space between the case walls and your phone are concerned.
Is it just me, or do none of the pins fit in the case holes?
It can be very hard to tune your printer to print properly sized holes. The files have the holes slightly larger than the pins (~.2mm) but if your printer is extruding more plastic than your slicing program thinks it is, your pins will be oversized and your holes will be undersized due to excess material
Other way around, holes were too big, and pins right height, but too small. Same slicer and same filament. I was able to make up the difference, and then found that the phone I was printing one for was just exchanged.
Would love to see one of these for a 5C, so I can print one out as a gift.
Great design, but I'm having netfabb issues too. Only 3 pieces would slice right from the download. I tried to netfabb the others but the 21toothupperleftconnectedtobiggeara ndupperleftconnectedtogene.stl failed netfabb.
I get no issues when downloading the parts individually, are you downloading them all at once as a zip? I think thingiverse may cause some issues when compressing files. Try clicking each individual file instead and let me know if it works
Hi guys,
I'm having hard time printing those pins. How did you guys handle that?
My pins are always tilted.
When you print a larger object with straight walls, are the vertical walls always perpendicular to the bed? If they are not your printer may not be square. It is also possible that you are extruding too much material and the print head is dragging through the pin, pushing it over. Your temperature may be set too high, so the pins do not get time to harden before the next layer. Fix this by lowering the temp slightly (probably no more than 10 degrees if printing ABS), slowing the print speed, and also spreading the pins around your print bed so the radiant heat from your print head doesn't keep them melted. If you aren't having trouble keeping the pins stuck, I would also lower the bed temperature or even add a fan. Don't go overboard with any of these things though, or you will likely have bed adhesion issues.
Thanks, my printer is fine I guess, the problem should be cooling. I slowed it down to 5mm/s even, still didn't work out very well. I ordered a fan and hope that would help!
Before you get your fan, I would just try printing 2 sets of pins at a time, spreading them across the build platform, lowering platform temp, and decreasing your flow rate to 90% of normal. If you can post a link to pictures of your print attempts I may be able to give a better idea
My son gave my daughters a Cubify Cube2 for Christmas. We've printed a few simple things. Now my daughter wants me to print this iPhone case. The Cube2 prints at 0.2mm resolution. Will this work, or will I need to upgrade to a different printer in a few months. I see lots of cool things on Thingaverse; I just need to know if my Cube2 will print most of these acceptably. Thanks.
Hello Quentin, very nice design! I built most of the parts fine on my MBot R2. The ridge piece however, seems like a corrupt file. It only builds the top 1/4 - 1/3 portion, and it looks messed up on top of that. I have resliced on Makerware, but it still it's just partial. Is it possible for me to re-download only the ridge piece as I'm thinking maybe it got corrupted in the download? Thanks
What is the issue exactly? I can open the file (iPhone_4s_Gear_Case_Ridge.stl) after downloading it from this page in netfabb with no issue, and also view and slice it with Slic3r. Netfabb also says that the mesh is clean. I'd be happy to help, but I don't really know what to do.
Thanks for the quick response. Okay, as I mentioned if it's corrupt it's probably due to my download. I downloaded the zip to my laptop and opened and printed in three batches, and saved the ridge piece for last. All of the first 14 pieces sliced and printed fine except the ridge, which *seemed" to slice fine but when printing was basically garbage (2 different efforts, inluding platen re-levels and one with rafts, one without. Maybe I'll just do a complete re-download. I just thought it would be easier to re-download just the one piece. Thanks.
PS I don't know what NetFabb or Slic3r are. Am I supposed to be using these? I've just been building straight from my prepared files from Makerware => SD card =>Makerbot
Slic3r is just a different software option that can be used for slicing STL files. Netfabb is a piece of software that I mainly use for fixing STL files with holes and other defects. And to download just one part, all you have to do is click on the "Thing Files" tab of the thingiverse page, then click on the picture of the file you want. The "Download all files" button is just there for convenience so you have all of the files in a single zipped folder after download.
Update: Downloaded the complete file again for the ridge file, reprocessed only the ridge file, it worked like a champ. Great assembly - Thank you very much. Please forgive my noobness. :)
I'm glad it worked out! No worries, everyone has to learn sometime!
101% ended up being the trick for me. Made the unit in ABS on a MakerBot 2X. Two shells and 100% fill with .10mm layers worked great on the gears and Geneva mechanism (no raft on the Kapton covered heated bed). Glued the shell together with Loctite Gel CA, but wish I would have used acetone. Popped the pins in and fused them to the inside of the case with a soldering iron.
I tried printing this out but it seems like I am missing a gear and it's pin, which would be 21_tooth_upper_left_connected_to_big_gear_and_upper_left_connected_to_gene. Which pin would go with this?
If you are using it in the same place as my images then you will need the 4x4 pin. If you are using it in the place above where I am using it, then you will need the 4x2.75 pin. Both gears are 21 teeth of the same dimension, so they are interchangeable. Their pins only differ in length, so the long one (4x4) goes with the raised gear, and the short one (4x2.75) goes with the recessed gear.
Do you have plans to publish an Iphone 5 Version?
I do, but I've been busy lately so I don't know how soon it will happen
Hi QuentinT, I've tried printing the case shell countless times and each time it's the same problem, The portion where the sides start to go vertical, the first 3-4 layers in that area just ends up being brittle because they seem hollow. The reason is clear when I look at the sliced gcode, the middle of the. Did you run into this problem? Here's a picture: img43.imageshack.us/img43/6553/4y8p.jpg

Slic3r 0.9.10b settings
layer height: 0.1mm
Perimeters (min): 1
randomize starting points: enabled
generate extra perimeters: disabled
Solid layers: top-3 bottom-3
If this fixes the issue please let me know, and I'll fix the instructions
Thank you for the amazingly quick response, I will definitely update here once I try your tips.
If you look closely at the file, that bottom edge that you are talking about is actually wider than the rest of the wall, because the screen of the phone is not as wide as the metal edges are. I added this extra thickness because I thought it would create more stability.

When I look at your print I notice that these walls have been filled with a pretty open infill, leading to the openness you are talking about. You may want to try adding another perimeter, so when Slic3r sees that this width is not quite wide enough for 2 outer and 2 inner passes, it will instead create 1 outer and 1 inner pass, but then fill the middle of the two passes with a solid infill. When I made my case I was using 0.9.8 I believe, so the algorithms may have differed and I didn't have to worry about this.

You could alternatively increase your solid infill threshold area to something like 360mm^2, which also may fix the problem.
Is this the design for the iPhone 5 or iPhone 4/4s case, because the dimensions looks like an iPhone 5 case, and i need an iPhone 5 case
This case is meant for the 4/4s
Hey I am in the middle of printing the case, and I was wondering which pins go in which holes, because it does not say in the instructions and it is kind of hard to tell from the pictures. Thanks. Great design by the way
Once you print out all of the pins you will see that they are pretty self explanatory, because there is only one way to arrange all of them without having them stick out of the back.

The largest pin will go into the main double layered gear. the second largest diameter pin will go into the geneva mechanism. The next diameter pins come in two lengths. They both go into the two equally sized gears on the side, with the longer of the two holding the elevated gear. There are three smallest diameter pins. The long one will go into the geneva mechanism's gear, and the short ones will hold the two smallest gears at the bottom of the case.
Ok thank you very much, I had actually lost one of the pins, so that didn't help
When I finish my case, it's shrinks... what I can to do to print correctly?
ABS tends to shrink about 1% after cooling. I only print in ABS, so I have fixed this by increasing my x and y axes by 1% in the firmware for my printer. Your other option is to import the .STL into netfabb and scale the X and Y axes of the model by 1%. If you are experiencing warping, try increasing the temperature of your bed up to about 115C, and covering it with a cardboard box. Raising the temperature of the ambient air around the print works wonders for preventing warping.
How protective is it if i drop my phone?
It's no Otterbox, but it does protect your phone better than most thin shell cases because the edges of the case are actually higher than the screen, so the case will absorb some of the impact when dropped on an edge. My phone has yet to break while using this case even though it has been dropped on tile and concrete. I'm very happy with it because of how slim it is while still protecting the edges of the phone.
Is this for the iPhone 4s??
It will work for both the iPhone 4 and 4s
About how much filament is needed to create the case and gears.
It will take about 2.8 meters of 3mm filament, or 8.2 meters of 1.75 mm filament.
is there any simple way to measure this? I would love to be able to calculate it for all the designs I want to print but have yet to find a way!
If you use Slic3r the easiest way is to open your gcode file as a text file, then scroll to the very bottom and it will say exactly how much filament will be used. If you want to do it by hand, you need to do some guess work and it won't be very accurate.

First you look at your 3D model in some sort of software that will tell the total volume in mm^3 and write it down. Next you decide what percentage of infill you will be using, and use that to guess what the density of your print is. You also have to realize that infill % is not the total print density, just the infill density, so you must account for the density that is added by the perimeters and solid layers. If your model has a lot of thin spots like this case, the overall density of the print will be close to 100%, otherwise it will be closer to the density of the infill. for most prints of statues and larger objects I assume a density of 10-20% higher than the infill just to be safe. So suppose you are printing a hollow box with an infill of 50%, you would assume a print density of 60%, and multiply your total volume of the part by 0.6. Now you divide that number by the radius of your filament squared and multiplied by pi (pi*r^2). This should give you the length of filament needed in mm.

Part volume of 1000mm^3
infill of 50%
assume total volume is 10% more
filament diameter of 2.84mm

(1000*(.5+.1))/(pi*1.42^2)=length of filament
Nice work. Quite amazed the gears are running smoothly! Pay attention when gluing the ridge, I was off a bit...
Thanks.
It would probably be possible to add a motor, but it would add a decent amount of thickness to the case. Also, a coreless motor like that is very weak and can not handle side to side loads very well. Even if a worm gear was used, the motor would probably have to be larger than that one.
Stupid Question as I am new to this... I am using Makerware and Skeinforge to slice this.. When you say 1 perimeter would that be 1 shell?? The default in Makerware is 3.
BTW - Printing on a Replicator 2 with 1mm layer thickness...
Stupid Question as I am new to this... I am using Makerware and Skeinforge to slice this.. When you say 1 perimeter would that be 1 shell?? The default in Makerware is 3.
BTW - Printing on a Replicator 2 with 1mm layer thickness...
As far as I know you are correct. Having one perimeter just prevents the printer from leaving holes in your teeth that are too small to be infilled. If you look at the gear teeth in the cases that other people have made you can see that some have gaps that could weaken the gear.
Ahhh... So I want 100% "Infill" so not to get the "Honeycomb" on the insides??

Also - Anybody have any ideas as far as temp goes?? Black PLA 1mm layer - I seem to have luck with 240c - Default is 230 but it doesn't seem to stick.

Thanks QuentinT!
Actually, you are going to want 3 solid layers on the top and bottom layers of the gear, and then 1 layer of partial infill in the middle (25%) to keep the gears from becoming overfilled. If you are a beginner you may want to just switch to slice3r instead of skeinforge. Its all I use and I get beautiful prints. It also has a new beginner feature that makes first time setup quite easy. I would try that out instead of trying to fight with skeinforge anymore.

And as far as temperature, the 230 degree default is meant for ABS. PLA should be printed around 180 degrees.
Thanks so much for the help...

I will try silce3r - I tried Replicator3 and it seems over complicated and when I am finished it gives me a GCODE (maybe?!?) file that I don't know what to do with?!? I try to print directly to the Replicator 2 (From RepG) and I get an error message telling me it was trying to heat my build plate (I selected Rep 2 - Not Rep 2x)

BTW - I was talking .1mm layers, sorry - I have actually printed some stuff I have been amazed by - this Iphone case is just my nemisis because it is so neat, and I want it immediately!

Thanks for the tip on the temp... I will try it at 180c... Perhaps I was going in the wrong direction with my temp.

Also - Anyone up for a challenge... I sell a product at Home Depot that is injected molded (Made in China) and I want to try to be able to print it out on my Makerbot but I have no Idea how to orientate the part and get a decent result. The supports, etc seem like a nightmare to me.

I have .step files I could email to someone and maybe you can convert them to the proper .STL's... I am not a CAD guy - So that is beyond my means. If you are interested send me a message or just leave me your email address.

This is not a spam or an advertisement - I am the person who invented this thing, and I believe in open source. A few geniuses' printing it out themselves won't make or break me :)

If anyone is interested please go to screenmouse.com - If you think you could print it from .step files let me know... The body is a left and a right that press fit together, and the two wheels are separate files. In my opinion a very complicated print - But then again I don't really know what I am doing.

Thank you to Quentin... and anyone else reading this.

I am only "3 days in" with the Makerbot but hope to learn quickly :)
this thing is outstanding!
Thanks- cool design. I was wondering. My large pin does not snap into place and even with glue is not holding. Any suggestions.on how to make the flange tip slightly larger?-wider? thicker?
I use a soldering iron the weld the pins into place, you may want to try that!
The easiest solution would be to scale up the pin by a few percent when slicing, or if your slicer doesn't allow scaling, scale the whole stl in the free version of netfabb. I'm hesitant to change the dimensions of the file because the big pin was difficult for me to snap in, and it has also been working for others. If you still can't get it to work just let me know and we can figure something out. Are you printing in ABS or PLA?
The large gear is in fact two gears intersecting, it can be repaired with the netfabb online service.
Worked in Kisslicer. Nothing I could do in RepG/Skeinforge worked.
Funny... Same thing happens using the gcode included in the files...!
Just tried to print the largest gear. Sliced in SkeinForge/RepG... It has some problems in the file:
" Warning, the triangle mesh slice intersects itself in getLoopsFromCorrectMesh in triangle_mesh." It then prints reversed with the gaps filled in and the gear body missing. I Netfabbed it... nope, no change. Netfab can't fix it. The smaller gear intersects the larger and somehow leaves gaps that Netfab Basic won't fix. Any chance you can fix it in the CAD file and export it to .stl again?
Try uploading it to cloud.netfabb.com, that's fixed all the issues I've had with errors during slicing.
I redrew the gears properly, so they should be good now. Let me know if you have any more issues.
Thank you. It now prints real nice after sliced with RepG and Skeinforge. Will post a Black + colored gears version real soon
I still have the same problem. I downloaded the file and it printed just as you described andychn, reversed with the gaps filled in and the gear body missing. I'm printing on a replicator 2 using skeinforge. Any suggestions for a fix?
All I can say is it works very well when sliced with slicer if you would want to try that. Andychn, did you do anything special to make it slice in skeinforge?
No. The new version of the gear was fine.
I used slic3r to slice mine and got no errors, and netfabb didn't see any problems. I used autodesk inventor to make the gears by assembling two gears in an assembly, then saving them as a part file. I wasn't very happy with the way that the gears appeared to be separate, but netfabb didn't give me any errors so I thought it worked. I'll redraw the gears later today and update them. I'll let you know when I do.
Really nIce!!
The 1% extra is a must in my case...
OK, same question as before: Is there an iPhone 5 version?
Ditto on the iPhone 5 version request
I have one drawn, but not tested. I need to refine the dimensions before I post it
Looks very nice, must give it a try.
I'd love to see a video of this in action.
I just made a link in the description instead
that second picture was actually supposed to be a video, but I don't know how to make it appear as a video instead of a picture
Wow that's great! I need to make one of these for myself!
I'd love to see a video of this in action.
I'd love to see a video of this in action.
I'd love to see a video of this in action.
I'd love to see a video of this in action.
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