Pimp my flip phone - critique

Esrever_reenigne

Hi Onshapers

This is a bit off the wall, I'm guessing you don't get many silly topics like this here - sorry if it's pushing the limits of etiquette. As silly as it seems sometimes the best way to learn is to attempt something and then present it to someone more experienced and let them pick it pieces to see where you could have done something better. So this is for the most part a novice model in need of expert critique.

Background story

My boy - 9YO (awesome kid) came home from school with an A4 sheet of paper folded up into the shape of a flip phone. He opens it up and it has all the features of a retro flip phone drawn on the inside, I didn't think much of it first but he's kept it for 2 weeks and it's become his fave toy. Every time he picks it up he tells me about some new feature or capability the phone has, it really gets his imagination going and he just loves it.

So to capture the moment (for him and myself) I thought I'd model something to similar dimensions that we can 3D print and give him something a bit more substantial than a folded piece of paper. I've made a few basic mistakes with the drawing and could have spaced things better or used the pattern tool to equally space the buttons. I did learn a bit in the process of the design but rather than guessing my way through it I thought I'd ask and see if anyone has any suggestions I haven't thought of.

So if anyone can spot any stupid mistakes I've made or show me how I could have employed a more efficient work flow feel free to show me how you'd do it. Feel free to make any suggestions or improvements and point out any mistakes. I have thick skin so be brutal

https://cad.onshape.com/documents/9ca8c8361824e4cca6b5a253/w/9f16909653dc458efff65373/e/95a220e6507742b2dcc8d072

Edit: Just reviewing it now I've already spotted one mistake, both inside faces are on the same plane so maybe the phone won't close all the way without leaving a gap at the bottom, maybe I need an small offfset there?

billy2

Phone looks good, but it won't close, there needs to be a gap between inner faces. 

How thick should the gap be? Welcome to the world of manufacturing tolerances. You stack them all up, cross your fingers, pick a number, then pay half $million to tool up.

Esrever_reenigne

Thanks @billy2 , I'll re-work that hinge now and print one up to see how good my guesswork is.. At least with the 3D printer the tooling costs are less than injection moulding, if the design is a lemon you can easily tweak it without much expense.

I actually wanted make the whole unit larger to fit a raspi zero W and a touch screen but my son was insistent on having it the same size as his paper phone. I still might make another one with as raspi in it and use it as a wifi scanner/jammer to prank people.

Fixed to allow a bit of extra clearance when closing the cover.

mahir

Maybe add some sort of a locking detent feature to the hinge so it stays closed/open?

billy2

Be careful inserting a pin between the 2 halves. I worked on a similar design where the pin was pressed into the plastic thinking this would hold the pin in place. Turns out the stresses were so high from pressing the pin in that the hinges kept cracking. The thought was the hinges weren't functionally big enough to handle usage, but in reality it was the press fit.

Since it's printed, I'd add bumps on the ends to retain the hinge pin and leaving the hinge plastic stress free after pin insertion.



Now we were molding with polycarbonate which has no resistance to press fit stress. In a couple of weeks the hinges cracked often. With FEA the hinge design was proven to be functionally good from a users perspective but the press fit sent the stress through the roof. Gluing wasn't an option, who wants to glue in production?

So, I'd print a bump on the ends (if your printer has the resolution) and then press the pin past the bumps. The plastic will become stressed and then relax once the pin is in it's place. The bumps will keep the pin from falling out and will allow you to create a kids phone without choking hazards.

Of coarse most printed materials are doughy and a press fit might work for your pin. But if you need to make 1,000's, you may want to figure out a good way to keep that pin in place.

billy2

@Esrever_reenigne you can always make 2: a big one, a little one.

Esrever_reenigne

Thanks for the feedback guys and sorry for my slow response, I've had lot going on in the last few days.

@mahir your idea of implementing a way to keep it closed and fixed at the correct angle became apparent after we printed it and put it together.

@billy2 that hinge would definitely need some re-work if I was going to press a pin in. I ended super gluing a piece of wire in as a hinge pin. The wire was a clearance fit but putting a slight bend in it made it slightly tight on lid hinge hole and gives it a tight feel and stops it flapping around.

It was just a learning exercise really and seeing your pic of the assembly showing that the lid wouldn't function sent me on path of discovery, so I learned a bit right there. I hadn't done an assembly until that point, I was just designing isolated parts. It was well worth posting this just to learn that. Thanks!

Now I just have to work out how to show a sectioned view like you've done.

& there is another slightly larger one in the works with a raspi zero W in it running aircrack-ng  

billy2

shift-x is the fastest way to cross section your geometry and I use it a lot.

Your phone was a nice 1st attempt. watch out i-phone.