3D Printing a Pinephone Back Cover

[Beattie]

Hey, y'all - I decided to download the 3d model of the pinephone's back cover as linked to from the wiki and give it a go through my 3d printer to see what happened.

Of course, I've only got a tiny printer, so I had to print it standing on it's side edge to get it to fit on the print bed.

The print quality wasn't high enough to actually use on my phone (I printed in PLA with 0.2mm layers for these initial attempts, will switch to a more appropriate material eventually) but it came close!

Here's a jumpy timelapse video of the case being printed that I posted to the fediverse last night:
https://toot-lab.reclaim.technology/@djs...5853072932

There are also some pictures in this thread:

https://toot-lab.reclaim.technology/@djs...1702310396

Has anyone gotten a good enough print to use on their phone yet? I'd love to hear about it!

I don't think an FDM printer is going to be able to print this, and SLA might be able.

[Beattie]

Hey, y'all - I decided to download the 3d model of the pinephone's back cover as linked to from the wiki and give it a go through my 3d printer to see what happened.

Of course, I've only got a tiny printer, so I had to print it standing on it's side edge to get it to fit on the print bed.

The print quality wasn't high enough to actually use on my phone (I printed in PLA with 0.2mm layers for these initial attempts, will switch to a more appropriate material eventually) but it came close!

Here's a jumpy timelapse video of the case being printed that I posted to the fediverse last night:
https://toot-lab.reclaim.technology/@djs...5853072932

There are also some pictures in this thread:

https://toot-lab.reclaim.technology/@djs...1702310396

Has anyone gotten a good enough print to use on their phone yet? I'd love to hear about it!

I've created an STL file with FreeCAD and loaded it in Slic3r. I'm having a problem, the STL does not lie flat because the raised lip around the camera cutout. I'm wondering if anybody has fixed this problem.

[NormandC]

Hello all,

I'm reviving this topic, has anyone done any more progress on that front?

I want to see if I can bring the decal closer to the edge/bezel of the case sides. Would anyone be able to export the pieces of the back panel as highlighted here? I'm trying in Fusion360, but I'm having no luck.

Are you still looking for this? In your screenshot, you highlighted the rounded edges as well. Do you mean to flatten them to get a complete single face? It's often tricky to do in CAD, but I could give it a try.

The corners would create creases when folding them over the back cover; a solution may be to make two small triangular notches for each corner.

I don't think an FDM printer is going to be able to print this, and SLA might be able.

AFAIK, SLA resin is pretty brittle, and unsuited for usable parts. An SLA cover might break as soon as you try to snap it in place. I think the best bet would be selective laser sintering (SLS) with nylon, or HP's Multi Jet Fusion which is a variant of this process. It's very precise and strong. As with SLA you don't need to worry about overhangs. Might be pretty expensive though, since you have to go with commercial services.

I've created an STL file with FreeCAD and loaded it in Slic3r. I'm having a problem, the STL does not lie flat because the raised lip around the camera cutout. I'm wondering if anybody has fixed this problem.

I would say that the simplest solution would be to thicken the whole back face to raise it up to the level of the lip. In Pine64's CAD model, I measure the lip's top 0.60mm in height. The Pinephone's back cover is pretty thin. At the battery area it's only 0.80mm thick, over the SIM/SD slot 0.75mm, over the battery connector 0.70mm; elsewhere it's 0.95mm. I'm not sure but the thermoplastic used may be polycarbonate, the letters "PC" are engraved on the inner side. I think this is a pretty strong an flexible plastic, which allows for a thin cover. For FDM/FFF personal 3D printers using PLA or ABS, I think a thicker back cover may be warranted. It would be 1.55mm at its thickest, 1.20mm at its thinnest. That's still not much plastic and should make it sturdier. I also think printing it flat might make a stronger case than printing it sideways up like sundog did.

As for me, I want to design a back cover with a quick access door for the battery, and possibly the SIM/SD slots. I'm tired of breaking my nails on this cover to open it, or to look for a guitar pick.  I have a 2012 Lulzbot AO-100 3D printer that has been collecting dust for the past 6-7 years, I want to try to get it up and running again to work on this.

There are some challenges!

• I doubt the very small inner "bumps" that snap into the front body can be printed effectively, at least with my old 3D printer. An alternative would be to fasten the back cover with some of the screws that go through the midframe. Longer screws might be needed though.
  
• The battery is quite big, there's not much space on the sides and the bottom for a frame.
  
• What type of door to make. Sliding, hinged... How to lock it effectively.
  
• For SIM/SD slots access, I was thinking of a secondary door, sliding, that you could open only by removing the battery door panel. You need to remove the battery anyway to access these slots.
  
• The Up/down volume & power buttons are attached to a thin rubber (?) strip, not sure how to make this into something that can be 3D printed.
  
• The whole basis of this idea is that power consumption in current Linux distros won't improve much for the short/mid term, so swapping between two batteries might be required to go through a full day (my UBports CE phone with Mobian drains its battery crazy fast). I really, really want to ditch my Android phone and make my Pinephone my daily driver! But if power usage improves drastically in the next few months, my project may become moot before I'm able to complete it. 
  

Cheers,

Norm

[KC9UDX]

I had some SLA parts made twenty years ago. I wouldn't call them fragile in any respect. They're in fact quite durable. But I don't know anything about the process to say "this is why" and "that is why not".

[tophneal]

Hello all,

I'm reviving this topic, has anyone done any more progress on that front?

I want to see if I can bring the decal closer to the edge/bezel of the case sides. Would anyone be able to export the pieces of the back panel as highlighted here? I'm trying in Fusion360, but I'm having no luck.

Are you still looking for this? In your screenshot, you highlighted the rounded edges as well. Do you mean to flatten them to get a complete single face? It's often tricky to do in CAD, but I could give it a try.

The corners would create creases when folding them over the back cover; a solution may be to make two small triangular notches for each corner.

I don't think I ever quite got the file how I was hoping to. If you're willing to give it a go, that'd be awesome!

You're right, it most likely would need a small slit/triangle removed from the corners. I also want to try using some thinner, stretchier vinyl (like is used for some vehicle graphics) to see how creases when laid down.

[NormandC]

I don't think I ever quite got the file how I was hoping to. If you're willing to give it a go, that'd be awesome!

Alright, played with it a little in FreeCAD tonight.  (Didn't even need to boot up the Windows work PC to use the pro CAD program I use for work - yay for open source )

This is a first try. Due to the process I used to flatten the faces, arcs and B-spline curves were interpolated to short straight segments. I figured that if you're using a CNC cutter, it wouldn't matter? I believe going from dxf to g-code automatically converts arcs and curves to straight segments. If you prefer true arcs and curves, let me know, and I can look into converting them.

For the grille area, I'm guessing you would just cut away the whole area in a rectangle shape?

I didn't take the time to add slits in the corners. Oh, and there's only a thin strip of material above the camera bulge... Might be best to cut it out?

HTH,

Norm

Pinephone-back-flattened.dxf (Dropbox link - 478KB)


Screenshot of the DXF from LibreCAD

[KC9UDX]

It depends on the software, and the machine. Many modern machining centres will cut NURBS.
Even forty year old machines will cut circular arcs if your software can handle that. But even using only linear moves, all that matters is the precision. You won't be able to distinguish between a B-spline cut and a bunch of linear cuts with .0003" resolution. Whatever you put into it, you get out of it.

[NormandC]

Whatever you put into it, you get out of it.

Reminds me of what I used to say to newcomers on the FreeCAD forum when they were asking about editing STL files: garbage in, garbage out.

My straight segments are considerably longer than .0003" (up to 0.020") but honestly, I doubt it would be noticeable.

[KC9UDX]

STL.

It depends on the material. But it's not the segment length that matters, it's the cusp height, which depends on the perpendicular step-over and the corner radius of the tool.

I know of a famous product that intentionally has a jagged finish from poor machining technique.

[tophneal]

Alright, played with it a little in FreeCAD tonight.  (Didn't even need to boot up the Windows work PC to use the pro CAD program I use for work - yay for open source )

This is a first try. Due to the process I used to flatten the faces, arcs and B-spline curves were interpolated to short straight segments. I figured that if you're using a CNC cutter, it wouldn't matter? I believe going from dxf to g-code automatically converts arcs and curves to straight segments. If you prefer true arcs and curves, let me know, and I can look into converting them.

For the grille area, I'm guessing you would just cut away the whole area in a rectangle shape?

I didn't take the time to add slits in the corners. Oh, and there's only a thin strip of material above the camera bulge... Might be best to cut it out?

HTH,

Norm

Thanks!

No worries about the arcs or slits/wedges in the corners. I'll be able to smooth out the corners pretty quickly and easily. I can figure out how little to remove from the corners with my buddy's PinePhone and a paper template.

You're right, I will likely use a rounded rectangle at the grille. I wouldn't imagine anyone could easily (or want to) line up a decal to those. Same with the thin strip above the camera, it will be easier for anyone to apply with it removed. I'll likely keep and round the corners created by removing the thin strip, to help frame the camera bulge and cover more area.

After I do some test fits with my buddy's PinePhone, I'll upload a PDF template for anyone to drop art in and be able to use themselves.