3D printable iMac G3 replacement screen bezel

[abernaert]

Hi all,
I recently worked on a 3D printable replacement inner bezel for the iMac G3. I think it fits quite well now, so the CAD and STL files have been released:

Github link

Thingiverse link

For the printing material I recommend ABS or ASA. Viability of PETG is still under investigation due to the temperatures it needs to withstand.

It's a work in progress, and I currently tested this only using my own printer. If you decide to give this 3D printed bezel a shot, feedback is appreciated.

 

[croissantking]

Great work!!

 

[iantm]

Wow — did you scan it as a basis? How did you manage the accurate dimensions?

 

[abernaert]

Wow — did you scan it as a basis? How did you manage the accurate dimensions?

Mostly by taking pictures of the curves where it had to fit, using caliper measurements on the original bezel (I had the chance of having an intact one) and quite some trial and error.
I don’t have access to a 3D scanner, unfortunately.

 

[iantm]

I don’t have access to a 3D scanner, unfortunately.

Me neither… nice work, that's a massive effort!

 

[Phipli]

Mostly by taking pictures of the curves where it had to fit, using caliper measurements on the original bezel (I had the chance of having an intact one) and quite some trial and error.
I don’t have access to a 3D scanner, unfortunately.

Nice work. Have you tried Photogrammetry as a starting point for complex shapes? Painting a texture on it might help with that as the uniform colour and texture will make it harder to get good results.

 

[croissantking]

How do the four pieces stick together and does it matter with respect to rigidity? I seem to remember the bezel was a structural part.

 

[Phipli]

How do the four pieces stick together and does it matter with respect to rigidity? I seem to remember the bezel was a structural part.

There are glues stronger than the 3D printed parts. This is one place the rough surface of the prints help, although I'd probably still run some rough sand paper over it.

Plexus MA 300 might work well for something like this? You'd almost certainly delaminate the part before you broke the bond.

 

[Phipli]

Another option is to use the 3D printed part as a pattern to cast a part in resin or even possibly metal, although I'm not sure if you could get these to come out of a flexible silicone mould, and I'm not sure if it would be possible to get the print out of a green sand mould or similar.

It would be awesome to cast an aluminium bezel! Although you'd have to increase the size of the print to compensate for shrinkage.

 

[abernaert]

Nice work. Have you tried Photogrammetry as a starting point for complex shapes? Painting a texture on it might help with that as the uniform colour and texture will make it harder to get good results.

Yes I tried Polycam initially but quickly lost patience with it. Didn’t try to paint a texture on the original bezel though.

How do the four pieces stick together and does it matter with respect to rigidity? I seem to remember the bezel was a structural part.

You’re right, this a structural part. You can see my model has a lot more larger volumes for that reason. There are four large dowels connecting everything together. Additionally, when you print in ASA or ABS, you can/should use acetone to weld everything together.

But trust me, when you just insert the dowels and screw the CRT onto the bezel, the structure is already very rigid without any glue (and can’t fall apart). I still recommend to glue/weld it though for optimal results, even it’s only to hide the seams – acetone is very good at this.