3D Printed Mod Corners - For 2D Panel Construction

[Thehack]

Spoiler: Original Post

- 3D printed
- Easy to implement
- Fast prototyping of panel based SFF cases
- Gives you clean corners


3mm Material, 9mm screw point version
- Used with M3 x 8mm self-tapping screws
- Not recommended for cases above 5L.

Download STL file here (google drive link).

Questions, comments?

INTRODUCING:
MOD CORNERS

- Easy to implement
- Fast prototyping of panel based SFF cases
- Gives you clean corners


3mm Material, 10mm screw point from corner
- Technical Diagram is for 3mm material, Mod Corners can be modified for any material between 1.5mm - 3.5mm
- Recommended screw is #6-32. Can be also be used with any coarse threaded or self-tapping screws including M3 Self-taping.

ModCorner
NAME - [Material Thickness] - [Diameter of Hole]
Download Here.

Need custom size? Send me a message.

Technical drawing for 3mm material. you need to vary the corners based on your material thickness. The horizontal and vertical cut in is the length of the material you use.

Examples of cases you can do:

 

[eggDK]

What material are you thinking? 316L or similar? Or just regular ABS or PLA? I'm thinking about durability..

 

[Thehack]

What material are you thinking? 316L or similar? Or just regular ABS or PLA? I'm thinking about durability..

This is an open source project, so I'm not selling it, just making it available. You can grab it and print at home if you want to.

Having held PLA and ABS parts, I expect any plastic material would be reasonably strong for it. I'd recommend Shapeways' SLS printed method however. It is very good quality plastic print.

Until 3d Printers hit the $100 mark for a small printer, I won't be owning one myself. They take a decent amount of maintenance and setup.

 

[eggDK]

Oh, yeah of course☺ Well, I love the idea and look forward to seeing it tested. Who knows, I may even try it out myself..

 

[firewolfy]

NIce idea. So the panels would have a 45 on the corners, right? About 4mm back from the corner?

 

[firewolfy]

LOL, based on the voting, looks like we are all a bit hungry for a sammich....

 

[Thehack]

NIce idea. So the panels would have a 45 on the corners, right? About 4mm back from the corner?

Yes. 45 degrees on the corner. 3mm cut in to line up with 3mm materials, see the updated pictures for a better look. Most common laser cut material is 3mm acrylic, but the idea is there so that you can just take it a modify it to your needs.

 

[wywywywy]

Hi.

Very nice design. I like it.

I hope you don't mind suggestions, but there's a few 3D printing specific changes required.

Firstly currently this design is not possible to be printed without support, no matter FDM or SLA or SLS. It needs to have the exposed corner face flattened, and the orientation changed so that all angles are 45 deg, like this -

Even then it will still need a brim, because the contact area to the bed is really small.

Secondly the internal corners should be filleted, this makes 3D printed objects much stronger.

And lastly screw threads CAN be printed, and this means we can use normal M3 screws instead of self tapping.

Thanks.

 

[Thehack]

Hi.

Very nice design. I like it.

I hope you don't mind suggestions, but there's a few 3D printing specific changes required.

Firstly currently this design is not possible to be printed without support, no matter FDM or SLA or SLS. It needs to have the exposed corner face flattened, and the orientation changed so that all angles are 45 deg, like this -

Even then it will still need a brim, because the contact area to the bed is really small.

Secondly the internal corners should be filleted, this makes 3D printed objects much stronger.

And lastly screw threads CAN be printed, and this means we can use normal M3 screws instead of self tapping.

Thanks.

Good points.

1. It can be printed SLS fine via shapeways' method as it is pretty advance.

2. There will be a 4x2 array of the corner pieces joined by supports. However I would need someone with a 3d printer help me refine the design as needed. Smaller supports should automatically be handled by the 3D printing software correct?

3. It wouldn't hurt to add fillets.

4. I'm reasonably cautious against adding threads as they require more precision. Would a cheap Prusa printer be able to handle M3 screws with low failures?

 

[wywywywy]

Oh yes sorry SLS can do that.

Support can be generated automatically yes, but it is generally to be avoided whenever possible, because it uses a lot more plastic, has higher risk of failure, will likely double the amount of time needed (for this print), requires manual cleaning up, and also the surface finish is not as nice.

Threads are ok especially printed at low layer height (e.g. 0.12mm). Not as polished as machined obviously. But the first time you screw a screw in will clean it up. Not suitable for higher layer heights (> 0.24mm). And yes a cheap Chinese i3-style printer can do that.

If you upload the STEP file I can print out a couple of these and give some feedback if you like?

 

[Thehack]

Oh yes sorry SLS can do that.

Support can be generated automatically yes, but it is generally to be avoided whenever possible, because it uses a lot more plastic, has higher risk of failure, will likely double the amount of time needed (for this print), requires manual cleaning up, and also the surface finish is not as nice.

Threads are ok especially printed at low layer height (e.g. 0.12mm). Not as polished as machined obviously. But the first time you screw a screw in will clean it up. Not suitable for higher layer heights (> 0.24mm). And yes a cheap Chinese i3-style printer can do that.

If you upload the STEP file I can print out a couple of these and give some feedback if you like?

here it is. i havent made any mods to it yet though.

 

[wywywywy]

I'll give it a try soon and post pics.

 

[Biowarejak]

Instead of threads being modelled in, you could just do a cutout for the hexagonal nuts that you can get for m3 screws

 

[jeshikat]

That seems like the best route, I've had SLS stuff made and I don't think it's really good enough for M3 threads.

 

[iFreilicht]

Very cool idea! I agree about the screws being best solved with hexagonal cutouts for M3 nuts, that is an extremely solid solution. Alternatively, you could also work with self-tapping screws, but I think the M3 route is more flexible and easier for people to understand.

I like the corner profile as well, looks pretty good.

I don't know how large the cross-section area of the connection between the visible and the structural corner is, but it seems relatively low and will be the point with the highest stress on the part. You might want to consider making the corner pieces a good bit larger.

For your sample case, I'd consider going with the smallest possible one first. Makes it easier and cheaper to try out

Oh, and for cases larger than 5L, it shouldn't be too hard to make a variation of this piece that fits between the edges of two panels.

 

[Biowarejak]

I've allowed machine screws to tap their own threads into parts I've printed, but the results weren't pretty when under heat and tension. So yeah, you'd want something meant for self-tapping into plastic if you don't go the M3 nut route.

 

[wywywywy]

Sorry I didn't have time to print it last night.

I'll try to print out a few different variations whenever I can.

 

[wywywywy]

Also the design at the moment is too small to capture an M3 nut.

 

[Thehack]

Very cool idea! I agree about the screws being best solved with hexagonal cutouts for M3 nuts, that is an extremely solid solution. Alternatively, you could also work with self-tapping screws, but I think the M3 route is more flexible and easier for people to understand.

I like the corner profile as well, looks pretty good.



I don't know how large the cross-section area of the connection between the visible and the structural corner is, but it seems relatively low and will be the point with the highest stress on the part. You might want to consider making the corner pieces a good bit larger.

For your sample case, I'd consider going with the smallest possible one first. Makes it easier and cheaper to try out

Oh, and for cases larger than 5L, it shouldn't be too hard to make a variation of this piece that fits between the edges of two panels.

I've had good success with using self-tapping screws. My 6L meanwell build uses them.

Most importantly it should be easy to source. The nice thing about self tapping screws is that the prints are simple and you only need to source the screws. The prints have more tolerance because the screws have a wide pitch.

Using nuts has advantages as well. You won't mess up the tapping and you have more screw types to choose from.

What do you guys think?

 

[iFreilicht]

Most importantly it should be easy to source.

Yes, very much. Admittedly, I don't know much about ISO standards for self-tapping screws, but you can get M3 screws and nuts everywhere in the world, no problem. Just provide people with the exact ISO number for the nuts, because there are different types of those.

The nice thing about self tapping screws is that the prints are simple and you only need to source the screws. The prints have more tolerance because the screws have a wide pitch.

I think with hexagonal inserts you also get a good bit of tolerance, because the nut can move around. Also, because holes in SLS prints aren't the same dimensions depending on which orientation you print them in, the screws might require differing amounts of force to screw in.

You won't mess up the tapping and you have more screw types to choose from.

Jup, both of those. There are a lot of different types of heads available, standard and non standard. Even stuff like knurled thumb screws are available in a multitude of different materials, finishes and lengths. That alone is a dead-set argument for M3.

The one point for self-tappers is cost. Because these pieces are 3D-printed anyway, making a separate version for those wouldn't cost you anything either.

How are you going to handle different panel thicknesses?