Idea for edge pcb spacers (any 3d printer owners about?)

[Ace`]

I've bought some boards recently that are badly warped 2 layer stacks. This is due to there being no spacers installed in the middle and only in each corner, some of them don't even have holes for the option to install them in the middle. This gave me the idea for some 'edge spacers' that just slide on the edge of the boards to support them at the proper height.

I thought someone would have already come up with something like this but couldn't find any thing, I've made this awful picture in photoshop that sort of shows what I mean.




If anyone with a 3d printer wants to give it a try I am happy to beta test and would also like to buy a load of them.

 

[Funhouse71]

A long time ago I used 4 short pieces of wood about 50mm long, 20mm wide and 10mm thick and cut 2 slots in each piece and slid these on the edges of any boards I was repairing so I didn't have to keep screwing the boards back together again during repair testing so was similiar thinking to your design.

If these got made I would also be interest as something more professional looking

 

[Phils Arcade]

Nothing hard about making those. Wonder how many different spacer sizes there are and thickness of boards.

Could expand on the idea and have a screw thread that allows the spacing to be adjustable.

 

[FrancoB]

Apologies, I had a bit of a play with this a while back but forgot to post.

Something along the lines of this?

Apologies for the image quality. MP4>GIF degraded it and then it really took a dive when I uploaded it You get the idea though.

Its not adjustable but I thought I would KISS for now.

I just chose 30mm as a random number, they could of course be any size you wanted. It's parametrically modelled so only takes a second to make the changes.

In this example 30mm is the space between the PCBs, so if you were using 30mm spacers at the corners then you would use 30mm ones of these in the middle.

More than happy to make any changes and then you could give them a go if you like.

 

[Ace`]

Very cool, nice work Franco. I'll measure my two stack boards and see what sizes are required. The spacers are usually only two different sizes so I think only two sizes would be needed, for the majority of boards anyway.

 

[FrancoB]

Good stuff. I'm assuming PCB thickness of 1.6mm but let me know if you need different. I'll have a bit of a play to get a nice fit, although any kind of curvature in the boards would hold them in position.

 

[Funhouse71]

I'm wondering if some plastic fingers can be incorporated into the slots to take up any slack of the different sized boards this would also help grip the boards.

A little bit like the plastic clip below replacing the metal biter insert with plastic as part of the clip model

 

[Ace`]

Didn't have a chance to check as many boards as I would have liked but for the most part the pcb thickness has been 1.5mm - 1.7mm with the only thicker one being a data east board that was 2mm.

For the gap it's mostly been 20mm, I measured the spacers rather than warped pcbs, I am sure there's other sizes but 20mm seems to be the most common as it's the only size I came across, I will check more though.

 

[FrancoB]

Thanks for checking those.

I think it's at least having one version with a fixed 20mm jaw then. One idea would be to angle the other jaw slightly:



This might compensate for the difference in board thicknesses. Prints do tend to lose their elasticity over time and the jaws wouldn't be gripping the boards 'tight' but their should be enough to keep them in place. it's the fixed jaw that's the important one anyway.

For the odd 2mm thick board we could do a version just for that, or increase the 1.8mm dimension on the version above but we might be reducing performance for 95% of them just for the odd one.

I'll print a couple of versions and I'll print some pieces of material 1.5-2.0mm and see how they perform initially.

 

[FrancoB]

Printed one as above and decided to increase the 'jaw' throat depth to 10mm:

Don't know if 10mm will be too deep, depends how close components are to the edge of the board.

Made a thickness gauge to check the spacer on various thicknesses:

Deeper one on the 1.5mm section, original on the 1.8mm.

Seems to work pretty well in the 1.5mm-1.8mm range. 1.5mm grips and then gets tighter as it goes up. You can fit it on the 2.0 but the whole thing does start flexing a bit.

Let me know if you want me to change anything or if you want me to print you a few to try out.

 

[Funhouse71]

Looking good so far, maybe both types might be required depending on how close some of the board components are placed near the edges of the boards as they seem to differ from one board to another, resistors and smoothing capacitors are the normal culprits

 

[FrancoB]

Yeah that's the type of components I was thinking about. Sadly I don't have any boards left otherwise I would check some myself.

@Ace` - (or anyone else) if you want to check some of your boards we can figure out the optimum depth(s).

 

[Ace`]

A lot of two layer boards seem to have a nice clear area around the edge for the power or ground traces like this Rygar board.



I think 1cm depth is spot on but in this case 1.5cm would fit in certain areas, 1.5cm is a little overkill though and 1cm depth with 2cm gap will be perfect for the vast majority of boards.

This is another board with exactly a 2cm gap. I am having a job finding any that aren't 2cm.

 

[Ace`]

Franco's great work in action.

 

[Ace`]

Some more pics, I love the green thanks again @FrancoB

This is a good example of the warping issue, a Kung Fu Master board with all the original spacers still intact and it has still warped over time.

Before




After

 

[Phils Arcade]

Doesn't help with the weight of the daughter board on top adding extra weight.

 

[FrancoB]

Apologies for the late reply, things are a bit manic as of late......

Added 15mm and 18mm versions to go along with the 20mm spacer, these are the common sizes based off @Ace` s measurements.

I just need to find time to upload all the files etc to Printables.com so people can print their own if they wish.

I'll include .stp files in case any one wants to edit them.

If anyone needs a different sized model making then just let me know.

 

[Flinnster]

Loving this. I had the same thought ages ago! Where can we order? 💳🤑💰

 

[FrancoB]

Great minds..... you and Ace

I would be more than happy to make some for you mate. I don't typically charge active members for small things but if you wanted a load then a charity donation would be appreciated. Just let me know what you need 🙂

 

[FrancoB]

Uploaded to my page on [Printables.com]