Apparently Boss is proposing some “bumps”/lens structures on the outside of the case. These are 0.5mm tall by 8mm in diameter, so smaller than they look.
I don’t feel like we have much choice, there will be a test molding with this effect. Boss says we can change the mold as we go, and if we don’t like it he can “fill them in”. As long as that is true, I’m willing to at least have a look at the result.
We went with this factory because the boss is really involved and genuinely seems to enjoy designing weird stuff. It’s obvious he’s putting a lot of effort into the LED effect.
I hope to talk about the internal structure and the button hole tomorrow.
I personally would have purchased a few of each: smooth, raised diffusers on inside only, and raised on inside and outside.
The areas in the mold can likely be filled in with weld and machined flat, but this seems like a lot of work to change after. I’m assuming that you have some samples of all iterations.
It is awesome to hear that the Bus Pirate has caused someone else, your boss of all people, to rabbit hole with an idea.
Tomorrow I think we will get a look at the inside modifications. The inset nuts should, hopefully, be changed to something proper that I understand is called a boss.
Does anyone have/remember the protocube? What we currently have is lower left (bad boss), we want something like the right. This will also open up a mm or two of extra board space.
It sounds like using inserts to change the bootloader button hole shape and location is doable. The tradeoff is that there will be some minor markings around the inserts. I’m ok with this, it’s the bottom of the case, and it allows us to play with locations and even shapes using the same tooling.
From my experience I can say that the combination of base material and glue used on the bumper is very important for longetivity and stick strength. So I suggest to ask your factory boss to send you some scrap material or whatever, but with the exact same plastics you plan to use. Then use this material to test if your sticky feet really stick and which work best.
Also the surface roughness is important, generally the more even, the better it sticks.
Most of the glues take some time to reach their final strength. So clean the surface, stick them on, wait a day, and then do your stickyness tests.
With some glue/surface combinations it works best to apply a thin spray with soapy water first, stick the bumpers onto the still wet surface and then let it dry for a few days (this could be for example during shipping). They are easily movable while the soap water is there, but once it has dried it reaches a higher glue strength than without. But as I said, this does not apply to all types of glue/surface combinations.
One final change request is to make the AUX connector easier to access. This was late in the day so it isn’t final yet.
Not a high effort example on my part, I’m afraid. The goal is to cut away material from the bottom so the edge of the AUX connector is just exposed. Then, chamfer the whole entry cut out for easier alignment.
This bit is hopefully sorted tomorrow. Our plan was to have SLA prints made and the fit test done in the Shenzhen office. However, Blinkinlabs has offered their epoxy printer so I can actually check the fit in person tomorrow.
If everything looks good, tooling will start next week. I learned a lot more about injection molding, and the boss has been super patient with us. This project came up unexpectedly and threw off my schedule a bit, but that’s our fault for not planning ahead. 5/5 experience so far.
No big update today, boss didn’t have time for us. Tomorrow I hope.
Small update: I looked for sticky feet on Amazon EU and the local big sites. There’s nothing smaller than 6mm. If we use 5mm then it might be hard for folks to replace any lost feet in the future. 6mm seems available if not super common.
A whole range of pads arrived at the shenzhen office, from 3.5mm to 6mm at various heights. Jam said 6mm looks and feels better than 5mm.
If Jam says it’s better, and it’s what’s generally available on Amazon, then that’s probably the way to go.
This is our current “keep-out”, the place we cannot put parts because they will touch the boss on the case.
Our current boss is big, so it has a big keep-out
Here is where the board and parts sit in the case
The new boss takes less space, so the keep-out will be smaller.
We’re waiting to hear the total diameter of the boss (plus tolerance) to see how much board space we’ll gain. It won’t be much, but it should make life a bit easier.
Printing the final draft of the enclosure for a fit test. You can see the new cut for easier access to the AUX connector.
Boss offered to do an over molding of silicone on the entire bottom for nonslip. That sounds like an interesting idea, but then we need a second mold or something. Maybe in the future.
Here’s the REV0 case as an STL file if anyone wants to print it:
The inside circle (red arrow) is the new keep-out. The outside circle is the old keep-out. The adjustable power supply can move up quite a bit and take advantage of the new space.
Printed the final draft in PLA and almost everything looks good.
Old case AUX slot. The 1.4mm pegs close the case around the AUX connector, but the entry is offset by about 0.7mm, giving a clean shot at the connector.
You can see that here.
The new case doesn’t have the same offset so access to AUX is actually somehow more weird. Will ask for this change tomorrow.
