I wanted to redo an old project and convert it from SMD to "surface mounted thru hole parts" with the extra twist of having the parts *inside* the PCB.
The old design looks like this:
The prototype for the new design:
But Seeedstudio managed to not understand my instructions of how to do the milling. So all the holes are too small :-(
I made the milling layer with a 1.2mm milling bit in mind and should have got the correct hole sizes if they had followed my instructions to have the center of the 1.2mm bit follow the milling lines precisely.
Previously I've got a question from their pcb department how I wanted the milling to be done - inside or outside milling of the milling line. I then asked what milling bit sizes they had and how I would communicate my requirements to them in the future.
Discussion for a previous order:
Me: Can you tell me the size of the cutting tool so I can compensate for it future orders?
Seeed: Hi,there The size of the cutting tool is 0.8MM 1.2MM.1.5MM.1.6MM. Any helps needed ,please feel free to contact us. Thank you.
Me: What is the best way to tell Seeedstudio my cutting preferences and other information when I make an PCB order? Should I write in the TOP SILK layer? Write in the TOP COPPER layer? In a readme.txt file and include in the zip file? Just as general comments to the order?
Seeed: Hi,there You can put it on GML layer. Thank you.
And then for this order
Seeed:We find that about your file D82284_BlingTag_1_6mm_Green_10pcs.zip ,in your file we find you note that the thickness is 1.2mm,but when you place the order the thickness is 1.6mm. So i need to check with you about the thicknees,please answer me as soon as possible,if we don't receive your reply ,we will produce it as your file (1.2mm) to make it. Thank you.
Me:I want to use the 1.2mm cutting tool for the milling. And I want the *center* of the tool to follow the milling outlines in the GML layer. I have already adjusted the size of the milling outlines to give me the correct hole size if the 1.2 mm tool is used. If there is a way that I can give this information in a clearer way for my next orders please tell me how to write it.
And for this order I had written instructions in the .GML layer as instructed. And they apparently saw them since they asked about the 1.2 mm.
So I'll have to dremel them up a bit for the prototypes, and then complain to Seeed and see if they can make a free replacement set since they failed to follow my (at least to me) very clear instructions. Maybe they will, but I don't expect them to ship the replacements by DHL.
I was under the impression that you specified mill instructions based on the final result of the milling and they worried about how to generate the tool paths, but then again I may not have any idea what I'm talking about :)
I like the idea of the battery being inside the PCB, but I'm not sure I follow the logic on the others :)
The next time I'll include measurements Then nothing should go wrong. ;-) But the size of the tool is important when doing sharp corners. If they use the 1.6 mm tool the corners will be more rounded compared to a 0.8mm tool and I then need to increase of the hole to be able to fit a square object in it.
I wanted to put as many of the parts inside the PCB in order to make the entire unit as thin as possible. The resistor and the cap fits fully inside, and with a correct sized hole for the IC it will only extend 1 mm on each side. With flat top 3mm leds they would also be mostly inside the pcb.
But mostly it's just for fun. To try something new. To boldly build something that haven't been built before! (or at least not too often) :-)
After some hackish dremelling of one of the pcbs I could fit the parts in it. The green color looks horrible, but if I make a new batch of these I think I'll go for black and gold.
if you place the uC upside down, would that make the pcb slimmer?
Hmmm.... Good question. I'll try some different ways and see what's thinnest and also somewhat easy to bend and solder. I might run a small batch of these as kits and I wouldn't want the newbies to have a hard time :)
I love the negative-space battery holder.
The LEDs look great! I also really like the battery!
A++ for trying something different
[quote author="matseng"] The green color looks horrible, but if I make a new batch of these I think I'll go for black and gold.
You could order from Osh Park, and get purple and gold :-)
[quote author="techie"]You could order from Osh Park, and get purple and gold :-)[/quote]
Yea, that's an alternative to try. They are a bit expensive though.
Detected 2 layer board of 1.69x1.97 inches (43x50mm). $16.65 for three.
That's $5.50 each, I can get 50 pcs for $70 from Smart = $1.40 each
Still, $16 is not bad for three prototypes - I really don't need 10 or 50 of them until the prototyping stage is done.
I think I'll put in an order at OSH and see how it turns out.
OSH Park doesn't officially support internal milling.... That is a problem.
Cutouts aren't officially supported, but the fab has been doing them pretty regularly as long as they're drawn on the board outline layer, and are at least 100 mils wide.
Yeah, I need to fix that. Internal milling is now officially supported for all slots 35 mils wide and larger.
I love the battery holder. Where did you get the clips - or did you just bend wire?
It's just a standard paper clip. The part on the top is the outer loop of the clip. The parts on the bottom is just the straight parts of another clip.
Same thing as I did here: viewtopic.php?f=56&t=4750&p=45963&hilit=paperclip#p45940 (http://dangerousprototypes.com/forum/viewtopic.php?f=56&t=4750&p=45963&hilit=paperclip#p45940)
I'm not sure I've seen this somewhere else, but I'd be very surprised if someone else haven't done the same and published on the 'net. :)
Oh, very clever. I'm going to have to use that on my next battery powered board.
This wearable exploited the idea nicely ->