Kicad

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leavesw
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Re: Kicad

Post by leavesw » Sun Feb 26, 2017 5:06 pm

I am playing KiCAD these days - just because AutoDesk increased the price on Eagle - and I do hate it @.@
And I just found that KiCAD can do slot drills and 3D modeling which Eagle cannot for years (esp. slot drills - a real pain)
RogerClark wrote:@racemaniac

I see what you mean about not letting you route anything invalid

Its just the board I'm doing is quite complex and I didnt realise what was going on. Sometimes it let me route tracks and sometimes it didnt

Re: vias without holes

I'll see if I can convert the altium design reference files as they appear to have a PCB where some SMD pads are via'ed though to a middle layer on a 4 layer board, without a separate via

I'm not sure how that is physically / mechanically achieved

Here are screengrabs from a ref design

Red is the top layer , yellow is a mid layer
For the VIA in the middle - Similar to QFN packages, I suppose it is ground and connected to the middle ground plane - for heat dissipation in most cases. (I have those on one of my board as well when using PIC32MX QFN packages). To prevent it from being an open via, you can put solder mask on the bottom side to close it off. I do not think there is extra cost to that - if the vias are standard sizes. (I have not get to that step in KiCAD yet).
If you want to have VIA underneath BGA ball pads (e.g. Xilinx FPGAs) - there is a significant increase in PCB cost I believe.

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RogerClark
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Re: Kicad

Post by RogerClark » Sun Feb 26, 2017 8:52 pm

@leavesw

The last board I made with KiCad had slots and it worked fine.

Size limitation was probably the main reason I dont use Eagle any more. The 10cm x 10cm limit for the basic commercial version is a pain. Albeit the basic commerical version only cost me $100 USD, but next tier version which allows larger boards was $1000 last time I looked, which IMHO is completely overpriced. I would have probably paid $250 or $500 for larger board capability but not $1000, especially as Eagle is never that easy to use, and for many years looked like. piece of shareware.


With the BGA chip, I contacted the manufacturer / PCB company, and I will need to use 4 layers, but will just use traditional vias under the middle of the BGA, because the nRF52840 only has to rows of pads around the perimeter of the device and there is room under it for the necessary vias. The PCB company can do 0.2mm vias, but I will try to avoid going that small and see if I can use 0.3 or 0.4 and stagger

I decided to use 4 layers because routing from the BGA to the 2 rows of DIL pins e.g. like. Blue Pill was a nightmare on 2 layers and also because the board needs good ground planes as it an RF device as its Bluetooth.

The vias will still go through all layers, hence the ground and power layers will not be absolutely continuous, but I dont think its going to impact the RF performance.

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Squonk42
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Re: Kicad

Post by Squonk42 » Sun Feb 26, 2017 9:56 pm

RogerClark wrote:The PCB company can do 0.2mm vias, but I will try to avoid going that small and see if I can use 0.3 or 0.4 and stagger
Yes, a much better approach IMHO: the board house can probably reach 0.2 mm, but you will pay premium for it, you'd better stay with 0.3 mm, this is a standard capability and will cost you less.

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RogerClark
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Re: Kicad

Post by RogerClark » Sun Feb 26, 2017 10:24 pm

Squonk42 wrote:
RogerClark wrote:The PCB company can do 0.2mm vias, but I will try to avoid going that small and see if I can use 0.3 or 0.4 and stagger
Yes, a much better approach IMHO: the board house can probably reach 0.2 mm, but you will pay premium for it, you'd better stay with 0.3 mm, this is a standard capability and will cost you less.
True

I've not had a quote for the PCB yet, but I'm trying to keep it as standard as possible.

Going to 4 layers will cost a bit more, but 4 layers not a new technology so should not be an issue.

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leavesw
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Re: Kicad

Post by leavesw » Mon Feb 27, 2017 2:20 am

RogerClark wrote:@leavesw

The last board I made with KiCad had slots and it worked fine.

Size limitation was probably the main reason I dont use Eagle any more. The 10cm x 10cm limit for the basic commercial version is a pain. Albeit the basic commerical version only cost me $100 USD, but next tier version which allows larger boards was $1000 last time I looked, which IMHO is completely overpriced. I would have probably paid $250 or $500 for larger board capability but not $1000, especially as Eagle is never that easy to use, and for many years looked like. piece of shareware.
I have through hole USB connectors on my board - and the slot drills are really a pain to draw in Eagle - and I also have to put notes in measurement notes when I generate Gerbers... I am still in the process of getting used to KiCAD's library management system and shortcuts @.@.
RogerClark wrote: I've not had a quote for the PCB yet, but I'm trying to keep it as standard as possible.

Going to 4 layers will cost a bit more, but 4 layers not a new technology so should not be an issue.
I think 9 mil drills (0.2mm) are pretty standard - should not be too much an increase - and the breakout of BGA needs narrow wires as well.
The fab I used to make my boards last time supports 8mil drills and 5mil wire in their lowest priced bracket.

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RogerClark
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Re: Kicad

Post by RogerClark » Mon Feb 27, 2017 5:50 am

leavesw wrote: I think 9 mil drills (0.2mm) are pretty standard - should not be too much an increase - and the breakout of BGA needs narrow wires as well.
The fab I used to make my boards last time supports 8mil drills and 5mil wire in their lowest priced bracket.
Thats good to know.. I didnt ask if using 0.2mm vias would cost more, I just asked if it was possible, and as its being made in China they just answer the question and dont tend to give additional details unless I specificity ask ;-)

I don't think track thickness is too much of a problem for most of the BGA if I use vias in the middle of the chip. I can use 0.25 mm tracks for them

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Squonk42
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Re: Kicad

Post by Squonk42 » Mon Feb 27, 2017 6:06 am

leavesw wrote:I think 9 mil drills (0.2mm) are pretty standard - should not be too much an increase - and the breakout of BGA needs narrow wires as well.
The fab I used to make my boards last time supports 8mil drills and 5mil wire in their lowest priced bracket.
Most cheap Chineese "prototype-grade" PCB services are going down to 12mil (0.3mm) drils and 6mil track width / 6mil track spacing only, check SeeedStudio Fusion service, for example:
https://www.seeedstudio.com/fusion_pcb.html

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RogerClark
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Re: Kicad

Post by RogerClark » Mon Feb 27, 2017 10:40 am

I'm actually getting the board assembled in china, as I can't solder these devices, so I have to use whatever PCB house they use.

But I've checked and they are OK at 0.2mm vias

racemaniac
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Re: Kicad

Post by racemaniac » Sun Sep 03, 2017 5:55 am

This week i have been working in KiCad (making new revision of my saber board ^^. hopefully the final one :) ).
And i may be starting to feel the opensource side of KiCad a bit >_<.
I used to work in 4.04, had 4.06 now.
What i'm not so sure about is if anything changed in switching between tools in pbnew, it just felt less smooth than i remembered (i thought pressing escape a few times would completely get me out of the drawing a track tool, but it seems not >_<)
What i am sure about however is that suddenly all my projects defaulted to a solder mask margin of 0.2mm (which is huge on my tiny boards >_<). At first when designing i saw this purple border around my pads that i didn't seem to recall ever having seen before. When rendering i also saw parts of the tracks bare next to the pads, but thought it was maybe a slight rendering inaccuracy. When checking my gerbers i saw the same problem again, and verified my older gerbers, they were not like that >_<.
So after a bit of googling i found that there is a setting for this solder mask margin, and it somehow was 0.2mm now, set it back to 0 as i had it in the past, but that was a bit of a nasty surprise >_<.

I guess that's part of using open source software, it's less consistent in usage, and often a bit less user friendly >_<. The first time i've felt KiCad let me down a bit >_<.

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