[Gta04-owner] [Tinkerphones] Status of GTA04A5 production +++ has started +++ video available

tgrauss tgrauss at f-gp.eu
Tue Sep 27 16:08:25 CEST 2016 

The "Solder Paste Dipping" on page 3 is a very interesting chapter. It 
is more related to BGA soldering than PoP.

Best regards

Thierry

On 27/09/2016 16:05, H. Nikolaus Schaller wrote:
> Hi Thierry,
> 
>> Am 27.09.2016 um 15:16 schrieb tgrauss <tgrauss at f-gp.eu>:
>> 
>> Hello,
>> 
>> 
>> 
>> Did you see this paper 
>> http://www.nordson.com/-/media/Files/Nordson/dage/Products/X-ray-Technical-Papers-and-Articles/Semiconductor-Inspection-and-Assembly/POP-paper-SMTA-2009-final.pdf 
>> ?
> 
> Not yet. It is really well written and gives a good overview of the
> challenges and the process.
> 
>> 
>> They are giving other possible soldering failure causes for POP 
>> packages. I hope this will help...
> 
> I have worked through it to find a hint but unfortunately, I did not 
> yet :(
> 
> The issue we have is not really PoP related. We have soldered two
> DM3730 chips without PoP and they show the
> same short circuit pattern in the middle as those with PoP. So it is
> more a "soldering the DM3730" problem.
> 
> We already have checked the whole placement process by X-Ray and
> placement is exact.
> 
> And we have tried placing the DM3730 into solder paste and just
> dipping it into flux. Again no difference.
> 
> Interestingly the paper says that warpage usually leads to open solder
> joints. This is not what we have seen. Not now and also not during the
> GTA04A4 production.
> 
> So I would even conclude that warpage is not the problem. Unless the
> DM3730 is very special with warpage so that it squeezes the BGA balls
> in the innermost ring.
> 
> In addition, I have done a lot of experimentation today by unsoldering
> chips and resoldering manually, trying different things.
> But I never succeeded. I always have short circuits :(
> 
> One thing I can't easily compare and find out is if is an effect
> created by the PCBs. For example the solder mask.
> 
> BR and thanks for this good paper,
> Nikolaus
> 
>> 
>> 
>> 
>> Regards
>> 
>> 
>> 
>> Thierry GRAUSS
>> 
>> 
>> 
>> On 26/09/2016 18:51, H. Nikolaus Schaller wrote:
>> 
>>> Hi all,
>>> today we tried to solder the other side and get working GTA04A5 
>>> board,
>>> but sadly we failed.
>>> 
>>> The boards look optically fine
>>> 
>>> 
>>> 
>>> but DM3730 has short circuits in the middle under the chip :(
>>> 
>>> The production company has recently bought their own X-Ray machine so 
>>> that we can immediately see the problem.
>>> 
>>> 
>>> 
>>> But we don't know the reason.
>>> 
>>> Well, we know this problem exists with all OMAP3 and DM3730 chips and 
>>> it
>>> is warpage during the soldering process. Texas Instruments has 
>>> published
>>> some documents and application notes about this problem, but 
>>> basically they
>>> have no clear solution. Just a recommendation to experiment.
>>> 
>>> We already did fight a while with this during the assembly of GTA04A3 
>>> and
>>> GTA04A4 boards,  but finally using a vapor phase soldering machine 
>>> its was solved.
>>> 
>>> This time we also use a vapor phase machine right from the beginning. 
>>> The
>>> same that was used to produce some of the 600MHz OpenPandora and all 
>>> 1GHz
>>> OpenPandora devices. Which were successfully produced after some 
>>> startup
>>> issues.
>>> 
>>> We simply do not see any obvious reason why it fails so badly this 
>>> time.
>>> 
>>> This needs some time to analyze and make more experiments (but 
>>> ideally
>>> not by wasting expensive and scarce chips and PCBs).
>>> 
>>> So I have to regret that we can't ship the first GTA04A5 boards this 
>>> week
>>> as planned.
>>> 
>>> I will keep you updated as soon as we find out something.
>>> 
>>> BR,
>>> Nikolaus Schaller
>>> 
>>> 
>>>> Am 25.09.2016 um 18:02 schrieb Neil Jerram 
>>>> <neil at ossau.homelinux.net>:
>>>> 
>>>> Thanks for creating that video; previously I had no direct idea of 
>>>> what this kind of production is like.  It's very illuminating to see 
>>>> it.
>>>> 
>>>>     Neil
>>>> 
>>>> 
>>>> On 24/09/16 08:38, H. Nikolaus Schaller wrote:
>>>>> Am 22.09.2016 um 17:31 schrieb H. Nikolaus Schaller 
>>>>> <hns at goldelico.com>:
>>>>> 
>>>>> Hi,
>>>>> we are coming closer...
>>>>> 
>>>>> I had a short meeting to discuss placement of some components 
>>>>> today.
>>>>> For example the position of the two LEDs is not easy to determine 
>>>>> because
>>>>> they are tilted a little.
>>>>> 
>>>>> But the whole GTA04 design is more complex than they thought, so 
>>>>> that
>>>>> they had much more work than planned to program the Siplace system.
>>>>> This was intersting to see.
>>>>> 
>>>>> Basically they have a CAD system where they read in the Gerber 
>>>>> files
>>>>> and overlay Pick&Place positions and component packages. Components
>>>>> can be shifted and rotated manually if needed. This is 
>>>>> automatically
>>>>> replicated for a multiple panel.
>>>>> 
>>>>> I have already seen the boxes with all components. Those are 
>>>>> tempered
>>>>> tonight and tomorrow they do the setup. Depending on how long it 
>>>>> needs,
>>>>> they can start tomorrow. Or Monday latest.
>>>>> 
>>>>> All this means they are again behind schedule. But not much and we 
>>>>> can
>>>>> be happy to have someone who produces so small quantities for us 
>>>>> with
>>>>> such elaborated machinery. And they have already produced many 
>>>>> OpenPandora
>>>>> devices so they know how to solder the PoP chips.
>>>>> 
>>>>> Anyways I will take a camera with me tomorrow so that I can show 
>>>>> some
>>>>> scenes from setting up GTA04 production then.
>>>> Yeah! Here it is:
>>>> 
>>>>  https://youtu.be/8PZOa-789eY
>>>> 
>>>> Everything looks good and the first boards have been populated by 
>>>> chips
>>>> and connectors on the bottom side. This is the side where the 
>>>> display
>>>> will be installed.
>>>> 
>>>> The complex top side with OMAP3, package-on-package RAM+NAND and the
>>>> 3G module will be done on Monday.
>>>> 
>>>> Then we will also x-ray the boards to check if they are soldered 
>>>> properly
>>>> without short circuits - and I will do the first function tests.
>>>> 
>>>> Let's hope that there is no hidden design bug.
>>>> 
>>>> BR,
>>>> Nikolaus
>>>> 
>>>>> It remains thrilling :)
>>>>> 
>>>>> BR,
>>>>> Nikolaus
>>>>> 
>>>>> 
>>>>>> Am 20.09.2016 um 09:04 schrieb H. Nikolaus Schaller 
>>>>>> <hns at goldelico.com>:
>>>>>> 
>>>>>> 
>>>>>>> Am 14.09.2016 um 11:16 schrieb H. Nikolaus Schaller 
>>>>>>> <hns at goldelico.com>:
>>>>>>> 
>>>>>>> Hi,
>>>>>>> "next week" has arrived and it looked good for Friday
>>>>>>> and I just waited for the final confirmation to take
>>>>>>> my handy-cam and make a video of the production run.
>>>>>>> 
>>>>>>> Now I got an info that everything is prepared.
>>>>>>> 
>>>>>>> But it has turned out that the dipping machine for the
>>>>>>> package on package memory chip is defective. It will
>>>>>>> be repaired and is planned to arrive on Monday.
>>>>>>> 
>>>>>>> So production run will be Tuesday or Wednesday.
>>>>>> It is now scheduled for Thursday... We have to wait 2 more days.
>>>>>> 
>>>>>>> Please cross fingers :)
>>>>>>> 
>>>>>>> BR,
>>>>>>> Nikolaus Schaller
>>>>>>> 
>>>>>>> 
>>>>>>>> Am 07.09.2016 um 19:21 schrieb H. Nikolaus Schaller 
>>>>>>>> <hns at goldelico.com>:
>>>>>>>> 
>>>>>>>> Next progress: it looks as if the first 20 units are built 
>>>>>>>> before end of next week.
>>>>>>>> They will notify me and I can go there to make some videos.
>>>>>>>> 
>>>>>>>> BR,
>>>>>>>> Nikolaus
>>>>>>>> 
>>>>>>>>> Am 05.09.2016 um 14:26 schrieb Roland Häder 
>>>>>>>>> <roland at mxchange.org>:
>>>>>>>>> 
>>>>>>>>> Hi,
>>>>>>>>> 
>>>>>>>>> good to hear about the progress. :-)
>>>>>>>>> 
>>>>>>>>> Roland
>>>>>>>>> 
>>>>>>>>> 
>>>>>>>>> H. Nikolaus Schaller – Mon., 5. September 2016 13:49
>>>>>>>>>> Hi,
>>>>>>>>>> production time is coming very close. Last Friday we discussed 
>>>>>>>>>> the final fine-tuning for the
>>>>>>>>>> stencil for printing the solder paste.
>>>>>>>>>> 
>>>>>>>>>> And now I got the confirmation that all components (incl. PCBs 
>>>>>>>>>> and BNO055) now have
>>>>>>>>>> arrived. So I am eagerly awaiting when they have time on their 
>>>>>>>>>> production machines to
>>>>>>>>>> build the first 20 units. I will go there and try to make some 
>>>>>>>>>> videos.
>>>>>>>>>> 
>>>>>>>>>> So you can probably feel my excitement :) And nervousness 
>>>>>>>>>> (because I don't know if
>>>>>>>>>> there is still one catastrophic mistake or bug in the design).
>>>>>>>>>> 
>>>>>>>>>> BR,
>>>>>>>>>> Nikolaus
>>>>>>>>>> 
>>>>>>>>>> Preorders:
>>>>>>>>>> http://shop.goldelico.com/wiki.php?page=GTA04
>>>>>>>>>> http://shop.goldelico.com/wiki.php?page=GTA04%20Complete
>>>>>>>>>> 
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