---------- Forwarded message --------- From: Luke Kenneth Casson Leighton lkcl@lkcl.net Date: Wed, Jul 3, 2019 at 8:16 AM Subject: [eoma68 update] report back from factory on HDMI
Mike's staff began the PCB assembly of the run of 100, and had to stop at 36. 20 were ok: 16 of them, the HDMI connector refused to fit. The reason: the CNC machining on the edge of the PCB has not been done accurately enough: it's simply too ragged. The staff did some experimentation, cleaning up some of the edges in the cut-out with an xacto-knife: this did the trick, even though it is shaving something like 0.01mm off the ragged edge of the PCB.
The left and right edges do not matter too much, however where the HDMI connector comes in close, it definitely does. Mike is going to talk to the PCB factory to see if there is anything that they can do in future, however with 1,000 PCBs already manufactured, the safest thing to do is probably to *hand-trim* that PCB edge, removing the burrs, on all 1,000 PCBs.
Again, to reiterate, because I am still seeing evidence of "complaints" out there, from people who believe this should be easy: these are absolutely ridiculously tiny components and tolerances, and the budget on which it's being done is equally as frugal. 0.05mm on the edge of a PCB. 0.2 mm wide pins, with 0.2mm clearance between them. A "normal" Single-Board Computer product from any other well-funded Corporation would use large (Type A) HDMI, top-mounted, with plenty of tolerances and no need for the PCB edge to be accurately milled.
Again, to reiterate: we do not know what will need to be solved next. Therefore, a production date simply cannot be provided, and that really is the end of the matter. Or, the answer is: the production date is "the production time plus the unknown time to solve unknown and unknowable future issues".
Mike is sending me the 20 "good" PCBs so that I can test them here, to see if they are okay. The staff will continue with the rest by shaving the burrs on the PCB on every single one of the remaining 80 with an xacto-knife, before putting them through the production line. It is looking like I will need to do the testing of all 100 of this preliminary production run, here, at my home, in Taiwan.
arr no, poor you and poor them... These things are never easy... and i thought it was hard enough manually putting audio power amplifier boards and bits into a box, with a compact fit... I make lots of little mistakes. lots of using a knife to trim a hole... ;)
My thanks to the staff, mike and you.
On 07/03/2019 04:03 AM, Luke Kenneth Casson Leighton wrote:
---------- Forwarded message --------- From: Luke Kenneth Casson Leighton lkcl@lkcl.net Date: Wed, Jul 3, 2019 at 8:16 AM Subject: [eoma68 update] report back from factory on HDMI
Mike's staff began the PCB assembly of the run of 100, and had to stop at 36. 20 were ok: 16 of them, the HDMI connector refused to fit. The reason: the CNC machining on the edge of the PCB has not been done accurately enough: it's simply too ragged. The staff did some experimentation, cleaning up some of the edges in the cut-out with an xacto-knife: this did the trick, even though it is shaving something like 0.01mm off the ragged edge of the PCB.
The left and right edges do not matter too much, however where the HDMI connector comes in close, it definitely does. Mike is going to talk to the PCB factory to see if there is anything that they can do in future, however with 1,000 PCBs already manufactured, the safest thing to do is probably to *hand-trim* that PCB edge, removing the burrs, on all 1,000 PCBs.
Again, to reiterate, because I am still seeing evidence of "complaints" out there, from people who believe this should be easy: these are absolutely ridiculously tiny components and tolerances, and the budget on which it's being done is equally as frugal. 0.05mm on the edge of a PCB. 0.2 mm wide pins, with 0.2mm clearance between them. A "normal" Single-Board Computer product from any other well-funded Corporation would use large (Type A) HDMI, top-mounted, with plenty of tolerances and no need for the PCB edge to be accurately milled.
Again, to reiterate: we do not know what will need to be solved next. Therefore, a production date simply cannot be provided, and that really is the end of the matter. Or, the answer is: the production date is "the production time plus the unknown time to solve unknown and unknowable future issues".
Mike is sending me the 20 "good" PCBs so that I can test them here, to see if they are okay. The staff will continue with the rest by shaving the burrs on the PCB on every single one of the remaining 80 with an xacto-knife, before putting them through the production line. It is looking like I will need to do the testing of all 100 of this preliminary production run, here, at my home, in Taiwan.
It does sound complicated, I wish you the best on this. My hope is that you will find the correct balance and succeed Luke.
When it ships successfully, let us all know with some big bold letters email title please. :)
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Again, to reiterate, because I am still seeing evidence of "complaints" out there, from people who believe this should be easy: these are absolutely ridiculously tiny components and tolerances, and the budget on which it's being done is equally as frugal. 0.05mm on the edge of a PCB. 0.2 mm wide pins, with 0.2mm clearance between them. A "normal" Single-Board Computer product from any other well-funded Corporation would use large (Type A) HDMI, top-mounted, with plenty of tolerances and no need for the PCB edge to be accurately milled.
Again, to reiterate: we do not know what will need to be solved next. Therefore, a production date simply cannot be provided, and that really is the end of the matter. Or, the answer is: the production date is "the production time plus the unknown time to solve unknown and unknowable future issues".
Mike is sending me the 20 "good" PCBs so that I can test them here, to see if they are okay. The staff will continue with the rest by shaving the burrs on the PCB on every single one of the remaining 80 with an xacto-knife, before putting them through the production line. It is looking like I will need to do the testing of all 100 of this preliminary production run, here, at my home, in Taiwan.
It does sound complicated, I wish you the best on this. My hope is that you will find the correct balance and succeed Luke.
When it ships successfully, let us all know with some big bold letters email title please. :)
Actually... I just realized I didn't trim it enough, my bad. :(
On Wednesday 3. July 2019 09.03.44 Luke Kenneth Casson Leighton wrote:
Mike's staff began the PCB assembly of the run of 100, and had to stop at 36. 20 were ok: 16 of them, the HDMI connector refused to fit. The reason: the CNC machining on the edge of the PCB has not been done accurately enough: it's simply too ragged. The staff did some experimentation, cleaning up some of the edges in the cut-out with an xacto-knife: this did the trick, even though it is shaving something like 0.01mm off the ragged edge of the PCB.
I can imagine how frustrating this can be, but it is good that some experimentation on the spot was able to identify the likely cause.
(My own limited experience with PCBs, albeit with "maker"-level producers, suggests that some PCB cutting/milling is not done as accurately or in as tidy a way as one might expect. There have also been some other interesting experiences with production quality with some producers, but that is another story.)
The left and right edges do not matter too much, however where the HDMI connector comes in close, it definitely does. Mike is going to talk to the PCB factory to see if there is anything that they can do in future, however with 1,000 PCBs already manufactured, the safest thing to do is probably to *hand-trim* that PCB edge, removing the burrs, on all 1,000 PCBs.
It is too bad that this adds another step to the process, but it at least hopefully remedies the issue. I guess it shows that minor faults can become more serious problems further down the chain of production.
Again, to reiterate, because I am still seeing evidence of "complaints" out there, from people who believe this should be easy: these are absolutely ridiculously tiny components and tolerances, and the budget on which it's being done is equally as frugal. 0.05mm on the edge of a PCB. 0.2 mm wide pins, with 0.2mm clearance between them.
Having seen the measurements related to various parts, I can more easily believe how challenging it is. And it seems intimidating when considering the demands of production to such levels of accuracy.
A "normal" Single-Board Computer product from any other well-funded Corporation would use large (Type A) HDMI, top-mounted, with plenty of tolerances and no need for the PCB edge to be accurately milled.
Yes, it seems that the larger but less ambitious players get off easy again.
Again, to reiterate: we do not know what will need to be solved next. Therefore, a production date simply cannot be provided, and that really is the end of the matter. Or, the answer is: the production date is "the production time plus the unknown time to solve unknown and unknowable future issues".
Well, I hope that you, Mike and his employees feel that valuable experience is being gained that will pay off in future. It would certainly be nicer if everything went more smoothly, but one might then wonder which potential problems are being missed.
Mike is sending me the 20 "good" PCBs so that I can test them here, to see if they are okay. The staff will continue with the rest by shaving the burrs on the PCB on every single one of the remaining 80 with an xacto-knife, before putting them through the production line. It is looking like I will need to do the testing of all 100 of this preliminary production run, here, at my home, in Taiwan.
And I hope that the rest of the run and the testing go a bit better than how things have gone so far. Keep up the good work!
Paul
Luke Kenneth Casson Leighton wrote:
Again, to reiterate, because I am still seeing evidence of "complaints" out there, from people who believe this should be easy:
Thanks, as always, for the updates. If we can somehow help, please do let us know.
I do not envy you having to deal with the perversity of matter. One of the niceties of working in software. I don't have to worry if two lines of code are too close together and will cause problems to assemble.
Thanks again.
@ Luke -- as the old Latin phrase goes -- *festina lente*. Proceed with haste, but slowly ;)
Also, things rarely, if ever, turn out the way one initially expects. This is obviously one of the more 'scenic route' examples of that... but it is nonetheless quite understandable.
Carry on!
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On Wed, 3 Jul 2019 09:03:44 +0100 Luke Kenneth Casson Leighton lkcl@lkcl.net wrote:
---------- Forwarded message --------- From: Luke Kenneth Casson Leighton lkcl@lkcl.net Date: Wed, Jul 3, 2019 at 8:16 AM Subject: [eoma68 update] report back from factory on HDMI
Mike's staff began the PCB assembly of the run of 100, and had to stop at 36. 20 were ok: 16 of them, the HDMI connector refused to fit. The reason: the CNC machining on the edge of the PCB has not been done accurately enough: it's simply too ragged. The staff did some experimentation, cleaning up some of the edges in the cut-out with an xacto-knife: this did the trick, even though it is shaving something like 0.01mm off the ragged edge of the PCB.
The left and right edges do not matter too much, however where the HDMI connector comes in close, it definitely does. Mike is going to talk to the PCB factory to see if there is anything that they can do in future, however with 1,000 PCBs already manufactured, the safest thing to do is probably to *hand-trim* that PCB edge, removing the burrs, on all 1,000 PCBs.
Again, to reiterate, because I am still seeing evidence of "complaints" out there, from people who believe this should be easy: these are absolutely ridiculously tiny components and tolerances, and the budget on which it's being done is equally as frugal. 0.05mm on the edge of a PCB. 0.2 mm wide pins, with 0.2mm clearance between them. A "normal" Single-Board Computer product from any other well-funded Corporation would use large (Type A) HDMI, top-mounted, with plenty of tolerances and no need for the PCB edge to be accurately milled.
Again, to reiterate: we do not know what will need to be solved next. Therefore, a production date simply cannot be provided, and that really is the end of the matter. Or, the answer is: the production date is "the production time plus the unknown time to solve unknown and unknowable future issues".
Mike is sending me the 20 "good" PCBs so that I can test them here, to see if they are okay. The staff will continue with the rest by shaving the burrs on the PCB on every single one of the remaining 80 with an xacto-knife, before putting them through the production line. It is looking like I will need to do the testing of all 100 of this preliminary production run, here, at my home, in Taiwan.
Maybe you should be focusing on FLOSS PCB tooling instead of Laptops. (-; More seriously, from my experience it seems as though a lot of the "professional" tools have major design problems. As though the engineers gave up halfway through at the "test it in the real world" phase.
Sincerely, David
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