EEZ Bench Box 3 - Sequel to EEZ H24005

[prasimix]

Unlike last update this time I have so much to say. However for today I will limit myself to the following: MCU and DCM220 modules arrived last week, and I tested them all. So all that remains is to get the DCP405 modules. The last promise is that they will be finished last Friday or Saturday but yesterday I found out that the promise was broken once again. The last info that I got is that the delivery from a third party to which the DCP405 is supposedly outsourced is 4 days late. I don’t know since when that counts: since yesterday or since last Friday.

Until my next post which will not be later than next Tuesday when I will have to make certain decisions, I would like to hear from you what are the standard and acceptable failure rates for PCBA service. I assume that manufacturing errors can be roughly divided into two categories: a) errors that could be easily detected by simple visual inspection or mechanical tests and b) those that can be detected only when the power is turned on and test procedures are started.

Thank you all for your patience, understanding and support!

[danielbriggs]

Thanks for the update Denis.
(For my order at least)... take your time, and do not stress about any delays, we know you are doing quality work on a great project so all is well.

I can’t comment about PCBA, but about 70% of the last 35-40 courier delivered I’ve placed at work over the last month have been delayed or severely delayed.

[prasimix]

Yes, but one thing is delay, and another is quality of what is delivered (with or without delay). That's why I would like to hear from you which PCBA service failure rate can be considered acceptable or not. Of course, I will do my best that everything that will be delivered is free of errors.

[Andrew McNamara]

Yes, but one thing is delay, and another is quality of what is delivered (with or without delay). That's why I would like to hear from you which PCBA service failure rate can be considered acceptable or not. Of course, I will do my best that everything that will be delivered is free of errors.

What's the nature of the failures? Bad PCB, incorrectly loaded components, soldering failures, bad components, or? If you supplied them with a test jig, I would say 100% pass is reasonable... 

Are they doing flying probe testing? Are they "owning" the problems or claiming it's out of their control?

[prasimix]

What's the nature of the failures? Bad PCB, incorrectly loaded components, soldering failures, bad components, or? If you supplied them with a test jig, I would say 100% pass is reasonable... 

Are they doing flying probe testing? Are they "owning" the problems or claiming it's out of their control?

You’ve already guessed a few issues like incorrectly loaded components and soldering failures. Additionally, we have missed components, damaged components that were soldered by hand, and badly soldered component (e.g. not positioned under right angle).

Our agreement was that due to the initial delay back in February, that they only needed to deliver the correctly soldered components, and that I will take care of the functional testing. So the question is what is the acceptable failure rate for things that could be easily visually and mechanically checked before sending. For example: The SD card holder could be mechanically tested in a few seconds by inserting and removing an SD card. It does not require any special knowledge and equipment. Another example: the PCB is missing an IC or the IC is rotated, which is again very easy to detect by taking just one look.

[jbb]

Where I work we get board populated and Optically Inspected by contract manufacturers and do our own electrical testing in house.

The incidence of mangled connectors or missing medium to large components should be well under 5%.  But every now and again you might get a bad batch issue (wrong part reel, swapped part, wrong way around, connectors damaged in reflow oven etc.)

[prasimix]

Thanks, what is the agreement with the manufacturer for boards that have not passed electrical/functional testing? Do you send them back for corrections?

[jbb]

Hmm, not sure on the details of that part of the ageeement. I believe we diagnose them and send them back to the CM for rework. Not sure if that’s included or extra cost.

[Berni]

We return boards with assembly mistakes back to the assembly house for them to fix by hand. Its there fault for the mistake anyway. To aid in finding the mistakes they are marked with red dot stickers.

But you can't so easily return boards that look fine but don't work for some reason. They won't be able to magicaly find the fault to be able to fix it. But you can aid the assembly house by providing a test jig. So if they have a magical device that can be plugged into the board and 3 seconds later a green light comes on then they can pull out all the bad boards. They get put trough extra closer inspection and they will fix the mistakes themselves rather than you having to send things back. Tho if the testing is slow or involves a lot of work you will likely get charged for it appropriately in the price.

We don't tend to make test jigs due to the small volumes, also we tend to just fix easy mistakes ourselves. If you find a missing or damaged resistor its easier to just grab a soldering iron and stick a new one on rather than documenting the fault and sending it back to have it fixed.

As for the yield it depends a lot on the board. If its a simple board with 50 large SMD components you might get >99% yield. If you have a complex board with 1000s components, tiny 0201 capacitors it might be >90%. if you badly screw up the pad size or paste mask on a component the yield might suddenly be 20%

[prasimix]

Thanks once again to everyone for their inputs on the PCBA failure rate. Now I have a better picture of what to expect. I was surprised by the number of errors that could have been avoided by a simple visual inspection. Anyway, there is nothing that cannot be solved.

Everything is ready in warehouse and waiting for DCP405 modules, and I still waiting for new estimate. Today I got a few pictures with the THT components prepared for production.

Firmware v1.0 was released yesterday which has already been downloaded to all MCU modules (except those that need to be fixed).
This release also includes the SCPI reference guide, a PDF version of which can be downloaded at the bottom of this page.

[Andrew McNamara]

CS instructed me to send everything to Mouser when it was ready for delivery. Mouser took over CS a couple of years ago, and now is Mouser in charge of logistics. I've talked with DHL Air Cargo. I do not know what to expect from sea freight, that could take quite a while. I'm in touch with CS and we need to discuss possible alternatives.

It was many years ago now, and my memory is hazy, but we always used to arrange international shipping through a freight/customs expediter, rather than dealing with the details ourselves. Didn't entirely eliminate hold-ups with customs, but certainly helped (I know that's not your problem... yet). I wonder if someone like that can help your shipping woes?

[prasimix]

CS instructed me to send everything to Mouser when it was ready for delivery. Mouser took over CS a couple of years ago, and now is Mouser in charge of logistics. I've talked with DHL Air Cargo. I do not know what to expect from sea freight, that could take quite a while. I'm in touch with CS and we need to discuss possible alternatives.

It was many years ago now, and my memory is hazy, but we always used to arrange international shipping through a freight/customs expediter, rather than dealing with the details ourselves. Didn't entirely eliminate hold-ups with customs, but certainly helped (I know that's not your problem... yet). I wonder if someone like that can help your shipping woes?

That's right. I am in contact with DHL Air Cargo and one freight expediter who should arrange the shipment.

[prasimix]

I wish I could say more today, apart from quoting a portion of the email from Wednesday last week that I received from a PCBA provider:

In order not to delay, we can split the shipment and send in batches, so that you can have ready sets of modules for assembly of devices as soon as possible. I would like the packages to take place next week. Because DCP405 have small SMD components - each piece will be checked additionally by automatic inspection (pattern recognition) so that problems from previous batches do not recur.

I'm sorry that the situation seems to be out of control and that I am currently at the mercy of a PCBA provider who, I believe, will contact me this week. BTW, I don't know what "small SMD components" means to them. The DCP405 module is not significantly different from, say, a DCM or MCU module.

[danielbriggs]

Just out of interest: what's the smallest components on there? 0402?
Any crazy small pitch QFP's?

[prasimix]

All passives are 0805 with exception of 100nF for decoupling and few ferrite beads that are 0603.
The smallest IC can be found on the MCU module, not DCP405.

[exe]

They might be just looking for a plausible excuse for delays. I wouldn't take their words too seriously. I read it as "we screwed deadlines, but we think we are on a right track". But don't take my words too serious too. Better ask them if details are important, or there is a way to help them with quality.

[danielbriggs]

Their P&P's should have no problem with that. Even my fingers can throw those components on quickly and accurately.

I think ^exe is correct; some kind of weak excuse.

Notwithstanding, thanks so much for your efforts on this, even if you feel they are frustrating, I love your continued updates on all this. Never seen a project quite like it with so much atttention to detail and transparency. Good effort! 

[prasimix]

Another week has passed and I still have not the slightest idea what is going on with the production of the DCP405 module. All I got was a promise that the contact person would contact me.

[prasimix]

Finally good news, I got these pictures recently...

[Andrew McNamara]

Finally good news, I got these pictures recently...

Whew! I expected something more like...



 

[AlanS]

Finally good news, I got these pictures recently...

Whew! I expected something more like...

(Attachment Link)

 

Well @AndrewMcNamara, I've had my laugh for the day. Time to change my soiled underwear. 

[AlanS]

Finally good news, I got these pictures recently...

3 boards per panel, 20 panels counted and they're part of a batch. All good news.

[prasimix]

As time goes on I feel more and more like a fraud . I truly believe that this will soon come to an end and that I will finally be able to deliver what was promised a long time ago.
The update for this week is plain simple: I still don't have any information when the DCP405 modules will be ready for shipping, not even partially.

[danielbriggs]

It's ok! Do not worry.

They are obviously doing something from your pictures, just a lot slower than you would like. I do not mind waiting. 

[mcdanlj]

I agree with @danielbriggs, we're all waiting extra time for things right now, and you're being super transparent about the whole process. I'll say it again, i was sad when the H24005 went out of production and a big reason I bought in on the BB3 was having reason to hope that we would see it, and its modules, stay in production, and that new modules would come out. I'd love to see 2Q and 4Q modules become available, for instance. Don't break that by spending extra to work around one problem now. Focus on a healthy BB3 ecosystem for the long term!

Don't feel like you have to make huge apologies there for our current global situation, we get it. Just keep the transparency going, and thanks for the frequent updates here!