Production PCB And Pogo Pins Produce A Clever Test Jig

[Hans Summers] runs a site qrp-labs.com, selling self-assembly kits mostly for radio gear and GPS applications, and had some production problems with his QCX+ 5W QRP transceiver kit. They were using an assembly house that had some problems with a sub-contractor going under during the pandemic, and the replacement service was somewhat below the expected level of quality, resulting in a significant number of SMT populated boards coming out non-functional. Obviously, not wanting to pass these on to customers as a debug problem, they set to work on an in-house QA test jig, to give them the confidence to ship kits again. The resulting functional test jig, (video, embedded below) takes a fairly interesting approach. Skip the video to 9:00 for the description of the test jig and detailed test descriptions.

By taking an existing known-good PCB, stripping off all the SMT parts, and moving the through hole components to the rear PCB side, pogo pins could be soldered to strategic locations. Building the assembly into a rudimentary enclosure made from sawn-up raw copper clad board, with the pogos facing upwards, and a simple clamp on top, allowed the PCB-under-test (let's call it the UUT from hereon) to be located and clamped in place. This compressed the pogos in order to make a firm electrical contact. A piece of MDF that had been attacked with a dremel did duty as a pressure plate, with cutouts around the SMT component areas to achieve the required uniform board pressure and keeping the force away from the delicate soldered parts. All this means that with an UUT connected via pogo pins to a through-hole only test PCB, the full circuit would be completed, if and only if the UUT was completely functional, and that means defect-free soldering and defect-free components.

Next the firmware was rewritten to do duty as the test controller, which when powered up would step through a sequence of test scenarios and measurements, logging the results to an OLED display and a serial interface. This rig survived 1,000 SMT tests without failing, giving [Hans] the confidence to ship out new kits and providing a database of datalog results as a backup should a customer have an issue during final assembly. All-in-all a smart idea to solve a difficult problem, with nary a custom test jig PCB in sight!

These pages have been graced with many a pogo-based test rig over the years. Here's one to start, and if you've got a handy laser cutter and some scrap wood, making an accurate test rig is no bother either.

Thanks [Paul] for the tip!

#hardware #toolhacks #ate #pogopin #testjig

How the Flipper Zero Hacker Multitool Gets Made and Tested

Flipper Zero is an open-source multitool for hackers, and [Pavel] recently shared details on what goes into the production and testing of these devices. Each unit contains four separate PCBs, and in high-volume production it is inevitable that some boards are faulty in some way. Not all faults are identical -- some are not even obvious -- but they all must be dealt with before they end up in a finished product.

One of several custom test jigs for Flipper Zero. Faults in high volume production are inevitable, and detecting them early is best.

Designing a process to effectively detect and deal with faults is a serious undertaking, one the Flipper Zero team addressed by designing a separate test station for each of the separate PCBs, allowing detection of defects as early as possible. Each board gets fitted into a custom test jig, then is subjected to an automated barrage of tests to ensure everything is as expected before being given the green light. A final test station gives a check to completed assemblies, and every test is logged into a database.

It may seem tempting to skip testing the individual boards and instead just do a single comprehensive test on finished units, but when dealing with production errors, it's important to detect issues as early in the workflow as possible. The later a problem is detected, the more difficult and expensive it is to address. The worst possible outcome is to put a defective unit into a customer's hands, where a issue is found only after all of the time and cost of assembly and shipping has already been spent. Another reason to detect issues early is that some faults become more difficult to address the later they are discovered. For example, a dim LED or poor antenna performance is much harder to troubleshoot when detected in a completely assembled unit, because the fault could be anywhere.

[Pavel] provides plenty of pictures and details about the production of Flipper Zero, and it's nice to see how the project is progressing since its hyper-successful crowdfunding campaign.

#crowdfunding #hardware #wirelesshacks #crowdfunded #flipperzero #multitool #pogopins #production #testjig #testing

Manufacturing Test Fixture for bike lights? Teardown and Quick Look

https://diode.zone/videos/watch/e384afb6-f1f6-463b-8bba-62ee7e029f20