Page 52
www.us-
tech.com
August, 2015
Tester Aims for Zero Defects When Manufacturing PCBs
By Peter van den Eijnden, JTAG Technologies, Eindhoven, The Netherlands
(PCBs) are doing absolutely everything in their power to make this happen — knowing full well that they cannot possibly achieve 100 percent zero defects when building PCBs. In quest of the zero-defect PCB manufacturing
Z
goal, JTAG Technologies of Eindhoven has devel- oped a test instrument that can help reduce the chance for “slip” or having defective PCBs sent to a customer. In developing the PCB test solution, JTAG Technologies received a great deal of help from tbp electronics (
www.tbp.nl), a manufacturer of PCB assemblies in Dirksland, The Netherlands. The new test instrument controller checks
PCBs for structural rather than functional defects. It employs boundary-scan techniques for checking PCBs and determines not only whether a PCB is defective, but also where the defect is located.
The average PCB contains around 500 components and about 2500 soldered joints. With this kind of printed circuit board, there is the
risk of 3500 errors. And, with a larger PCB, the error probability can easily be around 10,000...
Boundary-scan approaches support the testing of multilayer PCBs with miniature, densely pack- aged components, such as surface-mount devices and components. This new test controller not only measures digital signals but analog signals as well, enabling PCB manufacturers to take the next step towards virtually error-free assembly. The average PCB contains around 500 compo-
Test system jointly developed by JTAG and Tbp Electronics for mixed-signal testing.
probability can easily be around 10,000 — while just a single error can result in a defective board. Errors can come in many forms, including struc- tural errors, such as the wrong components (improper resistance values, capacitors, etc.), incorrect polarity, missing components, and incor- rect or missing solder joints. PCB manufacturers such as tbp electronics
ero defects for a manufacturer means never delivering a defective product to a customer. Manufacturers of printed circuit boards
nents and about 2500 soldered joints. With this kind of printed circuit board, there is the risk of 3500 errors. And, with a larger PCB, the error
are striving to minimize such structural errors when assembling PCBs. They work with the best component suppliers possible in quest of zero PCB defects and continuously investing heavily in state-of-the-art automated assembly machinery which reduces error probability. Such PCB manufacturers also lead a client’s
engineers in the use of Design for Manufacturing (DfM) so that a PCB can be designed for assembly with the lowest chance of defects. One step further in pursuit of PCBs with zero defects is the use of Design for Testing (DfT), in which testability can be incorporated into the circuit design process.
Systematic Testing There are all kinds of rules for DfM and DfT,
and if you stick to them, you’ll increase the quality of the assembly: the first-pass yield will be higher and, consequently, the risk of introducing errors smaller. But zero errors and 100 percent perfect PCBs? That’s impossible. It’ll never happen. While some errors will inevitably occur, by
employing such practices as DfM and DfT, the PCB defects can be controlled and minimized. Preventing defective PCBs from being sent to a customer can also minimize any negative impact from defective products. If the customer places a board in his product and it doesn’t work, that’s going to cost a lot of time and money. Time spent by the PCB manufacturer testing
every PCB at the end of the production flow, can save the loss of time and money by the customer. And that is the crux: you want to be able to test for assembly and production errors, especially the strength of the soldered joints, using a method that is inexpensive, guarantees the highest possi- ble level of error detection and, if an error is detect-
Continued on page 68
CONNECTED ST COOL &
AY GET SARCON® Thermal Interface Materials and ZEBRA® Setting the Benchmark for Performance and Value. Elastomeric Connectors.
For Technical Data, Samples, Fast Quotes and Engineering Support Visit
www.fujipoly.com or Call 732-969-0100
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76 |
Page 77 |
Page 78 |
Page 79 |
Page 80 |
Page 81 |
Page 82 |
Page 83 |
Page 84 |
Page 85 |
Page 86 |
Page 87 |
Page 88