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Beginning of the End for SMT Component Markings?

When I started off in electronics, it was the heyday of lead through-hole technology. I used to love all the colors associated with various components, such as the colored bands on the resistors shown below.

It wrote in a September blog post: “When I'm building a circuit, if I have a selection of capacitors (for example) of the required type and the same value but of different shapes, sizes, and colors, then I will select the one that best matches, complements, or contrasts the other components on the board.”

Of course, quite apart from their aesthetic qualities, the colored bands on the resistors served to distinguish their values, tolerances, and so forth. This is particularly useful when you are a hobbyist, because you are constantly hunting for parts in your component treasure chest.

I understand that some people think it's less important in a full-scale manufacturing and production environment in which automatic machines populate the components on the boards. However, I cannot imagine a world in which lead through-hole components were all a drab gray color without any identifying markings to distinguish one from the other. Apart from the blandness of it all, can you conceive how difficult it would be to troubleshoot such a board? All of which leads me to an email I just received from my chum, Rick Curl:

Hi Max, last month I received a bunch of circuit boards that Whitesburg Electronics assembled for me and I was surprised to see that some of the 1206 resistors had no markings on them. We have used Yageo brand resistors (that we purchase through Digi-Key) for several years and have not changed the part numbers that we order. I called Digi-Key about this. They said it was obviously a manufacturing defect and to throw any remaining parts away and they replaced our remaining stock with resistors having proper markings.

Last week I received a new shipment of resistors — about half had no markings. A little searching on the Internet turned up this troubling press release.

I spoke with the people at Digi-Key and this was news to them.

I have always wondered why most surface mount ceramic capacitors were not marked. I would gladly pay double to get capacitors with markings on them. I hope we're not about to see resistors go the same route.

Have you heard anything about other manufacturers removing the markings from surface mount resistors? It really makes it tough to do a proper visual inspection of the board. And what about Yageo's justification for this move? Environmental protection? Sounds like a smoke screen to me. Will IC's be next?

I emailed Curl to ask him about my thought that some people think it's less important to have component markings in a full-scale manufacturing and production environment in which automatic machines populate the components on the boards. He replied:

We are a small company and we have third parties assemble boards for us. Not having markings makes visual inspection very difficult. Troubleshooting bad boards becomes much more difficult because, over time, there may be component value changes, and we will no longer be able to look at a resistor to verify its value.

With regard to Yageo's justification of “environmental protection,” it would be wonderful if manufacturers did such things voluntarily. If I were a more cynical man, however, I might be tempted to think this was more of a cost-cutting exercise.

The strange thing to me is that, as big as Digi-Key is and as many Yageo parts as it carries, it is hard to believe that the company was blindsided by this. The fact that it assumed the unmarked parts were defective speaks volume. It's also interesting that Yageo didn't modify the part number when it made this change. And another strange thing is that the specification sheet for these parts on Yageo's website still indicates that they are marked. If a bunch of Yageo customers expressed their concern, it might be possible to nip this in the bud. What do you think about the idea of unmarked surface mount parts?

This article was originally published on EBN's sister publication EE Times .

16 comments on “Beginning of the End for SMT Component Markings?

  1. prabhakar_deosthali
    March 5, 2014

    Since I am also from the older electronics generation, I fully oppose any move to remove component markings.

    The memories of the days when we leant that

    BB ROY G REAT B RITON V ERY G OOD W IFE

    to remember the color codes of the resistors ( Black, Brown, Red, Orange, Yellow, Gray, Blue, Violet, White) are still freash in the minds of that older generation engineers.

    Visual inspection of an assembled board is the first step in the quality control.  Also the component markings are a huge help when troubleshooting /repairing a board received from the field or even a new prototype.

    If not in the manufactruing, then can it be done by those automated Assembly machines – they can actually measure and print those markings on the components on the go.

  2. Hailey Lynne McKeefry
    March 5, 2014

    @Prabhakar, you brought back memories! Clearly the human eye is a big part of spotting issues. On an unrelated but similar vein, i've heard that some libraries are doing away with the Dewey decimal system–beloved by many including me. It seems like change is often seen as a must have as a way of moving forward.

  3. Daniel
    March 5, 2014

    “”When I'm building a circuit, if I have a selection of capacitors (for example) of the required type and the same value but of different shapes, sizes, and colors, then I will select the one that best matches, complements, or contrasts the other components on the board.””

    Max, the artistic way of arranging components on PCB is designers/soldering persons skill. I think other than resistors; all other components can be possible with different colors and sizes.  Resistors have a fixed colors and its values are measured based on colors and counting rings.

  4. Daniel
    March 5, 2014

    “The memories of the days when we leant that BB ROY G REAT B RITON V ERY G OOD W IFE.  To remember the color codes of the resistors ( Black, Brown, Red, Orange, Yellow, Gray, Blue, Violet, White) are still fresh in the minds of that older generation engineers.”

    Prabhakar, I think still that code is relevant. Other than soft coding with embedded and VLSI design, physical components are using in PCBs and values are measured by old conventional method.

  5. SP
    March 7, 2014

    Quite surprising. How the quality check department of Digikey would have allowed these resistors or capacitors to go to the customer end.No wonder counterfeit is such a big industry globally.

  6. FLYINGSCOT
    March 7, 2014

    In the modern world of automation it should be possible to hav no markings on components.  It will only be an issue when there is a problem to solve and the component needs to be visually verified.

  7. SP
    March 8, 2014

    Practically there is always a problem on the board when youa re trying to bring up the board. Markings are the must.

  8. _hm
    March 9, 2014

    Now, I need to use many of 0402 and 0201 in new design. These parts or so small, it is little difficult for me to see them.

    I suggest some alternate method of identification. Like RF tag as suggested in some other blog.

     

  9. Daniel
    March 10, 2014

    “Quite surprising. How the quality check department of Digikey would have allowed these resistors or capacitors to go to the customer end. No wonder counterfeit is such a big industry globally.”

    SP, in certain cases counterfeit components are at par or more in quality than original components. W e cannot say such components are counterfeit because they can be substitute for the originals.

  10. Wale Bakare
    March 10, 2014

    >>It will only be an issue when there is a problem to solve and the component needs to be visually verified<<

    That states the importance of color markings of the component. Unless there is a unique means of identification better than that, i dont think it should be unmarked for now. Any modern identification in offing?

  11. Wale Bakare
    March 10, 2014

    I can hardly disagree with you on that but I think some if not majority are counterfeit components because they are of less quality and risky.

  12. t.alex
    March 11, 2014

    Having been through the troubleshooting phases of product development, I would say without component markings may lead to doubling development time! And it can be catastrophic at times.

  13. Hailey Lynne McKeefry
    March 11, 2014

    @Flyingscott, it would be interesting to figure out, based on how often problems occur, how long it takes to solve if the problems are marked and unmarked and how much is saved by not marking, whether it's a real savings to go without.

  14. ahdand
    March 12, 2014

    @hailey: Yes what matters is the time frame of errors. If it's a constant issue that happens from time to time on a regular basis then it's a big issue indeed. After identifying the error rate the solution can be planned properly. 

  15. ahdand
    March 13, 2014

    @Hailey: Also it is important to find out the response time as well. Errors do occur but if we cannot provide a solution in quick time then the service is poor. If the response time is good then the users will not feel the issues in a big manner. 

  16. Daniel
    March 16, 2014

    “I can hardly disagree with you on that but I think some if not majority are counterfeit components because they are of less quality and risky”

    Wale, still I didn't get what is counterfeit components. All components have their own identity, some with high quality and other with medium or low quality; which can satisfy all level of components. So customers have the choice to select all type of components based on their application requirements and thickness of wallet.

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