I used to work at Nordson Corp., and it was there that I ran into two Sherlock-worthy problems:
First, the company had hot-melt glue applicators ranging from units with small tanks (that glue was added to as small pellets or chips), up to a 55-gallon drum in heated-platen units. One of the 55-gallon drum units had an overheating problem.
When the line started, the LED indicators flashed, showing the heating cycle. The temperature display showed the temperature was rising. As the temperature neared the set point, the PID (proportional integral derivative) compensation was supposed to reduce the heat, and the LED flash rate slowed to mimic the change. But the temperature kept increasing until the over-heat tripped.
When this happened, the unit had to be allowed to cool before any testing could be done. The heating was controlled by a triac (triode for alternating current). When the unit cooled, I monitored the triac control voltage and output voltage. Even when the triac control was not on, it was heating, so the triac was shorted.
When I explained to the manager that I would need to replace the triac, he said that there wasn’t a replacement in stock. I checked stock myself, and found a replacement that would work. The triac for the 55-gallon unit was the same triac as was used on the tank-style unit. The two had different Nordson part numbers, but they were the same triac. After I replaced the triac, the over-heat problem was fixed.
Next, I experienced another line snafu. Our company had sealant dispensing units at the General Motors Oshawa Car Plant. There were two units on one line, and one wasn’t working properly. The plant was still in start-up, so the problem was not urgent. Another technician had been working on the unit, but had not been able to fix the problem. I was asked to look into the situation. I asked the technician for the details of all the testing he had done.
He narrowed the problem to a ribbon cable, but when he replaced the cable, it didn’t fix the problem. When I got to the plant, I asked if it would be a problem to shut down the other, working unit. We shut the working unit down, pulled the ribbon cable, and installed it on the non-working unit. That unit powered-up and worked. We then installed the suspect cable in the first unit. That proved the cable was the problem. The replacement cable also happened to be faulty. When available, swap-tronics can be a big help.
This entry was submitted by Glenn Aitchison and edited by Rob Spiegel.
Glenn Aitchison’s first field service job was in 1987. Since then he has worked in robotics, automotive, as well as industrial automation and machinery. He received his Certificates of Qualification as an Industrial Electrician and as an Industrial Mechanic (Millwright).
Tell us your experience in solving a knotty engineering problem. Send stories to Rob Spiegel for Sherlock Ohms.
I have teenagers, too, Nancy, so I know what you mean. One of the problems with counterfeiting in China is there doesn't seem to be any negative consequences. The government in China seems to be a buffer between the counterfeiters and their victims.
You are so right Rob - I face that with my teenagers everyday! We always follow through with consequences because if we don't, they think that they can still get what they want even though they knowingly broke the rules. It's just easier to apply that to your kids than to a whole country!
Nancy, I think part of the problem with counterfeiting is that we tend to do what we get rewarded for. If those doing the counterfeiting are not facing any negative impact, they'll keep doing it.
Oh, I agree Rob. You have to draw a line at some point. There is even an ethical system called ethical egoism which says that selfishness should not be feared but rather embraced as the highest principle of morality. But just because someone subscribes to a certain ethical system, it doesn't mean that it is an acceptable system. Counterfeiting is such a gross violation of standard business practice - and if they expect to participate in the global economy, they should recognize standard business practices...but another issue that is part of our global economy is that we are all coming from different worldviews. It is a challenge to be sure!
Yes, Rob - and when it is an ingrained mindset it is really hard to change. There are so many ethical systems and when doing business with folks who don't subscribe to the same ethical standards - people call foul on one side while the other side is scratching their heads thinking, but we aren't doing anything wrong...
That's an interesting story, Bob. And it certainly illustrates a culture that is far different from the business culture in the U.S. We would replace all of the workers if we could.
Trouble shooting a problem in any complex product isn't always straight forward.
I have had hundreds of product returned because it didn't work like the prior production build lot... Only to find out what was assumed to be the "same"... wasn't. In this case, the customer incorrectly documented the cables required - and fooled themselves during the course of swapping things around, into thinking the only item changing was the interface board we shipped to them. The problem was the cables they built.. and had their end users build (incorrectly) in hundreds of airports across the world!
Simply put.. they thought the only thing they were swapping out was the interface card we were providing. They were certain this was the only thing being done.
It required a third party to discover the real cause (we didn't have examples of "their" bad cables).
Any single level failure is generally easy to fix with swapping out components with known good components.
But if that is your only skill set during trouble shooting, YOU are in trouble.
Your trouble shooting skills are really "put to the test"? ... when fixing a system with 2 or more different failures at the same time. No one component swap out will "fix" the system.
And a variation of this scenario .. swapping components from questionable stock (never assume "new" = good/working)
This issue is not directly related to Nationality or even counterfeit components. I have seen bad "new" components from nearly all countries / companies on occasion. Counterfeit parts (aircraft industry) happen in the USA all the time. And corrupt business leaders happen everywhere. Little value in making sweeping generalizations on the subject.
Having the skill to not to depend on assumptions.. is the real lesson being presented.
Your story reminds me of a recent trip to China where I went to a KFC for dinner. At the completion of my meal, I picked up my tray to discard my trash, and a KFC employee agressively approached me telling me something that I did not understand. My interpreter explained to me that the employee was telling me that I was trying to take her job, and clearing tables was only her responsibility. It is a different culture.
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