In this story, my own products were made by monkeys. My company had a great staff that assembled the radio receivers that we sold. Staff members were able to follow instructions and use their initiative when something unexpected arose. Sometimes, however, the instructions did not reach everyone.
Our top-quality radio used an oak cabinet. Inside the cabinet we mounted a four-inch speaker. The inside of the cabinet was just slightly larger than the speaker, typically by 1/8 inch. The speaker could be dropped into place and then held with four wood screws. Because wood is not as precise as metal, occasionally the inside of the cabinet was smaller than the frame of the speaker. I had instructed the staff to bring these few cabinets to my attention. Since I had more physical strength than anybody on my staff, I took a sharp knife and cut the inside of the cabinet so that the speaker would fit, and then they mounted the speaker in the normal fashion.
One day, someone from the office was helping to mount the speakers. She was not told about those cases where the speaker would not fit. Instead of giving the cabinets to me, she bent the frame of the speaker so that it would fit. Needless to say, the cone was distorted and I considered the speaker destroyed. I checked and found another cabinet with a bent speaker and had it replaced. A month later, a new radio was returned with the complaint of excessive distortion. To my dismay, the speaker had been bent to fit the cabinet.
Our speakers were made in China and supplied by a local distributor. Once, when our supplier was out of stock, we bought a shipment of very high quality speakers from another source at a good price. The magnets were heavy and the speakers sounded great. We installed them into the cabinets and sold the radios.
A few months after shipping, some of the radios were returned marked “no sound.” Upon examination, we discovered that the magnet had fallen off, probably because the radio was dropped. Then it would grab the frame, which was made of steel. In other radios the speaker appeared normal, but with a sharp pull, the magnet could be removed. There was no sound because the voice coil was pinched between the magnet and the frame.
It seems that the magnet was glued to the frame, carefully centered so that the voice coil could move freely through the steel projection from the center of the magnet. When the glue aged, it lost its strength and the magnet either fell from the frame, or moved sufficiently to pinch the voice coil.
The speaker was well designed and carefully built, but somebody substituted cheap glue that didn’t have the strength to hold the magnet. Or perhaps the glue was not properly applied. Clearly, monkey business!
This entry was submitted by Frank Karkota and edited by Rob Spiegel.
Tell us your experiences with Monkey-designed products. Send stories to Rob Spiegel for Made by Monkeys.
The choice of a poor quality glue is as much a design flaw as any other. Of course, a much better design would have included a shape detail that would hold the magnet in the correct position. And some speakers haveincluded a sheetmetal stamping that serves no purpose except to assure that the magnet stays in the correct position.
The fact is that delivering top quality usually means providing more than only just enough to meet the specifications. I am fully aware that there are those that will challenge this concept, and claim that just barely meeting specifications is all that it takes, but those folks only know about maximizing profit and probably are unaware of what actual high quality consists of.
One of the hardest parts of manufacturing is quality control, especially for a small company. As noted, the cabinets were made of oak. The saw mills do not have tight quality control and thus occassionally wood is slightly thicker. This was too rare to make a fuss and took only minutes to correct. Occassionally mistakes are made and must be corrected.
Regarding the speakers, they appeared to be very high quality. The problem could have been poor glue, or improper application. It could also have been too cold when the speakers were made. Or maybe the manufacturer was just sloppy.
Getting good parts is not as easy as it seems. A number of years ago, I bought 10,000 capacitors from a highly reputable US manufacturer. They were used for general bypass and coupling. After six months of use, they started leaking (internal resistance dropped) and the commercial receivers started failing to the point where the system failed. It was expensive to recall and replace perhaps 5000 capacitors. I have never had that happen with Chinese parts.
Regarding documentation, with a staff of four employees, we did not have time to document everything, especially if it was a rare occurance, such as cabinets out of tolerance. Nobody is perfect!!!
Get the dimension of the speakers, both mean and standard deviation, and makes sure that the inside dimension of the cabinet is at least mean + 3 sigma. This will fix the root cause of the problem.
Frank, when you had the problem with the capacitors did you investigate to determine whether the capacitors were counterfeit? This sounds like a classic counterfeit problem.
This was back in the mid 1990s and I got the capacitors directly from the manufacturer--no middleman. Of course, they might have outsourced the parts. It was one of the most reputable makers of capacitors in the world. You just can't tell!
I have never had that problem with Chinese made capacitors. The company is still in business, so what happened to me must have been an aborration, a very costly aboration.
Thanks Frank. Counterfeit parts can come through reputable dealers or suppliers when the accept returns. Also, I would guess the legitimate parts made in China would be fine. So the problems I hear about are not from all Chinese parts, just the counterfeit parts.
Hi Cadman-LT. Yes, counterfeiting is widespread. It takes a wide range of forms. In some cases, a factory that is making components for a U.S.-based company during the day shift will run a nightshift where they make the same components to sell as counterfeits. So the parts are good, but they've stolen the IP from their customer.
It seems obvious in hindsight that the reason for the really good price on the speakers was that they had a hidden flaw, which was discovered after the horse had left the barn.
If it seems too good to be true, it usually is.
Buyer beware etc. etc.
Q.C. and testing on a limited budget are hit and miss when you don't know what you're looking for. I'm sure in the future, any speakers will be tested for magnet retention.
Why do the counterfeit on the night shift? Daylight is good, too. Our former CEO once worked for a company which outsourced production to a nameless country (whose national flag is mostly red in color), and on a visit to the factory they discovered that alongside parts being produced with the company logo, identical parts were being produced with no logo. They probably went to the internal market, not export.
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