Hi Vic, Thank you for this "demonstration". In my case, for little enclosures used with optical encoders, for delivery delay reasons, the factory don't execute the post molding process, (some heating with a well defined temp=f(time) profile. The contract or shrink (tnx to Terry, K4RX) was not done before assembly. Between 1 or 2 months after, ~75% of the enclosure were broken...
My best 73, Rudi, HB9ARI On 24.06.2011 18:02, Vic K2VCO wrote: > This happened more than 30 years ago so I can tell the story. I worked at a > kibbutz > factory in Israel where we made plastic faucets by injection molding. The > correct > adjustment of the temperature profile of the molding cycle was critical to > many > characteristics of the finished parts. > > Our engineer was going to Germany to demonstrate some products, so we > carefully tested his > samples so that he would not be embarrassed in front of the quality-conscious > Germans. > > At the demonstration, he turned the knob on the hot-water side of the faucet: > snap. Then > he tried the cold-water side: snap. Both stems broke off neatly inside the > faucet! > > The German engineers were not amused. Ultimately we learned how to adjust the > molding > machines properly! > > On 6/24/2011 7:12 AM, hb9ari wrote: >> Hello Guy, >> >> I think that you have found the good explanation! >> >> May be some of these knobs don't get a correct or sufficient pre-aging (?) >> procedure before leaving the factory; at my QRL pro, we get this kind >> of problem with molded plastic enclosure breaking some time after >> they were bee assembled. >> >> In French, we are speaking of "retrait" but i don't find >> the correct translation! >> >> My best 73, >> Rudi, HB9ARI ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
