On Sunday, July 31, 2011 03:42:41 PM cogoman did opine: > I read in Machine Design, or some other tech mag in one of those device > forensics columns about a company that was getting their servo drives > back from just one company at a rate of 4 failures a month. The > engineer sent to check on it did some checking before he left and found > that there was metal particulate matter on the circuit board that > shorted it out. When he got to the factory, the machine it was on > produced a lot of metal dust and shavings, and their control box had > fans, but no filters on it. And mine does not have filters, but is on a shelf about 80" off the floor. I can see a slight coat of dust on the stopped fan blades, but the shelf itself doesn't seem to collect a 'worth blowing it off' layer of dust at all. I have a lexan sheet on the side of that 'cage' that does an excellent job of deflecting swarf, much of which is wood dust. The building does get warm in the afternoons as it looses the shade of a maple tree on the adjacent property to the south, and the ambient air temp at the time it smoked was likely 100-105F at the shelves height as it was about 97F at eyeball height. It had previously functioned well at those temps several times, a lot better than I do. ;-)
The filter is something I will consider when I build it back up. In the garage, I have a 20" box fan with a std pleated paper furnace filter duct taped to the back of it to blow cleaned air on the area where I'm applying finishes. After replacing the filter it takes it about 2 weeks to get dirty enough to really clean the air, and I let it get about an extra 1/2" to 3/4" of dirt on it before I swap it for a fresh one. > At work we have FADAL machining centers, and they have a fan and > filter on the outside which blows cool air over a heat sink mounted in > the side of the cabinet. on the other side of the heat sink was a fan > to circulate the cool clean air from the heat sink to the drives inside > the cabinet. With coolant flowing there is still enough airborn debris > to clog a 4" by 4" filter in a few weeks. Not enough area, air velocity is so high it will suck dirt on through till it gets good and dirty. Then of course, not enough flow. Could an auxilary box carrying a 14x20 hepa filter be fitted above that? Sounds like it would be good insurance. > I suggest buying an A/C > filter from the big box store, and building a mount for at least a 12" > by 12" piece of filter on the input side of your air-stream. > A very Good Idea if I can find the space. These appear to be all heat sink on one side & that tempts me to seal the other side off, but Murphy says there will be a hot part or 6 on the other side too, so that's probably not a great idea. Looks like I have started a good thread for swapping ideas, lots of good suggestions here. Thanks guys. Cheers, gene -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) "We want to create puppets that pull their own strings." -- Ann Marion "Would this make them Marionettes?" -- Jeff Daiell ------------------------------------------------------------------------------ Got Input? Slashdot Needs You. Take our quick survey online. Come on, we don't ask for help often. Plus, you'll get a chance to win $100 to spend on ThinkGeek. http://p.sf.net/sfu/slashdot-survey _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
