On Thursday 23 July 2020 15:26:06 Chris Albertson wrote: > I would very much like to hear what the experts at Mobile say, if you > can get an answer from them. > > But what I do is save fail and redesigned printed parts so I can do > experiments on them like testing of Epoxy or CA glue is best or just > put them in a vice and bend 'till they break. I've never done grease > and oil tests but you likely have enough reject parts not to at least > test of the oil dissolves PLA or not > > They say PLA is made of corn oil and is biodegradable. But I've yet > to see any biodegradation even with part soaked in water. > > But I do see very fast wear with PLA parts. If I put a steel shaft on > a PLA bearing the bearing hole gets worn out. What I found is I can > but bronze bushings and pres fit them in the PLA hole. Oilite bronze > on steel works well untill in get hot and melts the PLA. Another > solution is skateboard bearings. These are cheap > > The best harmonic redcer designs I've need use bearing for the pins so > the PLA is not needing to rub on a pin. > > I've foubd PLA does not like friction so pressed in sleave or sealed > bearinbg units are best. and these are really cheap on eBay and can be > re-used on furute projects many times. But plain bearing made of PLA > just don't last. > > On Thu, Jul 23, 2020 at 12:01 PM Gene Heskett <[email protected]> wrote: > > Greetings all; > > > > Slow, makes watching grass grow exciting... 3h:40m into making the > > housing cup, its claiming 6% done. And still doing infill for the > > end wall stuck on the bed. > > > > Someone said that it will need grease and mentioned the silicon > > stuff used in power tool gear boxes. But one of the features of si > > stuff is its total lack of surface tension which generally prevents > > actual contact between the parts. And thats good. Thats what the EP > > of a grease is all about. But I've no clue how PLA and petro based > > greases get along, so what is the best grease for PLA parts? Do we > > have to use si based stuff which equals a higher wear rate to keep > > the PLA from deteriorating from the petro based grease? > > > > Inquiring minds would like to hear the merits discussed. Or should > > I call the Mobil Oil warehouse in Omaha and put it to the real > > experts? > > > > Thanks all.
Thanks for all the replies from everybody. But except for the anecdotal stuff, PLA is basically missing inaction in the link supplied. Since PLA is supposedly vegetable based, I think I'll try canaba wax, which should, once the solvent naptha has evaporated, leaves a hard, non-stick coating on the PLA. Might be an interesting experiment as I get the impression it would have the cahones from a 3NM motor, to turn the bs-1's worm under a cutting load. I have a much larger 100/1 gear box for that if this fails. =================== As for calling Mobil, the last time I did that it was getting on into cold weather in 1973, with a Nebraska ETV transmitter that needed a barrel of tech grade ethylene glycol for antifreeze. I found a barrel, sitting just inside the dock door in Omaha and bought it, but I probably ran the station's LD bill up as I called all over the country looking for it. It was scheduled to be shipped to Sprague in Lincoln the next monday, who would share it with Cornel-Dubilaire in makeing electrlolytic capacitors. Due to the OPEC embargo, it turned out to be the last barrel of tech grade in the country, and I got it for KXNE for $8.50/gallon. They hadn't paid mobil for it yet and I had a state PO in hand. Car antifreeze can't be used due to the high voltages involved, the anti this and that additives make it almost a shorrt circuit, and the additives would have killed a couple thousand in deionizer cartridges just undoing what 1 gallon of auto antifreeze would have done to the system. So I single-handedly caused the capacitor shortage in the service industry that winter of 73 by putting Sprague abd C-D out of the business. One of those now it can be told stories. Cheers, Gene Heskett -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) If we desire respect for the law, we must first make the law respectable. - Louis D. Brandeis Genes Web page <http://geneslinuxbox.net:6309/gene> _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
