Gene, The replacement ball bearing fan isn't on the bed fan duct but cools the top part of the hot end where the filament enters the PTFE lined feed pipe.
Problem solved which the new blower duct, now not aimed at the hot end, did not completely fix. Wrapped hot end block in insulating paper and Krylon tape. Now nice flat curves and no drop in temperature even with 98% bed fan speed. John > -----Original Message----- > From: gene heskett [mailto:ghesk...@shentel.net] > Sent: March-20-22 2:50 PM > To: Enhanced Machine Controller (EMC) > Subject: Re: [Emc-users] Because I can't seem to finish anything... Nebel > lathe conversion. > > On Sunday, 20 March 2022 16:46:17 EDT John Dammeyer wrote: > > Story of my life. Fan failed on 3D printer. Repaired feed tube and > > replaced with ball bearing fan I had from power supply manufacturing > > inventory. Almost 1 week later still not working quite the way it > > was and the way I want. John > > ball bearing fans start easier, leads to over cooling the early layers. > Change the min speed so its stopped for the 1st layer like it used to be > at 25% power. Sleeve bearing fans often don't start at all till the mid > 30% range. > > Try zero for the first layer or even as high as the third layer before > the fan actually starts. I have a ball bearing fan on my BIQU BX and it > runs plenty fast enough at 30% of max in cura for PETG which needs far > less cooling than PLA. I don't mess with PLA at all, too brittle. > > I've also put a diamonback .4mm PCD nozzle in mine so I can use the > carbon fiber filled PETG but haven't yet seen the need for its improved > strength. I'm running the nozzle at 252C and the bed at 90C and my > printed air manifold is air tight. Bed adhesion is only a problem getting > stuff loose. Its almost too good. If the nozzle is slobbering, check how > tight it is, then reduce the flow 2% at a time to stop the overflow, this > PCD nozzle conducts heat into the filament better than brass, melting it > better which can increase the flow. At 245C the part will not be airtight > if you need that. At 252C the part gets noticably glossier because its > more liquid and bonds well to the next layer down before it cools and > solidify's. > > Take care and stay well John. And my teeny version to be used as the B > axis driver on my 6040 mill, the one that costs around a tenner to make, > seems to be pretty solid, got several hundred hours on it now but it > probably going to get another 200 running a hard maple stick for a > woodworkers leg vise screw. I've got to make an idler yet to tighten the > belt as that is the only backlash it it. > > 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, 1940) > If we desire respect for the law, we must first make the law respectable. > - Louis D. Brandeis > > > > > > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users
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