On Sunday 16 August 2020 13:07:41 Gene Heskett wrote: > On Sunday 16 August 2020 11:57:31 John Dammeyer wrote: > > What type of 3D printer did you buy? > > A Creality Ender 3 Pro. Quite highly recommended. > > > > -----Original Message----- > > > From: Gene Heskett [mailto:ghesk...@shentel.net] > > > Sent: August-16-20 5:24 AM > > > To: emc-users@lists.sourceforge.net > > > Subject: Re: [Emc-users] found a harmonic drive set of .stl's on > > > thingiverse > > > > > > On Saturday 15 August 2020 09:05:48 Gene Heskett wrote: > > > > Slim chance I might get the rest of the screws I need later > > > > today. > > > > > > I did, almost, get enough screws to put one together & take it for > > > a spin. Screw lengths very critical. Works but the motor only has > > > enough torque to turn it at over 2.5 amps/coil drive. But that > > > will get the motor hot enough to soften the plastic in about 15 > > > minutes so I quit at about 5. > > > > > > Now the 64k$ question is, it is worth building an air cooled shaft > > > extension to isolate these from the motor heat? I'll have to > > > think on that. I've been thru hell with this printer and anything > > > I need is 3-5 weeks away. The whole hot end of it is a pisspoor > > > design, leaking hot plastic out thru the nozzles threads. Or > > > anyplace else. The si sock on it is dragging on the work as its > > > filled up, now that its cooled, with about an eighth of and inch > > > of solidified plastic from the leakage. Its also ripped up from > > > the leaking PLA glueing it to the hot end, and damaging it during > > > removal. The final fix might be a strip of teflon pipe tape on > > > the nozzles threads, but that would have to be done to brand new, > > > clean parts I don't have. > > > > > > > And thats the news from Lake Woebegon. :( > > I have an inquiry in at PrintedSolid.com for a bullseye hot end > conversion kit WITH a new ptfe bowden tube, but being the weekend, no > reply as yet. I like that design better than this one whose weak point > is the shark bite style connection used at the top of the hot end. No > provision to maintain the pressure of the tube against the nozzle, so > as the tube twists with the x motions, it gradually cuts the shark > fingers into the plastic of the tube, and the pressure and the > twisting wears ditches in the tube wall letting it back away from the > rear face of the nozzle. That lets hot plastic backup the outside of > the tube until it cools and freezes as a big plug trapped between the > now retracted end of the tubing and the nozzle. And the ejector motor > just sits there skipping steps. > > There is a possible fix, which consists of cutting a piece of the > tubeing off just long enough to fill the space between the shark bite > and the nozzle, so I've done that, and placed a teeny steel washer > above it, so the rear of the shark bite then traps the tubing against > the back of the nozzle, the guy on y-t showing a razor blade being > used in a jig, hopefully to get a square cut. Not having a razor > blade, or the jig he was using, I cut it about half a mm long and took > the hot block with it sticking out to a piece of 320 sandpaper and > sanded it flat, reversed the tubing and sanded the other end flat. > This left the shark bite about 1/2 turn from tight when it was > clamped, which I noticed was turning with the motion halfway thru the > next part, so I took the wrench and drove it tight while it was > printing, releasing and relocking the shark bite before restarting the > next part. But the silicon rubber sock on the hot block is so badly > damaged from being filled up by hot plastic coming down past the > nozzles threads that its no longer staying in place like it should. > And the shark bites grip on the long tube is on only whats inside the > shark bite. I don't expect it to last forever before the locking > fingers slide off the end of the tube. > > Hence the query about the bullseye hot end conversion kit. Guessing > about half the cost of a new printer. I asked for a meter of the > teflon tubing and some spare nozzles since thats a different design. > Includes a new cooling fan, mine is rattling its cage as I broke a > blade off trying to clear a dust bunny from it while it was running. > And I wound up buying a micro swiss hot end, it moves the ejector motor to the hot end carriage too, but doesn't replace my broken fan. All joints are cold in this design.
As a side note, I have it doing the last of 3 output shafts that actually are a press fit in the main bearing, running without the silicon sock on the hot block. When this is done, I've dialed it up to 300% speed, seems to be doing ok. I'll measure the DC psu, as enders were made in both 12 and 24 volt versions, and I can't find a voltage marked anyplace, and I need to buy fans that match the voltage. I suspect, from the heavy gauge of the output cable that its a 12 volt model. > Cheers, Gene Heskett 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 Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
