while the original hotend so far runs without major problems, changing from ABS back to PLA can be quite an annoyance. Even after lots of ‘new’ filament every now and then a small amount of ABS hidden somewhere inside the heater block would find it’s way towards the nozzle, adding dark spots (or rather stripes) to the surface. So, I decided to get a second hotend, so I’ll have one for PLA and one for ABS. Or perhaps one for dark colors and one for light ones? Or … well, you get the picture.
I choose the “E3D”, which is full metall (pro, ymmv) and thus needs extra cooling (con). Furthermore, it features the Jhead-style groovemount and, this is the nice part, is nearly of the same length as the original hotend (~3 mm diff). Thus, adjustment of the z-height upon changing the hotend will be a matter of seconds.
The good news is, the groovemount (OD 16 mm, h 4 mm) fits directly into the cavity in the extruder base and the original nuts can be used together with two M3 screws to mount the hotend:
It’s not yet electrically connected (didn’t want to break the thermistor while test-mounting), but mechanically it looks good; filament can be pushed through the barrel without any effort.
The adaptor still needs a bit of re-design as it took several attempts to properly print it. Afterwards, I’d say the E3D should be ready for a test run.
If successful, next question will be how to get it into the existing wiring - as said before, I’d like to have the possibility to quickly change back to the original hotend. So, probably this K8200 is going to get some kind of plug connection or screw terminal for the hotend assembly soon.
personnaly when i build my k8200 in case of change the hotend
i’ve cut a 4 pin molex connector like that: ebay.fr/itm/28cm-P4-Power-Ex … 0729366341 (just because i found it in my house) for connecting the hotend to the K8200
2 wires for the NTC Thermistor (black)
2 wires for the heater cartridge (yellow)
there is a lot connectors that can support the hotend, preferably hard and easy to connect and disconnect
please be patient, I’ll need a few days to transfer the design to scad and get those parts out that caused problems in the print.
bour12@casema.nl, you mentioned the Prusa nozzle. Since the source drawings are not yet published on the official website, I can only interpret the images available on the web, but it seems to me the barrel is a lot thinner compared to the E3D, maybe about OD 16? You might end up having to reshape the whole thing in order to get a proper airduct for the fan, especially if the height doesn’t match either. Have you measured the dimensions of the barrel?
ncls18, thanks for the idea, a locking connector is of course preferable.
Also ordered this hot-end, very curious to see how it works.
Technical description seems to suggest it should work without needing to modify the firmware.
For those who got one already, could it fit into the standard mouinting hardware ? (I think not)
Reason I bought one, is because I did overtighten mine after yet another disassembly due to stuck ABS. In that processs I killed it…
So now will order one sdtandard hot end and did also order the E3D one.
@Velleman mods, do feel free to remove below link to the reprap forum with an extensive story on this hot-end, but it does contain a mass of truly good info
looking good, I tested it to print the second (well, actually third or forth) revision of the adapter in ABS, and the result looks very promising. Although I’m not so sure about printing PLA, I didn’t like the surface quality there. Could just be that the settings need to be adjusted. Files, as mentioned around the corner, are awful when generated from OpenSCAD - lots of errors. But the end is near …
looking good, I tested it to print the second (well, actually third or forth) revision of the adapter in ABS, and the result looks very promising. Although I’m not so sure about printing PLA, I didn’t like the surface quality there. Could just be that the settings need to be adjusted. Files, as mentioned around the corner, are awful when generated from OpenSCAD - lots of errors. But the end is near …
Cheers,
kuraasu[/quote]
Hi Kuraasu
Hope you will post the stl file so we also can fit our E3D on the K8200
kuraasu, Im volunteering to help clean up the 3D model if you need a hand. I dont know openscad, but if I can import the model in sketchup, im willing to chase down geometry issues and generate a clean STL.
Got mine to day and have already tested it with the 0.4mm and only with PLA. I could not go lower than 0.2mm layers but here it is ok.
Tomorrow i will try printing with ABS, here I expect the biggest difference compared to the original hotend.
Yes i still need a proper fan/mount for the hot end. Right now it is mountet (for the test) but it is not nice.
there’s a grub screw to fix the cartridge. You can use heat-resistant glue (special silicone for >= 300 °C), too, if you wish.
Cheers,
kuraasu[/quote]
Yeah I know of the screw, but I still expected a tighter fit. On the velleman unit the fit is extremely snug, but like I said, maybe when it heats up it will expand…
As for the glue or thermal paste; Ive been looking for something heat resistant, also for fixing and better conducting heat to the thermistor, do you have a specific product recommendation (heat resistant, and electrically non conductive) or a suggestion where to buy it?
no, not really. I have to admit that I did just the opposite of what you’re suggesting: I mounted the thermistor without special heat conductor on purpose. Why? Well, I like the thermistor mount on the original hotend very much, the hole matching the thermistor’s diameter, the screw to fix the cables etc. The E3D was quite bad in this point. Most prominently, the supplied thermistor was very small, which seemed nice, until I noticed, that it didn’t fit any of the three (!) holes in the hotend prepared for different kinds of thermistors - they were all much too large. So, when I accidently broke one of the thermistor’s legs (very delicate), I decided to use a different thermistor as replacement, one that’s larger, so it would fit with less tolerance.
Finally, I ended up carefully drilling another hole (matching my thermistor’s size - ha!) into the hotend. It’s on the verge of looking like Swiss cheese now, but still ok as it seems. Stripes of Kapton were then used for isolating the thermistor wires against the alu body, and fixing them at the same time, nothing more. They easily withstand 300 °C, so the break-in of the hotend as described in the installation manual was no problem. Since the Kapton also covers the opening of the hole used for the thermistor, airflow from the fan cannot disturb the temperature measurement - good enough for me.
Somewhere else I found the tip to wind a small piece of alu foil around the thermistor’s glass, or to put the foil into the hole for the thermistor. That’s of course far from being electrically isolating, but the thermal conductivity would benefit greatly from such a measure. I shortly though about trying that with the small thermistor, but decided against it because it was so small and the tolerance in the existing holes so large.
Ill probably end up like you, drilling a new hole and using no more than kapton tape, but some products IM looking at:
JB weld. Temperature resistance is a bit tight (stated max=287C) and being an epoxy, its probably not a great heat conductor
exhaust glue (eg amazon.co.uk/TEMPERATURE-ADH … uctDetails)
1200C should be enough but I dont think it will be electrically insulating and its probably going to be very permanent. Im not even sure its a great thermal conductor either.
I was looking in Thingiverse fo the number 221997 but can not find it?
How is the final finish when printing compared to the original? in the meantime I have fitted the Prusa Mk2 was not impressed (PLA) and returned to the original, I will order a e3d and see if that is ok, did you also try smaller sizes nozzles (0,3 or 0.25) as these are easy to order on their site?
