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Re: Snapped Hot End

Posted: Tue Dec 08, 2015 2:45 am
by Mach
I believe it is for the heat break to prevent too much heat from creeping upward. Scott explained the following:
The v4 can be loosened with a few thermal cycles as long as the nozzle is loose or removed. Just heat to 270ºC then cool to room temp a dozen times or so and see if the heat block falls off. I've managed to separate a few that way. http://www.makergear.com/collections/ho ... /v4-barrel
I'm assuming at temp it would be easy to pull it out instead of pressing it out.

Re: Snapped Hot End

Posted: Tue Dec 08, 2015 3:21 am
by sthone
Mach wrote:I believe it is for the heat break to prevent too much heat from creeping upward. Scott explained the following:

I'm assuming at temp it would be easy to pull it out instead of pressing it out.
Yeah I guess the idea of a heat break does make sense just wish it was a tad bit thicker there.

I think it would expand when hot though making it harder to remove though.

Thanks for that link I couldn't find the barrel on the site... and $25 is a lot better than $75 to replace the whole thing. You have to love MG for offering all these spare bits and pieces. :D

-Steve

Re: Snapped Hot End

Posted: Tue Dec 08, 2015 3:09 pm
by ednisley
sthone wrote:expand when hot though making it harder to remove
It's seated in an aluminum plate: the hole gets bigger faster...

Re: Snapped Hot End

Posted: Tue Dec 08, 2015 3:30 pm
by sthone
ednisley wrote:It's seated in an aluminum plate: the hole gets bigger faster...
Good point.. I was figuring when installing the new barrel I could just put the barrel in the freezer and heat the block up then just drop the barrel in and let them both cool. One shrinks one expands... it works for putting bearing in motorcycle cases at least :)

-Steve

Re: Snapped Hot End

Posted: Wed Dec 09, 2015 5:00 am
by Mach
Woot, thanks for the tip on the c-clamp. I heat cycled it without much success but the c-clamp did the trick. Replacement barrel arrives Friday so hot block vs freezer test imminent. :)

Re: Snapped Hot End

Posted: Wed Dec 09, 2015 1:34 pm
by PcS
All you need to do to re assemble it is slide barrel in heat block and screw nozzle on other end and tighten. It does not need pressing in or freezer or otherwise. :D

Re: Snapped Hot End

Posted: Wed Dec 09, 2015 4:20 pm
by Mach
Thanks PcS. Decidedly less dramatic but less drama is a good thing these days.

Re: Snapped Hot End

Posted: Mon Dec 21, 2015 11:11 pm
by MG-Scott
I've had some luck removing barrels from V4 hotends be simply heating and cooling using the normal controls. Here is some gcode for doing that if you need to:

Code: Select all

M106 S0
M109 S250
M106 S255
M109 R30
M106 S0
M109 S250
M106 S255
M109 R30
M106 S0
M109 S250
M106 S255
M109 R30
M106 S0
M109 S250
M106 S255
M109 R30
M106 S0
M109 S250
M106 S255
M109 R30
M106 S0
M109 S250
M106 S255
M109 R30
M106 S0
M109 S250
M106 S255
M109 R30
M106 S0
M109 S250
M106 S255
M109 R30
M106 S0
M109 S250
M106 S255
M109 R30
M106 S0
M109 S250
M106 S255
M109 R30
M106 S0
M109 S250
M106 S255
M109 R30
M106 S0
M109 S250
M106 S255
M109 R30
M106 S0
M109 S250
M106 S255
M109 R30
M106 S0
M109 S250
M106 S255
M109 R30
M106 S0
M109 S250
M106 S255
M109 R30
M106 S0
M109 S250
M106 S255
M109 R30
M106 S0
M109 S250
M106 S255
M109 R30
M106 S0
M109 S250
M106 S255
M109 R30
M106 S0
M109 S250
M106 S255
M109 R30
M106 S0
M109 S250
M106 S255
M109 R30
M106 S0
M109 S250
M106 S255
M109 R30
M106 S0
M109 S250
M106 S255
M109 R30
M106 S0
You should be able to just let the heater block with the broken barrel in it dangle by the wires while the magic happens. This just waits for the hotend to hit 250ºC, turns on the fan, waits for it to cool to 30ºC then repeat a few times.

New barrels are here:
http://www.makergear.com/collections/ho ... /v4-barrel

Re: Snapped Hot End

Posted: Tue Dec 22, 2015 7:26 pm
by insta
Can the new barrel be seated just by tightening the nozzle down?

Re: Snapped Hot End

Posted: Tue Dec 22, 2015 8:11 pm
by sthone
insta wrote:Can the new barrel be seated just by tightening the nozzle down?
Yeah mine just dropped in and I screwed the nozzle on..