Easy Filament Changing with a Mk8 Hot End

Some time ago, I printed a little guide in the form of a convex-sided wedge with a central hole, that guides flexible filament to the heatbreak tube of a Mk8 hot end.

There are various versions on thingiverse, none of which fits as-is but some can be cut down to make a good fit.

I've since done some experimentation and the reliability can be greatly increased by fitting a short length of heatbreak above the normal heatbreak to ensure a continuous path from the feed rollers to the nozzle.

The great benefit of this come when changing filament. Set the hotend to a suitable temperature, cut the filament (nice and squarely) close to where it enters the Mk8 then tell the extruder to extrude about 40-50mm of filament. Once the filament has cleared the wheel you can manually release the sprung roller and pop in the new filament, without any fiddling, until a bit of ooze comes from the nozzle. If changing colour now feed until the new colour runs true and you are good to go.

This is MUCH easier than the hit and miss of pulling out hot filament hoping it won't snap or get stuck and it also makes threading the new filament easy instead of rather fiddly.

I've done this several times with PLA and today I changed from PLA to nylon with no problems at all, although it did take a while for the PLA to clear.

Neil

I did something similar, changed the 30mm heat-break tube for a 40mm one. The tube then sticks out of the top of the lower Mk8 body and can be adjusted to be close to the drive wheel and roller.

Much easier to load the filament up.

John

Edited By Journeyman on 21/09/2018 18:39:10

Ooops. It's been a while since I last had a serious accident with a mouse but it was only a matter of time before it happened again. Enforced time away from the workshop seems to significantly increase the risk of such an accident. Somebody ought to do something about it.

Last time I ended up with 3 tonnes of Japanese cast iron turning up at the house, which caused the Domestic Manager some consternation. This time I received (at work!) a small box containing a Cetus 3D MkII, less than 48h after ordering. I've only bought one 3D printer before (an Ultimaker) which cost about £4k at the time. This one is pretty much £400 and sounds as if it is capable of similar precision.

Couple of video reviews by myfordboy and some Mercan both sound good.

I'm not going to do one of those pathetic unboxing stories but will let you know how it turns out once I get back to Bristol after the weekend.

Murray