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Extruder hot end

Posted by scwimbush 
Extruder hot end
June 06, 2011 01:32AM
Has anyone found a reliable source of the parts for some form of extruder hot end (ideally compatible with Wade's extruder)? These seem to be the least reprappable (neither printable nor standard) of the parts required, and probably not coincidentally, the sticking point for my build (at least until I hit the next one).

I've found botmill.com, but their shipping is too high, and mendel-parts.com, but they don't seem to actually be operating.

Thanks for any pointers,

Re: Extruder hot end
June 06, 2011 03:37AM
send vik an email. he gave us some pretty good info
Re: Extruder hot end
August 21, 2011 01:05AM
I'm looking for some extruders to fit a wades might be looking for at least 4 could be more in the future, if anyones found a decent supplier

Experimenting in 3D in New Zealand
Re: Extruder hot end
August 21, 2011 04:54AM
I've got one of Vik's (nichrome wire over a brass barrel, PTFE insulator at the top) and it's worked fine but I'm thinking of making some based on the resistor heat core and PTFE inner tube type design that has been popular for a while. If anyone would be interested in one and/or has any thoughts/links to good designs please let me know.
Re: Extruder hot end
August 23, 2011 05:46AM
Just upgraded my Makerbot Mk3 brass barrel that had nichrome wrapped around it with a MakerBot MK6+ assembly on my Restrap machine.

The MakerBot MK6+ uses a PTFE tube down a stainless steel tube with a heater block. You also need to install a thermal protector PCB to protect should a failure occur and the heater ends up with continous power. I have found that the new heater takes a little longer to heat up.
I had to fit a PC CPU fan (running slow +5v ) to keep the temperature down at the top of the tube as the filament was getting hot and buckling as it entered the PTFE tube. Also had to stop the PTFE tube from rising out of the stainless steel tube - the hot plastic was pushing the PTFE up.

Overall I have found a big improvement with oozing and delayed extruding - I put this down to a reduced heat zone and lower fiction with the use of a PTFE tube.

Using 3mm PLA filament and extruding at 0.4mm.

I found that my earlier brass barrel assembly made a strong smell, I put this down to the Kapton tape or the nichrome insulation slowly burning away. When you disassemlby the brass barrel, the kapton and insulation appears to very burnt. Over all the new assembly is slightly longer than my earlier one.

I have also tried making some brass barrel extruder heads, while they sort of worked I was not that happy with the ooze factor and they would jam easily. I put this down to not getting a good smooth surface when drilling holes.

I had no issues with ordering parts or delivery from MakerBot but there was a $40 freight cost.

Edited 1 time(s). Last edit at 08/23/2011 05:48AM by RepRot.
Re: Extruder hot end
September 25, 2011 06:14PM
I just bought another big bag of brass M6 bolts, so I hope some more people will want them smiling smiley

Vik :v)
Re: Extruder hot end
September 27, 2011 05:17PM

Do you have pictures of how you have yours set up? I have 'Greg's Hinged Accessible Extruder' Thingiverse with a hot-end kit from Makerbot, mainly because they plate their hot end with Teflon.
My setup is:
- Greg's Hinged Accessible Extruder
- PTFE rod with hole cut in for stainless steel makerbot tube and sized to fit into extruder base
- Stainless steel tube with PTFE sleeve (for 3mm)
- Aluminum heating block
- Aluminum bracket to attach tip to extruder body
- 0.4mm nozzle

When I test this, it will start pulling plastic in and I will see some plastic start coming out of the tip. But at some point, the plastic always jams and the teeth in the hobbled bolt start stripping the plastic until it just starts spinning freely. I've tried both increasing and decreasing the tension on the hinge of the extruder, but no luck. The only way I can get it to go again is to reverse out the plastic, and start feeding in new plastic at which point it will extrude for a bit until it gets stuck again (even if I slowly turn the gears by hand). I've tried all temps between 190-250.

Any ideas?
Re: Extruder hot end
September 27, 2011 05:27PM
I suspect the stainless tube is conducting the heat. Point a fan at it and see if the problem goes away?
Re: Extruder hot end
September 28, 2011 01:04AM
I would also subspect the stainless tube is conducting the heat and the plastic is getting soft at the upper area of the stainless tube and explanding with the pressure of the motor pushing the plastic into the tube.
Also make sure the PTFE tube sleeve is position right to the nozzel. If not an amount of plastic will form there which can cause problems.

Try some cooling..

Some pictures of my printer here [www.reprap.org]
Re: Extruder hot end
October 05, 2011 12:19AM
Hi Vik,
I would be interested in a couple of M6 brass bolts.

Re: Extruder hot end
October 05, 2011 03:31PM
Sure. Would you like to use my "vik" e-mail address at diamondage.co.nz and we'll not bore people in the forum with the minutae of transactional details.
Re: Extruder hot end
October 06, 2011 12:27AM
I'll try the fan to cool down the stainless steel tube. to give you guys an idea of my setup, I've taken a bunch of pictures. Looking at it, it might be a cooling issue:
Re: Extruder hot end
October 21, 2011 04:36PM
I'm looking into importing some hotends at the moment so if your interested PM me and I'll get back to you if I go ahead

Experimenting in 3D in New Zealand
Re: Extruder hot end
October 21, 2011 05:18PM
I pm'd you.

edit: actually, you are probably talking about importing into NZ.. I'm in the US now. Sorry.

Edited 1 time(s). Last edit at 10/21/2011 05:20PM by sxt173.
Re: Extruder hot end
October 21, 2011 09:18PM
Yes importing into NZ, so please ignore my PM to you

Experimenting in 3D in New Zealand
Re: Extruder hot end
October 22, 2011 08:55PM
A friend is doing a bunch of 38mm x M6 3mm i/d brass heater barrels for my DIY heater making empire. I'm happy to flog a few on to enthusiasts smiling smiley

These are the same ones I wrap in nichrome and fire cement for my versions of the Wade and direct-driver extruders.

Vik :v)
Re: Extruder hot end
October 29, 2011 05:38PM
Hey Vik - I see your complete extruder on TradeMe, noticed you'd got the Nema17 from mindkits.
I've ordered mine from the same place, though I was wondering how well it would hold up in the extruder, iirc they're only 23Ncm (still the highest I've been able to find in NZ though) however Wades calls for 40Ncm? - or maybe I've just misunderstood something.

was going to give the mindkits one a go and see how it faired, but looks like you've already 'been there done that'.

probibly would have gone for your one if I'd not already had the parts on order,
Might be interested in just hotend bits though.
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