Does anyone still use Nichrome for hot end?
June 19, 2011 03:18PM
I took the plunge a few weeks ago and bought the parts to build a Reprap Prusa. The low Gen6 stocks at Mendel-Parts prompted me to make a swift decision on which items to order (Gen6 stocks ran out a day later). I opted for the V5 hot end along with some Nichrome wire for heating. My parts have been dispatched now, so I'll hopefully be assembling this in a few days! However, since making the order I've gathered the impression that using Nichrome for heating is less popular now, and heater blocks with resistors are generally the preferred method.

Anyway, I was just trying to find out if any Reprappers still advocate the use of Nichrome wire to heat the hot end? If I can find a way of effectively mounting the PEEK block to my Wade extruder I would hope to make the hot end similar to this – [www.mendel-parts.com]. Is this a good idea?

Alternatively, I've seen some examples of hot ends that omit the use of PEEK and seem to depend on PTFE for insulation, but I'm assuming that this wouldn't be sufficiently robust to last many hours of use. Any thoughts?

Thanks!
Re: Does anyone still use Nichrome for hot end?
June 19, 2011 03:21PM
Personally I still love nichome/keysert heaters. It's hard to get a more thermally effecent hot end than that.


repraplogphase.blogspot.com
Re: Does anyone still use Nichrome for hot end?
June 19, 2011 04:06PM
I prefer to use NiChrome too, even though I have a very nice block-based hot-end sitting there. One benefit is that the warmup time is quicker by a good minute or two.

PEEK or PTFE both work fine - though PEEK is a better insulator it is hard to work with than PTFE. The secret is to make sure you attach it to your extruder securely- such as in the way in the photo you linked to. The older way of attaching was to use two screws at the top of the insulator, and it's happened to me that the heat deformed the extruder around these screws and caused the hot-end to drop into the print.

I've also had success using Bamboo as an alternative, and it's been running well since the beginning of May. Of course if you do try this then take proper precautions - it shouldn't be a fire hazard, but I am always around when my machine is running.

Good luck with whatever option you choose.


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Re: Does anyone still use Nichrome for hot end?
June 19, 2011 09:58PM
I have a nichrome heater that has been working brilliantly so far. I think one of the advantages of the heater block design is that the thermistor is well buried in the block, as opposed to just being taped on like most of the nichrome designs I have seen. If the thermistor comes loose you will definitely destroy your hot end.


Germanicus
Re: Does anyone still use Nichrome for hot end?
June 20, 2011 12:34PM
I'm using a makergear hotend, and those use nichrome encased in ceramic on a brass sleeve that screws over the barrel. It works great, my nozzle heats up fast and hold temperature steady.
Re: Does anyone still use Nichrome for hot end?
June 20, 2011 04:02PM
Many thanks to everyone who responded. I'm glad to hear that I won't be alone in the world of Nichrome heated hot ends. smiling smiley

@garyhodgson

If only I could attach the hot end in a similar manner to the photo, but the Wade extruder seems designed for the older "two screws at the top" method. I could perhaps drill a couple of extra holes into the bottom of the Wade extruder to accommodate some bolts holding the Mendel-Parts PEEK block. Do you think ABS would respond well to being drilled (i.e. not shatter)?

It would be easiest for me to assemble the hot end using the method you used here - [garyhodgson.com], but I note that you had reservations about the design's longevity. Did that hot end ultimately have a short life as you predicted? Was that hot end the culprit that deformed your extruder?

BTW, I really appreciate the time you put in to making the visual instructions for the Prusa and Wade extruder. I have found them to be extremely helpful! smiling smiley


@germanicus

Yes, this is one of the things that worried me about using a hot end without a heater block. I've heard stories about thermistors reporting false temperature readings, and the hot end gets way too hot. If the thermistor broke wouldn't there be some safeguard in the electronics firmware to stop printing? I'm guessing that if the thermistor merely moved out of place it would be difficult for the electronics to detect such a fault.
Re: Does anyone still use Nichrome for hot end?
June 20, 2011 05:25PM
In the setup I had in that photo the screws held the hot end in pretty well - my experience with my other extruder is that it deformed due to it being PLA. ABS would be more resistant I think.

I can't say whether ABS is good for drilling. PLA is fine so long as the speed is kept way down, otherwise it starts melting.

Once you get printing (or you have access to one beforehand) you might want to check out this adaptor, it's for connecting a v6 hot end to a wade's extruder, but with a bit of manipulation in openscad it could probably handle a v5. I actually used it to connect my experimental bamboo hotend to one of greg's accessible extruders (which has the same holes as a wade's).

In the end I would say to go for the screw option until you get up and printing, and put "improving the hot end" on your to-do list.


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Re: Does anyone still use Nichrome for hot end?
June 22, 2011 02:43PM
garyhodgson Wrote:
-------------------------------------------------------
> In the setup I had in that photo the screws held
> the hot end in pretty well - my experience with
> my other extruder is that it deformed due to it
> being PLA. ABS would be more resistant I think.
>
> I can't say whether ABS is good for drilling. PLA
> is fine so long as the speed is kept way down,
> otherwise it starts melting.
>
> Once you get printing (or you have access to one
> beforehand) you might want to check out this
> adaptor, it's for connecting a v6 hot end to a
> wade's extruder, but with a bit of manipulation in
> openscad it could probably handle a v5. I
> actually used it to connect my experimental bamboo
> hotend to one of greg's accessible extruders
> (which has the same holes as a wade's).
>
> In the end I would say to go for the screw option
> until you get up and printing, and put "improving
> the hot end" on your to-do list.


Thanks, that's interesting stuff! I've just bought some bamboo plant labels from Wilkinson's. They are about 3mm thick and 17mm wide, so I thought cut to the right length it could perhaps be used to substitute a PEEK block on a Wade extruder. Holes could be drilled in the bamboo to align with the bolts that pass from the extruder through the x-carriage to hold the block in place. Do you believe bamboo would be a suitable substitute for a PEEK block, and do you think it would help to reduce the temperature of the PTFE?
Re: Does anyone still use Nichrome for hot end?
June 23, 2011 03:50AM
Sounds like it might work - I would certainly give it a go. In my setup I have a wooden cross bar as PEEK replacement and so far (2 months) it's been working great. the only reason I didn't use bamboo for that too is that I didn't have the right size to hand. I'll probably try with my next incarnation.

Let me know how it works out.


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garyhodgson.com/reprap | reprap.development-tracker.info | thingtracker.net
hi guys i"m new to the reprap phenomenon, i'm waiting for my parts as we speak but i am a machinist and i bit of a home handy man (well i like to think so)

anyway i am designing a hot end based on what i think will work, i by no means consider myself an expert or anything even close but worth a shot.

i have a whole pile of pictures but no idea how to put them up?

i have just renovated my bathroom ( a bit off topic but you will see where I'm heading) while doing this i had some leftover flooring that went down under the tiles.

i have no idea what is used in other parts of the world but here in Australia we use what is called compressed fiber cement, this stuff is hard as hell but can be

drilled easy and can also be tapped effectively, it is called fireproof and i done a few tests on it myself today,

1piece of 200mm x 200mm 15mm thick compressed fiber sheet.

1 heat gun

1 laser thermometer

i heated one side of the sheet to 240 deg C and even before i dropped the gun to grab the camera it had dropped to 185degC the reverse side was only at 70deg and falling rapidly.

i plan to use this as a ridged insulator between my extruder mount and hot end the hot end will tap directly into it and it will boly to the extruder. ( no need for long bolts and cross bars)

anyway let me know your thoughts as im the inexperienced one here has this already been tried?

Cheers Dave
Re: Does anyone still use Nichrome for hot end?
June 25, 2011 03:16AM
Hi Dave,

Sounds insteresting. If you're looking for a place to document your design and host you images, then I would recommend you creating a page on the wiki. It's always good to see new developments!

Cheers,
Gary


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