Nichrome wires vs resistor?

So I've heard a lot of talk about these resistors mounted in aluminum blocks used to heat extruders, and it seems to me like a move in the wrong direction. I've prepared a list of percieved advantages and disadvantages of nichrome vs resistor designs:

Resistor Disadvantages
- excessive mass
- wasted heat
- requires precisely milled aluminum block to acheive press fit over hot end
Resistor Advantages
- Easy to assemble (the aluminum block is not easy to build!)
- little risk of shorts (however the resistor can still chip..)
Nichrome Disadvantages
- Annoyingly difficult to assemble
- Insulating (get insulated nichrome!)
Nichrome Advantages
- Cheap and easy to get all the parts
- Very light
- Easy to insulate, save wasted heat.

Based on this the nichrome has more advantages and fewer disadvantages than the resistor design.

Why do we use the resistor design?

destroyer2012 Wrote:
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> So I've heard a lot of talk about these resistors
> mounted in aluminum blocks used to heat extruders,
> and it seems to me like a move in the wrong
> direction. I've prepared a list of percieved
> advantages and disadvantages of nichrome vs
> resistor designs:
>
> Resistor Disadvantages
> - excessive mass once you cover your nichrome in ceramic cement it weighs more than a resistor
> - wasted heat The heat is being evenly distributed by the block and adds thermal stability
> - requires precisely milled aluminum block to acheive press fit over hot endAll of mine are made with a hand drill and cheap drill bits. They are threaded so it just screws on, no press fit.

> Resistor Advantages
> - Easy to assemble (the aluminum block is not easy to build!) easier than using nichrome
> - little risk of shorts (however the resistor can still chip..) So can insulated nichrome

> Nichrome Disadvantages
> - Annoyingly difficult to assemble So true
> - Insulating (get insulated nichrome!) Can be scratched off and short just like the resistor

> Nichrome Advantages
> - Cheap and easy to get all the parts Resistors are available at every electronics supplier. Nichrome is not stocked at most places I have seen
> - Very light Not once covered in ceramic cement
> - Easy to insulate, save wasted heat. No thermal mass so it's almost always on to maintain temperature as the filament draws away heat


> Based on this the nichrome has more advantages and
> fewer disadvantages than the resistor design. I see it as just the opposite
>
> Why do we use the resistor design? Easier, rebuildable, pre set wattage, basically its nichrome based cartridge heater.

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Another disadvantage of nichrome is that it is difficult to make connections to it. Having used both methods I much prefer the resistor heater.

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Polycarbonate needs around 300 C to print, which i think would shorten the life of most resistors significantly, if they could reach those temps at all.

Otherwise, i don't see any advantage of nicrome over resistors.

A RWM04106R80JR15E1 6.8r resistor is rated 30 watts @ 450c. Although it would shorten the life dramatically, I wouldn't think nichrome could handle it very long either.

It says a word in my post has been banned when I try and post the link to the PDF datasheet.

Edited 1 time(s). Last edit at 03/12/2012 02:58PM by Sublime.

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FFF Settings Calculator	Gcode post processors	Geometric Object Deposition Tool Blog
Tantillus.org	Mini Printable Lathe	How NOT to install a Pololu driver