100k vs 200k thermistor

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introspector
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Joined: 2010-05-07
Posts: 1
Points: 11

hey,

Recently completed my bfb rapman at the mixed media lab of the sint-lucas school of architecture.  I actually shorted my extruder, so with some tips from batist i rebuild  using kapton tape instead of firecement.  I also broke the thermistor in the process, and replaced it with a 100k thermistor (used in makerbot).  The 100k thermistor is also considerably bigger then the 200k bf one, so it didn't completely fit in the hole.

After some fidling with loose belts, it printing a decent mini mug ;)  But i still feel the temperature is a bit of.  I was wondering if other people have experience with running a rapman with a 100k thermistor?  Is there some general change i should make, or is it just down to tweaking in skeinforge till i find the right temperature for each material?

regards,

corneel

Bogdan Kecman
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Joined: 2009-04-21
Posts: 2634
Points: 2667

100K thermistor have completely different curve (they do not linearly change resistance with temperature) so you cannot make a simple formula to calculate your temperature. I suggest you contact bfb and ask them to sell you a 204-gt thermistor, or try to find one yourself.

http://www.datasheetarchive.com/204GT-1-datasheet.html

they are made by this guys: http://www.semitec-usa.com/sales_rep/index.html

john348
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Joined: 2009-06-15
Posts: 677
Points: 837

I broke mine and went to the company to buy one.  I had to buy 100 minimum quantity so I can now break a lot more  ::) before I run out.

Szilard
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Joined: 2009-12-18
Posts: 321
Points: 48

awesome ... you have than thermistors for all of us ;)

CBlair
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Joined: 2010-05-12
Posts: 8
Points: 18

We have the same problem, shorted the thermistor. The Canadian Semitec supplier was willing to provide samples of the 204GT, unfortunately with a 3 week lead time. We're going to try a few parts from digikey that are similar; let you know how it goes!

jhdgkss
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Joined: 2010-05-03
Posts: 88
Points: 126

HI i used 2 100k thermistors from maplin in seris,on either side of the hot end works a treat. :)