Arnitel

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rad
Posts: 36
Joined: Thu Apr 18, 2013 7:33 pm

Re: Arnitel

Post by rad »

Actually the Thermistors we have in the Felixprinters gets destroyed by 240 degree over a longer time!!

I just blew another one. The one from a brand new Extruder that I ordered lately.

After giving up with Arnitel I set up one of my normal green PLA high quality print. I extrude this PLA at 240 degree. I had it run over 10 hours. (never had the green PLA at 240deg run that long)

Then the Extruder jammed like I have never seen it before. The whole Extruder was black. Attempting to free the jamming on the printer it self ended in pushed out a lot of dark smoke!!
I demotaged it. The plastic has build a very dark black cloag in the extruder.

After freeing it I measured the thermistor. It reads 300kOhm! ..which according to the 100k thermistor table is equal to a temperature of about 0 deg. (100k is at 25 deg)
Well my room is at 24 degree.

Almost exatcly the same thing happend with my old extruder thermistor. Well the replaced one. It read 400kohm at room temperture before it got destroyed. Therehowever I used white PLA and it didnt jam but the the part I printed showed intense flow and brown and black parts. Clearly it left the 240 degree and went much higher.

This byway is the third such Felix-Sensor that got destroyed. Felix urgend have to check about this sensors with the supplier. The ybecome destroyed if you applay 240deg for a longer time.

In my old Extruder I replaced the damaged sensor with this one
EPCOS - B57560G104F - THERMISTOR,NTC
you can see it in my last picture. I simple centered it and filled it with the black silicon.
So far I haven't had any problem with this. It has very stable temperture readings.

About the cold end ..well
if the PLA get's weak a little it maybe requires less force to re-shape after the deformation of the pushign wheel. :)
60deg is probabily still no problem but if it gets to 100 deg I agree that a bit more cooling wouldnt hurt.

After the 10 hour run I couldnt touch the cold end for longer. So I guess it got to 100deg which would be bad. But I believe my extruder was far above the 240degree due to the damaged thermistor.

Hugues
Posts: 270
Joined: Thu Apr 04, 2013 5:36 pm

Post by Hugues »

Lioric wrote:The thermistor is NOT going to be damaged by the "relative" lower temp needed by ABS (~240), the thermistor works all the way up to ~350 (being 300 the typical "safe" top end)

About the part not sticking to the bed, well the only solution: MUSE EARS...
Hi Lioric,

I'm not sure I understand what are muse ears exactly , do you have a picture to show for a newbie like me ?

Thanks a lot
Hugues
Regards from Switzerland

Lioric
Posts: 116
Joined: Wed Aug 15, 2012 1:13 am

Post by Lioric »

@hugues

Sorry, I meant MOUSE EARS:

http://www.makerbot.com/blog/2011/02/25 ... g-monster/


rad wrote:Actually the Thermistors we have in the Felixprinters gets destroyed by 240 degree over a longer time!!
Please stop spreading FUD, this is simply not true

I'm pretty sure you are not the only one to have printed for more than 10 hours at 240 (I have printed more for than 10 hours at 250 with ABS, and there are several reports on this forum about printing "overnight")

How long do you think printing the complete set of printer parts take at the Felix HQ? and consider that those machines, most probably are working 24/7
After giving up with Arnitel I set up one of my normal green PLA high quality print. I extrude this PLA at 240 degree. I had it run over 10 hours. (never had the green PLA at 240deg run that long)

Then the Extruder jammed like I have never seen it before. The whole Extruder was black. Attempting to free the jamming on the printer it self ended in pushed out a lot of dark smoke!!
I demotaged it. The plastic has build a very dark black cloag in the extruder.
See, your issue is different, is a wrong hardware or firmware setup, because unless this is some really hard (and bad) PLA, 240 is way past the working extrusion temp for PLA, at 230 you start to get steam bubble jets out of the extruder and the printing quality is affected, at 240 PLA starts to burn to a brown colored plastic, yet you seem to be printing at this temp.

And dark smoke doesn't sound like PLA, the only time I saw smoke coming from the extruder was when the heater cartridge did get loose and it started to overheat in air contact

So probably your firmware (or the connections) are wrong so the reported temp is different

rad
Posts: 36
Joined: Thu Apr 18, 2013 7:33 pm

Post by rad »

Lioric wrote:
rad wrote:Actually the Thermistors we have in the Felixprinters gets destroyed by 240 degree over a longer time!!
Please stop spreading FUD, this is simply not true
In my case this is true. When a thermistor should have 100k at 25 degree and it reads 300k in the one case and 400k in the other then I don't consider them still OK. The 400K ended in "infinite ohm/open wire" shortly thereafter. The 300k I don't know yet but I am not going to wait till the one is gone. And the first sensor ended in a short cut.

All in all I have 2 granted destroyed Felix thermistor now and the third has wrong readings and therefore unusable and I don't have the printer that long.

I had not yet any problems with the sensor that I bought from an electronic store.

Sorry but for me the case is clear.

If it's not for you fine.

Lioric wrote: How long do you think printing the complete set of printer parts take at the Felix HQ? and consider that those machines, most probably are working 24/7
I doubt they use 240 deg. But I don't know it of course.

Lioric wrote: See, your issue is different, is a wrong hardware or firmware setup, because unless this is some really hard (and bad) PLA, 240 is way past the working extrusion temp for PLA, at 230 you start to get steam bubble jets out of the extruder and the printing quality is affected, at 240 PLA starts to burn to a brown colored plastic, yet you seem to be printing at this temp.
Yes I print the green PLA at this temperature to ensure the flow in the fills keep up on the fast moves. Also the plastic gets harder and actually it makes more proper print then at 220deg. The extreme flow reduces a bit past 230 deg. It's a strange setting I know but I had the best results with this. (on normal 0.2mm not high quality 0.1mm prints)

In cold it reads 25 deg on a non damaged sensor when I have 25 deg room temperature. The rest is a programmed table. The 300k and 400k ohm I measured outside with disconnected sensors and not with the printer electronics.

It might be that my printer measures a bit bad.... however that doesn't change that the temperature sensors got destroyed.
Lioric wrote: And dark smoke doesn't sound like PLA, the only time I saw smoke coming from the extruder was when the heater cartridge did get loose and it started to overheat in air contact
It came from inside. And yes this surprised and shocked me a bit.
Lioric wrote: So probably your firmware (or the connections) are wrong so the reported temp is different
Oh please stop it. Even if it were wrong it doesn't change the case that after printing the PLA fine for 10 hours the temperature sensor is now destroyed.

Again no issue with the one from the electronic store SO FAR.

P.S. oh forgot: Thank you for the Mouse Ears hint! That is useful to me! :)

rad
Posts: 36
Joined: Thu Apr 18, 2013 7:33 pm

Post by rad »

Maybe I have to apologize. It's not my intention to spread FUD. (had to wiki it up. :lol: )

I am all behind the Felix-Printer. In fact I see it as one of the best printers if not the best for your home that you can have. I especially like the simplistic and stable design. It's all well thought trough.

However everything has it weakness and in my opinion on the Felixprinters this are those thermistors. If you read the forum you see I am not the only one with that thermistor problem.

Now such a thermistor isn't a big deal if you consider that you can simple order it in an electronic store for 1 or 2 euro and replace the supposed "weakness"

I am someone that talks open and address things I see as "bad" directly. It was meant to put some weight on the thermistors waekness so that FelixPrinters knows it's importand to check about that.

I have carefully removed the damaged 300K Sensor. It still reads 300k at 25deg where it should read 100k.

If you want to have it for analysis and check backs with your surpliers let me know.

hvdd
Posts: 71
Joined: Tue Jul 24, 2012 11:43 pm

Post by hvdd »

there was a problem with the temp sensor, i had 4 times one broken or short circuit.

Felix send me some others - replaced and i have no problem anymore.
i have seen several DIY 3D printers and felixprinters is the best compared to others.
considering price, possibilities , support and quality.
the new sensor is now in for more than one month without problems .

for me problem solved .
rgds

Lioric
Posts: 116
Joined: Wed Aug 15, 2012 1:13 am

Post by Lioric »

If you read my previous posts (specially the "I'm done fighting the extruder") then you already know that I'm on my fifth thermistor, so I know about its issues. The thing is that for me all those thermistors were damaged as a result of the constant dismantling of the hot end to unjam it. The wires are really fragile and are not meant for constant manipulation (a thermistor is just a thermal dependant resistance, and very very hard to just "blew"). And seeing that your have to disassemble the hot end constantly as well, then your thermistor issues most probably are related to that (and have nothing to do with a bad batch or underspecs)

Anyway, that is the reason I'm replacing the stock extruder with a E3D unit

hvdd
Posts: 71
Joined: Tue Jul 24, 2012 11:43 pm

Post by hvdd »

yes, it is possible that dismantling the head is a part of the problem, i agree.
in the beginning i had also to unjam the head after each print...
the last 2 months ( printing almost every day or night and in different colors) i did'nt have to do it anymore.
just change in the softwaresettings retract to 0.5 and problem solved .... and printing at 195° for PLA.
and for each print i modify manually the Gcode at the end. E-10 to E-1
it seems to work for any color, at speed 100.

my experience is , if hot PLA is coming above the isolating part of the hot end and cool down overthere,
next time you have to dismantle the head.

rad
Posts: 36
Joined: Thu Apr 18, 2013 7:33 pm

Post by rad »

Didn't wanted to post to the thermistor thematic anymore to not start a fight.

The following is my personal opinion:
I consider it as a bit unlikely that you can damage a thermistor through dismantling that it changes it's base value to another one.
You can have shortcuts and open wires and an instable on/off connection. But getting a value change through this would be a bit strange. It's not that the 300 kOhm that my sensor has at 25deg now is instable in anyway or changes when I move around the wires a bit.
The only thing I consider as a possibility that could have an affect on it is water. Of course I used water to clean my extruders.
Water in combination with high temperature can have a destructive effect when it gets to the thermistor.
However the thermistor/thermistor capsule has to be designed that the water on cleaning shouldn't be a problem

The Extruder I used was one of the new ones and it wasn't in contact with water for a longer time (1 or 2 days)
The TempSensor was ok before and it gave in after the 10hours. The only thing I see that could have caused this is the high temperature itself because there isn't anything else there.

It wasn't so clear on my previous thermistors due to the heavy dismantling and cleaning procedures I did. In this case however I see it as rather very impossible that the failure is caused by a dismantling.

p.s. Just a loud thought: The soldering of the thermistor contact is inside that thermistor capsule. Normal tin-solder does not hold that temperature and melts. This could be one cause in case it hasn't been taken care to take the right solder. There is a lot in this capsule. So it doesn't necessarily has to be the thermistor itself inside that capsule that fails. Although for me it most looks like it is the thermistor itself.

Lioric
Posts: 116
Joined: Wed Aug 15, 2012 1:13 am

Post by Lioric »

And there you have it, nothing to do with bad thermistors or underspec'ed

Water and thermistors DO NOT MIX. You can clean with ethyl alcohol based cleaners,but not water.[1]
Water in combination with high temperature can have a destructive effect when it gets to the thermistor.
However the thermistor/thermistor capsule has to be designed that the water on cleaning shouldn't be a problem
They are NOT designed to withstand water and even less, thermal shocks from water and heat, that produces small cracks in the ceramic, and as you might already know, that changes the resistance and results in what you are experiencing

[1]From B57560G104F datsheet page 12: "Cleaning agents based on water are not allowed."

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