Temp sensor error

[bez 9]

Hi Guys,

I have recently taken the hot end apart on my UM2 to check the PTFE isolator as I have been suffering some really bad under extrusion ....... upon inspection I discovered the isolator has deformed after about 280 hours of printing <240°C :(

Long story short I wanted to get the nozzle off to clean it properly as even after a few atomic pulls it was coated with some gunk ....... but the PT100 B Sensor (I think that's the name for the smaller one that inserts into the nozzle block) was jammed solid into the brass block, i thought i was gentle enough in my approach to wiggle it free but I guess I broke it as when i tuned it on again i got the:

"ERROR STOPPED - Temp Sensor ........ Contact support@ultimaker.com"

........ My first response was "you idiot ...... you need to print something this week and now you have gone and broken it" No problem I thought I will order another however NO STOCK :(

Is there another option to replace the sensor? Or do I have to wait for stock to become available?

Edit: Also any suggestions on how to remove the sensor from the block?

 

[gr5 2,265]

To remove the sensor someone said to put a small wood screw in there that is the right diameter to get a good grip then pull it out with pliers.

The sensor is repairable. Split it down the side with dremel, locate the tiny temp sensor (it's very very very small - like grain of sand) and attach it to fresh wires and pack it back in there with maybe kapton tape. Beware normal solder melts well below 230C so you need solder that is mostly lead. Check melting temp of the solder before using it. Good article on melting points of different types of solder in wikipedia.

Kapton tape can handle 300C no problem.

 

[bez 9]

Thanks for the reply, I've ordered up some 300c melting point solder, I will also pick up a couple of spare sensors from the place 3Poro mentioned in his topic.

I need to order up a couple of isolators from ultimaker, so i will give it a couple of days to see if they respond to my email. In the meanwhile I'm going to gather the parts/materials for the repair job. Why is it these things always happen when its the worst possible time for the machine to have down time? lol

 

[donmilne 2]

Isn't the temperature probe a standard component? E.g. I see hundreds of PT100 temperature probes on RS, though it would be nice to have a less generic part number.

 

[bez 9]

I've ordered a couple of 3mm diameter probes to replace the one that's stuck in the block, I will just solder it to the existing wires from the dead sensor ....... not that I plan to use more than 1, but as sods law tends to go if you don't have a spare you can gaurente you will need it lol

 

[bez 9]

Good news: I finally managed to pry the little bugger out of the brass block

Bad news: I still have to wait for parts to arrive to fix it :(

 

[donmilne 2]

Ordered from where? Do you have a link for the part you ordered?

 

[bez 9]

I ordered a few from here http://www.tme.eu/en/details/pt106054/resistive-temperature-sensors/

I found the link in this topic: http://umforum.ultimaker.com/index.php?/topic/5431-thermocouple-failure/%20It%20seems%20to%20have%20worked%20for%203Poro%20so%20fingers%20crossed%20it%20does%20the%20job%20for%20me%20also

The part is such a fragile design, the next challenge will be dissecting the armor on the cable to get enough wire to allow me to solder the new sensor to.

Oh you will also need some high temp solder, the brand multicore do a 301c solder, I just bought a length of 1m from ebay to cover this particular task as all my other stuff is about 260-280c melting point.

 

[gr5 2,265]

Unlike thermistors, all PT100 sensors have the exact same temperature to resistance curve. Which means you can use any pt100 sensor that will fit.

With thermistors, there are hundreds of different kinds of 100K thermistors. All of them are 100K at 25C but are varying resistances at 100C depending on the "beta" value.

 

[bez 9]

erm yeah ........

So it looks like i will be testing out the uber fine tip on the soldering station later lol I also predict lots and lots of swearing lol

Edit: I think i will try getting one of these also as a backup plan

 

[bez 9]

Update:

Well good news, the sensors arrived from Poland in under 48hrs, and the high temp solder arrived this morning.

A couple of things to note:

 

• The sensors arrived were 3.1mm and just a tiny bit too tight for the existing hole, nothing a 3.1mm brill bit and VERY slow drilling couldnt cure. Sensor slides in and out no problem without slopping about. Grub screw locks it snugly into place.
  
• I tied a peice of string to the wire to make re running it through the mesh easier, you will have to cut off the heat shrink both ends of the mesh, Personally i didnt bother replacing the mesh by the control board as it would be a nightmare to unplug/screw all the wires. Where as the top is really simple. Lets face it you only see the top one anyway
  

My new PTFE isolator hasn't turned up yet but i smoothed out the old one a bit just to get the sensor tested and I'm pleased to say its all back together and working fine and dandy. I need to calibrate it properly but I will do that after I fit the new isolator.