PTC Heater Thermal fuse and sensor addition

[Apfelwurm]

 

Hello guys,

i am adding a PTC Heater to one of my enclosed 3d printers at home.

I got myself this one: https://www.amazon.de/gp/product/B08P16773V/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

To protect the whole setup i want to install a 125c° thermal fuse, so i got these: https://www.amazon.de/gp/product/B0924KPSBB/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

Additionally, since it will be controlled with an SSR, i want to add a temperature sensor to it, so i bought these ones: https://www.amazon.de/dp/B0CJHRYSRB?psc=1&ref=ppx_yo2ov_dt_b_product_details

I have disassembled the heater and there is enough room at the top to fit the thermal fuse, if i remove a little bit of one of the plastic spacers.

The sensor is a bit more tricky, since the wires should go out on the side of the existing ones, and it has quiet a long "metal crimp tail" before the cable begins, so i can not fit it above or below. I already made sure that the metal part of the Sensor is not conductive with one of the pins, so i don't fry anything hooked up to it if it touches the bare metal of the heater.

Now i have a few questions:

• Do the 3 zones reach the same temperatures or is there one that gets hotter? so does the positioning of the termal fuse makes sense at the top? if one of the parts gets hotter, where to put the sensor?
• How do i attach the thermal fuse the right way? Thoughts i had:
  • Thermal glue, but could not really find anything that i can order in Germany that looked trustworthy
  • High temperature silicone, but i have concerns that it would not transfer the heat good enough to the fuse
  • drilling a hole into the heater and tapping it, adding thermal paste and simply screwing it into place, but as i don't understand how these heaters work, i did not want to risk damaging it
• How do i attach the sensor? Currently i only see drilling a hole (if it does not break the heater) between one of the cable ends and screwing it in there

 

I appreciate any help and information, since i could not really find anything that made me confident enough to do the modifications so far, since i really don't want to burn my house down

Thanks!

 

 

 

Edited April 6 by Apfelwurm

[RopusLongus]

First of all dangerous if the heater is powered by 110 or 2230 volts.

Second : the heater carddriges are between the metal ones (the white stuff were the cables are added)

The function of the heater is pretty simple : the ptc carddriges heat the metal and the airflow takes the heat from the metal to the environment.

 

Adding a thermal fuse is a good idea when you couple it with the ssr but a electronic heat control device (Amazon sells them about 18 to 90 Euro depending on what kind you get)

The simple version is like a bed heater where it takes the temperature from the metal fins and controls the on off cycles like a pid from a heatbed.

 

If you want to set up a environment control system you need actually 2 sensors ( one at the heater and one for the chamber) im not sure if you have to set them electronically in a row or parallel)

Remember the heater always will be hotter then the envirement air.

 

 

My system reaches 65 degree without any additional heater just by blowing air underneath the heatbed.

I did a pid at 100 degree with heaters at full speed and never got heatbed problems even with 110 degree using abs cf or pa 12.

But my chamber is fully isolated and has a double acrylic door.

 

If you still have questions write em down.

 

[Apfelwurm]

Hey, thanks for your answer

On 4/23/2024 at 4:05 PM, RopusLongus said:

First of all dangerous if the heater is powered by 110 or 2230 volts.

 

Thanks for pointing that out again, i'm aware of the dangers of that

 

On 4/23/2024 at 4:05 PM, RopusLongus said:

Second : the heater carddriges are between the metal ones (the white stuff were the cables are added)

The function of the heater is pretty simple : the ptc carddriges heat the metal and the airflow takes the heat from the metal to the environment.

Thanks for that explanation. So does that mean that the lower part with the bigger white stuff does get warmer? and does that mean i can drill into the metal (ofc without 220v attached  ) without damaging it and without changing its function?

On 4/23/2024 at 4:05 PM, RopusLongus said:

Adding a thermal fuse is a good idea when you couple it with the ssr but a electronic heat control device (Amazon sells them about 18 to 90 Euro depending on what kind you get)

The simple version is like a bed heater where it takes the temperature from the metal fins and controls the on off cycles like a pid from a heatbed.

If you want to set up a environment control system you need actually 2 sensors ( one at the heater and one for the chamber) im not sure if you have to set them electronically in a row or parallel)

Remember the heater always will be hotter then the envirement air.

My system reaches 65 degree without any additional heater just by blowing air underneath the heatbed.

I did a pid at 100 degree with heaters at full speed and never got heatbed problems even with 110 degree using abs cf or pa 12.

But my chamber is fully isolated and has a double acrylic door.

Yes, i have the SSR here and also an additional chamber sensor, and i'm going to control everything with klipper. I already have that in one of my printers, but that is implemented without any additional safety (and suboptimal sensor placement at the heater), why i only use it when babysitting it. Thats what i want to change with that one

On 4/23/2024 at 4:05 PM, RopusLongus said:

If you still have questions write em down.

Sadly to be honest, all of my questions above are still not really answered:

On 4/7/2024 at 12:18 AM, Apfelwurm said:

Now i have a few questions:

• Do the 3 zones reach the same temperatures or is there one that gets hotter? so does the positioning of the termal fuse makes sense at the top? if one of the parts gets hotter, where to put the sensor?
• How do i attach the thermal fuse the right way? Thoughts i had:
  • Thermal glue, but could not really find anything that i can order in Germany that looked trustworthy
  • High temperature silicone, but i have concerns that it would not transfer the heat good enough to the fuse
  • drilling a hole into the heater and tapping it, adding thermal paste and simply screwing it into place, but as i don't understand how these heaters work, i did not want to risk damaging it
• How do i attach the sensor? Currently i only see drilling a hole (if it does not break the heater) between one of the cable ends and screwing it in there

Thanks again, Alex

 

[RopusLongus]

12 hours ago, Apfelwurm said:

Hey, thanks for your answer

Thanks for pointing that out again, i'm aware of the dangers of that

Thanks for that explanation. So does that mean that the lower part with the bigger white stuff does get warmer? and does that mean i can drill into the metal (ofc without 220v attached  ) without damaging it and without changing its function?

Yes, i have the SSR here and also an additional chamber sensor, and i'm going to control everything with klipper. I already have that in one of my printers, but that is implemented without any additional safety (and suboptimal sensor placement at the heater), why i only use it when babysitting it. Thats what i want to change with that one

Sadly to be honest, all of my questions above are still not really answered:

Thanks again, Alex

Hi Alex,

The 3 heaters have a konstant temperature and usually should heat up the same (with a difference of 2-4 degrees).

 

The thermal fuse attachment depends of the manufacture type of it. If it is a cheap fuse that's blank then you can't atach it to the metal directly under the circumstance of a shortage (did learn that the hard way ). A ceramic one could be attached with some 300 degree silicone there is also a special silicone compund for ovens that you can buy at Obi or other markets in Germany. It gets hard as a rock after 2 days and can take up to 800 degree.

 

Drilling the metal is not such a good idea cause you can always have bad luck and hit some of the core. I would use a small housing in the air stream and atach the sensor there.

Edited April 25 by RopusLongus