[SOLVED] Temperature drop during print

Vertex 3D Printer Vertex - Issues while printing
21

Those values seem to be the usual ones (I can’t check right now as I’m at work far from my printer).

22

Did you check the wiring to the thermistor at the print head? It can shake loose during a print, that might be why you see sudden variations in your temp graphs over the duration of the print. I had something similar, and unscrewed and refastened all those little wires that go to the green connector in the head.

056.jpg1024×751

Next print was perfect and back to normal.

23

[quote=“raby”]You could try tuning the PID parameter. The goal is to stabilize the temperature curve.
[/quote]

Guy, you’re amazing!!!
I did it and i had no temperature problems since then!
Thank you so much for your help!

Also thanks to all the other people wo helped me out!
I really appreciate this forum! :slight_smile:

Best,

24

Glad you could solve your problem. Happy printing :slight_smile:

25

Hi there,

had the same issue again! Did the same approach as last time.
The result is devastating. My whole printhead is screwed… What can i do now? :(((

Thanks for help :<

26

so, here’s the unmounted printhead. Guess the temp.sensor didn’t measured the correct temp so the heater cartridge overheated…

27

Yes that looks like it. The original sleeve wears out pretty fast. I used kapton tape in the past to get it a tight fit in the hole. That worked for me for a long while.

Kind regards
JeAfKe

28

Make sure your thermistor is properly installed.
Spare parts can be ordered on the following link.

support.velleman.eu/

29

[quote=“VEL678”]Make sure your thermistor is properly installed.
Spare parts can be ordered on the following link.

support.velleman.eu/[/quote]

Thanks for your reply, the thermistor is perfectly installed.
As you can see in the posted picture it sits thight an and the wires have the slight twist to holt it in place.
That thermistor caused trouble some months ago as you can read in this thread.
I fixed it by calibration the autotune PID, so it worked a while but now finally stopped working, obviously. Caused in the complete meltdown.

So this printer isn’t 7 months old, shouldn’t that be covered by warranty? A defective thermistor that causes a overheat is a malfunction, isn’t it?

I opened a ticket on Jan 15th, but until now haven’t heard from you.
Thanks in advance for your help!

Best,
Mario

30

Just as follow up:

Velleman where kind enough to sent me the required spare parts! So thanks a bunch for that!
I’ll post it here when they arrive and hopefully a report that everything works like a charm :slight_smile:

Knock on wood!

Best,
Mario

31

Also make sure both fans keep running while heating and cooling down. They don’t need to be on 100% but just make sure they move a little bit of air.

Kind regards
JeAfKe

32

[quote=“jeafke”]Also make sure both fans keep running while heating and cooling down. They don’t need to be on 100% but just make sure they move a little bit of air.

Kind regards
JeAfKe[/quote]

They’re always on :slight_smile:

33

I’m sorry for your problem, but from my point of view this is due to a design weakness.

Please remember your physics teacher:

What happens to a rod if you heat it up: yes, it becomes longer.

How is a ring changing, when heated up: the inner diameter will widen.

Now you put a thermistor into this inner ring. What do you expect?

My explanation is:

  1. the opening in the brass block is widening.
  2. The thermistor in the isolator tube will follow the temperature, but:
  3. the thermal coefficient of the brass is much larger than for glass, any gap between sidewall of the brass hole and sidewall of the glass will increase.
  4. if the distance between brass block and thermistor becomes larger, the thermal resistance increases, generating a temperature drop between brass block and thermistor.
    Be aware, that the white isolator tube is also a thermal isolator, which is generating an in-situ temperature drop between the brass block and the thermistor.
  5. You have the fan always on: you are cooling the electrical connections to the thermistor and by this the thermistor too. The heat transferred from the brass block to the thermistor is removed by the cables, reducing the effective temperature of the thermistor and consequently increasing the nozzle temperature.

With this mechanism you will loose thermal control over the time.

One comment to the Kapton solution: If the gap between the brass hole and the thermistor with isolator tube is still that large that a kapton tape will fit in the hole, it will be an improvement, even if Kapton is a thermal isolator, too. It is much better than air.

The only improvement I can think about is to use silicone based thermal paste, which should be applied excessively inside the isolation tube (around the thermistor) and within the brass hole. Make shure that this paste is not conductive!!

Finally, try to measure the temperature in the nozzle. This will give you an idea about the remaining temperature error.

However, I didn’t like this workaround, I did a little homeworking.
http://forum.velleman.eu/viewtopic.php?f=62&t=15032&p=76296#p76296
http://forum.velleman.eu/viewtopic.php?f=64&t=16458

34

Replacement Parts from arrived! Everything works perfect now!

THANKS A BUNCH!

35

either the hotend wire is compromised or the thermistor wire is damaged…First double check all of your connectors from the board to the hotend. What type of power supply did you swap it with?