My dual head printer worked perfectly for more than two months
In a next step I increased speed parameters within the specified values. I’ve printed a couple of parts with quite good results.
Today when printing a bigger part second hot end temperature suddenly went down to less than 150 deg. I had to stop the job.
Now printing with second extruder is not possible at all anymore. Also when choosing default cura settings.
After starting the job, temperature increases to 210 deg, but when the print head starts moving temperature drops off to 150 deg and I have to stop the job. Red lamp at the head is constantly on.
Everything else seems to be fine except that also the first hot end shows the irregular temperature behavior. It is not able to maintain the initial temperature of 210 deg anymore. After starting a job, temperature increases to 210 deg, but when the print head starts moving temperature always goes down to 190 deg and then fluctuates around 195 deg. 210 deg is not reached anymore. Red lamp at the head is constantly on.
As nothing was changed except the speed parameters I suppose electronic is defect.
Thanks. Was my first guess too. Cables are correctly stripped and connected, screws are tight. I’ve double checked. Nothing wrong there.
Voltage is around 13 V when preheating. But I’ve noticed that green connectors are getting pretty hot. Something wrong with the board?
Hi,
I’ve removed the board and examined each single solder joint. Like you I supposed a loose connection. But they are ok.
Something I’ve noticed in addition is that preheating is not possible once heating breaked-off. And unloading does not work. It seems that noozle first has to cool down completely before preheating is possible. Any idea or do I have to send main board to vellemann for replace / inspection?
You can open a support ticket here: support.velleman.eu
Did you check the screws for the thermistors as well.
You might try reloading the firmware.
Since you made some changes in maybe you accidentally change something else.
yes, I checked all screws, all solder joints. Everything is fine.
I’ve reloaded the firmware according to the instructions.
I’m using the default cura settings which come together with the software.
You can see how temperature in increasing up to 210 degrees C, then, when print head starts moving, there is a strange, short dropping, then temperature is decreasing. At a temperature around 150 degrees C extruder is not able anymore to feed filament and I have to stop the job.
Also the other print head is not able to maintain the specified temperature. But here temperature does not go below 190 degrees C.
I measured the cable from main board to extruder board. Actually one wire seems to be broken somewhere in the middle. I fixed it for the moment. Problem of nozzle 2 seems to be solved. I will ask Vellemann for replacement.
Still have the problem that the nozzle 1 is not able to maintain temperature. If I compare temperature plot https://drive.google.com/file/d/0B4SprONC86u8YWhaVnJnV0hQVDQ/view?usp=sharing
of both nozzles running exactly the same job I see that it takes much longer to heat up nozzle 1 and although I’ve increased target temperature to 220 degrees C actual temperature is around 205 degrees C. For bigger jobs it goes down to 190 degrees C.
Now I’ve also measured temperature at the nozzles. Although sensors are properly placed temperature seems to be too high. 240 °C instead 210 °C. Maybe heating is already at its limit. I will lower temperature, should be sufficient for PLA.
Hi,
last picture I have posted shows both extruders, I’ve switched from the second extruder to the first extruder for comparison.
Now I’ve set temperature to 180C. Actual temperature is around 200C. That’s what my temperature measuring device is telling me.
I think temperature sensors are not accurate.
Thanks.
[quote=“mats19”]I think temperature sensors are not accurate.[/quote]Certainly they’re not but there are two other reasons for the inaccuracy : bad thermal contact between the heater block and the sensor and the fan blowing on it.
[quote=“mats19”]Has the fan always to blow 100%?[/quote]The top one should (it’s cooling the PEEK tube). Anyway I’m slowing it down during the heating phase to let the heater warm up more quickly.As for the small one it seems it’s essentially cooling down the heater (I’ve modified its tilt so it doesn’t blow directly on the heater block). I’m only printing with ABS and after many month my PEEK tube is still alive.
Thermal compound is a good idea (avoid any conducting material).