There seems to be a number of threads now talking about print bed temperature for the UM3 and 3X. I wonder if the worldwide fleet is aging together and hitting the same issues in batches. We're seeing a lot of worn and broken capacitive sensor wire questions for example.
Would there be any interest in trying to consolidate the print bread temp stuff together on a topic? Maybe with a guide to diagnosing issues and possible fixes?
J
1) the bed temperature: does it also show as way too hot on the temperature logging page?
2) the hotend: the most likely cause is the printhead's front fan not spinning correctly anymore this causes the hotends to heat up beyond the heat break and can be caused by very thin strands of filament ending up in the fan.
The fact that your hotend melted the plastic at the top of the hotend probably means you have indeed baked you Teflon insert in the hotend (this shouldn't be heated to PLA melting temperatures!!! that damages it for sure).
So like @gr5 said you should replace the hotends, but the cause is likely still there (E.G: a broken fan) so I'd advise you to replace/clean/fix the fan as well.
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3 hours ago, robinmdh said:1) the bed temperature: does it also show as way too hot on the temperature logging page?
Could I ask two (hopefully) related questions regarding troubleshooting the heated bed?
a) I'm assuming the only correct way to validate the heated bed temperature is independently, ideally via thermal imager or IR thermometer. Is there a recommended surface treatment - i.e. PVA glue stick? I know glass is opaque in the wavelength range of these uncooled IR sensors, but as a smooth, specular surface it would still be prone to reflection errors. Would a matte glue finish be better?
b) In the event one does find a delta (cold or hot), is there any way to correct this without replacing hardware?
Thanks and sorry for any inadvertent thread drift.
John
Hi @JohnInOttawa,
As I've been a teacher in IR theory and how to use those cameras that's installed/used in mission helicopters ( rotary wing) and mission aircraft (fixed wing), -allow me to answer this one.
The infrared specter consist of three band: Lo band - Medium band and High end band.
For 3D printing we are in Lo and Medium infrared spectrum band.
The colors is a key factor when it comes to heat radiation in our 3D printing "temperature area".
Black is the color that radiate and attract heat best! Withe is the poorest heat radiator in both, radiating or attracting heat!
All this is widely explained int the thermodynamic theory.
This also tell us why some type of color is harder to use than other..
In order to measure the "most" correct temperature from a "surface" for calibration check, we mark it with a black spot (very thin layer black matte color). For the high end temp a boiling kettle (aluminum type) of water 100 deg Celsius and for the lo end zero deg. Celsius we're using a mix of water plus ice cubes that's stirred. Aluminum is used the cold end container.
To measure the temperature of the glass surface of the bed, use a black white board pen and make a big enough spot to measure on for your type of camera an you'll read the most correct temperature.
You may also use the above method, to check your IR thermometer using same distance from object to IR sensor.
Good luck
Thanks
Torgeir
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Thank you @Torgeir. It's too bad there is so much distance. It would be good to be able to chat about some of this, and a number of other areas of your clear expertise.
You'll clearly understand the background behind my question. My imager is uncooled, a Fluke TI32, 7.5 μm to 14 μm, so toward the long end of medium wave. While I can certainly treat the glass to enhance emissivity with a matte finish, my hope was to try to use an in-service material, like a PVA coating, to do this. Mostly because I am too lazy to have to remove and retreat the surface afterward 😉 , but also because I can get a nice big spot size that way and control reflections.
What I may do just for fun is take a glass build plate and stripe it. Clean, PVA and dry erase black. I'll try and post the result here.
Thanks for your post - Inspired experimentation!
Cheers
John
On 3/2/2021 at 4:48 AM, JohnInOttawa said:There seems to be a number of threads now talking about print bed temperature for the UM3 and 3X. I wonder if the worldwide fleet is aging together and hitting the same issues in batches. We're seeing a lot of worn and broken capacitive sensor wire questions for example.
Would there be any interest in trying to consolidate the print bread temp stuff together on a topic? Maybe with a guide to diagnosing issues and possible fixes?
J
On 3/1/2021 at 2:36 PM, gr5 said:The second problem is probably related to your core - the teflon inside is probably too big of an inner diameter. If it's at all old I'd just get a new one. Or try your other AA core. Core's are considered expendable and when you think about it you spend MUCH less money on cores than on filament.
Do you have an IR temperature gun? How do you know it's too hot? This is pretty rare for the print bed - if anything it tends to be the other way around - increase resistance makes the temp sensor read too hot even though it isn't and the bed ends up being too cold.
Hi , the printcores have just very recently been replaced , is there anything else which could affect this ? cheers.
Yes! The fan as robinmdh said. If the front fan (not the side to fans - the fan in the print head) stops spinning then that's the problem. You can manually heat one or both cores and as it passes around 40C or so the fan should start up.
The newer cores might be faulty. I kind of doubt it but it should be a strong possibility. Try an old core if possible.
I didn't ask the first time but - how did you get the filament out if you couldn't get the filament out?
Hi John,
Hi John, thanks.
I do not want to worry too much about the reflection in this situation, as the object is rough and has no real reflection surface, but also because you're very close to the object with minimal conflict issues.
We do worry much about that, when doing "thermal photography" inspection of power lines, this as those "big" splices are made of aluminum that's having (when it is not oxidized) a mirror like surface. Under such conditions, we sometimes got reflection from the helicopters turbo engines "exhaust duct" (or other external heat sources) when trying to read the temperature here, -we would get the radiation from the "hot failed splice" plus the added radiation(the mirrored radiation) from the helicopters exhaust duct. So we are reading to high temperature. To avoid this we just move the helicopter to another position..
I would like to see the result of your emission test experiment. Another one might be to see how good/even the "surrounding" heat will be around a "bigger" object when printed. Just to see if there's any cold zone that may develop warping, would be very interesting I'll think..
Did you ever have a problem with low bed temperature?
Hmm., -this bed test will tell. 🙂
Very interesting.
Cheers
Torgeir
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gr5 2,271
The second problem is probably related to your core - the teflon inside is probably too big of an inner diameter. If it's at all old I'd just get a new one. Or try your other AA core. Core's are considered expendable and when you think about it you spend MUCH less money on cores than on filament.
Do you have an IR temperature gun? How do you know it's too hot? This is pretty rare for the print bed - if anything it tends to be the other way around - increase resistance makes the temp sensor read too hot even though it isn't and the bed ends up being too cold.
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