Inconsistent Heat Bed Temperature
Hello everyone,
Summary
I only have been printing since April so I am pretty new to this so forgive my ignorance. I am having a lot of trouble troubleshooting my Prusa i3 for the last two weeks where the temperature of the heat bed keeps bouncing around. I have checked the Rambo and tightened terminal 3 times and still the same problem still happened. Just yesterday I found that some glass from the bed fused to the bottom of a part... and I honesty have no idea what to do now or where to start.
Problem in Detail
Again my temperature doesn't stay consistent, I primary print in ABS and set my temperature at 255/100C for my settings. The temperature bounces between 85C ~ 100C, it stays at 100C for the first few minutes of a print then sinks down and back up again later in the print which repeats.
What I Tried/Use
I tried opening up the Rambo and checking if anything was melted and found nothing, I tightened the terminals and check the wires for my damage and again nothing was found. For my gcode, I use Simplify3D and I use the profiles that was supplies from the forums and only made little changes to the settings. On the glass bed, I only use a glue stick and ABS spray before I heat up the bed as well as calibrating the Z-Axis before every print.
Misc Info
I have the printer in a enclosure to help prevent warping and keep a consistent temperature also because I don't want my cat getting into it.
Here are some pictures that I took yesterday afternoon
Bottom of the Part (I tried to sand it off)
Glass Bed, there's nothing stuck to it, I can feel it concave down
Re: Inconsistent Heat Bed Temperature
Hi Kenzo,
Regarding the temperature, there a several factor that can explain that. Does this happen if you print without fan activated, or with low fan percent ? Does it take a very long time to reach 100 °C ? (Mine which is isolated from below with a cork tile reach it in 10~15 minutes). Is the bed temperature sensor sticken well under the bed ?
Regarding the glass it's impressive ! I didn't know it was possible ! Do you print with layer of glue, and with ABS jiuce on top of that or directly on the glass (it seems very clean) ? Did you wait the bed to cool down before unsticking the printed part ?
I'm like Jon Snow, I know nothing.
Re: Inconsistent Heat Bed Temperature
Hi Kenzo,
Regarding the temperature, there a several factor that can explain that. Does this happen if you print without fan activated, or with low fan percent ? Does it take a very long time to reach 100 °C ? (Mine which is isolated from below with a cork tile reach it in 10~15 minutes). Is the bed temperature sensor sticken well under the bed ?
Regarding the glass it's impressive ! I didn't know it was possible ! Do you print with layer of glue, and with ABS jiuce on top of that or directly on the glass (it seems very clean) ? Did you wait the bed to cool down before unsticking the printed part ?
- Fan speed is at 100% during the print process
- Not sure if it's long but if I can remember, maybe 15-20 min for it to hit 100C
- The Sensor is not loose and flat against the bed
- I apply glue first (I apply at least 3 layers) and let it dry, spray ABS Juice on top, and then start the Pre-Heating Process
- I cleaned the glass after the parts was taken off because I thought at first it was a blob of ABS Juice stuck to the glass and so it will show up in a picture better
- The print was finished when I went to work in the morning (I printed overnight) and didn't take it off the glass in'till late afternoon.
Re: Inconsistent Heat Bed Temperature
Hi Kenzo,
Fan should be disabled for ABS printing, this can give you issues as shown in the thread http://shop.prusa3d.com/forum/prusa-i3-kit-building-calibrating-first-print-main-f6/bananas-t860.html , and a constant 100% explains the nozzle temperature variation.
If you search a bit in the forum, you'll find a modified version of the fan duct published by Peter (user PJR) which reduce the fan flow on the nozzle.
For your glass you are following the proper process, strange.
You can order a proper spare glass on the PR shop site, or go to your closest hardware store to buy some 20*21 3 mm glass.
Tempered glass is recommended, however since I didn't find any on local store I use 2 mm standard glass with no issue until now, and for the price (some euros for 3 glasses) I do not care if I break one, which never occurred.
That way, I have one with Kapton sheet for PLA, and 2 spare glasses (in addition to the one provided with the printer) so that I always have one ready when needed 🙂
I'm like Jon Snow, I know nothing.
Re: Inconsistent Heat Bed Temperature
Hi Kenzo,
Fan should be disabled for ABS printing, this can give you issues as shown in the thread http://shop.prusa3d.com/forum/prusa-i3-kit-building-calibrating-first-print-main-f6/bananas-t860.html , and a constant 100% explains the nozzle temperature variation.
If you search a bit in the forum, you'll find a modified version of the fan duct published by Peter (user PJR) which reduce the fan flow on the nozzle.
For your glass you are following the proper process, strange.
You can order a proper spare glass on the PR shop site, or go to your closest hardware store to buy some 20*21 3 mm glass.
Tempered glass is recommended, however since I didn't find any on local store I use 2 mm standard glass with no issue until now, and for the price (some euros for 3 glasses) I do not care if I break one, which never occurred.
That way, I have one with Kapton sheet for PLA, and 2 spare glasses (in addition to the one provided with the printer) so that I always have one ready when needed 🙂
Sorry if it's a very stupid question, even with the fan ON the hand-full of parts I printed was perfect (Besides the one that ruined the glass lol) so what relationship does the cooling fan on the extruder have with the heatbed temperatures jumping around because the extruder temperature was fine on my end?
Re: Inconsistent Heat Bed Temperature
Hi Kenzo, the glass can do this sometimes, when we used regular non hardened glass, this happened in 50% of prints. You can rotate the glass while you wait for a new piece 🙂
Fan should be disabled for ABS, it is the reason for temp drops. Can you verify it is the cause?
Re: Inconsistent Heat Bed Temperature
Hi Kenzo, the glass can do this sometimes, when we used regular non hardened glass, this happened in 50% of prints. You can rotate the glass while you wait for a new piece 🙂
Fan should be disabled for ABS, it is the reason for temp drops. Can you verify it is the cause?
I will check it out later, I'm currently at work so I'll update when I get time to do it.
Re: Inconsistent Heat Bed Temperature
Sorry if it's a very stupid question, even with the fan ON the hand-full of parts I printed was perfect (Besides the one that ruined the glass lol) so what relationship does the cooling fan on the extruder have with the heatbed temperatures jumping around because the extruder temperature was fine on my end?
There's no stupid question, and my answer was too much focused on the extruder temp.
But the issue with the fan can be the same for the heatbed, because the fan blow below the extruder. As Pepa told, can you check with the fan off ?
I'm like Jon Snow, I know nothing.
Re: Inconsistent Heat Bed Temperature
Extruder fan should always be on. The part fan needs to be off.
Re: Inconsistent Heat Bed Temperature
Sorry if it's a very stupid question, even with the fan ON the hand-full of parts I printed was perfect (Besides the one that ruined the glass lol) so what relationship does the cooling fan on the extruder have with the heatbed temperatures jumping around because the extruder temperature was fine on my end?
There's no stupid question, and my answer was too much focused on the extruder temp.
But the issue with the fan can be the same for the heatbed, because the fan blow below the extruder. As Pepa told, can you check with the fan off ?
So I turned off the part cooling fan which solved the problem and the temperature is now stable on the heatbed 🙂
I printed from Slic3r and Simplify3D just to make sure there isn't any differences in the same problem, just gotta adjust something since the part of I printed using S3D came a little messed up oh well.
Only other problem is I gotta find a new sheet of glass or wait for my back order for the MK2 ¯\_(ツ)_/¯
Extruder fan should always be on. The part fan needs to be off.
That was what I meant to say, long day at work... haha oops
Re: Inconsistent Heat Bed Temperature
Extruder fan should always be on. The part fan needs to be off.
That was what I meant to say, long day at work... haha oops
I think we all meant that, but Richard is right to point that to avoid ather new user to get confused by that.
I'm like Jon Snow, I know nothing.