Heated bed print quality issue

[Calan]

Hey guys,

I have a printrbot simple metal with an e3d v6 and the x axis heated bed v2 upgrade. I am having an issue where my print quality suffers when I print with the heated bed on.

You can see in this picture the difference between printed with the heated bed and without. Unfortunately the print didn’t stick without so that’s why its so small. (sorry about the fingers, My camera wouldn’t focus without them.)

This does not just happen near the bed. I have this issue on prints that are 150mm high.

I am printing at 200 degrees and the heated bed at 55.

Things that I have tried to fix this.

- PID tuning

- Reducing heat on both the hot end and heated bed

- Reflashing the firmware

- replacing the power supply (I now use a 500W with 40amp in the 12V channel)

- reducing extrusion

- tightened belts

- lubricated bearings

If anyone has any ideas on why this is happening, please let me know

[MSdesignCo]

With the heated bed, the upper layers might not be getting enough cooling once they are printed.

What material are you printing with and do you have a fan blowing on the parts?

Also, how rigid is the heated bed? It could be shifting around slightly during the print.

[k5o52]

What are you using on top of your heated bed? The kapton tape supplied by PrintrBot or other bed adhesives? From my experience I use either BuildTak with my PrintrBot + heated bed upgrade or 3M painters tape + wood glue (PVA). Without the added adhesives it isnt reliable as I want especially when printing larger objects.

[Calan]

Unfortunately I think your thought process is going in the wrong direction. My issue isn’t a bed adhesion issue. The issue is that the heated bed is causing lines in the print. I can get good adhesion with heated or not with a little adjustments. But I am using BuildTak.

[Calan]

I am using an after market blower fan focused at the hotend tip. At first I thought this was the issue as well but the fact that if I am printing high off the heated bed where the bed shouldn’t be affecting the print; I still get the issue. I don’t the issue at all if I am printing with the heated bed off. The bed is very rigid and I don’t think that it shifting would be the issue either because printing with it turned off, the print turns out just fine.

[Calan]

I have a theory, should PID tuning be done with the heated bed running. The issue looks kind of like in this link https://www.simplify3d.com/support/print-quality-troubleshooting/#lines-on-the-side-of-print .

[wirlybird]

If this only happens with the heat on and the bed was an upgrade then that is the clue. The heat from the bed would normally not cause anything like this. The most you would really see is warping or melting/collapsing from excessive heat.

My guess is that the heat from the bed is causing a mechanical problem with the mounting somewhere. Also, the heating circuit could be interfering with other electronics causing irregular operation of the steppers.

[Calan]

This seems like a good theory. This is the official printrbot heated bed upgrade so I couldn’t imagine that this heat isn’t accounted for. I know with some upgrade kits, it came with shielding but unfortunately mine didn’t come with it. I could try adding tinfoil to protect the board.

[wirlybird]

See how low you can run the heated bed. Maybe it can go low enough that the heat is at about room temp but it is still on and see what happens. Try to see if it is heat related or electrical.

[Perry_1]

Somehow, your heated bed is draining too much power, and your steppers or extruder is losing power when your heat bed turns on and off to maintain the print temperature. This is a classic power drain print, and the clue is always that the prints look like this when the bed is on, but not when it is off.

[Calan]

Hey guys, this has been solved the issue was that I didn’t enable PID tuning in Marlin. Once I did that, all of my issues went away. Thanks for the help everyone.

[Perry_1]

Yeah, that would have been my first guess, but you said you already did PID tuning!

[Calan]

Turns out that it doesn’t prevent you from doing PID tuning even when it isn’t enabled in the firmware. It just doesn’t do anything when you set it