Heatbed Question

[goetzmoritz]

Hi there,

recently I broke my glas-Heatbed and had a similar round shape made of aluminium laying around useless in my garage. it's exactly 3 mm in height and 280 mm in diameter.
I cleaned it, put some 3M-paper-tape on and installed it on the printer. Of course I had to re-do the PID-tuning of the heatbed and the z-max-position but afterwards I was ready to go.

After I printed the first 3 layers the printer just went offline just like a fuse stopped it from working. When I tried again the same thing happend after layer 1. And after that it happend just beforde even it started printing.

My question is now: What's about the glas-plate? Is it mandatory that it is glas? Why not aluminium as it stores the heat much better? And why does the printing just stop?

Thanks and greetings

goetzmoritz

[Eaglezsoar]

Hi there,

recently I broke my glas-Heatbed and had a similar round shape made of aluminium laying around useless in my garage. it's exactly 3 mm in height and 280 mm in diameter.
I cleaned it, put some 3M-paper-tape on and installed it on the printer. Of course I had to re-do the PID-tuning of the heatbed and the z-max-position but afterwards I was ready to go.

After I printed the first 3 layers the printer just went offline just like a fuse stopped it from working. When I tried again the same thing happend after layer 1. And after that it happend just beforde even it started printing.

My question is now: What's about the glas-plate? Is it mandatory that it is glas? Why not aluminium as it stores the heat much better? And why does the printing just stop?

Thanks and greetings

goetzmoritz

There are areas on the heat bed that must be covered by Kapton tape before using anything made of metal is placed on the heat bed. They are known as vias or "through holes" and are identified as small silver colored holes on the surface
of the heatbed. If these are not covered by Kapton tape, the metal plate can short them out and blow the fuse. I also recommend covering the aluminum plate with the glass as it helps to maintain flatness and gives the ability to
easily remove the glass for cleaning or parts removal. Happy Printing!

[goetzmoritz]

I just put some original Kapton-tape on top of them but still having this issue. What could it else be? I just fixed the broken glas-plate, tried it on and it worked like a charm, so I'd also think it's fuse that fires, but I don't see where. I covered every bit of the alu-plate with ductape, so it doesn't conduct electricity after all I guess.

[Eaglezsoar]

I just put some original Kapton-tape on top of them but still having this issue. What could it else be? I just fixed the broken glas-plate, tried it on and it worked like a charm, so I'd also think it's fuse that fires, but I don't see where. I covered every bit of the alu-plate with ductape, so it doesn't conduct electricity after all I guess.

Are you sure that you covered all the vias with Kapton tape? Inspect the heatbed closely and make absolutely sure that they are all covered. What you are experiencing is illogical except that something must be shorting.
Duct tape really is not the correct tape to use on a heatbed of a printer, it turns brittle and the adhesive is not designed to for the type of temperatures experienced.
Normally the heatbed vias are covered with Kapton Tape and the the aluminum is placed on top with no issues. While inspecting your plate look for any silver or solder colored areas anywhere on the Bed and put a piece of Kapton on
those areas.
Also if the printer continues to have this issue, look at the lcd display and see if the word def is displayed anywhere on the display. That would indicate a problem with the thermistor. It is possible that the weight of metal is somehow
causing the thermistor to short. I am searching for straws here because this is not a usual problem.

[goetzmoritz]

Now I'm very sure that I covered everything as I covered the whole alu-plate with kapton. Besides the fact that I covered every hole (even the metal-screws) of the onyx-bed with kapton twice.
But I'm still getting this failure. I tried glas again, it works. What can that probably be? I really don't get it as it looks illogical to me too because the aluminium of the plate is not in physical contact with the onyx-board at all!

edit: the aluminium-plate is not heavier than the glas-plate I guess but I didn't measure the exact weight.

edit: No the LCD doesn't say anything, it just turns off.

[Eaglezsoar]

Now I'm very sure that I covered everything as I covered the whole alu-plate with kapton. Besides the fact that I covered every hole (even the metal-screws) of the onyx-bed with kapton twice.
But I'm still getting this failure. I tried glas again, it works. What can that probably be? I really don't get it as it looks illogical to me too because the aluminium of the plate is not in physical contact with the onyx-board at all!

edit: the aluminium-plate is not heavier than the glas-plate I guess but I didn't measure the exact weight.

There is no way that the Onyx can possible know what is setting on it so it continues to look like a short is taking place. Where or how is what does not make sense.
One thing I would try is to take a multimeter set to a medium ohms settings and making sure the printer is off, take the black lead of the multimeter and connect to a
black wire (ground) connection of the Orion and the red lead to the aluminum plate. If any resistance is measured that would indicate a problem.
What happens with the aluminum plate in place with the glass on top of it, does it work under those conditions? (don't forget to reset your z-height)

[goetzmoritz]

I guess it was a problem with the heating element and the thermistor as the multimeter showed no extension. After all I bought a new glas plate. strange issue anyways and I didn't solve it. Thanks anyways!