hot bed rambo connector melt

[duvdev]

Hi all.

This is the seconf time I have this problem in the same printer.
As you can see in picture attached the negtive wire of the hot bed melted on the end when it connects to the rambo.
in the dirst time it happend I was told by seemecnc support to recheck the screw and to make sure it is properly close.
I did that and now in the middle of a 9 hours print i saw the bed is in 40 deg while set to 95.

can some one please advise.
I must make that printer ASAP

plwase help

[bot]

Next time you do it, make sure the wire, terminal, and everything that touches them are sterile clean. Also make sure the terminal is screwed as tight as it can be. And be sure not to tin the leads of the wires before inserting them into the terminal.

[duvdev]

I did all that after the first time.
Now I cant open the screw.
I messuered the current and it is 14 amps until it heat up to the temp I set and then drops down but while heating up the negative black wire gets really hot.

[Polygonhell]

This is pretty "common", if there is any sort of poor connection in the loop, it becomes a significant part of the resistance in the circuit and you end up dissipating watts of power at the bad connection point.

[lightninjay]

This is pretty "common", if there is any sort of poor connection in the loop, it becomes a significant part of the resistance in the circuit and you end up dissipating watts of power at the bad connection point.

I see wat you did thar

[jesse]

Upgrade to 12 AWG wire

[rpress]

Upgrade to 12 AWG wire

This.

The larger wire will run cooler, and it will also pull more heat from the terminal block.

[Eaglezsoar]

The 12 gauge wire that you are using is stranded and not tinned with solder, correct?

[rpress]

Ideally it would have a ferrule crimped onto it. The problem with tinning with solder is that the connection will loosen over time.

You could use wire that is tinned from the factory. The amount of solder on the wire is very minimal, just enough to keep it from oxidizing. With bare copper wire, what I like to do is to tin the end with solder, and then I hit the wire end against the table while it's still hot, so all the extra solder falls off. The usual disclamer with safety glasses and long sleeve clothing applies.

In any case though, I still tighten all the connections again. If this is going into a machine for somebody else, where it won't be re-tightened, then the ferrule is the right way to do it. With a proper crimp, the crimp is so tight that it's air tight; this way the copper does not oxidize.

[teoman]

I highly recommend silicone wire. The type used on RC cars and planes. It is a bit more expensive but much more pleasant to work with.

[teoman]

Well. Today I opened up my printer for an upgrade to a 24V power supply. Only to discover:

luckily it still works and is salvageable with a bit of work.

[Eaglezsoar]

Well. Today I opened up my printer for an upgrade to a 24V power supply. Only to discover:

IMG-20141120-WA0019.jpeg

luckily it still works and is salvageable with a bit of work.

Thank God that you got it before it became completely destroyed.

[duvdev]

To solve the problem once and for all is took 2 18 gage wire and soldered them in parallel. The I soldered one end to the rear of the Rambo card and the other end to the hot bed.
then I heat up the bed and then I checked that the wires won't heat.
they stayed at a low temp and I am happy with that.

[bot]

Another reason I'm glad I upgraded to a monster fan behind the rambo. It is directly cooling those wires as we speak. (I'm testing 50 micron layer printing with PLA. Going well so far.)