Broke fan, and noticed extruder motor getting extremely hot.

[sapient24]

I have been having extruder problems on my Replicator 2, and was making sure nothing was jammed and such. When I was resembling the extruder assembly, my hex screwdriver slipped and broke the fan.

I then started the loading filament process, and smelled burn, and saw smoking coming from the assembly. My thinking was that it was probably the fan, so I went to unplug the fan, when I notice that the extruder motor was extremely hot. I had just started the loading process. I did test and it heats up quickly. I would say around 60-110C. Scary hot that I had to turned off the machine and unplugged.

My questions are if I may, could this possibly just because the fan broke. I doubt it.
Second. Could I just replace the motor, or could this be a problem with the board, or wiring? The exposed wiring looks fine to me.

FYI The fan I speak of is the one in front of the machine. And my machine has 800K hours.

[sinful]

Hi sapient24,

you should check the extruder assembly again, maybe some broken pieces of the fan got stuck somewhere in between motor and the extruder kit, make sure you clean everything there. You should chance the fan anyways because you wont be able to print anything good with the broken fan. check the connections on the motherboard if there is no burned connectors. It would be great if you post the picture here, how your assembly looks like, and how many fins the fan got left Total absence of fan could cause overall heat increase in your assembly too.

[Mjolinor]

They do run scary hot. Presumably you touched it and thought it too hot?

Try the other one, is it the same temperature?

think you should not worry, you would be surprised how hot they can run and I doubt that it would be over 100. If it is then you can lick your finger and touch it, it will hiss if it is over 100 c.

[sinful]

They do run scary hot. Presumably you touched it and thought it too hot?

Try the other one, is it the same temperature?

think you should not worry, you would be surprised how hot they can run and I doubt that it would be over 100. If it is then you can lick your finger and touch it, it will hiss if it is over 100 c.

Its Rep2 I doubt it has second extruder you are right about the temperature, they tend to get hot, but usually after some work hours not instantly.

[sapient24]

Its Rep2 I doubt it has second extruder you are right about the temperature, they tend to get hot, but usually after some work hours not instantly.

I have worked with clogs before with the machine running, and never felt the motor get this hot. And yes, it does get hot fast.

[sapient24]

Hi sapient24,

you should check the extruder assembly again, maybe some broken pieces of the fan got stuck somewhere in between motor and the extruder kit, make sure you clean everything there. You should chance the fan anyways because you wont be able to print anything good with the broken fan. check the connections on the motherboard if there is no burned connectors. It would be great if you post the picture here, how your assembly looks like, and how many fins the fan got left Total absence of fan could cause overall heat increase in your assembly too.

I think I need to check connections to the mothe board. I'll have to google how to do this. Not really sure what I'm looking for. But I'll check for abnormalities and burn marks. I'll post pictures when I do this. thanks

[sapient24]

I took some pictures. I don't see anything wrong. Could it be the wire that heats up the nozzle, its next to where the motor would go. You can see in picture.

http://imgur.com/a/H9J9F

[sapient24]

I think you might be right Mjolinor. Maybe I just missed it before. The motor does press against the "heat block?". So it has to get hot somehow.

I had the motor running just hanging on the side, and it doesn't get hot. When I placed it on the assembly, it started to get hot immediately. And it doesn't sizzle on my wet finger, as well as with the heat block.

For now I'm going to see if I can run it, and meanwhile, I'm going to order a new fan and spring for my extruder.

[Mjolinor]

On my Wanhao I have added a Bakelite shim between the stepper motor and the heat transfer bar.

The risk with that is that it will prevent enough heat being removed from the bar and you will suffer melt back in the filament tube. Removing heat from that bar is what the fan does and it is critical to get it right. If too much heat is removed the filament will not flow and if not enough is removed then the filament will melt too far up the tube.

With a damaged fan the stepper will get hotter than normal but still probably not too hot and it will not print because of melt back.

Too hot to touch is quite a low temperature, certainly 60c is too hot to hold for more than a couple of seconds but a stepper is fine at that all day long.

[sinful]

I took some pictures. I don't see anything wrong. Could it be the wire that heats up the nozzle, its next to where the motor would go. You can see in picture.

http://imgur.com/a/H9J9F

sapient24,

thank you for pictures, I found the issue:
1. change your fan to the original one, and don't use cheap chineese junk, because it could lead to such problems.
2. your fan is looking the wrong way, so instead of blowing to the heat sink and cooling it, together with the bar mount and the motor, it sucks up the air from the heat sink and increases the heat inside your assembly.

Solution: Buy new fan from makerbot, mount it with the sticker looking inside and you should be good.

On a side note, you dont need any spacer between motor and bar mound to keep it cool, motor should be firmly attached to the aluminum block using 2 long screws which also attaches the fan and the heat sink to the whole assembly.