Solved Extruder heat loss

Last night I tried to print my second ever project. It was a 7" clock face that needed 6 hr, 45 min to print using PLA in high quality mode. After about 5 hours, the extruder temperature started to drop from 210 C and continued down to room temperature. While this was happening, the printer was whirring merrily along thinking everything was okay. In fact, once the temperature got below about 180 C the extruder could no longer pump the PLA out and the gears stopped moving. It eventually reached 24.6 C .The bed and the gantry continued moving along as though printing was still occurring.

To me this represents two problems, obviously the temp dropping is a big issue, but the fact that the temperature dropped so low and the printing continued is a second issue. In a better world, the printer would have paused once the temperature got too low and given the operator a chance to resume when the problem was corrected.

Anybody else see something like this? Is there a firmware update for my Robo 3D R1 that was one of the very first R1's to ship?

Am I looking at a bad heater, loose connection, or some type of software/firmware issue?

Thanks,

Mike

 

Keep the terminal window open during a print and be on the lookout for an error message.

A drop off like that might have been a polyfuse shorting out or it could be something more complex like a temp fall error.

Be sure your ramps fan is running.

 

I have an electronics background. Is there a schematic available for these Robo 3D R1 machines?

 

It's the same as any other ramps based board:

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http://reprap.org/wiki/RAMPS_1.4

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If I am reading that correctly, the block diagram and board schematic show no polyfuse symbols.

 

F1 and F2 under power are the polyfuse

 

Okay, I see the 5 amp and 11 amp polyfuses. Yes, the fan and the hotend heater run off the same 12v protected by the 5A polyfuse. As you suggested, I'll check to see if the fan is running when the heater quits.

Thanks!

 

Well so do the stepper motors. If your polyfuse is tripping everything will pause.

 

Yes, that means it's not the polyfuse because the steppers are still humming along.

 

Yeah I think it's probably a temp fall error. I don't know why mattercontrol hides that from users. That software man...

 

Is a temp fall error supposed to stop or pause the print job? As you know, mine just keeps printing along.

 

No. It'll just shut off the extruder

 

It is freezing outside so it's a good time to dig into this problem.

 

It didn't take too long to figure this out. There was no voltage at the connector for the heater at the head. I flipped the machine over and found the connections for the heater at D10. The black wire was touching the connector, but it wasn't actually being gripped by the connector screw. I loosened the screw all the way, inserted the wire and tightened it. Just to be certain, I tightened the screw on all of the wires in that connector and tugged on the wires. The 6 hr and 45 min is now under way and I am confident it will be fine now.

 

Glad you got it sorted. I generally try to avoid having people mess with wiring unless we eliminate all other variables.

QC definitely needs to do more pull tests

 

I'm having a similar problem with my Kickstarter PLA / ABS R1, but it's not a loose wire, unfortunately.

It started happening back in the fall, but I haven't had time to address it until now.
In the past, I've been able do full prints, but now, I can only get the extruder to heat up to temp for a short while before it starts losing temp stops working. If I start from "stone cold" I get maybe 10-15 minutes of operation. After that... I'm done.

I was sent a small cooling fan a while ago, but never got the instructions on where or how to connect it to the controller board.
Since I wasn't having a problem at the time, I didn't pursue it.

I suspect some kind of overheating, but don't know how to find out for sure.

I did email support and Brian got back to me with some questions, but he's at CES and can't help until he gets back. He suggested I try here in the mean time so I was wondering if anyone here might have any ideas.

Thannks,
Chris

 

When it trips off feel the smaller polyfuse. If it's too hot you need to be running a fan. If it's split open at the top then it's faulty and needs replacing.

The fan is just a 12v fan. Did it come with a connector on the bottom? Didn't really think fans required instructions...

Either of these points will work: http://i.imgur.com/25qxaXV.jpg http://i.imgur.com/zx6cYNb.jpg

 

It's a 40mm square fan. Yes, has a 2 pin connector, but I wasn't sure what pins it could go on. The photos help. I will try it out and see what happens.

Thanks

 

Note in the picture with the plug the black wire (negative) is closer to the view