why did my Printer melt?

[Phaedrux]

@Killernoy said in why did my Printer melt?:

every heater output is set to 100% at startup?

Every heater was on full power at startup?

[Killernoy]

This post is deleted!

[Killernoy]

@Phaedrux said in why did my Printer melt?:

@Killernoy said in why did my Printer melt?:

every heater output is set to 100% at startup?

Every heater was on full power at startup?

Yes

[Killernoy]

@Phaedrux said in why did my Printer melt?:

@Killernoy said in why did my Printer melt?:

every heater output is set to 100% at startup?

Every heater was on full power at startup?

3.0 beta12 2019-11-02b1

[Phaedrux]

Is it still doing it? Can you get an M122 diagnostic report from it?

[Killernoy]

@Killernoy said in why did my Printer melt?:

@Phaedrux said in why did my Printer melt?:

@Killernoy said in why did my Printer melt?:

every heater output is set to 100% at startup?

Every heater was on full power at startup?

Yes

correction not every just Bed and E2 E3 and E6

[Killernoy]

@Phaedrux said in why did my Printer melt?:

Is it still doing it? Can you get an M122 diagnostic report from it?

Yes it is

=== Diagnostics ===
RepRapFirmware for Duet 2 WiFi/Ethernet version 3.0beta12 running on Duet WiFi 1.02 or later + DueX5
Board ID: 08DGM-95BLL-N65TJ-6J9F4-3S46L-1JWVL
Used output buffers: 1 of 24 (1 max)
=== RTOS ===
Static ram: 25812
Dynamic ram: 99608 of which 0 recycled
Exception stack ram used: 256
Never used ram: 5396
Tasks: NETWORK(ready,1448) HEAT(suspended,920) DUEX(suspended,160) MAIN(running,3652) IDLE(ready,200)
Owned mutexes:
=== Platform ===
Last reset 00:00:43 ago, cause: power up
Last software reset at 2019-12-17 16:50, reason: Unknown, spinning module Webserver, available RAM 4992 bytes (slot 2)
Software reset code 0x40b2 HFSR 0x00000000 CFSR 0x00000000 ICSR 0x0041f80f BFAR 0xe000ed38 SP 0x20001ec4 Task 0x5754454e
Stack: 0044f28f 00450e22 81000000 00000000 40740000 3edb6db7 b7b4d800 3331bb4c 40000000 3f317200 b5ddea0e 388aa908 41e2ece8 00000000 00000000 00000000 00000000 00000000 40400000 80000010 00449277 00000001 004067db
Error status: 0
Free file entries: 10
SD card 0 detected, interface speed: 20.0MBytes/sec
SD card longest block write time: 0.0ms, max retries 0
MCU temperature: min 24.9, current 29.1, max 29.4
Supply voltage: min 0.3, current 0.5, max 0.6, under voltage events: 0, over voltage events: 0, power good: no
Driver 0: ok, SG min/max not available
Driver 1: ok, SG min/max not available
Driver 2: ok, SG min/max not available
Driver 3: ok, SG min/max not available
Driver 4: ok, SG min/max not available
Driver 5: ok, SG min/max not available
Driver 6: ok, SG min/max not available
Driver 7: ok, SG min/max not available
Driver 8: ok, SG min/max not available
Driver 9: ok, SG min/max not available
Date/time: 1970-01-01 00:00:00
Cache data hit count 132068223
Slowest loop: 0.76ms; fastest: 0.07ms
I2C nak errors 0, send timeouts 0, receive timeouts 0, finishTimeouts 0, resets 0
=== Move ===
Hiccups: 0, FreeDm: 169, MinFreeDm: 169, MaxWait: 0ms
Bed compensation in use: none, comp offset 0.000
=== MainDDARing ===
Scheduled moves: 0, completed moves: 0, StepErrors: 0, LaErrors: 0, Underruns: 0, 0
=== AuxDDARing ===
Scheduled moves: 0, completed moves: 0, StepErrors: 0, LaErrors: 0, Underruns: 0, 0
=== Heat ===
Bed heaters = 0 -1 -1 -1, chamberHeaters = -1 -1
=== GCodes ===
Segments left: 0
Stack records: 1 allocated, 0 in use
Movement lock held by null
http is idle in state(s) 0
telnet is idle in state(s) 0
file is idle in state(s) 0
serial is ready with "m122" in state(s) 0
aux is idle in state(s) 0
daemon is idle in state(s) 0
queue is idle in state(s) 0
autopause is idle in state(s) 0
Code queue is empty.
=== Network ===
Slowest loop: 15.55ms; fastest: 0.00ms
Responder states: HTTP(0) HTTP(0) HTTP(0) HTTP(0) FTP(0) Telnet(0)
HTTP sessions: 0 of 8

• WiFi -
  Network state is running
  WiFi module is connected to access point
  Failed messages: pending 0, notready 0, noresp 0
  WiFi firmware version 1.23
  WiFi MAC address 2c:3a:e8:0a:f2:1b
  WiFi Vcc 3.41, reset reason Turned on by main processor
  WiFi flash size 4194304, free heap 26096
  WiFi IP address 192.168.178.77
  WiFi signal strength -72dBm, reconnections 0, sleep mode modem
  Socket states: 0 0 0 0 0 0 0 0
  ok

[dc42]

I'm sorry to hear of your misfortune. The only time I have heard of this happening before was when there was over-voltage on the +5V rail (due to a short to +12V or +24V) which resulted in failure of the mosfet driver chip. It's labelled U11 and it's close to the reset button and extruder heater mosfets. Does it look damaged?

Are you powering anything external to the Duet from the +5V supply? What fan voltage are you using?

[Killernoy]

@dc42 said in why did my Printer melt?:

I'm sorry to hear of your misfortune. The only time I have heard of this happening before was when there was over-voltage on the +5V rail (due to a short to +12V or +24V) which resulted in failure of the mosfet driver chip. It's labelled U11 and it's close to the reset button and extruder heater mosfets. Does it look damaged?

No it does not look damaged to me, but take a look for your self

Are you powering anything external to the Duet from the +5V supply?

The fans

What fan voltage are you using?

5V

[jay_s_uk]

U11 looks damaged to me. it has a hole in it

[Killernoy]

@jay_s_uk said in why did my Printer melt?:

U11 looks damaged to me. it has a hole in it

I don´t know if I´m right but to me it looks like a Texas Instruments Logo

[dc42]

U11 looks OK to me in that photo, but the symptom suggests to me that it has failed.

As you are running 5V fans. I suggest you check very carefully that there is no possibility of a short between the fan wires and the hot end heater wires. We've seen users damage Duets before because of such shorts. That's why I argued (successfully) for us not to provide a jumper to select 5V fans on Duet 3 (OTOH, Duet 3 has a 12V regulator on board so that 12V fans can be used).

Some fans and other devices (especially servos) pump power into the supply rail when they turn off, although in the case of small brushless fans, the smoothing capacitors on the supply rail should take care of that without excessive over-voltage.

[Phaedrux]

This post is deleted!

[Killernoy]

@dc42 I checked with a multimeter on continuity-mode one probe at the fan voltage select the other on the Heater out put screws one at a time. No short was found but strangely the 3V+ LED lit up

[dc42]

@Killernoy said in why did my Printer melt?:

@dc42 I checked with a multimeter on continuity-mode one probe at the fan voltage select the other on the Heater out put screws one at a time. No short was found but strangely the 3V+ LED lit up

That sounds a little suspicious to me. What voltage battery does your multimeter use?

[Killernoy]

@dc42 said in why did my Printer melt?:

@Killernoy said in why did my Printer melt?:

@dc42 I checked with a multimeter on continuity-mode one probe at the fan voltage select the other on the Heater out put screws one at a time. No short was found but strangely the 3V+ LED lit up

That sounds a little suspicious to me. What voltage battery does your multimeter use?

9V

Pleas say i didn´t destroy it with the multimeter

[Killernoy]

Update on the damage:
4 Heater-Blocks melted
3 Thermistors molten into them (could save 1 don´t know if it is fine)
3 Heaters molten into them (could save 1 don´t know if it is fine)
2 Nozzels molten into them (could save 2 think they are fine)
2 heat-brakes molten into them (could save 2 don´t know if they are fine)

Cooling block saved only had to melt out the plastic from the collet and collet-clip

[zapta]

When running PID calibration Duet warns about the max reachable temperatures (~500-600C depending on the heater) and this thread suggests that those warnings should be taken seriously.

One option is to wire the Duet back to the power supply such it can turn it off (assuming the heaters are powered from the power supply), I think I will bump this up my TODO list.

A question for the OP, when this happened, did you see on the PanelDue a message indicating that the Duet detected the abnormal temperature and tried to turn off the heaters?

[Killernoy]

@zapta said in why did my Printer melt?:

When running PID calibration Duet warns about the max reachable temperatures (~500-600C depending on the heater) and this thread suggests that those warnings should be taken seriously.

I did not even come that far

One option is to wire the Duet back to the power supply such it can turn it off (assuming the heaters are powered from the power supply), I think I will bump this up my TODO list.

how do I do this?

A question for the OP, when this happened, did you see on the PanelDue a message indicating that the Duet detected the abnormal temperature and tried to turn off the heaters?

I don´t have a PanelDue

[DocTrucker]

@zapta it is certinally a nasty demonstration of what can go wrong and fortunately I think this is only about damage to the printer and nothing relating to secondary fires.

PS_ON has been available from year dot for Duets, and it has been on RAMPS too. The main use with these now is to allow the reliable cut of power to heaters in the event of a fault via mechanical relays not SSRs. The latters common failure mode is closed circuit on too, and if you read the Omron SSR docs they advise against their use in safety critical systems, whuch this clearly is. A pair of guided contact safety relays cutting the mains side of the of the PSU would be ideal, but a pair of them and bases and you've already spent a serious proportion of a cheap printer. I've got a comprimise at the moment. I found the four relay arduino boards can switch a DC current in excess of what my heater bed and nozzle take individually, so I've tied two relays in series for the bed, and for the hotend and used an inline fuse to protect the contacts.

Looking further ahead the passive safety isn't always practical, especially when you want to process hotter materials. We accept this everyday we drive since they got rid of the fella walking in front waving the flag. But if we exceed that passive safety limit we need to ensure we would need two or more things to go wrong before a dangerous situation occurs. With the hotends as they are it is difficult. Really we should have two thermistors and room for a thermal fuse, but that just isn't the case at the moment.

It's definately a work in progress for me and I'm not happy about leaving my printers unattended yet.