Printer heating issue
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New and exciting issue. I changed out the extruder and carriage and everything so switch to a new direct drive set up, and this included a new cooling fan. It doesn't feel like the fan is blowing directly on the nozzle, and the whole heating block is covered in a silicone jacket, but now it can't get up to temperature at all. I am trying to run M303 to get my settings dialed back in but I get the message "Auto tune cancelled because target temperature was not reached" in the console window. Any ideas on how to fix this one?
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Still using same heaters? If not, make sure your new heater is for 12v, not for 24v. If same heater, check all connections, electrical and also mechanical (heater to heating block).
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@deckingman said in Printer heating issue:
@jasonpgr said in Printer heating issue:
Glad you got it fixed. In fairness, the instructions for tuning heaters doesn't explicitly state that if you use M500 to save the values, then you need to add M501 to the end of config.g to read in those values. So it's an easy thing to miss if you are a new user.If you use M500 but no M501 command was executed in config.g when you started the Duet, the firmware will warn you.
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@aidar yep, same heaters, same block. I just unscrewed it from the old heatsink and put it into the new Titan Aero. The part cooling fan is new though, so I'm thinking that might be blowing on the hotend too much. I was trying to do the M303 while the fan was on, so it would compensate for the fan during printing.
@deckingman I have M501 in the config file as of a couple weeks ago, but I don't recall there being M500 as well. Do I need both in order for the m501 to work? Where would I put the M500 in the config file? Does it matter if it's at the beginning or end? I'm trying to use the override file for my heater settings so it will come up automatically if I run the autotune again.
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M500 is used to save heaters parameters after autotune to config-override file using DWC gcode console. To call this file duering booting you must have M501 in config file. So you config should include M501, but not M500 .
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"aidar" beat me to it - so what he said..........
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I just checked the impedance of my heater cartridge by putting the meter on the wires right where they go into the board (I disconnected the leads from the board first) and it came out to be 6.7 which sounds like almost double what it should be.
The printer has some pretty lengthy cable extensions on it since it's a really big printer and they have to run to the back side of the printer, up to the top, and along the cable chain to the actual print head. Is it possible that the amount of cable is raising the impedance and cutting down on the amount of power my heater cartridge is able to put out? Should I use a thicker wire to make this run? Maybe get rid of the butt connectors and solder the wires to the cartridge to make sure I'm not adding any resistance? These seem like super minor changes to cause such an annoying problem, but it's all I can think of.
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@jasonpgr Assuming it's a 40 Watt heater, then the resistance (at 12V) ought to be around 3.3 Ohms if my elementary understanding of Ohms law serves me correctly. So yes, 6.7 ohms would mean that it would draw about 1.8 amps which at 12V would be about 21 Watts. That explains why you are struggling to get up to temperature.
From you've said, it could be a dodgy connection - that's more likely than simply the wire length unless you are suing really thin wires (but I'm not an expert on these things). If it was me, I'd cut the wires back to about say 100 to 200 mm from the cartridge, then measure the resistance. If it's still high, then it's the cartridge. If it's low, then it's the wiring.
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New heater cartridge and we're up and running without any issues at all. now just trying to get my z probe height dialed in perfectly. I love the Z axis baby stepping option to compensate for not having the perfect probe height going. Especially with PETG since that first layer is kind of a bitch. I've got a couple successful prints in the bag now though. So far so good.
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@jasonpgr Great. Looks like you can now mark this as solved.
