Question on Z-Offset and Start Script, Also Nozzle Adjustment.

justinds89

That is fine. I appreciate the help as I'm stuck on what to do.

I am fairly certain I have the thermistor values correct in config.g.

I have not PID tuned them and I'm not really familiar with the process.

Phaedrux

According to this: https://duet3d.dozuki.com/Wiki/Connecting_thermistors_or_PT1000_temperature_sensors#Section_PT1000_sensors
I don't think you have your PT1000 configured correctly.

You currently have

M305 P1 T100000 B4138 C0 R4700               ; Set thermistor + ADC parameters for heater 1

but should have

M305 P1 X501 R4700

That could explain your actual temperature being different from what's reported.

Phaedrux

Here is the wiki for tuning the heaters.

https://duet3d.dozuki.com/Wiki/Tuning_the_heater_temperature_control

Getting the temps correct will be first step.

justinds89

Okay, I will check this out and report back. Thanks!

I can confirm it does the same thing with different filament.

justinds89

@phaedrux

I looked at the config and everything as far as the heaters go looks correct. This is the settings.

; Heaters
M307 H0 B0 S1.00 ; Disable bang-bang mode for the bed heater and set PWM limit
M305 P0 T100000 B4138 C0 R4700 ; Set thermistor + ADC parameters for heater 0
M143 H0 S120 ; Set temperature limit for heater 0 to 120C
M305 P1 X200 ; Configure thermocouple for heater 1
M143 H1 S280

justinds89

Heater 0 is the bed.
Heater 1 is the hotend for extruder 1.

justinds89

Wow, I upped the temp by 20 degrees and it is now printing fine.

I guess it was grinding filament because it wasn't hot enough to melt it properly.

Looks like I will be PID tuning it when I figure out how.

Thanks for the help man!

dc42

@justinds89 said in Question on Z-Offset and Start Script, Also Nozzle Adjustment.:

Wow, I upped the temp by 20 degrees and it is now printing fine.
I guess it was grinding filament because it wasn't hot enough to melt it properly.

Your slicer may be configured to reduce the extrusion temperature after the first layer. Also, if your print cooling fan is directing too much air at the heater block and the nozzle instead of at the print, the nozzle temperature may drop a little when the print cooling fan turns on, which is usually at the start of the second layer.

justinds89

@dc42

That makes sense, but when monitoring what the temperature shows in the web interface it shows that the temperature is what is set and steady.

I'm using 200 for PLA which is what I've always used in the past. Now though I had to up it to 220 to get a successful print.

I still have no clue on how to PID tune things if that is the route I need to go after reading the wiki.

I can confirm my Slicer isn't dropping the temperature after the first layer.

justinds89

@dc42

I will try to check again and make sure the temperature doesn't drop when the fan kicks on.

Phaedrux

Did you correct the PT1000 configuration for heater 1 as mentioned above? That could easily explain why you're 20 degrees off expected.

justinds89

@phaedrux

I didn't change anything as my configuration has this set for heater 1:

M305 P1 X200 ; Configure thermocouple for heater 1
M143 H1 S280

I thought this was correct?

justinds89

@phaedrux

I should note I have a PT100 connected to the daughterboard.

Phaedrux

Ah I see. Earlier you had said pt1000. Easy typo to make. I wish they had slightly different names.

The link I posted earlier for PID tuning has a lot of information but basically start from a cold machine and run the M303 command with the parameters for the heater you want to tune.

https://duet3d.dozuki.com/Wiki/Gcode#Section_M303_Run_heater_tuning

M303 H1 S220 ; tune hot end to 220c
M303 H0 S60 ; tune bed to 60c

After they are finished you can send M500 to save the values to config-overide so they are loaded at startup, or ~~send m303 again with no parameters~~ Send M307 H1 and it will report the PID values it found for heater 1 which can manually be entered into config.g. it's easier to just use m500 and then copy and paste the values over if you wish. M307 H0 will give the results for the heated bed.

justinds89

@phaedrux

Sorry for the confusion.

As I understand I need to just run the M303 command? I don't need to plug in specific values?

Appreciate all the help. Getting closer to having this up and running!

Phaedrux

M303 H1 S220 The H1 tells it to tune heater 1 which is the hotend, and to target 220c as the temperature. The tuning will give some messages about what it's doing in the console. It will heat up and cool down the hotend which can take 10 or more minutes. When it's done you can send M307 H1 and it will tell you the values it came up with for heater 1. Then send M500 to save the values.

justinds89

@phaedrux

Ah okay, I will try this tonight!

Thanks again.

I will post back if it helped or not.

I'm assuming I'm good to go as soon as I get this temp issue sorted.

Phaedrux

PID tuning will help the temperatures be more stable, but won't account for being off by 20 degrees.

Definitely keep an eye on the temperature graph as it transitions from the first layer to the next. Does the set temperature get lowered? That would indicate that the slicer has a too low temp set for later layers.

justinds89

It looks like my cooling fan is dropping the temperature of the nozzle down for a little bit before it picks back up and stabilizes.

I take it at this point I need to figure out a way to direct the cooling more downward away from the nozzle and heat block?

Phaedrux

You have 3 options, choose any or all.

Find a better cooling shroud that can direct the airflow better.
Insulate the hotend block in some way. This can be as simple as kapton tape and a high temp insulation pad. Or you can maybe find a silicone sock that can slide over the hotend. If you have the means you can also make your own.
PID tune the hotend while the fan is running at a speed similar to what it would see during an actual print, That way the system can adjust for the heat loss and maintain a more stable temperature.