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Marlin UI Nozzle Temp stops at 245C

Posted by Roberts_Clif 
Marlin UI Nozzle Temp stops at 245C
April 06, 2019 09:46AM
With a few configuration.h changes I have found that when I set my Max temperature to 260C, this caused the problem.

#define HEATER_0_MAXTEMP 260

Edited 4 time(s). Last edit at 04/06/2019 01:11PM by Roberts_Clif.


Electronics Technician / Computer Programmer
Re: Marlin UI Nozzle Temp stops at 245C
April 06, 2019 01:11PM
Well found my own solution

I appears that in the firmware there must a temp calculation from HEATER_0_MAXTEMP
To cacluate the the Max UI temperatures difference of 15C.

when I changed the firmware to 260C the UI control range is 245C
when I changed the firmware to 275C the UI control range is 260C

Unfortunately, hot-end tubes made with both PEEK and PTFE begin to breakdown at temperatures above 240°C
This make me deduce that if I want to keep the Hot-end using PTFE tubing that I should not Print above 240°C.

ultralcd.cpp // Marlin 1.1.x

#if HOTENDS == 1
MENU_MULTIPLIER_ITEM_EDIT_CALLBACK(int3, MSG_NOZZLE, &thermalManager.target_temperature[0], 0, HEATER_0_MAXTEMP - 15, watch_temp_callback_E0);
#else // HOTENDS > 1


menu-temperature.cpp // Marlin 2.0.x


void _lcd_preheat(const int16_t endnum, const int16_t temph, const int16_t tempb, const uint8_t fan) {
if (temph > 0) thermalManager.setTargetHotend(MIN(heater_maxtemp[endnum] - 15, temph), endnum);



So as not to over heat the throat PTFE liner will set to 270.
Still would like to know why! -15 degrees is subtracted in the LCD menu section.

Edited 1 time(s). Last edit at 04/06/2019 01:17PM by Roberts_Clif.


Electronics Technician / Computer Programmer
Re: Marlin UI Nozzle Temp stops at 245C
April 07, 2019 10:10PM
MAX_TEMP is defined primarily for safety - i.e. "if the printer goes over this temperature stop the print/shut down the printer/etc." It is defined as a temperature that you would not expect to reach in normal operation, even if your PIDs aren't quite up to snuff and the temperature oscillates somewhat around the set point. That's why there's the 15C difference between the temperature that is allowed to be set and MAX_TEMP.
Re: Marlin UI Nozzle Temp stops at 245C
February 13, 2020 12:09PM
It's still 15°C in Marlin 2.0.3 ... I'm trying to print an HDPE that the manufacturer says they use at 300, so I set Max_Temp to 300 and reinstalled ... but in the screen, I can't go over 285°! I found this thread when I was looking for reasons why...

I guess I'll just have to put 315°!!


Vid
Re: Marlin UI Nozzle Temp stops at 245C
February 13, 2020 02:03PM
Quote
Vidius
It's still 15°C in Marlin 2.0.3 ... I'm trying to print an HDPE that the manufacturer says they use at 300, so I set Max_Temp to 300 and reinstalled ... but in the screen, I can't go over 285°! I found this thread when I was looking for reasons why...

I guess I'll just have to put 315°!!


Vid

It is quite logical because the temperature overshoots a bit when warming up. Normally this is mitigated by using a well performed PID tune but still, setting the limit to the exact temperature you are going to print at will cause issues.

Good luck printing at 300ºC smiling smiley


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