OhmEye

A recurring issue that I see often for many reprap 3D printers that have carriage-mounted fans is seeing the hotend temperature plummet when the fans turn on. The common scenario is printing PLA, which benefits from having strong fans cool the plastic as it prints to prevent curling and improve perimeter print quality. Typically the fan is off for the first layer which prints at a slower speed, then turns on when the second layer starts, and the hotend loses temperature quickly due to the increased extruder feedrate and fan airflow, and can take tens of seconds or longer for the PID function to recover and return hotend temperature properly. What’s happening is the PID function is getting caught off guard since plastic is suddenly feeding faster and removing heat from the hotend more quickly, as well as fan airflow kicking in to increase the rate the hotend is dissipating heat and once the temperature falls it struggles to return temp to normal. In the worst case scenario, the hotend loses enough temperature that the hotend stops extruding and/or the MINTEMP cold extrusion protection kicks in on Marlin firmware. ↓ Read more…

In rare situations there is an issue that can cause your 3D printer running Marlin firmware to suddenly stop during a print, leaving you to troubleshoot without knowing for sure if you have fixed the cause. One of the first things I look for is something being wired to use the Kill Pin, such as a GLCD panel. Many LCD panels include a switch to press to emergency stop the printer. Most people don’t use it at all and without a panel many printers do not have any kill switch other than the reset switch on the electronics they use. There is no direct danger by not having a kill switch, in my opinion. If you do have a LCD panel with Marlin, there is a Stop Printing menu item on the main menu that works just fine for me. ↓ Read more…