I’ve been trying to do some modification on the K8400 myself and wanted to change the nozzle. Does anyone know what the nozzle thread is? My measurement is an M7 thread which seems quite unusual. The nozzle thread is M6 for the K8200 according to one of the posts in the forum. I don’t know if they are the same thread.
The other question is related to heating. I found that once the print job was nearly finished like 99%, the printer would stop heating. I understand that the remaining heat might be sufficient for printing the rest part, but sometimes it is not the case. There are prints that start cooling too soon, thus the parts are not completely finished. Is there a place that can be changed in the firmware to solve the problem?
To your first question: Yes, it is M7 thread with 1mm slope.
For the second question it is quite easy to understand: the move commands send to the K8400 are lined up in an internal queue which is filled permanently to the maximum size. After putting the move command onto this queue the interface is ready to process the next command. At the end of the print the command for switching off the heaters will be processed immediately, despite the buffered moves. So the processing of this command has to be inhibited until the movement queue is empty.
For this feature the firmware has to be slightly modified, this mechanism is not foreseen in the Vellemann firmware.
P.S.: The internal ring-buffer size is 16 by default setting. So if you add 16 dummy steps before temperature shutdown in your epilogue of your slicer file, then you stop the heating with the last active extrusion.