At our maker space there is a distinct lack of air conditioning. This is problem if you have an unattended 3d printer and load up the queue. 

The spool of filament had been on the printer for about 3 weeks and the electronics space is right next to the kitchen. This coupled with the fact that we have no AC resulted in the filament picking up water. I thought that there were going to be some big problems when I came in to a box full of spaghetti. It turns out I got all worked up over nothing. A few tests of pushing some filament through the extruder  you could see the water bubbling an vaporizing on its exit.  I replaced the filament with a new spool that I did not remove from its bag and every thing started working again.

I did not really think that water absorption with PLA was going to be a big deal but it was. 

Other than that there have been a few other developments.

One of the guys at the maker space just got a new 3d printer. We hooked it up to a raspberry pi 0W and used the bash script for the unattended printer with a few modification to make it print off the queue also. Right now you have to open a terminal and let the computer know you have cleared the bed before it checks for a new print but it is able to be started and print an object with out human interaction. 

The bash script that functions as the job retrieval mechanism is set up so that prior to a job starting it re-positions the head to the center of the build area. A normal prusa style printer has 0,0,0 in one corner of the bed. The gcode produced on the server was made for a delta 3d printer. Because deltas have 0,0,0 is the center of the bed and can move in both the positive and negative directions for x and y the gcode could not work. That was until we added those extra commands to the start script. 

Now all we have to is rig up a button to one of the gpios on the pi to indicate when the bed has been cleared so it can retrieve a new job from the server in a completely headless fashion. 

This project is really turning in to a complete solution on the software side to print to multiple printers. Some with auto ejection capability and even those with out.