# Large 3D printer 10'x10'x4' - Need G-code to tell when it stops extruding and to stop machine

We use Simplify and have a large 10’x10’x4’ printer. We need G-code that when the extrusion stops the machine will stop and raise 10 mm as to not to burn the print, so we know where the extrusion stopped.

We are using beads instead of filament, which work great. We have a mechanical pusher of beads that once it stops spinning, we need a G-code to recognize it is not spinning anymore and to stop the printer at that point and to lift up 10 mm. Printer might go 3-4 days sometimes a week with no problems and all of a sudden no extrusion and machine keeps thinking its printing. We have to start all over.

Any suggestions?

• The control should be like normal extruder, the machine starts printing once the temperature reach 175°C (safety extruder temp) so, if your printer is moving with no printout is due your extruder is not working or is clogged. For moving up after printing use G91 G1 Z10 Instead waiting the extruder waits to send a command to say "I'm stopped" also use G92 E0 and G1 E-3.000 F1800 to make a retraction while the Z goes to safety position. I'm planning to use a pellet extruder instead filament, so this way will be easy. – Fernando Baltazar May 9 '18 at 17:24
• Thank You. We got the one problem fixed and now realize we are going to have to put in a new controller and servo motors instead of the traditional steppers that came with it. Turns out the hardware that came with the ErectorBot is very low end and not as billed. Does anyone know where to get reliable inexpensive controllers and servos..? – Joe M. May 19 '18 at 17:20
• From eBay? China? Ali-express? Are you sure you need servo motors, and not new steppers? See reprap forum: steppers for a list of good steppers. The most commonly used stepper motors in Reprap–based 3D printers are the Kysan 1124090/42BYGH4803, Rattm 17HS8401, and Wantai 42BYGHW609. – Greenonline Sep 22 '18 at 18:15

You'll likely want to configure your pusher to somehow act as a filament runout sensor. This is a feature in Marlin (smoothieware has something similar) that allows you to pause the print by making an input on one of the control board's pins. You'll need to build hardware that detects the motion of the pusher, and if the motion is interrupted, pulls the FIL_RUNOUT_PIN low (in the case of Marlin). You can then configure what should happen next (e.g. raising the head and stopping the print) using FILAMENT_RUNOUT_SCRIPT (again, only if you're using Marlin).