# Multiple unattended prints using extruder to sweep build plate?

I read something the other day about a guy who found a way to knock over completed prints with the printer head itself, then slide them to the edge of the build plate, where they fall into a box/basket. This allows printing several Eiffel Towers while you sleep for example. It doesn't work with skirts (duh), and the adhesion has to be just right not to wake up with a pile of spaghetti, but it still sounds useful.

Well, now I cannot re-find the description I read; does anyone know what this process is called? Is there an easy way I can perform such an end-of-print action on my CR-10 with a cura plugin? If such a thing takes a touch of end-time custom gcode, is there a proof of concept rough draft or demo I can start tinkering with? Any more info is helpful.

• Welcome to 3D Printing.SE! It will probably not work with brims either. The process is called series production. – 0scar Jul 12 '18 at 9:02
• – Greenonline Jul 12 '18 at 11:01
• And for fun, from Thingiverse - Automatic Print Ejector - The Punching Machine. There's even a video: MatterHackers Punch-Out! – Greenonline Jul 12 '18 at 11:04
• @Greenonline: thanks. I checked those out to see if they had this technique covered, but the one I saw/lost needed no extra parts or mods, which is what excited me most about it... – dandavis Jul 12 '18 at 18:03
• If you could relocate the link that you first saw, that would be great – Greenonline Jul 13 '18 at 10:43

You could cool down the heated bed (with e.g. [M109][1] R28) and cool down the hotend (with e.g. [M190][1] R40). This will usually release the print from the plate, perform the actions to move the head (e.g. go to the largest X, Y position G1 X{max} Y{max}, move down G1 Z10 to then move to minimum X, Y G1 X0 Y0 position such that it sweeps the print to the origin) that it knocks it into the basket and start printing again by copy pasting the whole G-code beforehand a couple of times. Note that this all depends on the product you are printing. You should at least use the end code scripts for the specific tasks to cool down, and start scripts to heat up again.

You can write a Cura plugin to implement a new GUI item to copy the G-code multiple times or create a post processing plugin.

• I was planning to use cura or repetier host's end/start snip sections, with AutoIt to re-print when done. Sounds like I need to learn about gcode commands and the few above will cover me. It takes per-print setup and hard-to-perform testing but should be workable. I was secretly hoping that someone would know the article I saw, link to it, and it would have a low-effort plugin or example gcode, but you make it seem pretty simple... – dandavis Jul 12 '18 at 18:41

I would advice against it, or at least have some detection for when the object won't budge:

Leaving a printer unattended needs special care too (fire alarm springs to mind but not only).

• Agreed -- using the print head as a wedge/driver is far worse than those homeowners who use a screwdriver as a can-opener. – Carl Witthoft Jul 12 '18 at 12:21
• This is caused by the horrible build platform. With a glass bed like the Ultrabase this wouldn't happen. Good point about the fire alarm. – AndreKR Jul 12 '18 at 15:57
• @CarlWitthoft - More like those home owners who check the electrical output of a wall socket with said screwdriver ... – Pᴀᴜʟsᴛᴇʀ2 Jul 12 '18 at 17:34
• Good point about monitoring, something I will take into consideration for sure. w/adhesion, I don't use tape anymore (glass+hairspray only), and can adjust 1st layer temp and whatnot to get it barely cling through the printing. Applicability depends on the print I suppose: a maker coin would be much harder than the almost-ideal Eiffel Tower... – dandavis Jul 12 '18 at 18:09
• @dandavis You can do multiple coins on the build plate at once or sequentially, unless they are huge coins – 0scar Jul 12 '18 at 18:46