So when visiting the huge CNC shop where they build my hotends I saw an awesome auto-feed lathe that you load up with bar stock, it turns a workpiece, parts it off whereupon it falls into a little chute, and it then pops out the back of the lathe into a little basket for collection. The guy running the machine shop says he just fills the machine, presses "go" and goes home for the night! Well, I had massive engineering jealously right there. If he could do it, then why not me on my little RepRap?!
Another motivation was that as well as running E3D with David I am also a full time teacher of Engineering at a high school. I want to teach the kids about gearing and so on, so I want to print literally hundreds of these gears: [www.thingiverse.com] But unloading and resetting prints is a real chore.
In simple summary here is how I did it:
Use PLA on hot glass - the parts come completely loose from the bed once it cools.
Print an item
Cool the bed (parts come loose once cool)
Use a little ram attached to the X-Carriage to push the part off the bed into a chute
Print next item
Here are some video detailing the process:
(Warning - I talk a lot...)
End of print procedure
Ejection of print and starting of next print
Another print ejection
I have left the GCODE files used and the associated slicer config on my work PC and can't retrieve them. However it really is very - using slic3r I have a normal start GCODE that homes the machine and sets the machine to printing temps and waits for those temps to be reached.
I set my custom end gcode to something like:
M104 S0 ; Set extruder temp to 0C
M140 S0 ; Set bed temp to 0C
G1 Y195 ; Brings the bed all the way forward - so the ram is behind the part
G1 Z0 ; Homes Z axis, which touches nozzle to glass stopping any leaking and brings the ram down behind the part
G4 P360000 ;Do nothing for 360,000milliseconds (6 minutes) in order to allow the bed to cool so the parts come loose
G1 Z0.2 ; Lift the nozzle slightly so it doesn't scrape along the bed during the ramming movement
G1 Y0 F6000 ; Sends the bed moving backwards, print impacts ram and is pushed off front of bed onto paper chute
You then just copypaste as many GCODEs as you want items into one file, you can obviously combine different objects so you can produce a varied run of parts.
I have a test run of 10 or so parts printing right now, which hopefully will be waiting for me in that little tray on Monday. No way to know till then...
This kind of approach combined with octoprint with webcam monitoring is a absolute winner in my eyes. I really would love to get this set up at my school in a sort of vending machine that kids can feed STLS and recieve parts out. The little rotters are always bugging me to print me stuff and I never have time. They are so enthusiastic about 3D printing that it's a shame they can't use it directly.
Edited 1 time(s). Last edit at 06/08/2013 11:43AM by SanjayM.
I Design/Sell all-metal hotends. My company is called e3d-online - you can buy at [www.e3d-online.com]