SoliForum - 3D Printing Community — push printed objects in a basket using the print head

Re: push printed objects in a basket using the print head

2013-09-12T22:38:39Z

Thank you for your insights Sanjay! This is the proof that it can be accomplished.
But the "ram" method could only work with only certain kind of objects. The ram covers only a small surface of the printbed, therefore you have to carefully program the gcode to swipe where the object has been printed.
I've made a sketch of a full-length sweeper moved by a stepper motor with a threaded rod, now I will have to find the time to put it into practice.
But another idea could be some gcode that sweeps the entire bed surface like an a iRobot vacuum cleaner sweeps the rooms...

Re: push printed objects in a basket using the print head

2013-09-08T23:16:05Z

Sanjay from E3D here,

I'm the guy who created the thread linked by IanJohnson and the video linked by 2n2r5, you might also like this thread:
http://www.soliforum.com/topic/3427/aut … -ejection/

and these videos from my YouTube channel which explain the process in detail.
http://www.youtube.com/watch?v=gVsNwLVF43w
http://www.youtube.com/watch?v=c4S2eFJmhOQ
http://www.youtube.com/watch?v=KxU3ElVlLPw
http://www.youtube.com/watch?v=j8qVSvukxug

The GCODE needed is posted on the thread linked by IanJohnson, but the numbers will obviously need a little tweaking to account for the geometry of your particular machine and ram.

I use this auto-print system in a production environment, I literally run 4 machines 24 hours a day, 7 days a week when I need parts. I have auto-printing completely nailed, to the point where I leave the machines running in my industrial unit overnight while I go home to bed. This has taken a lot of tweaking and observation to get to this point, but it isn't really that hard. The key to all of this is careful selection and preparation of your bed surface. Along with some cunning use of temperature contractions to detach parts when needed. PLA is easy with this setup, ABS is more finicky but certainly doable - most of my autoprints are ABS, and I have done print runs of a whole kilo spool of ABS without stopping the machine.

I use Boots hairspray (contains acrylic-copolymer) on glass for both PLA and ABS.

Re: push printed objects in a basket using the print head

2013-09-07T09:06:27Z

travis7s wrote:

My problem with this is the hairspray comes off with my parts, so if I'm not there to re-apply the spray I think I will have issues with it not sticking.

Out of curiosity? What plastic? Abs or pla?

Re: push printed objects in a basket using the print head

2013-09-06T22:17:26Z

My problem with this is the hairspray comes off with my parts, so if I'm not there to re-apply the spray I think I will have issues with it not sticking.

Re: push printed objects in a basket using the print head

2013-08-10T15:40:15Z

agentsmith wrote:

It could be as simple as a springed arm under the filament that is pressed down when the filament tension increases, and hits a limit switch that sends an abort command to the host

You'll find http://www.soliforum.com/topic/2516/wip … when-idle/ has all the mechanics and firmware mods you need...

Re: push printed objects in a basket using the print head

2013-08-10T09:33:53Z

I've setup Octoprint server on a Raspberry Pi with a webcam, therefore I could play that game as well
But sinc we are talking about a robot, I'd like to have my Solidoodle as automated as possible.
After developing the automated sweeper, we should think about a soft of sensor to detect tangled filament condition, which is one of the possible failure modes.
It could be as simple as a springed arm under the filament that is pressed down when the filament tension increases, and hits a limit switch that sends an abort command to the host.
No idea however on how to detect clogged extruder...

Re: push printed objects in a basket using the print head

2013-08-10T07:53:26Z

I quite regularly VNC into my desktop when I'm away and use the print head to push parts off the glass bed so I can print again. I only do it when the temp is < 40c for fear of ruining something. Besides, it's like trying to use a skill tester with a 1-2 second lag not to mention avoiding the bulldog clips holding the bed on!

Re: push printed objects in a basket using the print head

2013-08-09T14:41:46Z

Thank you Pastprimitive for you feedback, I'm eager to know what's going on with you prototype.
I'd like to work on it but right now my n. 1 priority is to eradicate z-wobble which is severely affecting my prints

Re: push printed objects in a basket using the print head

2013-08-07T15:52:59Z

I'm working on solving the problem as we speak, and gearing up to build a prototype. I'll let you know how it goes, and PM you if I create something worth while.

Re: push printed objects in a basket using the print head

2013-08-07T14:36:54Z

that's a cool idea! a limit switch!
But I have no idea on how to position the sweeping device.
If it's attached to the printer floor, its own threaded rod could only get positioned on the front, and the sweep would push the item through the left or right side. But there is little clearance in the front side for a threaded rod, for a self-contained device, especially if you are using office clips to put glass sheet into place.
Probably easier if the whole device sits on the back of the heated bed. That meanse that a printed assembly should be designed to house the stepper motor and threaded rod, but unfortunately my 3D design skills are pretty non-existent at this point
At least I can write some Arduino code to run the stepper motor with the delays Randavian said.

Nick

Re: push printed objects in a basket using the print head

2013-08-07T14:13:06Z

If you wanted to avoid using the extruder as a bulldozer, and don't have motherboard that you can add more motors to, you could always just rig up something that works off of a limit switch. The idea that came to mind is when the print is finished, have the G code lowered the bed all the way down. When the bed reaches that point it triggers a limit switch that activates either a sweeper like in the first video or a dozer type arm. then after a delay in the G code the bed raised up just enough to break the contact of the limit switch which will retract the sweeper or dozer. Then after another set delay, the printer homes all the axis points and starts another print.

Re: push printed objects in a basket using the print head

2013-08-07T11:48:21Z

wow happy to have sparked such an interest on this guys!

Yeah, the method I thought is exactly shown in the second video 2n2r5 posted, but here the printer removed the part as soon as it finished printing it, doing this as some of you objected it could damage your belts if too much resistance is applied on them.

Also first video is very interesting with the broom concept, but they didn't post any details on how it works apart saying it doesn't require any firmware modification, just gcode.

On my glass tile I've noticed when the temperature goes down past a certain point, something like 60°C, the printed part is not stuck at all anymore.

Any other devices that requires active parts such as stepper motors or electromagnets would be the ultimate choice but also the most complicated, since they would require some sort of interfacing to the Sanguinololu board which features NO spare I/O unfortunately

Re: push printed objects in a basket using the print head

2013-08-07T04:45:32Z

IanJohnson wrote:

I've been looking all over for that, couldn't remember how I ran across it before, and couldn't get it to come up in any searches.

I finally found it by going through my browsing history. I couldn't find it for the life of me either.

IanJohnson wrote:

Putting a ram on the extruder is pretty simple though, all you need is some gcode.

Do you mean like this?

I feel like the first one could be done using an extra stepper driver using the E1 (second extruder ) slot.
Just wait for bed to be X temp. Lower Bed. E1 motor attached to threaded rod goes 250 mm then returns. return bed and wait for temp, repeat

Re: push printed objects in a basket using the print head

2013-08-07T04:30:36Z

I've been looking all over for that, couldn't remember how I ran across it before, and couldn't get it to come up in any searches. Putting a ram on the extruder is pretty simple though, all you need is some gcode.

Re: push printed objects in a basket using the print head

2013-08-07T04:02:55Z