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BigBrain3D Purge Mechanism  

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x50arm
(@x50arm)
Estimable Member
Topic starter answered:
RE: BigBrain3D Purge Mechanism

I had some problems with the mechanism consistently placing the bucket under my nozzle so I designed this z-rod brace to keep the bottom of the bracket from moving around.  Just something else you can try if you have similar issues.

 

This post was modified 4 years ago by x50arm
Posted : 22/01/2020 1:22 am
KennyB
(@kennyb)
Trusted Member
RE: BigBrain3D Purge Mechanism

@vintagepc

With regard to the purging volumes, I wonder if you could leave the wipe tower on in slicer and basically just extract it from the gcode with your script.  I think the wipe tower can overlap your parts in the print without detriment to extracting it later (as it will just print them in interference otherwise).  I threw a comment on your github regarding that.  That is sorta how the old script you had worked right?  Except you tried to move the wipe tower off the bed?

Between the purge volumes comments at the end of the gcode and calculating what is in the wipe tower, you might be able to re-enable the wipe to infill and wipe objects stuff.  

Posted : 22/01/2020 6:04 am
gnat
 gnat
(@gnat)
Noble Member
RE: BigBrain3D Purge Mechanism
Posted by: @kenny-b2

@vintagepc

With regard to the purging volumes, I wonder if you could leave the wipe tower on in slicer and basically just extract it from the gcode with your script.  I think the wipe tower can overlap your parts in the print without detriment to extracting it later (as it will just print them in interference otherwise).  I threw a comment on your github regarding that.  That is sorta how the old script you had worked right?  Except you tried to move the wipe tower off the bed?

Between the purge volumes comments at the end of the gcode and calculating what is in the wipe tower, you might be able to re-enable the wipe to infill and wipe objects stuff.  

That's actually what we started off doing in the original script. They do not comment the gcode well enough to easily identify it, especially if you try to overlap as you suggest.

Had we known about the custom gcode section and disabling the block that would have made our efforts much easier and the code so much simpler.

MMU tips and troubleshooting
Posted : 22/01/2020 8:15 pm
vintagepc
(@vintagepc)
Member
RE: BigBrain3D Purge Mechanism

Oops, I thought I answered that but I was thinking of the github issue with a similar comment. It's basically as Gnat said. There are some less-than-obvious subtleties about the purge tower that you don't immediately see until you actually try to implement things that way

https://github.com/vintagepc/RPM-Post/issues/1

Q:

In the old script on gitlab, you left the purge tower active but moved it off the bed basically correct so you could get these volumes? Was the reason you ditched that method in the new script because it was painful to put a wipe tower out off the bed?

Couldn't the prints technically overlap with the wipe tower in PSlicer and you still extract them from the gcode later? I thought it the tower code is pretty clearly remarked in the gcode at the start and end with the "CP EMPTY GRID" or "CP TOOL CHANGE START (end END)". When you arrange your print bed and put the wipe tower overlapping with your actual parts, it'll try to physically print them both in the same space even though they will interfere.

A:

Complexity. I wanted to greatly simplify a lot of the handling, this old code comprised a good chunk of the code and it was not maintainable (at some point between 2.0 and 2.2, it broke and I didn't get very far at locating the issue. I'd rather strip it out and rewrite that path if I have to (there are some other options for volumes - I may just submit a PR to the plicer project for the 2.20 release to get access to the volumes directly). than continually chase bugs in it as the upstream project changes the output format.

If I can't get direct access to the volumes I think the way forward is still sans purge tower, but just to peek ahead from the toolchange. There's a generally useful "PURGING FINISHED" comment that indicates when wiping operations finish (but even that has a subtle bug in the first layer). 

 

That said, I haven't actually tried doing a wipe-to-X object with the wipe tower disabled, it's quite possible that might not even be supported.

Posted : 22/01/2020 8:38 pm
akku3D
(@akku3d)
Active Member
RE: BigBrain3D Purge Mechanism
Posted by: @allen-m2

I made a bracket that connects the bottom of their bracket to my x-axis rail to stop this.

Do you have a photo of this mod?

This post was modified 4 years ago by akku3D
Posted : 28/01/2020 9:57 am
x50arm
(@x50arm)
Estimable Member
Topic starter answered:
RE: BigBrain3D Purge Mechanism

@matthias-k9

I could take a pic, but it won’t show anywhere near the detail shown in the pics above.  It’s all printer black and you can’t see it very well at all.

Posted : 28/01/2020 12:25 pm
akku3D
(@akku3d)
Active Member
RE: BigBrain3D Purge Mechanism

@allen-m2

OK, you're right.

Do you share the CAD model of the bracket?

Posted : 29/01/2020 6:20 pm
x50arm
(@x50arm)
Estimable Member
Topic starter answered:
RE: BigBrain3D Purge Mechanism

@matthias-k9

I have not finalized everything yet.  I am running the Bondtech extruder with the Mosquito hotend.  My adjustments when finished will only work with this configuration as it is different than using stock extruder or E3DV6 hotend.  Once done I won’t mind sharing though.

Posted : 30/01/2020 12:52 am
akku3D
(@akku3d)
Active Member
RE: BigBrain3D Purge Mechanism

@allen-m2

That sounds very interesting. I also have the BMG with mosquito hotend.
Let me know if you have something that I can test.
Do you also have a silicone sock on the heating block?

Posted : 30/01/2020 8:07 am
TickTock
(@ticktock)
Estimable Member
RE: BigBrain3D Purge Mechanism

Now that folk have had theirs for a while I was wondering if anyone is still using theirs successfully.  I built one but was never able to get it reliable enough for a long print so I took it off.

 

 

P.S.  I looked and didn't find any sticky threads on forum policies. I hope resurrecting this is OK.

Posted : 13/05/2020 1:22 am
vintagepc
(@vintagepc)
Member
RE: BigBrain3D Purge Mechanism

Can't say I've used it much beyond casual initial testing, but it's also partly because I haven't done any MM prints since getting it; I've mostly been doing single-color functional ones, taking advantage of the time stuck at home to cut down the print backlog. 

Posted : 13/05/2020 2:10 am
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