Need help with travel path or part placement

[SharonLuo 0]

Hi! 

I am trying to do a print with multiple items. However, when I view the toolpath, it just looks all funky. 

It doesn't seem to be going in a logical fashion, but maybe I am not understanding some of the travel settings. 

Is it just choosing the fastest path? Even if it doesn't seem to be following the parts in a "strategic" order? Or should I be placing my parts on the build plate differently? 

 

Thanks in advance for all the help. 

 

These are my travel settings 

 

When it prints the brim, it starts in the bottom left, but then moves to the middle. 

 

Then when it prints the other layers, it starts in the middle of the plate

 

 

Edited August 28, 2019 by SharonLuo

[SharonLuo 0]

Please ignore the bottom 2 screencaps! I thought they were deleted... 

[Cymon 5]

Can you explain your current placement? I don't know the shape of the part, but the placement of parts 10 and 11 (referring to the first picture) seems a bit of. Is there a reason for this?

I would turn 1 and 2 by 90 degrees and place them where 3 to 9 are placed, next to each other. Then, all the long parts evenly in a group right beneath them, also turned 90 degrees.

Make sure to place them with a minimum of space between them, this reduces stringing.

 

Yeah, toolpaths...

As far as I know, you can't have any influence on the toolpaths directly or the order of the printed parts. What you can play around with are the Layer Start X and Y values and in the "shell" group the Z Seam Alignment.

 

 

Edited August 28, 2019 by Cymon

[geert_2 557]

I believe it often has to do with "the shortest distance between the end of the current item, and the next item". So when the nozzle finishes one item, it will search for which next item is closest by from its current position. I think... Correct me if I have this wrong.

 

At least, I found that carefull aligning indeed helps often, but not always, to improve printing order.

 

As Cymon said above, I would also align the long items much compacter, maybe even so close to each other that their brims overlap so they combine into one big brim. Gives less travel time, less leaking while traveling, and often print quality is somewhat better in the center of the glass than on the extremes.

 

[SharonLuo 0]

There was no real "thought" that went out to my placement. I just sort of placed as they fit. 

How do I specify a minimum distance between the parts? 

 

I was trying to look at the Layer Start X and Y values, but I don't really understand what to change

[Cymon 5]

On 8/28/2019 at 5:05 PM, SharonLuo said:

How do I specify a minimum distance between the parts? 

What exactly do you mean? You can just place the objects so close to each other, that they just don't overlap in another. Brim is as @geert_2 said pointless and will be connected together, but the parts themselves should not overlap.

 

The Layer Start values say your printer, where to start looking for parts for the next layer. Honestly, I am not sure how it comes together with Z seam alignment, but it would be interesting to know if they point right to the middle of the plate. That would explain your printer starting with the middle part.

 

[geert_2 557]

Older versions of Cura don't allow parts to overlap: if you place them too close together, one will jump away to a safe distance. I don't know how the most recent versions do this, probably the same?

 
Most of the time I place all models into one CAD file, so Cura sees it as one model. For their placement, I use common sense: I place them as close together as practical, so that they won't fuse, and so that I can still grab and wiggle individual parts to remove them. For narrow but high parts (e.g. vertical rods), I make sure the brim overlaps, which gives much more stability against falling over. Or I design a custom brim and sideways supports in CAD to provide the desired vertical stability.