strange tool paths with slic3r

[rs50pilot]

My nc background is going on 2 years. Been a machinist for 10. I know it's been said but slic3r makes some strange tool pathes. I have been trying to print a tornado I found on thingiverse. Im getting lots of stringing.
Hotend is 230 bed 100 then down to 90. 30mm speed across the board and 2mm lift.
You would think that it would make the perimeter in complete circle moves but it prints half a circle then jumps to the other half, which makes a lot of strings.
Extrusion stops at anything lower in temp and I end up with filament wrapped around everything at the extruder.

So I'm trying kiss and I like the paths alot better. Doing first print now so we will have to see how it goes.
Any input on kiss is welcome. Thanks guys. I'm really liking my max.

[mhackney]

This has been my observation as well. I've tried all of the slicers and analyzed their gcode. They all seem to do non-intuitive things at some point or another. It isn't a trivial problem to solve and it is exacerbated by the loss of information from design to STL file. The designer of a part actually knows quite a bit about how that part should be made. Many designers design for manufacturing / assembly. But in creating the STL all of that knowledge in the source CAD like layers, part descriptions, etc, are lost. The slicer has to do its best starting with a "black box" to create a workable toolpath.

[Polygonhell]

This has been my observation as well. I've tried all of the slicers and analyzed their gcode. They all seem to do non-intuitive things at some point or another. It isn't a trivial problem to solve and it is exacerbated by the loss of information from design to STL file. The designer of a part actually knows quite a bit about how that part should be made. Many designers design for manufacturing / assembly. But in creating the STL all of that knowledge in the source CAD like layers, part descriptions, etc, are lost. The slicer has to do its best starting with a "black box" to create a workable toolpath.

And it's even worse than that, every CAD program I've used creates bad geometry in the STL's, if you're lucky it's just degenerate or near degenerate tris.
KissSlicer has an issue with these, Cura/Skeinforge's algorithm seems to be the most robust.
Additionally both Slic3r has issues with long thin parts coming to a point, creating phantom tool paths for geometry that doesn't exist.
It's a hard problem to do right and harder to do right and fast, something seemingly simple like offsetting a polygon inwards is hard to the point there are hundreds of research papers about it, and every useable algorithm has numerical instability to worry about.
I use KissSlicer most of the time, I Slice with it check the paths run it through Netfab Basic if there is an issue and try again.
If there is still an issue I resort to Cura.

[Eaglezsoar]

This has been my observation as well. I've tried all of the slicers and analyzed their gcode. They all seem to do non-intuitive things at some point or another. It isn't a trivial problem to solve and it is exacerbated by the loss of information from design to STL file. The designer of a part actually knows quite a bit about how that part should be made. Many designers design for manufacturing / assembly. But in creating the STL all of that knowledge in the source CAD like layers, part descriptions, etc, are lost. The slicer has to do its best starting with a "black box" to create a workable toolpath.

And it's even worse than that, every CAD program I've used creates bad geometry in the STL's, if you're lucky it's just degenerate or near degenerate tris.
KissSlicer has an issue with these, Cura/Skeinforge's algorithm seems to be the most robust.
Additionally both Slic3r has issues with long thin parts coming to a point, creating phantom tool paths for geometry that doesn't exist.
It's a hard problem to do right and harder to do right and fast, something seemingly simple like offsetting a polygon inwards is hard to the point there are hundreds of research papers about it, and every useable algorithm has numerical instability to worry about.
I use KissSlicer most of the time, I Slice with it check the paths run it through Netfab Basic if there is an issue and try again.
If there is still an issue I resort to Cura.

If Cura had a faster slicer would you use it exclusively or is repetier host better, in your opinion.

[Av8r RC]

I'm a machinest too, Only been doing it for 4 years now and still learning just about everyday. But i do all the programing, and run the shop.

Slic3r used to be pretty good with the paths. But since, I think, they added the randomize start point option. It does some of the dumbest paths and wastes so much time with random pointless moves. Even when the option is turned off. Just about every thing I've sliced with it lately I've thought to myself, What the F are you doing Slic3r. I just tried KISSlicer yesterday, and really like the paths it computes. Way better than what slic3r does today. Just wish the had a z lift option in KISSlcer right now.

I need to try Cura when I get a chance.

[Av8r RC]

Anyone know of a cad/cam program that supports 3d printing?

[gabrielk]

KISSlicer has Z-lift option in Material tab. You have to download beta from KISSlicer forum after you register, not from downloads on their site


http://kisslicer.com/forum/index.php?topic=382.0

[mhackney]

Yes, the beta has Z-lift and a lot of other features.

Funny you should ask about a CAD program that supports 3D printing... (stealth mode) ...

[Av8r RC]

gabrierlk, thank you. There it is.

[dbarrans]

Michael, that's cruel. You gave us the teaser, now 'fess up.

- dan

[mhackney]

Hey Dan, it's actually been a background project of mine that is picking up some steam now. I'm a software guy and it really seems like there is an opportunity to really simplify and improve 3D extrusion printing. Too early to say much more!

[rs50pilot]

Well put me down for that software. I use solidworks to model what I need. Cant understand why if you have a circle slic3r prints half of it then lifts and starts to do the other half at the opposite end. I know it's how the triangles are read but seems really funny.

Just have to get my stringing under control and I will be good to go.

[Eaglezsoar]

Hey Dan, it's actually been a background project of mine that is picking up some steam now. I'm a software guy and it really seems like there is an opportunity to really simplify and improve 3D extrusion printing. Too early to say much more!

Michael, if you add many more projects to your list you will have to clone yourself and we wouldn't be able to keep up with that number of posts!
Do you have room for all the hats you wear?

[mhackney]

@Eaglesoarz - you don't know the half of it! I think you've checked out my fly fishing reel business? www.eclecticangler.com, www.reellinespress.com and www.reelsmithing.com/forums. I've been doing that for 4 years or so now. I manufacture all of the parts in my reel kits and I've shipped over 1000 all over the world. I also wrote the first book on making reels - The Reelsmith's Primer and now have published 6 books for other authors too. On top of that I travel around the US and conduct reelmaking workshops for a variety of groups including my favorite - Project Healing Waters (an organization that uses fly fishing as a form of therapy for disabled and wounded US soldiers).

Everyone always asks me how I can do all this and my answer is simple; "I don't watch TV"! I figure I have a couple of hours here and there during the day that aren't put to good use yet!

Cheers,
Michael

[Eaglezsoar]

@Eaglesoarz - you don't know the half of it! I think you've checked out my fly fishing reel business? http://www.eclecticangler.com, http://www.reellinespress.com and http://www.reelsmithing.com/forums. I've been doing that for 4 years or so now. I manufacture all of the parts in my reel kits and I've shipped over 1000 all over the world. I also wrote the first book on making reels - The Reelsmith's Primer and now have published 6 books for other authors too. On top of that I travel around the US and conduct reelmaking workshops for a variety of groups including my favorite - Project Healing Waters (an organization that uses fly fishing as a form of therapy for disabled and wounded US soldiers).

Everyone always asks me how I can do all this and my answer is simple; "I don't watch TV"! I figure I have a couple of hours here and there during the day that aren't put to good use yet!

Cheers,
Michael

Yes, I've checked out the sites you have, very impressive and very high quality reels. Do you have a CNC machine to fabricate these parts?
A few pictures of your shop would be off topic but neat to see.

Carl

[mhackney]

I'll post some over on my build thread...