Gap in external perimeter

It is sort of hard to see with the black but for the life of me I can't get my printer to make a cylinder with no void when it stops on the perimeter. I have a Da Vinci 1.0 and I am using Repetier with the luc firmware and Slic3r. I have tried tweaking every setting I can think of to no avail. I searched quite a bit but I could find anyone having this same issue. I am getting good prints, about .1mm variance on the diameter when running slow and .2mm to .3mm faster setting but they all have the same gap. I changed the starting point from aligned to random and that just made the whole part look like crap. No matter how slow I go it is still there. I tried having it push out more material when it stops and that just made a mess. Any help or insight you can offer is greatly appreciated.


http://3dprintboard.com/attachment.p...tid=5470&stc=1
http://3dprintboard.com/attachment.p...tid=5471&stc=1
http://3dprintboard.com/attachment.p...tid=5472&stc=1

Picture please, it's much easier for us to know what you're describing.

Not sure why the attached pictures didn't come through. Hopefully these URLS will do the trick.

https://lh4.googleusercontent.com/-z...2015-03-30.jpg

https://lh6.googleusercontent.com/-D...2015-03-30.jpg

https://lh6.googleusercontent.com/-M...2015-03-30.jpg

Ah that line? It's typically a slicing problems and the thickness of your cylinder. Thick circular circular shape tends to negate that effect, but the main problem itself is the slicing.

Curious has experienced with Simplify3D, I think he can confirm what I said, since he has the option to check generate random?

Yes it is that line, that evil little line. It is about 1mm wide and deep. I usually only run 2 vertical perimeter I haven't tried more but I have ran full solids that have the same issue. I haven't tried Simplify3D.

Do try a cilinder about 5mm wall+ try an infill of 35%, let me know if it solves your problem.

It has also to do with the settings, basically overextrusion and other mistery...

Yes, The last time I saw that one the resolution was to increase perimeter overlap.
It looks like your infill overlap is not high enough over your perimeters. It may be an unfortunate number rounding issue for that direction/case on infill. The rest of the fill to perimeters look like they are just touching- but fine. Skeinforge has a setting for that, I cannot remember about Slic3r.
I only used slic3r for a little while until I got to the point in my machine calibration where I wanted more control. But you go from like 20 settings to like 100, so a little good and bad- mostly good, but more work.

I truly appreciate your feed back and help with this issue but a 5mm wall isn't always an option. I will definitely give it a shot tonight to see if it resolves any issues.

Quote:

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Originally Posted by richardphat

Do try a cilinder about 5mm wall+ try an infill of 35%, let me know if it solves your problem.

It has also to do with the settings, basically overextrusion and other mistery...

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Thanks for the idea. I did some research on infill overlap and I guess the newest experiment version of slic3r has an infill overlap option but the current stable version doesn't. I found someone suggesting reducing the extrusion width to adjust the overlap for the 1.1.7 version of slic3r. My understanding is for it to increase the overlap by drawing the lines closer together but I am not sure this will fix my issue with the perimeter gap.

I thought slic3r had a lot of options, skeinforge is a little overwhelming. I might upgrade someday but for now I think I will stick with

Quote:

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Originally Posted by MercedesStolp

Yes, The last time I saw that one the resolution was to increase perimeter overlap.
It looks like your infill overlap is not high enough over your perimeters. It may be an unfortunate number rounding issue for that direction/case on infill. The rest of the fill to perimeters look like they are just touching- but fine. Skeinforge has a setting for that, I cannot remember about Slic3r.
I only used slic3r for a little while until I got to the point in my machine calibration where I wanted more control. But you go from like 20 settings to like 100, so a little good and bad- mostly good, but more work.

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I have found that to be a problem at times. I think its a result of the start/end points. But thats just a guess. Closer photos would help.

I use Simplify3D and it has an option to randomize the start/end points of each layer, otherwise slicers will try to put start/end points as close together as possible to reduce travel time and thus print time. Frankly, the difference, even in long large prints has been mere seconds in overall print time. So worth the option.

I have no experience with slicr so I don't know if it has that option. I don't think Cura does either.

Technically, in order to "try" Simplify3D, you have to buy it. They have removed the demo option. But, if you search the underground of the internet, you can find the old demo. If you try hard enough. I did. And I bought S3D because once I played with it I saw how much better and easier it is to use.

Slic3r does have the ability to random the starting points but then the entire outside perimeter looks like someone drilled a bunch of small holes in it. I think it has to do with the start and stop point as well but I am not sure how I can tell it to stop 1mm later then it wants. I have some blue PLA that should show the defects better. I will get some better pictures uploaded this evening.

Here is the better picture I promised. I tried all the tip and tricks that were suggested but I still can't get rid of that gap. Using a hollow cylinder I found out there there is the inverse on the ID. There is a nipple where it starts/stops the inner most layer. The thicker wall made no difference, upgraded to slic3r 1.2.6 which was better the 1.1.7 out the gate but the gap is still there. I tried to change my extruded width and I tried adjusting the overlap. Anyone have any other options?

http://3dprintboard.com/attachment.p...tid=5503&stc=1
Since the last one didn't work here is the url as well
https://lh5.googleusercontent.com/-c...331_205532.jpg

Well, this is a long shot but...
Have you calibrated your extruder? Is it possible its under extruding due to mis-calibraton?
https://www.youtube.com/watch?v=JZGdMc2ebPo
I made a web page tool for helping to the calculations...
http://wolfiesden.com/TAZ/ExtruderCal.asp (should work with any printer)

S3D has a setting called "Coast At End". Possible you have a similar setting in slicr and its set too high? I use it with compressible filaments like FlexPLA and such to compensate for ooze. Basically it tells the extruder to stop extruding x MM before the end of travel and let the ooze take care of the rest of the track. Then I have it lift Z and retract to stop ooze and release filament compression.

Combine the Coast with an under extruding condition from a mis-calibrated extruder, it might produce your gap.

Do you have a bulge on the top surface of your print? It looks like you do from the photo. If you are, you're over-extruding - try dropping the extrusion multiplier by two percent increments until it goes away. The nodules at the back of your print may be caused by insufficient retraction. These two factors may or may not have an impact on the indent on the outer surface of your print.

Thanks for the suggestion I tried them all and again no success. I check the extruder length and it was spot on. I tried under and over on the extrusion multiplier. When I went over it got better at 1.05 but then the bulges at the top got worse. I just can't see to win this game.

Ok, I guess, one last suggestion...rotate the model 90deg (z-axis) on the bed. Does the line move from the front to the left/right? If so, its the model. If not its gotta be something in the slicing or possibly machine. From prior comments, I don't think it will make any difference. You said when you chose random start positions, the same effect (a gap) appeard all over the model? Yes? If so that says slicing as well. It also seems to eliminate mechanical slop (loose belt for example) which would show itself in a particular axis.

I presume you covered the basics like making sure the filament diameter, nozzle diameter, etc are set correctly in the config file for the slicer. I am out of ideas if this doesn't cover it. I just don't have the experience yet to get any deeper. I am still new at this too.

Why not download Cura and KissSlicer and see if either does any different than slicr?

When it is set to random you see a gap on every layer where it start/stop the external perimeter.

I am quite certain it is in the slicer program. I used Cura in the beginning because with the same setting it was faster but Slic3r was always more accurate on dimensions and cleaner. I have check and double checked all my settings. I guess the only thing I don't know for sure is the nozzle diameter, I read that it was .4mm but I have never measured it. I might try KISSlicer but I love having the slicer in Repetier Host. It is just so simple to make a small change and click print.