I am currently working on printing a box with a cavity that connects two of the walls so that things can be slid in and out either end. The holes on the parallel walls create a channel that should not have any strands blocking the way of the sliding objects. I imported the stl file into slic3r and generated the g-code that I then opened in Pronterface. When I look at the layers I am finding that the printer is going to leave small strands on the inside of the box (all along the channel) as it goes through the print job. This will not work for my purposes because it will make it impossible for anything to slide through either end.
Does anyone know if there is a command that can be used in slic3r to avoid this from happening. It looks like a fairly easy problem to fix. I am very new to 3D printing and this is only the second model that I am attempting to print.
Thanks in advance!
Small Strands in Gaps
Re: Small Strands in Gaps
Kinda hard to understand exactly what you mean, a screenshot would help.
It sounds like there is an overhang, and slic3r is generating supports for you. They are intended to be easily removable after the print is completed. You can disable support generation in slic3r, but you may find the overhangs don't print very well (and you will end up with not-easily-removable droopy bits of plastic in there.
It sounds like there is an overhang, and slic3r is generating supports for you. They are intended to be easily removable after the print is completed. You can disable support generation in slic3r, but you may find the overhangs don't print very well (and you will end up with not-easily-removable droopy bits of plastic in there.
Re: Small Strands in Gaps
They could be supports but this would still be undesirable because it would provide a rougher/sharper internal surface finish. I attached a screenshot of the cad model so you can see the empty gap on the inside and also a screenshot of one of the slices from the middle of the model. It can be seen in the sliced shot that there are strands that do not belong. They happen in different places on just about every layer.
- Attachments
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- Midway Slice.PNG (3.55 KiB) Viewed 12826 times
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- CAD Model Screen.PNG (51.59 KiB) Viewed 12826 times
Re: Small Strands in Gaps
Are you referring to the grey/green lines ? They look like rapid travel moves, where the print-head will move to get to the other side but not actually extrude material. They are to be expected.
Side note, you will need to generate supports if that top rail is to be remotely printable.
Side note, you will need to generate supports if that top rail is to be remotely printable.
Re: Small Strands in Gaps
Not necessarily. This is PLA, and will bridge well. There will be some sagging, definitely, but with the fan on full blast and a high-speed travel, it will likely print fine without supports, and need no more finishing than a bit (possibly a lot) of sanding on the surface suspended in air. Which is not to say that it wouldn't print better flat on its side, or could be cleverly split into two pieces that slide together, neither of which has suspended surfaces.Side note, you will need to generate supports if that top rail is to be remotely printable.
Re: Small Strands in Gaps
And if the gray lines are rapids (quick moves to another disjoint part of the layer with no extrusion) and you're getting fine whiskers there, you probably need to adjust your coast, retraction and return settings.
Coast: the distance before the end of an extrusion move at which the extruder stops extruding while the move finishes so that the last part of the move is fed by built-up filament pressure behind the nozzle rather than being pushed out by filament coming in behind it. This helps eliminate blobs and whiskers where an extrusion move ends and a rapid begins.
Retraction: pulling the filament backwards before doing a rapid, so as to remove pressure behind the nozzle and keep filament from continuing to come out during the rapid, which produces fine whiskers on the print. If the retraction is set to 2 mm, for example, the filament is pulled back 2 mm before doing the rapid move. It is returned to position (pushed in 2 mm) after the rapid, except as modified by the return offset (below).
Return offset (not the right name, but I don't recall the exact name right now): how much further (or less) to put the filament back into the extruder after doing the rapid. When the return offset is zero, the retraction is exactly undone -- if you retracted 2 mm of filament, you put 2 mm of filament back. If the return offset is slightly negative, you put just less than 2 mm of filament back in after the rapid; if positive, you put back slightly more than 2 mm of filament (of course, for the 2 mm example above).
These parameters are all on the same tab on S3D, and if I were at my laptop that I use for printing, I'd open up S3D and take a screenshot for you.... but if you're using S3D, you should be able to find them.
It takes some tuning to get the coast and retraction set so that you don't leave whiskers during rapids, but you don't leave gaps or blobs on the print at the points where extruding ends and rapids begin (and vice versa).
Check around other topics here and look for other people's ".FFF" files for PLA --- they are files of settings exported from S3D, but are human readable and can help you set up other slicers (like Slic3r, for example).
Hope this helps!
Dale
Coast: the distance before the end of an extrusion move at which the extruder stops extruding while the move finishes so that the last part of the move is fed by built-up filament pressure behind the nozzle rather than being pushed out by filament coming in behind it. This helps eliminate blobs and whiskers where an extrusion move ends and a rapid begins.
Retraction: pulling the filament backwards before doing a rapid, so as to remove pressure behind the nozzle and keep filament from continuing to come out during the rapid, which produces fine whiskers on the print. If the retraction is set to 2 mm, for example, the filament is pulled back 2 mm before doing the rapid move. It is returned to position (pushed in 2 mm) after the rapid, except as modified by the return offset (below).
Return offset (not the right name, but I don't recall the exact name right now): how much further (or less) to put the filament back into the extruder after doing the rapid. When the return offset is zero, the retraction is exactly undone -- if you retracted 2 mm of filament, you put 2 mm of filament back. If the return offset is slightly negative, you put just less than 2 mm of filament back in after the rapid; if positive, you put back slightly more than 2 mm of filament (of course, for the 2 mm example above).
These parameters are all on the same tab on S3D, and if I were at my laptop that I use for printing, I'd open up S3D and take a screenshot for you.... but if you're using S3D, you should be able to find them.
It takes some tuning to get the coast and retraction set so that you don't leave whiskers during rapids, but you don't leave gaps or blobs on the print at the points where extruding ends and rapids begin (and vice versa).
Check around other topics here and look for other people's ".FFF" files for PLA --- they are files of settings exported from S3D, but are human readable and can help you set up other slicers (like Slic3r, for example).
Hope this helps!
Dale
Re: Small Strands in Gaps
Thanks everyone for the replies! I was skeptical when I first came to this forum and now I see that everyone really is willing to help!
I printed a scaled down version of the model for testing purposes. I used the upright orientation with pillars for the supports and I also opted to build supports for the bridges. The part came out great for the most part. The biggest thing is that the support material was harder to take off and there are still pieces that don't want to be removed. Does anyone know if it would be better/easier to use one of the different patterning styles for supports? The options I have are Honeycomb, rectilinear, and rectilinear grid. Also, is it necessary to build supports for the bridges? or should I maybe just use supports for the bridges and ignore all else?
I really like the idea of printing the part on its side to speed up the process and make the overhangs smaller. However, I am using freecad and the software does not have a feature to reorient the file so that it exports differently in the stl. I also tried using slic3r but the software only has the option to rotate among the z axis. Does anyone know of a way to reorient the part? is there perhaps a good free software that will allow me to rotate the stl or maybe the original model so that I can then make another stl? Right now it seems that the only option is to redesign the part. The part is not very complex and I would not mind doing this but for now I think I want to learn an alternate method so that I can use it for more complex models.
I printed a scaled down version of the model for testing purposes. I used the upright orientation with pillars for the supports and I also opted to build supports for the bridges. The part came out great for the most part. The biggest thing is that the support material was harder to take off and there are still pieces that don't want to be removed. Does anyone know if it would be better/easier to use one of the different patterning styles for supports? The options I have are Honeycomb, rectilinear, and rectilinear grid. Also, is it necessary to build supports for the bridges? or should I maybe just use supports for the bridges and ignore all else?
I really like the idea of printing the part on its side to speed up the process and make the overhangs smaller. However, I am using freecad and the software does not have a feature to reorient the file so that it exports differently in the stl. I also tried using slic3r but the software only has the option to rotate among the z axis. Does anyone know of a way to reorient the part? is there perhaps a good free software that will allow me to rotate the stl or maybe the original model so that I can then make another stl? Right now it seems that the only option is to redesign the part. The part is not very complex and I would not mind doing this but for now I think I want to learn an alternate method so that I can use it for more complex models.
Re: Small Strands in Gaps
If you don't mind dancing on the bleeding edge, Slic3r acquired arbitrary-angle XYZ rotation about a month ago. You must compile from the Github source, which is not for the faint of heart, but ... it can flip solid models around!Waterfin wrote:I also tried using slic3r but the software only has the option to rotate among the z axis.
Re: Small Strands in Gaps
And if you're slightly less adventurous, you can use Netfabb Studio Basic - it allows arbitrary rotations, as well as choosing a face to orient "down". I know they have a Windows version, and from this morning I know they also have Linux.
Re: Small Strands in Gaps
MatterControl can rotate, scale, and mirror. It's free and easy. I pretty much just use it to rotate models then export and use Slic3r, but it can also slice and print as an alternative to Slic3r/Pronterface.