Surface finish of parts printed on support

[Jimustanguitar]

Hey guys!

I'm getting very nice prints lately, but I've never spent much time printing with support. When I print things at an overhang, support usually does the trick, but when I have a flat surface that prints completely on top of support, I don't have as nice of an outcome. Any advise for crummy layers on a print like this"

[img]http://i.imgur.com/mnwBLm6.png[/img]

[img]http://i.imgur.com/VBREIN3.png[/img]




(and in case you're wondering, it would require more support to flip it over )

[img]http://i.imgur.com/qjuRGaf.png[/img]

[nitewatchman]

For parts that must have good surfaces, I will cut the .stl files into two or several sub-files with netfabb, print then and glue or bound them back together. Find this works very well. See side rod example below.

[JFettig]

I know with S3D anyway - it skips a layer of support before it starts printing on it, and it looks terrible. Actually there is an option for that. I printed a test part directly onto support yesterday, and I'm printing a full part directly on it, but its going to look worse, but because there will be support stuck to the part in various places. I think the best way to get quality surface is to print on a soluble support that has 100% infill right below the actual part.

[Jimustanguitar]

I have yet to try the custom support options in Craftware... Not sure what it would do that's any different than Cura, though.

Good advice on cutting it in half. I'm also thinking about redesigning the part and incorporating some of the features into the piece that this connects to.

[Polygonhell]

The only slicer with good support is KissSlicer, it has a real interface layer and it doesn't skip full layers between the interface and the useful layer.
However if you are using PLA, it can be difficult to remove the support.
Cura's might also be useable, but I haven't messed with it recently.
S3d has easily removed support, but at the cost of very poor surface finish at the interface.

[VF_]

I was wondering, have you ever solved this issue?

I am getting the exact same results with concave/domed parts that require printing on supports and I am not sure what to do to improve the finish quality. Printing on soluble supports isn't really an option since I don't have a dual extruder setup. Splitting the model into chunks won't work either since the object is basically a compound curved surface with thickness.

Even with a dense grid support the material on the first useful layer still looks like spaghetti.

Any input would be greatly appreciated!

[TFMike]

I found that using the line option in cura is the best way around the problem other than going in and physically adding support in manually in CAD.

[Jimustanguitar]

I've learned a few things since that post, yep. I also changed the design a bit so that it requires less support. That's obviously the question to ask first.

When I was printing those parts, I was also using the "grid" shaped support material instead of "lines" in Cura, and I had to have the support infill % turned down because it would stick to the part too badly to remove if it was any higher. I've started using the linear support option since then and can make the support infill much more dense and still remove it. This is a recent example of a part I did:
[img]http://i.imgur.com/5SrLoMW.png[/img]

I've also learned some neat tricks for using MeshMixer to do "tree" supports on complex parts.

[youtube]http://www.youtube.com/watch?v=aFTyTV3wwsE[/youtube]

Bridges are easier to do than overhangs. It's easier to string filament up between two objects than it is to float it out in mid air. Go for an isthmus instead of peninsulas

High temps and quick speeds also seem to help, but reading other people's posts, it seems like there's a little bit of voodoo here and your mileage may vary.


Show us your part. Sometimes seeing it with a different set of eyes is the ticket.

[bot]

s3d support with no gap is amazing. Small lines left over, but they can easily be removed.

[Jimustanguitar]

s3d support with no gap is amazing. Small lines left over, but they can easily be removed.

Pics or it didn't happen

[VF_]

I've learned a few things since that post, yep. [...] I've also learned some neat tricks for using MeshMixer to do "tree" supports on complex parts.

Thank you for all the info! MeshMixer looks really awesome, I could definitely use that on more complex parts.

Show us your part. Sometimes seeing it with a different set of eyes is the ticket.

This is more like a proof of concept, really. I'm more interested in learning how to fish than to be given a fish, as the saying goes

Nevertheless, I have attached a simplified version of the part I was describing in my previous post. I recon that the best way to print this would probably be to split it in half along its longest side, print the halves vertically and then glue them back together. I am still curious however, how could I print it if for whatever reason I am forced to print it in one piece?