Overhang Improvements

Thoughts about Raise3D, 3D printing and making in general.
DeftCAD
Posts: 41
Joined: Wed Dec 20, 2017 11:15 am

Overhang Improvements

Postby DeftCAD » Fri Jan 05, 2018 8:33 pm

Just completed printing a part, which has an overhang in the design. I printed it with the small cylinder - the face of which you can see - on the bed as there's another shelf inside the part and that is the 'seen' side. As you can see, where it's placed support material the finish on the face of the overhang (the first layer of the overhang, I suppose) is very poor. I'm happy with the rest of the print, but this really lets it down!
DSC_0230.JPG

It's not my design so without modifying it is there anything I can do to improve the finish? It was printed on an N2, V2 hot end, IdeaMaker standard PLA settings with the 'Speed' option.

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Vicky@Raise3D
Posts: 4563
Joined: Fri Mar 25, 2016 3:54 am

Re: Overhang Improvements

Postby Vicky@Raise3D » Mon Jan 08, 2018 3:10 am

Try standard template with dense support layers.
Dense support layers have higher infill percentage when approaching model surface which can support the the whole surface to be more smooth and flat.

DeftCAD
Posts: 41
Joined: Wed Dec 20, 2017 11:15 am

Re: Overhang Improvements

Postby DeftCAD » Thu Jan 11, 2018 9:41 am

I've tried this on another model with the following settings:

- 'Speed' profile.
- Technology Outlet grey PLA
- Infill 100% (it's a functional part and will be bolted to other parts)
- Dense Support Layers set to 5 (complete guess...)
- Everything else standard.

The print is better, but WOW are those supports hard to remove! In places they were so well attached to the lower flange that they pulled off part of the layer below. The underside of the top flange is still rough, but improved. It's definitely usable but I'm keen to improve.

On the plus side, the print has stayed very flat and the layers look brilliant - very accurate and consistent - even using the Speed profile. If not for the couple of issues above it would be perfect!

Any tips appreciated.
Attachments
20180111 Fan Adaptor Rough Lower Flange.JPG
20180111 Fan Adaptor Rough Overhang.JPG

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Vicky@Raise3D
Posts: 4563
Joined: Fri Mar 25, 2016 3:54 am

Re: Overhang Improvements

Postby Vicky@Raise3D » Fri Jan 12, 2018 8:14 am

Change the support type from Normal to be Pillar. And still sliced with Dense Layer.
Slice and check the preview whether all the overhang surfaces and been supported properly or not.

DeftCAD
Posts: 41
Joined: Wed Dec 20, 2017 11:15 am

Re: Overhang Improvements

Postby DeftCAD » Wed Jan 17, 2018 5:13 pm

I had a go at this today: waaaaay better. I used 2x dense layers and the overhang was very much improved. Also, the supports came away very easily, which was impressive. I think they were so difficult before because the supports were between two flanges and the dense layers were used at both the bottom and top. Maybe there's a setting for this but I'll know to watch out for it in future.

Thanks for the input.

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Vicky@Raise3D
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Joined: Fri Mar 25, 2016 3:54 am

Re: Overhang Improvements

Postby Vicky@Raise3D » Thu Jan 18, 2018 7:07 am

Only change the layer quantity from 5 to 2? But no other parameter?

zemlin
Posts: 380
Joined: Sat Oct 21, 2017 2:02 pm

Re: Overhang Improvements

Postby zemlin » Fri Jan 19, 2018 1:07 am

I've found the most significant factor in getting a clean build that separates readily is the layer thickness. In my testing a layer height of 40-45% of the nozzle diameter is a good starting point. If the build is messy, reduce the layer thickness. If you can't separate the support material, increase the layer thickness.

DeftCAD
Posts: 41
Joined: Wed Dec 20, 2017 11:15 am

Re: Overhang Improvements

Postby DeftCAD » Fri Jan 19, 2018 5:38 am

@Vicky - I also changed the support type to pillar as you suggested.

@zemlin - thanks for the tip. I'm making notes!


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