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Underside of prints looking rough

Posted: Sun Feb 10, 2019 12:07 pm
by red
Pro2
Latest software and firmware
IdeaMaker Slice setting: Speed
Raise3D Premium PLA

Hey all, I’m on my 4th print with my new machine, and while the majority of it came out beautifully, the underside has some really bad spots. Additionally, some of the supports (particularly in the bad spots) were very difficult to remove.

I don’t have an IdeaMaker screenshot available, so I’ve included a pic of the print on the build plate.

Suggestions would be greatly appreciated. Thanks,

77DB9632-A352-4B9E-8207-5E8026AA607B.jpeg

073F7683-A35C-4E17-B098-0156F95C5D31.jpeg

C4112F43-D3E4-47B5-9BB2-69CBC338A3F5.jpeg

BD56EBDE-E38D-4549-A038-BB523E4C18A1.jpeg

Re: Underside of prints looking rough

Posted: Sun Feb 10, 2019 2:02 pm
by zemlin
In working with support the layer thickness of the build is an important variable, as you can only specify the separation from the support as a number of layers. I normally use a separation of one layer. My suggestion would be to make a small test part that requires support on a shallow-angle surface like you have in your model and experiment with different layer thicknesses. I generally start with a layer thickness that's about 40% of the extrusion width and work from there. If you can't get the support to break away increase the layer thickness. If the build on top of the support is loose, decrease the layer thickness. Once you home in on the optimal setting, try the build again.

The build on top of support (of the same material) will never look as good as the top side, but it shouldn't be messy like what you have there.

Re: Underside of prints looking rough

Posted: Mon Feb 11, 2019 6:09 pm
by Russ406
As the user above me has said, you'll never achieve great finish under support. Depending on what your printing with you could consider a water soluble support material. This enables you to do the support without any separation between it and the main model, and then dissolve it away. Although if this is PLA you'd want to use PVA and it's a PITA.

Re: Underside of prints looking rough

Posted: Wed Feb 13, 2019 6:07 pm
by red
zemlin wrote:In working with support the layer thickness of the build is an important variable, as you can only specify the separation from the support as a number of layers. I normally use a separation of one layer. My suggestion would be to make a small test part that requires support on a shallow-angle surface like you have in your model and experiment with different layer thicknesses. I generally start with a layer thickness that's about 40% of the extrusion width and work from there. If you can't get the support to break away increase the layer thickness. If the build on top of the support is loose, decrease the layer thickness. Once you home in on the optimal setting, try the build again.

The build on top of support (of the same material) will never look as good as the top side, but it shouldn't be messy like what you have there.


Thank you very much. I will research further and experiment as per your suggestions. I appreciate the help.

Re: Underside of prints looking rough

Posted: Wed Feb 13, 2019 6:08 pm
by red
Russ406 wrote:As the user above me has said, you'll never achieve great finish under support. Depending on what your printing with you could consider a water soluble support material. This enables you to do the support without any separation between it and the main model, and then dissolve it away. Although if this is PLA you'd want to use PVA and it's a PITA.


I have been thinking about soluble support material. It's part of the reason I opted for the Pro2. I think it's time to give that a go. Thank you for your suggestion. I think you're spot on.

Re: Underside of prints looking rough

Posted: Wed Feb 13, 2019 7:07 pm
by zemlin
Another thing you'll be learning soon is that with some materials the overhang will tend to curl up when printing regardless of the support you build underneath it, and that can lead to a rough under-side as well. Just something to watch for, and may drive you to settings on support that make it a little more difficult to remove than you'd like. It can be a balancing act. Reducing the density of the top support layers can make it easier to remove the support by spreading out the contact points.

You can also look at orienting your parts to reduce the amount of support necessary or to avoid shallow-angle overhangs. That skull, for example, might print better if angled up at 45 degrees.

Re: Underside of prints looking rough

Posted: Mon Feb 18, 2019 2:45 am
by red
zemlin wrote:Another thing you'll be learning soon is that with some materials the overhang will tend to curl up when printing regardless of the support you build underneath it, and that can lead to a rough under-side as well. Just something to watch for, and may drive you to settings on support that make it a little more difficult to remove than you'd like. It can be a balancing act. Reducing the density of the top support layers can make it easier to remove the support by spreading out the contact points.

You can also look at orienting your parts to reduce the amount of support necessary or to avoid shallow-angle overhangs. That skull, for example, might print better if angled up at 45 degrees.


Thank you again. I will have to experiment with support density, as I am not aware of that option. Optimal positioning makes sense. I’ve had to do similar with SLA printing.

Re: Underside of prints looking rough

Posted: Tue Feb 19, 2019 11:26 pm
by red
Hi Zemlin, thanks again. I've got a couple of follow up questions.

zemlin wrote: I normally use a separation of one layer.

Where do I specify this in IdeaMaker?

zemlin wrote: My suggestion would be to make a small test part that requires support on a shallow-angle surface like you have in your model and experiment with different layer thicknesses.

Layer thickness of my build or the support structures?

I appreciate your help.

Re: Underside of prints looking rough

Posted: Wed Feb 20, 2019 1:18 am
by zemlin
red wrote:Hi Zemlin, thanks again. I've got a couple of follow up questions.

zemlin wrote: I normally use a separation of one layer.

Where do I specify this in IdeaMaker?

It's called Vertical Offset Top for material building on top of support.
Vertical Offset Down Layers for support that starts on top of the build.

red wrote:
zemlin wrote: My suggestion would be to make a small test part that requires support on a shallow-angle surface like you have in your model and experiment with different layer thicknesses.

Layer thickness of my build or the support structures?
I appreciate your help.

They will both have the same layer thickness, so ... yes.

Re: Underside of prints looking rough

Posted: Wed Feb 20, 2019 2:58 pm
by red
zemlin wrote:
red wrote:Hi Zemlin, thanks again. I've got a couple of follow up questions.

zemlin wrote: I normally use a separation of one layer.

Where do I specify this in IdeaMaker?

It's called Vertical Offset Top for material building on top of support.
Vertical Offset Down Layers for support that starts on top of the build.

red wrote:
zemlin wrote: My suggestion would be to make a small test part that requires support on a shallow-angle surface like you have in your model and experiment with different layer thicknesses.

Layer thickness of my build or the support structures?
I appreciate your help.

They will both have the same layer thickness, so ... yes.


Great, thank you again.