Overhangs first layer
Hi everybody!
This is my first post here, being recently a happy new i3 MK3 owner!!! 😀 😀 😀
My first prints have been quite successful but I am having issues with overhangs and I hope I can get some help here!
Here is a picture of what is annoying me :
This is taken from below.
I used a 2 layers raft and supports.
The first layer above both rafts and support are quite ugly!
1 - filament doesn't stick in place, as if the (very) first layer calibration was too high.
2 - traces look spaced
My investigations :
1 - In Print settings > Support material > Don't support bridges option is checked by default... 💡 I am now printing without this option... I'll see... 🙂
2 - I have been watching at layers in Slic3r PE and found that, indeed, traces were spaced... But I can't find where I could modify this...
here is a capture of the first layer above support, you can definitely see there is space between traces:
And here is the second layer, you can definitely see there is no more space between traces :
Thanks in advance for your help!!!
Re: Overhangs first layer
From what I can tell from your photos it looks like you need to push the squoosh a bit more. Lower the z a bit until you get good flattish layers.
A raft does two things....allows a better chance of adhesion and kinda evens out the dips and rises of your bed. You still have to get the z adjust correct for the print itself.
Hope that helps,
Neal
Re: Overhangs first layer
Unless you're using dissolvable supports underneath, bridged and supported layers are going to look poor. These features print with no direct support underneath. As such, there's nothing to give the "squish" that provides good adhesion. Your printer is literally extruding into thin air. The extruded material will be cylindrical instead of the squished oval/rectangle that makes other layers look good. Cylindrical surfaces have poor adhesion. The spacing you're seeing directly above your supports or as the 1st layer of a bridge is bridge infill, which is not as dense as regular solid infill. This contributes to that "hairy" look.
[...] The first layer above both rafts and support are quite ugly!
1 - filament doesn't stick in place, as if the (very) first layer calibration was too high.
2 - traces look spaced
You can try adjusting supports to minimize the Z gap between support and supported layers, but you have to balance between looks and the ability to actually remove the support.
Unfortunately, this is the current state of FDM printing. Your best bet is to align your part to avoid needing supports. You can try adding supports of your own if designing parts in CAD, or using something like MeshMixer to add supports to the STL. Other slicers have a variety of support options you can try, but for now, supported and bridged under-surfaces are going to look rough compared to the rest of your print.
and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan
Re: Overhangs first layer
have you considered printing upside down?
like this
[attachment=1]20180914_153741[1].jpg[/attachment]
or print it as parts like this,
[attachment=2]20180914_153409[1].jpg[/attachment]
and assemble like this!
[attachment=0]20180914_180623[1].jpg[/attachment]
regards Joan
I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK
Re: Overhangs first layer
Thank you for your answers!
I was expecting bobstro's answer... I may try different settings to balance between ease of support removing and look. I think I can push the slider a good step into the "look" direction... 🙂
Joan, thanks for suggestion! I'll keep this option in mind for future prints!
But for that particular case, my part has extrusions on both sides, and the center hole is a threaded one, crossing most of the part, and that needs to be as robust as possible!
I'll post some pix if I manage to improve this print.
See you!
Re: Overhangs first layer
I second Joan's suggestions.
A huge part of learning 3D printing with good success is designing for the limitations of FDM printing.
It can be really challenging, but also fun and will reward you with better print quality and potentially stronger parts.