Print a flat object and having trouble figuring out what I am doing wrong?
 
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Print a flat object and having trouble figuring out what I am doing wrong?  

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Jdusk
(@jdusk)
Active Member
Print a flat object and having trouble figuring out what I am doing wrong?

I am pretty new to 3D printing and using CAD Programs.  I got my i3 MK3S+ in January.  I designed this particular part as a possible phone holder.  However, I have printed this twice now and seem to be getting this strange result as seen in the photo I have attached.  The images below are of the second print I made.  I used Shapr3D to create it.  I am using Overture Black PLA. It is weird that it is shiny in the middle but very flat and dull where the issues are.

I am worried something is wrong with my printer particularly the heat bed maybe.  If you look at the back side (side facing the print bed) of the print it seem to have odd marking that match up to the spots on the front.

Any guidance is welcomed!  Thank you in advanced

Back side:

Posted : 10/03/2022 4:45 pm
Neophyl
(@neophyl)
Illustrious Member
RE: Print a flat object and having trouble figuring out what I am doing wrong?

The print is bowing upwards away from the bed.  You can see this on the bottom, this means the higher layers get compressed more, the plastic squeezing into a space too thin than its supposed to be.  

You either need to increase bed adhesion or design stress relief into your parts.  Basically long runs, especially straight ones cause more shrinkage along them as the plastic cools and retracts.  An enclosure can help but it all depends on the material you are printing with too.  Some like pla don't do it a lot (but still do with some designs) but something like abs warps like crazy.  Large flat parts are especially prone to it.

Welcome to the joys of 3d printing and materials science.

Posted : 10/03/2022 5:30 pm
Jdusk
(@jdusk)
Active Member
Topic starter answered:
RE: Print a flat object and having trouble figuring out what I am doing wrong?

Thank you for your response.  May I ask how would you suggest I do either of those.  I ask because I want to learn... so maybe you have a link to a resource as well?

I guess looking at that part I didn't even notice the warping (I feel stupid).

You either need to increase bed adhesion or design stress relief into your parts.

 

Posted : 10/03/2022 5:41 pm
Jerry
(@jerry)
Estimable Member
RE: Print a flat object and having trouble figuring out what I am doing wrong?

For what it's worth.  I think you have a lot of adhesion to be gained by tuning you first layer. 

Posted : 10/03/2022 7:41 pm
Neophyl
(@neophyl)
Illustrious Member
RE: Print a flat object and having trouble figuring out what I am doing wrong?

There are a few general purpose guides like at https://www.hubs.com/knowledge-base/how-design-parts-fdm-3d-printing/ or https://all3dp.com/2/how-to-design-parts-for-fdm-3d-printing/ and I'm sure google will turn up many more as well as youtube.

Beyond that, looking at the available pics of the model you posted, do the bottom and sides really need to be completely solid ? 
Adding in holes or other cutouts with rounded radii could break up the print runs into smaller islands and so produce less stresses along the part.  While this would possibly increase print time slightly it would lower material used and if it results in better parts then probably worth it. 

Also don't use the default infill of gyroid.  I don't have anything scientific but for me I always had more problems with bowing on large parts when using it.  My personal theory is that the long sine wave lines that it consists of are free to contract.  I generally use cubic infill now, just as strong and the lines cross over so the stress is from multiple directions.  While gyroid does change direction it needs a considerable z height to do so.

Posted : 11/03/2022 9:32 am
Jdusk
(@jdusk)
Active Member
Topic starter answered:
RE: Print a flat object and having trouble figuring out what I am doing wrong?

Sorry I have not been back until today to respond to your reply.  Thank you for your information... I will check these links out and see what I can do.  

I do not need everything to be solid it is just what is was doing.  I have not figured out how to the hexagon patterns yet but that was something I could think of doing... coincidentaly I tried making a coaster last night quickly for someone and wound up having some similar things happened... but no warping that I can see on the bottom...

Prusament PLA... using the Prusamen PLA settings

You dont think it is a heat bed issue?

but again need to look at those resources you provided.

Posted : 14/03/2022 2:33 pm
Neophyl
(@neophyl)
Illustrious Member
RE: Print a flat object and having trouble figuring out what I am doing wrong?

Bottom on that looks ok, some might advise to lower the live z a bit to get a bit more squish.  I cant really tell from the pic though.

I'd guess you are are using PS2.4.x and the Snug support options, the bridging layer on that rim looks pretty good, far better than what used to be possible.

I would also say that the top surfaces are very slightly over extruded though.  Not by a lot.  That's usually down to not accurizing your filament settings though.  Everyone jumps on the extrusion multiplier as a first thing, when measuring the real filament diameter with a set of callipers to find the real average and then entering that into the filament diameter field usually is all that is needed.  

Posted : 16/03/2022 11:40 am
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