Delamination on curved surface

[MikeM70 0]

Hello everyone, I am a new user to 3D printing, having bought my Ender 3 pro about 4 months ago, I have printed about 30 parts so far in pla and all came out well. These were parts with horizontal and vertical surfaces. The latest part I am trying to print is all curved and there are serious problems in the lamination of the pla on the horizontal curves See first picture, inside the cup at the bottom. The item was printed with the rim on this picutre on the hotbed - as you can see the rest of the cup was printed fine.

The settings I am using are: 

Low quality

Layer hight 0.3

Line width 0.5

Wall line count 3

Infill 30% Grid

Support overhang 39 degrees

This is not so much a problem in this part, as it is intended to hold liquid, so I will be coating it in layers of epoxy resin. But I would like a better finish!

[GregValiant 1,142]

My printer is also an Ender 3 Pro.

That looks like it was printed without support.  If you DID have support enabled - did you use a "Support Interface"?

 

If you use "File | Save Project" Cura will create a Project File with your printer, your settings, and that model.  Post the 3mf file here.  

[geert_2 557]

For things like this I would recommend settings optimised for mechanical strength, if it needs to survive real use.

 

I guess this would require supports to prevent sagging of the overhanging areas. But removing supports from the inside of tubing might be difficult.

 

Does it have to be a round shape? If not, a teardrop shaped tube, or diamond shaped, might print much better: it would be cleaner, stronger, and better watertight. Look at the cross section of the model in the center below, and imagine the whole tube having this rounded diamond shape (disregard the other models, this is an old picture from something else):

 

[geert_2 557]

So I did a quick 5 minutes concept model: start with a square, rotate it 45° into a diamond, add a flange at the bottom to make in printable (you can make holes in that flange to mount the tube if desired), round the corners, and extrude into a tube. And that is it, basically. This might not work if it has to fit into an existing installation, but it might for a new one.

 

[GregValiant 1,142]

I was thinking to slice it in half and use locating pins to glue it together.

The picture below is 1/2 of a "fighting butt" for the end of a fishing rod.  I put 2.2mm holes in the mate surface, glue in short pieces of filament, and using them as locators for the other half - glue the two pieces together.  To give it some chance to be watertight I guess lap joints would be in order.

I tried printing this as a full model and standing up with the big end on the build plate.  The large bulb on the end requires support and I didn't like the finish at all.  When the first layer goes down over support there really isn't any "squish" to make a nice surface.  With the vertical model there was also the chance of breakage across a layer line.  With the model printed in two parts it is much stronger.

 

 

 

 

 

[MikeM70 0]

Thanks all for your replies, .3mf file attached. I particularly like the idea of printing in two halves and gluing together, this will enable me to clean up the inside easier and remove support, it was the devil of a job to remove the support from the inside.

CE3PRO_urine tube-Part001Pad001.3mf

[GregValiant 1,142]

Something didn't go right.  I can't load that file.

Load your model, set Cura up to slice and then try to create the 3mf project file again.  You can attach the STL file as well.

[MikeM70 0]

GregValient: Sorry no can do Cura just crashes with a bug report, and closes down after this has been sent. I tried it with a more simple file (just a large washer) same thing happened. Has been OK up to now, never saved 3mf file before, but id does run exceptionally slow on my Dell Optiplex 760 running Windows 7 pro. attached is bug report.

[GregValiant 1,142]

@MikeM70 if you would post that on Github it will get proper attention.  They will need your Cura.log file as well.  It will be in your ...\Users\UserName\AppData\Roaming\cura folder.

[MikeM70 0]

Just done that, thanks for the help