Top layer of print doesnt print smooth like sides and bottom

[deedot 0]

Hi All, Newbie here. 

I tried printing a 3D die with takeout choices for a friend, and its printed great ... except for the top layer. Each side is smooth but the top layer (KFC) printed differently, like it should have had a finishing layer to make it smooth like the other five sides. 

 

I looked through the settings and i think the option to add 'Ironing' may help but i wanted some advice as why this happens and how to correct it?

 

Thanks

[geert_2 557]

This looks like a bit underextrusion. There is a video on this forum about possible causes and solutions for underextrusion, I think from user gr5. See if you can find that (I don't know its exact name, nor link to it).

 

Further, if you could post more details such as material and settings, and a project-file of your settings, some people on this forum might be able to analyse it and give more advise.

 

[gr5 2,173]

Top surfaces are always going to look different on a 3d printer because they are printed in a different way.

 

But you do have some underextrusion.  Try printing at about half the current speed.  Underextrusion is more obvious on the top layers.

[deedot 0]

Hey, thanks for the replies. 

 

I slowed the print right down to 30/s but it's exactly the same. Any other suggestions?

[gr5 2,173]

Post the project file (it will contain your model).  Do "file" "save program..." and post that file here.

 

I'm wondering if your infill is non-existant or too sparse or if you don't have enough top layers - it takes a few layers (maybe 4 or 6) to recover from the bridging.

[deedot 0]

CE5P_food choice.3mf

 

I did choose the 'ironing' option on a 2nd Re-print and it seemed to help. but still looks like its missing a later. in cura, after slicing and using 'preview'. i can see that whichever face of the die is on top, it renders as yellow instead of red. 

 

I think red is outer walls? is there a way to get the print to print the top the same way it does the walls, ie as a shell rather than a top/bottom?

[gr5 2,173]

You can increase the walls until there is no more top - just set the wall thickness to 1 meter.  Seriously.  look what it does in preview.  I don't think you'll be any happier with it though.

 

 

[gr5 2,173]

I looked at your profile.  Didn't see anything bad.  Although I'd change the infill density from 15% back to the default of 20%.  This will provide a little more support when it is doing the final top 7 layers.  I'd have to see what it looks like on the 7th and 6th layers from the top to know if that's a problem or not.  That could cause underextrusion on the top layer.  Although it's relatively minor.

 

Still I don't think you are going to get the topmost layer as nice as the walls.  That's just how 3d printing is.

 

I suppose you could also change the flow for the top layer to 110% (because it looks to me about 10% underextrusion where the gaps in some of the lines are about 10% as wide as the nozzle width).  But I don't know an easy way to do that without sitting at the printer and waiting for it to print the last bit.  And then jumping in and going into the TUNE menu on the S5 and upping the flow there to 110%.

 

You could sink this die into the print bed and only print the top 20 layers to save time and experiment.  You need enough layers for there to be infill so about 20 layers would be the minimum.  In cura you have to go to settings and not force the part to fall to the bed and change the z position to a negative value with the move tool.

[deedot 0]

awesome, ill give that a try when i can and let you know how it goes 🙂 

 

Thanks again for the help