Top Layer Porosity  

RE: Top Layer Porosity

For reference, or comparison, here is on I did with another graphic, same filament, and as near as I can tell, same settings except top fill pattern.....

The top fill pattern is different between the two, but I can't understand why that would make it fill the top layer in on one and not on the other.

Thanks. Brad.

RE: Top Layer Porosity

A better picture.

It's hard to judge from a photo - for a better diagnosis provide a .3mf file

Files > Save Project as

Zip the .3mf and post it here. It will contain both your part and your settings for us to diagnose.

But my best guess is that some of those lines are too thin to allow proper infill, just a couple of perimeters with the odd scrap of fill between, whilst the later logo has bolder text with simpler curves.  Enabling Arachne may help.

Cheeri,

RE:

Diem,

I guess my question is why didn't the slicer fill in the top layers of the lettering like it did the rest of the model? Did it see it as "filled" because the infill was so minimal?

Zip file.... Reese - 2in - PQ

Thanks. Brad.

RE: Top Layer Porosity

As I suspected, you haven't given it enough room to arrange infill.  If the text strokes were wider, bolder, there would be more room and better chance of success.

Cheerio,

RE: Top Layer Porosity

Diem,

But why didn’t it just fill the top layer in? I would think it would just cover it solid either way….. (?)

I can’t/won’t change the graphic. It’s a pretty accurate reproduction of the PowerQuest logo. Can I just increase the vertical/outside perimeter thickness?

Thanks. Brad.

There isn't room, the extrusions are limited by nozzle size, if the gap is a fraction smaler than the extrusion width you will get a gap.  Wider sections can be filled by modifying the alignment and width of extrusion to lose the irregularity but it needs space ... your only option for this part is to change to a smaller nozzle.

Can I just increase the vertical/outside perimeter thickness?

This will probably make things worse.

Cheerio,

RE: Top Layer Porosity

Posted by: @diem

There isn't room, the extrusions are limited by nozzle size, if the gap is a fraction smaler than the extrusion width you will get a gap.  Wider sections can be filled by modifying the alignment and width of extrusion to lose the irregularity but it needs space ... your only option for this part is to change to a smaller nozzle.

Can I just increase the vertical/outside perimeter thickness?

This will probably make things worse.

Cheerio,

Diem,

I'd prefer the lettering being entirely solid over making it thicker.

I still don't understand what the infill has to do with the fact that it's not making to top skin solid. I would think it would decrease the number of layers required to cap the infill, not convince the slicer it's not necessary.

Thanks. Brad.

I'd prefer the lettering being entirely solid over making it thicker.

So either make the text larger or use a smaller nozzle.

I still don't understand what the infill has to do with the fact that it's not making to top skin solid.

This is the 'Top fill', the extrusion that fills in all the gaps in the top layer that it can.

Cheerio,

RE: Top Layer Porosity

Diem,

Neither are viable options. At least not changing the design. That is a fixed, to the purpose, aspect of the project. I could be talked into converting to a finer nozzle, but these are already 24+hr prints.

As I stated, the narrow cross section should make it easier to complete a solid top layer, not more difficult, given the reduced gaps in the infill to be bridged over. This is a glitch that the dev team needs to address.

I spent some time chatting with tech support last night, and he developed a potential work-around: a single perimeter with monotonic solid layer set to a reduced stepover. As soon as the printer is finished with its current job, I will be testing the suggested parameters. I'll report back.

Thanks. Brad.

Neither are viable options. At least not changing the design.

So you have to change the production method.  CNC milling might work.

I could be talked into converting to a finer nozzle, but these are already 24+hr prints.

Reasonably quick considering the scale.

As I stated, the narrow cross section should make it easier to complete a solid top layer, not more difficult, given the reduced gaps in the infill to be bridged over. This is a glitch that the dev team needs to address.

Sigh, try laying it out on paper - or by laying down cooked spaghetti.

I spent some time chatting with tech support last night, and he developed a potential work-around: a single perimeter with monotonic solid layer set to a reduced stepover. As soon as the printer is finished with its current job, I will be testing the suggested parameters. I'll report back.

You may get some benefit in the wider sections but in the narrow parts that's roughly what you're getting already.

Cheerio,

RE: Top Layer Porosity

Guys,

OK. So, after a convo with Andreas the other evening, he was able to work up some modifications to my project that have yielded some good results. I've made a small modification to it and another test print is currently underway. But now I have a new problem: I don't know how to add these mods on my own. I cannot find them in the slicer to add them to my original project. I mean, sure, I can just move forward with the project Andreas worked up for me, but I very much have a "teach to fish", rather than a "give a fish" mentality. Try as I may, I cannot find the settings he's applied to apply them to my own project, which means I will eventually be in this same boat again, sooner or later, on future projects.

Any help?

Reese - 2in - PQ

I have included both my original project, which has already been posted, and the "TestMod" project Andreas sent me.

Thanks. Brad.

The only significant change is to enable ironing - effectively just smoothing over the mistakes, it can cause as many issues as it fixes so wherever possible get the original design right first.

Cheerio,

RE: Top Layer Porosity

Diem,

No. We've made significant improvements. My question was in regard to how I implement these improvements to future projects when the need arises. I cannot seem to find the options in PrusaSlicer. Screenshots are perfect for this.

Thanks. Brad.

RE: Top Layer Porosity

Good morning Brad, 
Have you tried enabling single perimeters on all top layers and enabling Classic Perimeter generator?

.3mf file below  (Prusa slicer 2.8.0)

Reese - 2in - PQ JT
Ironing may also help, but I am not a fan of ironing on long print duration models. 

regards Joan