Question on infill

[happycamper 0]

I have a prusa i3 from makerfarm. I decided to try cura instead of slic3r. It only took a couple prints and I have switched to cura and haven't used slic3r for a while.

Can somebody give me a clue to what my infill is doing here? It seems sparse. Is this due to retraction or something?

All my infills do this with cura. It hasn't seemed to be a problem so far, but I think it might in the future be a problem with other models.

Thanks! Awesome software!

 

[gr5 2,167]

This is typical underextrusion.

You areprinting the infill either too fast or too cold. I guess I'll go with too fast.

Cura allows you to do a higher speed on the infill. This is not a good feature. Set this to 0 so that it goes at the same speed as the rest of the printing. Alternatively slow down the entire print or raise the temperature to allow more filament through the nozzle.

 

[happycamper 0]

Thanks for the help. Good to know where to look.

I figured I was going too fast because the temperature is set to 190 for PLA. I'd think thats enough isn't it?

I looked at the infill speed and it was set to the same as the regular speed. I set it to 0 anyway.

Maybe I have a clog or something? Not sure. Thanks for the tip on what to look for.

 

[IRobertI 520]

190C can be on the cold side depending on your speed. You haven't told us which speed you're running at but I'd say somewhere around 50-70mm/s is where 190C is getting too cold. But I'm not experienced your printer so I have no idea how much time the plastic has to get up to temperature before being extruded.

 

[happycamper 0]

Thanks! I'm only printing at 30mm/s The prusa i3 I have is not that fast I guess...

 

[gr5 2,167]

190C is very cold - toothpaste consistency for PLA. Although I often print at this temp. But when I *do* print at this temp I print slower. At 240C the PLA flows like warm honey. 210 to 220C is typical.

I prefer much colder (190C) when I have lots of stringing issues but I don't think you have any stringing so for this particular part I would consider going up to 210C rather than slow it down more.

 

[illuminarti 18]

Also, it looks like you might have quite a high infill percentage (although I'm not sure the scale of your photo). Infill of 25% and above is done with a different pattern that lays down plastic in on direction per layer, alternating from one to the next.

That can make it harder to get a good infill, as each line of infill is really printing over one layer of empty space, and only touching the layer below at the crossing points. If you go for 24% or less infill, it will draw the full grid on each layer, and give better results.

As others have said, I think raising your temperature will probably help quite a lot. Its very hard to compare temperatures between different printers with different nozzle arrangements, but on an Ultimaker, at least, 190 is pretty cool for PLA.

 

[happycamper 0]

Thanks guys. I have the infill set to 30. I played with higher temperatures and it seemed to maybe help a little, but the thing that helped the most was when I turned retraction off. It seems it kept doing retraction and not filling in all those spots...