Tip of the Day 7- Infill tab, a technical analysis

[KeyboardWarrior]

Infill tab:

A lot of the infill tab settings are

Infill Extruder: Pick which extruder you'd like to extrude the infill of your part with.

External Infill Pattern: The top and bottom solid layers will be printed with this choice. Either Rectilinear or Concentric. Concentric infill will mimic your perimeter outlines, coming inwards. For a cylinder, it would make smaller and smaller circles.

Rectilinear is the more common choice, it will fill in using straight lines.

Infill Fill Percentage: What % your part you'd like to be filled in.

Outline Overlap This value will dictate how far into the perimeter the infill goes. If this value was 0, the infill would start of the perimeter and not overlap at all. At 100%, you would have complete overlapping. Calibrating this value, I would say the average value I find that works well is 30% for the printers I've used, but it does vary.

Infill Extrusion Width: This % will modify your extrusion width under the extruder tab for the Infill. If you have a .5 mm extrusion width under the Extruder tab and set a 200% Infill Extrusion Width, your Infill will be 1 mm thick.

Minimum Infill Length: This is default set to 5 mm, if there are small sections in the G-Code previewer that aren't filling in, you may want to set this to a lower value.

Print Sparse Infill Every __ layer(s): If you'd like to only print Infill once every 2 or every 3 layers, then you'd place that number in the input. My experience has been that most printers can print infill at .3 mm just fine. Therefore, if I'm at .1 mm layer height, I'll use 3 sparse layers, and if at .15 mm I'll use 2 sparse layers.

Include Solid diaphragm every __ layers: A solid diaphragm is a layer of infill at 100%. For certain parts, this can be helpful, if you want to keep the infill % low, but also add the extra structural rigidity a 100% layer of infill can provide.

Use random Infill placement for each layer: When this option is enabled, each layer of infill will start at a random spot. This means that the lines of infill won't line up.

I personally am a fan of keeping this option off, stacking the layers of infill on-top of each other seems to provide stronger parts.

Infill Angles: Standard angles are 45/-45. That means that layer infill angles and external infill will print at alternating 45 degree angles. These values traditionally don't need to be adjusted, but I'm also a fan of using 0/45/-45/90 as the angle orientations.

[montressor]

Thanks for these, again, hugely useful. One question about the "Print Sparse Infill...": I assume using this to skip layers *must* be used in conjunction with increasing the "Infill Fill Percentage" to ensure the proper height of fill is being used, correct? I changed the number of layers I printed without an according increase in the fill percentage and wound up with a bit of a mess.

Subsequent question: how big a percentage can you do here? Up to the nozzle width? e.g.: with a 0.4mm nozzle printing 0.1mm layers, I could set "Infill Fill Percentage" to 400% and set my "Print Sparse Infill" to every 4 layers?

[KeyboardWarrior]

Thanks for these, again, hugely useful. One question about the "Print Sparse Infill...": I assume using this to skip layers *must* be used in conjunction with increasing the "Infill Fill Percentage" to ensure the proper height of fill is being used, correct? I changed the number of layers I printed without an according increase in the fill percentage and wound up with a bit of a mess.

Subsequent question: how big a percentage can you do here? Up to the nozzle width? e.g.: with a 0.4mm nozzle printing 0.1mm layers, I could set "Infill Fill Percentage" to 400% and set my "Print Sparse Infill" to every 4 layers?

The software will calculate and scale the extrusion amount for the sparse feature, so you don't have to worry about that. You'll still get your infill %, since the sparse infills will have modified extrusion values. That is a good thought though

[JFettig]

Infill extrusion width doesn't increase the width of infill except for where it crosses previous layers, it increases the depth - if you use only 2 orientations(45,-45) and 200%, it will make a relatively solid infill and not just be a pile of strings, it strengthens the part significantly, adding another angle to it negates that and the infill isn't stacked. Using random infill placement has no use, it only has negative effects.

Using sparse infill is also kind of pointless IMO - it extrudes more material per infill pass but only makes infill every so many layers specified - set to 2, every 2 layers of border, it'll infill once, but twice as much material, it'll be crude.

In my opinion, both angles the infill is laid, should be laid on the same layer to make solid infill and have to use the extrusion width at 100% like every other slicer does it, its stronger and more reliable, it only takes a little longer

[TenKOhms]

Infill extrusion width doesn't increase the width of infill except for where it crosses previous layers, it increases the depth - if you use only 2 orientations(45,-45) and 200%, it will make a relatively solid infill and not just be a pile of strings, it strengthens the part significantly, adding another angle to it negates that and the infill isn't stacked. Using random infill placement has no use, it only has negative effects.

Using sparse infill is also kind of pointless IMO - it extrudes more material per infill pass but only makes infill every so many layers specified - set to 2, every 2 layers of border, it'll infill once, but twice as much material, it'll be crude.

In my opinion, both angles the infill is laid, should be laid on the same layer to make solid infill and have to use the extrusion width at 100% like every other slicer does it, its stronger and more reliable, it only takes a little longer

Increasing infill extrusion width definitely helps increase the extrusion rate of infill. I've seen a couple pictures of a "whispy" infill vs one with increased extrusion width, and the width, solidarity, and rigidity were noticeably different. IMO, this is one of the most useful features I've seen added.

Sparse infill is not useless, and in most cases (at least when I last checked), many of lulzbot's company profiles (for a different slicer) use sparse infill. It helps save time by not having to do infill every layer. This way you can have a fine outer perimeter, yet have a coarse infill.

With an increase in my infill extrusion width, ive noticed much more strength in my parts.

[jimc]

x2 gotta agree with 10k. the infill width setting is great. jfettig is right though that in normal instances it does not actually increase the width because there is a 1 layer gap below it so ithe extrusion wont squish to the proper width. it just pumps out more material to make the infill solid and fill that 1 layer gap. the strength is night and day. sparse infill works great for time savings as well. it doesnt however work good for petg. abs it always worked great for.

[dsegel]

You may want to add something about the density that is required for a good surface finish - I find that you need at least 20% infill to get a smooth surface finish on top layers. Below that and the surface threads can fall between the infill layers, leading to a bumpy or less-than-solid surface.

[cssmythe3]

External Infill Pattern: The top and bottom solid layers will be printed with this choice. Either Rectilinear or Concentric. Concentric infill will mimic your perimeter outlines, coming inwards. For a cylinder, it would make smaller and smaller circles.

Rectilinear is the more common choice, it will fill in using straight lines.

Turning on Concentric disables all bridging - I'm not sure why.

Also, all solid layers, not just the bottom and top, get set to this method.

-Chuck
NYC 3DP Wrangler

[jmunkki]

My Wanhao i3 with a Flexion Extruder seems to have issues extruding PETG at high rates. I have had my infill width set to 125% for some reason and on large large infills, the extruder started skipping (motor stalling). The parts still come out OK, although the infill obviously has a few gaps here and there. Outer surfaces are fortunately perfect. It took me quite a while to figure out what was going on.

It would be nice if S3D had a flow rate limit somewhere. What I mean is that any extrude gcode would be limited by filament extrusion rate in addition to other speed limits. Whichever would be lower would set the limit.

Mechanical accuracy of course affects quality, but in my case the limiting factor is the extruder. For example, increasing the layer height can increase the flow rate beyond what the extruder can handle. I think upgrading to the HT version of the Flexion might improve my print speeds. I already upgraded the stepper a few months ago (the old one was dying), but I'll probably check the reference voltage in the near future to see if I can get a bit more torque out of the one I have now.

P.S. After the print, I tested a 0.3mm layer PETG print that worked two days ago and found that it was also making the stepper stall, so I took the whole extruder assembly apart, cleaned everything and replaced the PTFE tube (and ordered a Flexion HT upgrade). It's possible running some cleaning filament would have done the same trick, but at least now the 0.3mm print is working fine a again. What I said above still applies though: if your printer is thermally limited rather than mechanically, it would be nice if there was a filament mm/minute speed limit option. Also, the infill width setting can cause issues.

[Großschmackhaft]

Does the "Outline Overlap" affect both external and internal infill?