Through trial and error we have slowly honed in our PLA settings and print profiles along with many other 3D printing materials. Over the next few months we will be taking a look at these settings and profiles that have worked for us.
Further than just explaining preferred temperature settings, we will be taking an indepth look at advanced support and infill settings, as well as many other factors that go into making a clean and successful print.
***Disclaimer: The following settings are for Cura and work well on Lulzbot TAZ printers with an E3D hotend. We have used these settings on our TAZ3 and TAZ5 printers and HATCHBOX 3.0mm PLA with success. When using Simplify 3D we use very similar profiles. Environmental conditions and filament origin can heavily impact these settings as well***
The layer height of your 3D print is very dependent on the nozzle size of your 3D printer as well as the quality of the print you would like. A printer with a .6mm nozzle can go up to .4mm layer heights, and a part with .1mm layer heights will take twice as long as one at .2mm, so these factors are important to consider.
Our standard quality print settings are at a .25mm layer height. We then hone in the retraction settings for PLA. Upon clicking the “…” next to “Enable retraction” we have our profile as such:
Minimum Travel: 1.5mm
Enable Combing: All
Minimal Extrusion Before Retracting: 0.005mm
Z Hop When Retracting: .1mm
Combing refers to the printer head following the path of the print rather than attempting to clear gaps. This will help prevent “hairy” sides of a print. The Z Hop when retracting is set to a small .1mm so that skinny prints are less likely to be knocked off.
When clicking into the Advanced Settings tab we then take a look at the Retraction and Quality sections of Cura. We set our retraction speed to 10mm/s and our distance to 1.5mm. Within the Quality area of the Advanced section we do not increase the initial layer thickness but we do increase the initial line width to 115%. We have found this to help stick to the bed without impairing the print quality.
Pictured Below: From Left to Right – 100 micron layer height (fine quality), 250 micron layer height (standard quality), and 380 micron layer height (draft quality)
In order for a clean PLA print, we always make sure to include a minimum of 4 bottom/top layers (meaning you would multiply layer height by at least 4). This can increase depending on how flat the object is, how high fill density is set to, and how thick your layer height is. A long rectangle piece with a .1mm layer height will require over 10% infill and at least 7 bottom/top layers in order to not have a pitted look. The print to the right had that exact issue: too small of infill and too few bottom/top layers – leaving the print unacceptable for a final version.
Prefered fill density percentage is unique to your particular print, similar to the quality settings. That being said, you can click on the “…” on Cura in order to have some advanced settings. The infill overlap settings are where we want to focus in order to perfect the surface quality of the print.
Infill overlap refers to the percentage the infill will overlap onto the shells. When having a small numbers of shells, and infill overlap % is set above 12%, we notice a “veiny” look to the surface of prints – especially large parts in a translucent PLA color. We prefer almost all of our PLA prints to have an 8% infill overlap. The photo to the left is an example of two shells with a 15% infill overlap in a translucent blue PLA. While the effect is kind of cool looking, we needed to decrease that infill overlap in order for that “veiny” look to disappear.
Speed and Temperature
As we warned above, these PLA settings work well with our Lulzbot TAZ printers with E3D hotends. These temperatures (and speeds) may vary depending on the printer and hotends you use.
Our nozzle runs at a comfortable (but slightly hotter than average) 205°-210°C for PLA. We normally run our bed at 60°C, but since we added a thicker 1/4″ glass, we have increased that to 65°C. This thicker glass allows for bed leveling to be easier as well as prevents cracks and chips. We have run PLA on beds that do not have heating capabilities but we definitely prefer a heated build plate. Having a glass bed heated to 65° helps prevent warping and to stop parts from getting knocked off mid print.
We run our printers a bit slower in order to ensure the best surface quality possible. We normally set our average speed to 60mm/s, with slower settings for the outer and top/bottom layers. In the advanced we have our speed set to:
Travel Speed: 150mm/s
Bottom Layer Speed: 25mm/s
Infill Speed: 60mm/s
Top/Bottom Speed: 40mm/s
Outer Shell Speed: 40mm/s
Inner Shell Speed: 60mm/s
We have found that support settings are one of the hardest things to dial in. Each material requires a different fill percentage and angle. They each also require unique distances from the print for easy removal.
Anyone who has printed long enough has likely come to dislike working with support settings. We have been able to make support removal a minor chore and still have a clean under surface quality to our prints. After clicking the “…” next to “Support type” we have our specs as follows:
Structure Type: Lines
Overhang Angle for Support: 50°
Fill Amount: 15%
Distance X/Y: 0.8mm
Distance Z: 0.16mm
Within the same section as the support settings you will also find the platform adhesion type. While a brim is usually not needed on PLA prints, but larger prints can still warp and skinny parts have difficulty sticking to the bed without being knocked over. Our PLA settings usually have this set to off by default and we turn it on manually for these special occasions.
The problem with a brim, especially on PLA, is the difficulty to remove. We have had parts where the brim is far more difficult to remove cleanly than the parent support material. This has led us to change to a close “skirt” instead of a brim.
Upon choosing “None” for the Platform adhesion type, click on the “…” for more options. We then change the line count to 10-15, the start distance to .01mm, and the minimal length to 250mm. This allows for a brim to only be on the outside of the print.
While the outside still requires post-processing to remove the close skirt, this saves a lot of time removing brim from the inner thin parts of the print.
And then finally the last section in the advanced tab is the ability to activate the active cooling fan. We always have that checked for PLA and allow for a 20-30 second minimal layer cooling time for skinny prints and thin layers. If you try turning off the cooling fan you may have unpleasant surface quality results – such as the photo to the right. Please note that the fan speeds depend heavily on what fan, shroud, and hotend combination you are using.
Upon clicking the “…” next to the checked off “Enable cooling fan” our settings are:
Fan Full on at Height: .5mm
Speed Min: 35%
Speed Max: 75%
Minimum Speed: 10mm/s
Cool Head Lift: unchecked (unless needed for tiny complex sections)
While we have had success with these PLA settings, there are times when particular models and prints require minor changes to this formula. Specific angles on print may require your support settings to be slightly closer in the Z or X/Y direction. As with any 3D printing material settings, these PLA settings must be tweaked for each 3D printer make/model.
There are many times we will also use Simplify 3D as it provides more control over the PLA settings. Normally this occurs when Cura does not put support where it is required. Simplify 3D allows for the ability to add manual support when Cura cannot. Cura is also limited to a square infill pattern, so if you want to use the honeycomb, triangle, or another unique style of infill, you will need to use a different slicing program.
And finally a quick screenshot of our Basic and Advanced settings for easier reference: