What kind of print quality issue is this?

I’ve been looking at different guides and I’m trying to identify the problem. It looks like I have both ghosting issues and overhang problems?

I printed this model at 30% infill and high detail print in PLA with thin walls. A lot of it looks good but on the sides and the overhang it’s really bad and I’m wondering if the overall layer detail should be better as well.

Can you provide additional info?

Which printer? Which print-head?
Which PLA?
What print temperature, speed and retraction settings?

Are you using one of the supplied print profiles for your material or have you tweaked your settings?

It is sometimes (often times) useful to create and print a “temperature tower” and I also sometimes like to do a “retraction tower” as well. This helps me find a good temperature to reduce stringing.

For example, when I print with PolyLite PLA on my TAZ Workhorse, 230°C seems to be the magic temperature where I have the least amount of stringing and best print quality (but 225°C is also pretty good… I just think 230°C is a touch better). But that printer uses a hardened steel nozzle on an Aerostruder, so best settings for your printer wont necessarily be the same (and probably wont be).

I typically run these at whatever layer-height I plan to use for the parts I make (commonly for me, that’s .25mm layers) because just changing the layer height can mean needing to tweak settings.

For PLA, make sure the fans are on 100%. If you’re still getting the stringing, try:

  • Lowering the extrusion temp - this will help the extrusion cool to a solid. Check the filament manufacturers temp recommendations.
  • Retraction settings - increase the retraction distance to prevent oozing.

Try this guide also for other issues:

Printer: TAZ 6 with the I believe 2.1 Single Extruder tool head. Purchased 3 years ago
Polylite PLA
Print temp I think was 205. I used the High Detail Lulzbot profile that came with Cura and the only custom setting was enabling Thin Walls.

The 205 print temp is what the profile sets so I’ll have to manually change that to 230 and give it a try.

The reason I use 230°C is because my printer has an Aerostruder with hardened steel nozzle. It doesn’t conduct heat quite as well and needs to run a touch hotter. Your print head will not likely need 230°C.

You can download and print a temperature tower … like this one: https://www.thingiverse.com/thing:2729076 (If you search Thingiverse for “temperature tower” you’ll find lots similar items.

These things typically have several levels (like “floors” in a high-rise building) and each level is usually 10mm high. The idea is that each floor is printed at a different temperature. This doesn’t quite happen automatically but it isn’t hard to do.

Download a temperature tower, slice it with Cura. Find the layer heights where the temperature needs to change. In Cura pick (from the main menu) “Extensions” -> “Post Processing” -> “Modify G-code”.

This will open a new window and pick the “Add a script” pull-down. The script you want to add is called “Tweak at Z or Layer” (it may not have precisely that name).

This gives you some options to fill in… you want to “Trigger” on either the Height or Layer number (height in mm or layer number … it’s your choice). Suppose you go by height and you set the height to 10mm (but I think the base in this model was 1.4mm … so really you’d change the first temp at 11.4, then 21.4, then 31.4, and so on).

Pick the height, then tick the check box that says to Tweak Extruder Temp and type in the new temperature.

Then… click “Add a Script” and we re-add the very SAME script again. (You’ll add the script for each level change). And repeat until you’ve got every temp transition added.

Now slice and print the part … watching the performance of the printer as you do. You’re looking for the quality of the print at that level, if there is stringing, whether the bridges have sagging, etc.

When you find the best looking temperature, you know what to use for your parts.

But keep in mind that if you change filament type, layer thickness, speed, fan speeds, etc. that any change in Cura may change which temperature works best.

I’ve done enough of these that I’ve pretty much figured out what works best for my printer with the filaments I use. This is a great way to get your parts dialed in.

Also … keep in mind that retraction settings can affect stringiness when printing. If you don’t retract enough… you can get stuff oozing out as it moves. If you over-retract you can end up pulling in air … the air heats up, expands, and when it goes to extrude more filament it spits out that air bubble and you get a blemish on the part. So the idea is to find that perfect setting (direct drive printers usually don’t need a heavy amount of retraction when using PLA … I often find the ideal setting is close to 1mm. I’ve seen people use 0.8, 1.5, etc. but it’s usually not a big number (typically not 2.0 or above for PLA.)

IMPORTANT: When you add a script to Cura, you’ll get a little wrench & hammer icon in the corner next to the print button to remind you that you have 1 or more scripts active. EVEN If you clear the build plate and load a new part… those scripts are STILL active. You have to go back in and turn the scripts off (or just re-start Cura). Otherwise… you’ll be wondering why your regular parts have a whole new look at 10mm of print height.

Okay, I’m running the test now.

When I manually changed the Default Printing Temperature I set it to the initial 225 layer. This did not automatically change “printer temperature” so I then had to manually set that to 225 in the settings as well.

I thought that Printing Temperature should change since its tooltip said it would auto-calculate.

It’s going to take a while to print so I will come back with results when it is finished.

I usually let the base print at whatever temp gives good adhesion for the first layer, then start using the script to change the temps at the base of each new “level” on the tower. I have Cura ‘slice’ the part, then put Cura in “Layer view” mode. Select the part (make sure it has been slice) and you’ll get some controls on the right edge of the Cura build plate window … you can use your mouse to slide the layer number up/down … or click on the layer number and use the up/down arrow keys. This will let you see that layer and I use this to work out which layer number I should use to change to the next temp.

If you watch the printer display, you should see the temperature change when it transitions to a new level.

If in doubt, you can verify the temperature changes by opening the .gcode file that Cura created using any text editor (make sure it’s a text editor that doesn’t use special characters. For example, on Windows ‘Notepad ++’ is popular as an editor that is code-friendly. Some editors replace basic characters with special characters. For example using left & right quotation marks instead of the generic quotation marks. Those editors should be avoided.)

Cura puts a comment in the gcode on each new layer that looks like this:


The semi-colon means it’s a comment (anything after a semi-colon is ignored on that line). The “50” (in this example) means it’s layer 50. Doing this, it’s easy to find the right layer by searching for the layer number in your text editor.

There are TWO commands in gcode that control temperature. One is M104, the other is M109. The difference is M104 just sets the new temperature and keeps processing lines of gcode instructions (without waiting for the new temperature). M109 has the ability to force the printer to pause and wait for the new temperature to be achieved before it continues.

The ‘Tweak at Z’ extension uses the M104 version (which means it will keep printing while it switches to the new temp. But since the new temp is typically just 5 degrees different… it achieves that new temp in a matter of seconds and it doesn’t impact your part.)

In other words, when it’s time to change the temp to say… 220°C, you should see a row that says:

M104 S220

(If ever in doubt about what a gcode command does… they are all documented here: https://marlinfw.org/meta/gcode/ )

Attached are photos of the PLA test with 15% infill no supports as the thingiverse description said. You can open any of the images in new tab to see a much larger view.

The hottest temp looks quite a bit better than the others so that’s a good step towards improving prints, but I still see some detail issues in the overhang and on all the cones. Even the cone on the 225 temp has an odd extra distortion as it goes up.

Thoughts on that?

How does this look compared to your successful runs?

Thanks for your help