Occasionally when 3D printing, you may notice diagonal scars on your print. Annoyingly they only show up on flat surfaces, often making them really visible and meaning they can show up right at the end of a print and ruin the appearance. This happens between the printing of layers, as the print head moves from the last position of the current layer to the first position of the next layer.
Deep or wide intents are often a result of the hot print head directly colliding and dragging across the surface. In contrast, narrower raised lines tend to signify over extrusion, oozing, or stringing.
How to Fix Diagonal Scars on Prints – 3D Printing
The main way to fix these diagonal lines is to disable a feature called combing. Combing keeps the print head over the already printed material. This helps to speed up the printing time by reducing the number of retractions; however, it increases the risk that the head collides with the print. Disabling combing will increase your print times, potentially significantly, but can often eliminate most scarring issues.
If you’ve disabled combing and are still seeing scars on your prints, increasing the retraction amount can help to further minimize the issue. The Z-Life or Z-Hop setting can also be handy if you’re seeing the print head carve a line through the surface of your print. This adjusts how high the print head lifts when traveling from one layer to another. These settings shouldn’t need much adjustment, so try increasing it in increments of .25mm.
If you’re seeing raised lines being printed rather than grooves being carved into the print, then the issue you’re seeing is caused by too much material being printed. Over extrusion is a common cause of this. To address over extrusion, simply lower the flow rate in your slicing software. Typically a reduction of 5% is a good starting point. Nozzle temperature can also be an issue, especially with older or cheaper filaments.
Poor quality filament or filament that has been exposed to the elements can have lower tolerances. This makes it more likely to ooze or string when the printer is not actively printing. These issues are typically seen with the raised line across the print getting narrower, fainter, and potentially disappearing over longer distances.
With these tips, you should now be able to resolve scarring issues on your prints. If you’ve got any other tips for dealing with this issue, please feel free to share them down below.