Q9 Surface spots and streaks on the model

1.Retraction and wipe settings

If these issues occur before the start of printing, the value of "extra restart distance" in the slicing software needs to be modified to a negative value. For example, if the retraction distance is 1.00mm and the extra restart distance is -0.2mm, the printer will retract 1.00mm but only feed 0.8mm during printing, which should improve the appearance of these marks before printing. If these marks appear after each layer is printed, then the "wipe distance" setting needs to be adjusted to make the extruder stop extruding and release pressure before reaching the end of the print. Adjust this value until the marks disappear. Generally, this value is set to 0.2-0.5mm.

2.Avoid unnecessary retraction

In most slicing software, there is an option called "only retract when crossing open spaces", which, when enabled, prevents the 3D printer from retracting when printing inside the object. This can reduce the appearance of marks, and turning off retraction may work better for Bowden extruders and extruders with a large distance between the extruder wheel and nozzle.

3.Non-fixed point retraction

Conventional retraction will pause during the retraction process, which is not suitable for Bowden printers with high internal pressure. Some slicing software has the option to "wipe nozzle" during retraction, which allows the printer to continue moving during retraction. The wiping distance is usually set to 5mm.

4.Set the printing starting point

All slicing software provides an option to set the printing starting point, which allows printing to start from a user-specified location. For example, when printing a building, the starting point can be set at the back of the building, so that these marks will be arranged on the back of the building during printing and not visible on the front.