5.2: Settings and troubleshooting

FDM Slicer Settings

Each slicer allows you to control various aspects of your 3D print. For FDM printers, these settings offer in-depth control over print properties.

Layer Height

Layer height is one of the most crucial settings for print quality. For FDM printers, it’s recommended that the layer height does not exceed 80% of the nozzle diameter or go below 20%. With the standard 0.4 mm nozzle size, this translates to a layer height range between 0.08 mm and 0.32 mm.

• Higher layer heights result in faster print times but more visible layer lines, leading to a "stairstep" effect. Additionally, depending on the nozzle's capacity, larger layer heights may face flow limitations.

• Lower layer heights: Higher print quality but significantly longer print times.  The printer may run into speed limitations.

Nozzle Temperature

Nozzle temperature is essential for controlling the material flow and print quality. Printing too hot can cause the material to degrade, affecting surface quality, while printing too cold can prevent smooth extrusion.

Most filament spools provide a recommended temperature range. Use this range as a guide and consider running test prints (e.g., a bridging test) to refine the temperature setting.

Note: Many slicers include presets for popular filament brands, often including recommended nozzle temperatures.

Bed Temperature

The bed temperature affects adhesion and helps prevent warping. If the bed is too cool, prints may not stick well, leading to warping; if it’s too hot, the print may take longer to cool, extending print time unnecessarily. Generally, a hotter bed is safer for adhesion than a cooler one.

Note: Most slicers offer presets that set bed temperatures based on the filament type.

Retractions

Retraction pulls the filament slightly back to stop extrusion, helping to avoid stringing or material oozing when moving between sections of the print.

• Short retractions can cause unwanted oozing, while long retractions can leave gaps in the print if the filament isn’t fully retracted.

• Retraction length is influenced by the extruder type:

  • Bowden tube extruders: Typically require retractions up to 5 mm.

  • Direct drive extruders: Usually need shorter retractions, around 2 mm.

To find out what type of extruder your 3D printer has, check the location of the motor that drives the filament:

• Direct Drive Extruder: If the motor is on the toolhead (the part that moves with the nozzle), it’s a direct drive extruder.  An example of a direct drive extruder is located on the Prusa MK4.

• Bowden Extruder: If the motor is mounted on the printer's frame or gantry, separate from the toolhead, it’s a Bowden extruder.  An example of a Bowden drive extruder is located on the Prusa Mini.

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Note: Retraction settings aren’t typically material-dependent, though some materials benefit more from longer retractions. Hotter nozzle temperatures can sometimes cause extra oozing even after retraction.

Support Material

Support material is added to provide structure under overhangs or bridging areas in the print. The need for supports depends on the geometry of your model:

• Overhangs and bridges: Generally benefit from support structures, which improve surface quality.

• Bridging capabilities vary by printer. Stronger cooling systems improve bridging without supports, but a supported bridge generally has a cleaner underside.

Note: Higher printing temperatures may lead to poorer overhang quality and require additional support.

Cooling

Cooling helps solidify the printed material, improving quality. However, some materials, like ABS, are prone to warping if cooled too quickly. This setting is generally turn on and off and requires little tuning.

Settings quick reference guide

Setting	Determined by
Retraction	Printer
Nozzle Temperature	Material, filament brand
Support Material	Part geometry
Layer Height	Printer, nozzle size
Bed Temperature	Material
Cooling	Material

 

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Troubleshooting quick reference guide

Below is a chart of common 3d printer issues and how you might go about solving them

Problem		Solution	Details
Clogged Nozzle		Increase nozzle temperature	Check filament packaging for safe temperature range. For PLA, stay below 220°C.
Poor Bed Adhesion		Add a brim	Increases surface area for better adhesion; can be removed after printing.
		Increase bed temperature	Helps first layer adhere to the bed by slightly melting filament onto the surface.
		Use adhesive (e.g., glue stick)	Only for personal printers, not shared ones. Adds extra adhesion to the print bed.  Common adhesives are blue painters tape, and glue sticks.
		Adjust Z offset	Only for personal printers, not shared ones.  Reset Z offset and re-level the bed. Ensure nozzle is close enough to the bed for proper adhesion.
Corners warping		Increase bed temperature	Keeps filament warm as it contacts the bed, reducing warping.
		Round off corners	Sharp corners are more prone to warping; rounding them off can minimize this issue.
		Add a brim	Stabilizes corners by increasing the constant surface area in contact with the bed, reducing the chance of warping.