PETG Settings for Prusa MK3S+

Temperature Settings

Start with the nozzle at 240°C and the bed at 85°C. If you see poor layer adhesion, increase the nozzle temperature by 5°C increments. If you experience stringing, decrease the nozzle temperature by 5°C. For the first layer, you can increase the bed temperature by 5°C for better adhesion, then let it drop back to 85°C for subsequent layers.

The PETG filament has a recommended nozzle temperature range of 230-250°C and a bed temperature range of 80-90°C. The Prusa MK3S+ supports nozzle temperatures up to 300°C and bed temperatures up to 120°C, which fully covers the recommended range for this filament.

Speed & Quality

For the Prusa MK3S+, a print speed of 40-50 mm/s works well with PETG. The first layer should be printed at 15-25 mm/s for solid bed adhesion. Outer walls at 70-80% of the main speed produce cleaner surface finishes.

For quality-critical prints like miniatures or display pieces, reduce the speed to 40 mm/s and use a 0.12-0.16mm layer height. For draft or rapid prototyping, you can push the speed to 50 mm/s with a 0.24-0.28mm layer height. The standard 0.2mm layer height at 45 mm/s provides the best balance of speed and quality for most prints.

Bed Adhesion

PETG bonds extremely well to smooth PEI sheets -- sometimes too well. Use a textured PEI sheet or apply a thin layer of glue stick as a release agent on smooth PEI to prevent damage. On glass beds, always use glue stick (PETG can pull glass chips off). Let the bed cool completely before removing prints.

Common Issues with PETG on Prusa MK3S+

Here are the most common problems you may encounter when printing PETG on the Prusa MK3S+, along with proven solutions:

• Excessive stringing: Reduce temperature to 230-235°C, increase retraction speed to 60 mm/s, and dry the filament
• Foggy or rough surface: Reduce fan speed to 30% and increase temperature slightly
• Sticking too hard to bed: Let the bed cool completely before removal; use glue stick as release agent on PEI
• Brittle prints: Likely moisture-damaged; dry at 65°C for 6-8 hours

Tips for Best Results

Follow these expert tips to get the best possible prints with PETG on your Prusa MK3S+:

• Dry your PETG before printing -- even a new spool left open overnight can absorb enough moisture to affect quality
• Slow down the first layer to 15-20 mm/s for solid adhesion
• Use a lower fan speed (30-50%) -- too much cooling weakens layer adhesion with PETG
• If printing on smooth PEI, use glue stick as a release agent to prevent bed damage
• PETG is an excellent all-around material once you dial in the settings

Support Settings

For prints requiring supports with PETG, use tree supports for easier removal and less scarring. Set a 0.15-0.2mm Z-distance between support and model. If you have a dual-extruder setup, consider PVA (for PLA/PETG) or HIPS (for ABS) as dedicated water/solvent-soluble support material.

PETG at a Glance

Prusa MK3S+ Specifications

The Prusa MK3S+ features a 250 x 210 x 210 mm build volume with a maximum print speed of 100 mm/s. It uses a direct drive extruder system, which provides better control over flexible and specialty filaments. The hotend can reach 300°C and the heated bed supports temperatures up to 120°C.