Bambu Lab P1S — PLA Optimization

01Temperature Optimization

Your nozzle temperature of 215°C is higher than optimal for most PLA blends on the P1S. The sweet spot for generic PLA is 200–210°C — we recommend starting at 205°C, which provides good layer adhesion while keeping viscosity high enough to prevent ooze. If you see poor layer bonding, bump up to 210°C; if stringing persists, try 200°C. Bed temperature at 55–60°C is appropriate for PLA on the P1S textured PEI plate.

02Retraction Settings

The P1S uses a direct drive extruderwith a short PTFE tube between the drive gears and the hotend. Because the filament path is short, retraction distances are much lower than on Bowden setups — typically 0.4–0.8mm. Your current 0.4mm is on the low end; try increasing to 0.6–0.8mm with a retraction speed of 30–40mm/s to reduce stringing. Start at 0.6mm and increase in 0.1mm increments if needed.

Z-hop trade-off: Enabling Z-hop at 0.2–0.3mm helps prevent nozzle scarring on top surfaces during travel moves. However, Z-hop can increase stringing because the nozzle lifts and travels further, giving molten filament more time to ooze. If stringing is your primary issue, try fixing retraction first without Z-hop, then enable it only if you see scarring.

03Speed Optimization

Your outer wall speed of 80mm/s is contributing to visible layer lines. Reducing the outer wall (external perimeter) speed to 40–60mm/s allows the filament to settle more evenly, resulting in a noticeably smoother surface finish. For the best quality, try 40mm/s; for a balance of speed and quality, 60mm/s works well. You can keep infill and inner wall speeds at 100mm/s with minimal impact on total print time since outer walls are a small fraction of total toolpath.

04Cooling Optimization

PLA benefits from aggressive cooling. Your minimum fan speed of 60% is leaving too much residual heat, which softens already-deposited layers and worsens surface quality. Set the minimum fan to 100% after layer 3 for maximum cooling. The P1S aux fan handles this well. We also recommend adding a 3-second minimum layer time to ensure small features cool adequately before the next pass.

05Quality Improvements

Pressure Advance (called “Pressure Advance” in Bambu Studio, similar to “Linear Advance” in Marlin) compensates for pressure buildup in the nozzle during speed changes. This reduces blobs at corners and improves dimensional accuracy. For the P1S with PLA, a starting value of ~0.04 in Bambu Studio is a reasonable baseline. Note: this value is specific to Bambu Studio's implementation and is not the same as a raw Klipper PA value.

How to calibrate: In Bambu Studio, go to Calibration → Pressure Advance and run the built-in PA tower test. Print at your normal speed, then examine the tower to find the layer range with the cleanest corners and least bulging. Read the corresponding PA value from that layer. Additionally, calibrating your flow rate with a single-wall cube can further reduce layer line visibility.