LW-PLA speed sensitivity

Test prints / LW-PLA: the foam is the calibration

The same coupon at 15, 25 and 35 mm/s: does slower foam more, and by how much?

Rendered from the STL, standing as it prints. Bands tinted from amber (first) to blue (last).

Material

LW-PLA (PLA Aero)

Prusa Core One+

32 min, 2.9 g

Anycubic Kobra Max

35 min, 3.0 g

Files

• LW Vase Coupon (3 bands).stl

Slice it

tools/test_prints.py slice lw-speed

Toolpaths

Every extrusion move in the G-code, layer by layer. Drag the layer slider, scrub through the top layer, or play the print.

Slice

Prusa Core One+Anycubic Kobra Max

Toolpaths load when you open this view.

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3DTopFront

Colour by

Show

Top layer onlyTravel moves

Read from the G-code that the printer gets. The clock adds each move at its programmed speed, without acceleration or travel, so it is shorter than the slicer's estimate.

Bands

Each band starts with one G-code command on its first layer. The slicing script reads the G-code back and stops if a command is missing or lands at the wrong height.

1. 35 mm/s33–48 mmM220 S100
2. 25 mm/s18–33 mmM220 S71
3. 15 mm/s3–18 mmM220 S43

Base 0–3 mm at the first band's value

Settings

On top of the stack that the print jobs load. The printer tuning page shows that stack.

Printer	File	Changes
Prusa Core One+	lw-speed (core-one-plus).bgcode	spiral_vase 1support_material 0support_material_auto 0perimeters 1top_solid_layers 0fill_density 0%bottom_solid_layers 3slowdown_below_layer_time 0enable_dynamic_overhang_speeds 0thin_walls 0perimeter_speed 35external_perimeter_speed 35small_perimeter_speed 35
Anycubic Kobra Max	lw-speed (kobra-max).gcode	spiral_vase 1support_material 0support_material_auto 0perimeters 1top_solid_layers 0fill_density 0%bottom_solid_layers 3slowdown_below_layer_time 0enable_dynamic_overhang_speeds 0thin_walls 0perimeter_speed 35external_perimeter_speed 35small_perimeter_speed 35

Procedure

What it is for. The slicer slows down on short layers, for example at the wing tips. If LW-PLA foams more when it prints slower, those areas get a thick, heavy skin. This test measures how much.

Print. Print at the temperature from the expansion map (slice with --set temperature=<°C> --set first_layer_temperature=<°C>). The bands run at 15, 25 and 35 mm/s from the bottom.

Measure. The underside lists the band speeds, bottom band first. Measure and weigh each band as for the expansion map.

Pass. The 15 mm/s band is not more than 10 % thicker than the 35 mm/s band. If it is, the slowdowns at the wing tips make the skin fat, and a slowdown by height needs a flow correction.

Record. The wall and the mass of each band.

In the tuning log

• Flow (extrusion multiplier)To test
• Flow at slow layersTo test
• Nozzle temperature and flowTo test

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