Has anyone actually achieved the 18 minute Benchy claim?

I stumbled upon this YouTube video post a week ago claiming a sub-10 minute Benchy.

It occurred to me that in all this time, I never actually put Bambu’s 18 minute Benchy claim to the test, so I tried it. I wasn’t looking for quality but just proof that it could be done. The one thing that became obvious is that you can’t do it alone in the slicer, you have to set the printer to Ludicrous mode(166% speed).

Just for the record. I used Bambu’s X1 settings that they posted on YouTube over a year ago and used Bambu Studio not my preferred Orca Slicer. This was also done on a P1p with 1.04 firmware using Bambu Studio 1.8.4.51 and I used the Benchy baked into the 3D Primitive right-click submenu. So all things being equal, I tried to replicate Bambu’s video the best I could given the different printer, firmware and Studio revision.

image image image

Myth confirmed!

I was able to get an 18 Minute Benchy(note that I did not time this). That’s close enough to the 17:45 they claimed in the X1 video. I did give them the slight advantage of 0.28 layer height vs the 0.24 they stated above.

The filament I used was Overture PLA but I used the default Bambu “PLA Basic Profile” and the default 0.28 draft settings before making settings changes in speed that the YouTube video noted in the above screenshot. I did this primarily to eliminate any other filament settings from the experiment.

Speed version picture on left side of each image, quite mode(50%) 0.08 layer height version on the right using hand-tuned filament profile. I believe this represents the two extremes of what is possible. The quite mode 0.08 layer height takes over two hours to print. I also print at 20c higher temp in quiet mode as the temp tower I printed showed that to be the sweet spot for this Overture filament.

Scaled to 50%. Click to zoom in full resolution.

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I htink i remeber the one in the printer memory prints in 18 (in very good quality too, it’s sliced in a weird way)

This is the A1 Mini Benchy that came on the SD Card.
It came out a lot better then I thought it would.

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Testing out a new local manufacturer PLA, its the first time I’ve done the benchy on my X1C. I used the one in the local memory and ran at ludicrous start to finish, was happy it finished still located on the plate. I run the BL vibration damper feet and this thing was dancing a jig :joy:

Apart from the bow overhang deformity, the rest was 100% fine and I’d have problem picking it from a routine speed.

Hold this spot, I’ve just done a 13min benchy off the internal memory. I’ve got to downsize the 2.3g video first.

That’s actually quite fascinating. So I went back and dug out the original SD card that came with my printer. I found the Gcode Benchy file with a November 2022 timestamp but the slicer would not give me the option to slice or print in the current Bambu studio. This leads me to believe that Bambu Lab cheats on the files they include with their printer. It should be noted that I never tested to see if this would print from within the slicer when I first got the printer. So who knows, maybe this was always a print-from-sd-card test model. Either way, it feels like cheating.

However, when I did load the Gcode file from the original SD Card, Bambu Studio did report that it was a 20 minute print.

So I FTP’d the file directly onto the SD Card and printed it from the console and set it to ludicrous mode. Note that there are no layers reported in the slicer and that it did start out indicating an 11 minute print time once the printer was placed in Ludicrous mode.

Is Bambu Lab Cheating on the Benchy Test?

So clearly what Bambu is doing with these claims is they are playing the Captain Kirk-style Kobayashi Maru cook-the-books-cheat, where they are hand-coding and tweak the GCode. That’s cheating in my book. An honest test would be to do so in the slicer.

  • From left to right:
  1. Bambu Benchy using 3d Primative in ludicrous mode 0.28 – 18in

  2. Bambu Benchy from model found on factory supplied SD card, manually printed from console and printed in ludicrous mode 0.20 once print was started. – 11min

  3. Bambu Benchy using 3D Primitive in quiet mode(50% speed), Overture tuned filament at 0.08 – over 2 hours

To repeat from my post above. 1 and 3 were from the slicer. 3 Represents the best possible options for a quality print from the slicer while 1 represents pure speed.

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13min video. It surprised me the second time around. I think the last time I did it from the Bambu Studio Add Primitive.





Using the preloaded benchy .stl, I was able to get nice results. But, trying to get the same results without that specific .stl file has never given me good results.

This was using a local manufactured PLA which I’m playing with at present. So Bambu filament tuning tricks are not a factor.

The internal Benchy has some quirks. It uses the cold plate and doesn’t do the normal plate check, I originally fired it up on my Hot plate and it came adrift at the first deck part. It will only let you load up the first slot in the AMS, who knows why. And it won’t let you timelapse it.

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The presliced file is optimised.
You will not achieve the same results without “manually” tweaking the print settings.

It’s easy to use the settings comparison tool in Studio to see what they changed in the project for the presliced file. It’s not cheating, just optimizing. I’ll also comment that due to later firmware changes, the presliced file may not print as well as it did earlier.

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Would you mind illustrating that with screengrabs? I’m struggling to picture what you mean.

Download the presliced projects from Bambu Lab printer internally sliced files | Bambu Lab Wiki , extract the Benchy project and open it. Save user copies of the modified filament and print presets. I first note this (didn’t see this when I last did this comparison):

Screenshot 2024-01-28 111610

Then you can do this:
Screenshot 2024-01-28 111709

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Thank you sir. I’ve never used that feature before in that way. In fact, up until now, I couldn’t find a use-case for that feature. This is quite helpful. :clap:

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I just tried it. I loaded the “pre-sliced” project, transferred all the settings to a new project (since the pre-sliced one doesn’t include the STL), added the Benchy STL, sliced and printed. The actual time printing was 18 minutes 22 seconds. There was another 4:30 of preparation.

Not the best Benchy I have ever seen, but not bad as an amusing demonstration.

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Then again, it could look like this:


New world record: Modded 3D printer completes ‘Speed Benchy’ model in just 2 minutes! | Tom’s Hardware (tomshardware.com)

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I dug into the pre-sliced project for the settings, and found convenient summaries of which settings were changed from defaults:

“different_settings_to_system”: [
“bridge_speed;default_acceleration;detect_narrow_internal_solid_infill;detect_overhang_wall;gap_infill_speed;infill_combination;initial_layer_acceleration;initial_layer_infill_speed;initial_layer_print_height;initial_layer_speed;inner_wall_line_width;inner_wall_speed;internal_solid_infill_line_width;internal_solid_infill_speed;layer_height;line_width;outer_wall_line_width;outer_wall_speed;sparse_infill_line_width;sparse_infill_pattern;sparse_infill_speed;top_shell_layers;top_surface_line_width;top_surface_speed;travel_speed”,
“filament_max_volumetric_speed;filament_z_hop;slow_down_for_layer_cooling”,
“layer_change_gcode;z_hop”
],

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Downloading the gcode from their website and loading it into BS here are my notes as to what they changed from stock settings. The setting that changed things the most was:
cooling: slow printing down for better layer cooling: disabled

Here are all the changes:

Starting from:
0.4 nozzle
Bambu PLA Basic
0.20mm Standard @BBL X1C
Standard setting print time would be: 39m25s

Quality tab changes:
layer height: 0.25
initial layer height: 0.25
default line width: 0.5
outer wall line width: 0.5
inner wall line width: 0.5
top surface line width: 0.5
sparse infill line width: 0.5
internal solid infill line width: 0.5

Strength tab changes:
top shell layers: 3
sparse infill pattern: tri-hexagon
advanced, infill combination: checked
advanced, detect narrow internal solid infill: unchecked

speed tab changes:
initial layer speed: 150mm/s
initial layer infill: 300mm/s
outer wall speed: 160mm/s
inner wall speed: 500mm/s
sparse infill speed: 500mm/s
internal solid infill speed: 120mm/s
top surface speed: 80mm/s
bridge speed: 100mm/s
gap infill speed: 500mm/s
normal printing acceleration: 20000 mm/s^3
initial layer acceleration: 10000 mm/s^3

support tab changes:
support type: tree(auto)
support style: tree hybrid

filament settings changes:
max volumetric speed: 99 mm^3/s (only goes up to 70)
cooling: slow printing down for better layer cooling: disabled
setting overrides: z hop when retract: 0

machine settings overrides:
machine gcode tab:
layer change g-code:
{if layer_num == 161}
M204 S5000
{endif}
extruder tab:
z hop when retract: 0

BTW, I use Super Slicer for my Voron and when I took the above changes and applied them to my SS profile for the Voron it came out with a time estimate pretty close to the built in speed benchy on my X1C. The result wasn’t terrible but not as good as my X1C print.

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Interesting, That M204 is probably setting acceleration for normal moves, slowing it down a bit when it is doing the smokestack.

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I did one in 12:30 when I first got the X1C, following the speedboatrace rules and using only the slicer.

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Just got my 10min 30sec Bunchy printed on my P1S!

Inspired by the settings in SpeedBoatRace_Bambu Pla Basic Shared by Bambu Lab - MakerWorld and printed in Sports mode using Bambu Lab PLA Basic.

image1

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