Understanding bed hieght map results


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    Hello I am Jason, just wanted some understanding as to the meaning I should find in these figures. I built the printer from scratch. Fully machined components on my mill. How did I do as far as level? I don't understand the results. I have the bl touch probe newer version taking the readings.

    Number of probe points: 42

    Probe area: 480.0 cm²

    Maximum deviations: -0.189 / 0.178 mm

    Mean error: -0.033 mm

    RMS error: 0.105 mm



  • @sjason1377 Hi Jason,

    so I think the first two are quite self-explanatory, the height map was created by using 42 points probed on the bed and they do span an area of 480cm².

    Next up are the maximum value below and above Z=0.0 (defined by an endstop I guess).
    In your case the lowest point measured was about 0.2mm below 0 and the highest point about 0.2mm above 0.

    Mean error is just all values of all 42 probe points summed up and divided by 42, so on average your bed is 0.033mm below Z=0.

    Regarding RMS error I have to pass about the actual meaning.
    Just from what is calculated here it looks similar to standard-deviation but it seams to be something different (which should be obvious because it is named RMS and not standard 😁).



  • @sjason1377 Oh, and regarding how you did regarding being level: nearly 0.4mm difference between highest and lowest point is a lot when you look at the fact that many people print at 0.2mm layer height. But this could also be defined by outliers solely so (without fully understanding the meaning of RMS error) this is a little hard to tell. You might want to upload the image of the height map as displayed in DWC.


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