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0.3mm added to print


robertc

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Posted · 0.3mm added to print

I noticed with my first prints (basic settings) on my just received Ultimaker 2 that Cura added a 0.3mm layer to the model base.

Trying to figure it out, I started printing 1 inch cubes, but the height would always be 0.3mm over-dimension.

I tried adjusting the

I know my model is good (comes from Solidworks and validated my STL file).

In Cura, I can see that my cube is not even a cube - it's too high.

I tried to quickly adjust the initial layer from the expert settings, but (beside the fact that I can't print anything with the default settings in basic & advanced settings, as it won't even properly print the base layer) this settings actually crops the bottom of the model. With a ~5mm initial layer, I cut my cube's height in half...

All help is welcome.

thank you,

 

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    Posted · 0.3mm added to print

    Most likely your bed leveling is off by 0.3mm then.

    You can easy check if Cura is doing the proper thing. If you generate GCode for a cube, open this gcode in a text editor (like wordpad) and look for the last layer, and the last Z move it does.

    For example, my 20x20x10mm test cube has the following GCode:

     


    G0 F9000 X105.739 Y121.295
    G1 F3000 X106.202 Y121.758 E1969.46988
    ;LAYER:97
    G0 F9000 X105.600 Y121.900 Z10.000
    ;TYPE:WALL-INNER
    G1 F3000 X105.600 Y103.100 E1970.22188

    The G1 Z10.000 tells the nozzle to be 10.0mm above the bed. Which should result in a 10mm high cube, if Z0 is exactly touching the bed (as it should)

     

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    Posted · 0.3mm added to print

    No, it is in fact longer by 0.3mm.

    I tried to quickly use the expert settings (and cut off the object bottom), but I wasn't able to print anything - the PLA string is very thin, much thinner than when I print with th basic settings. I am guessing some the parameters are wrong, but I can't figure out which one(s).

     

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    Posted · 0.3mm added to print

    And we can't figure out what's wrong either unless you share those settings.

     

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    Posted · 0.3mm added to print

    here they are:

    BASIC

    QUALITY

    Layer height (mm) : 0.06

    Shell thickness (mm) : 1

    Enable retration : YES

    FILL

    Bottom/Top thickness (mm) : 1

    Fill density (%) : 50

    SPEED AND TEMPERATURE

    Print speed (mm/s) : 50

    SUPPORT (none)

    ADVANCED

    MACHINE

    Nozzle size (mm) : 0.4mm

    QUALITY

    Initial layer thickness (mm) : 0.3

    Initial layer line width (%) : 100

    Cut off object bottom (mm) : 0.3

    Dual extrusion overlap (mm): 0.15

    SPEED

    Travel speed (mm/s): 50

    Bottom layer speed (mm/s): 20

    Infill speed (mm/s): 0.0

    Outer shell speed (mm/s): 0.0

    Inner shell speed (mm/s): 0.0

    COOL

    Minimal layer time (sec): 5

    Enable cooling fan: YES

    EXPERT CONFIG

    RETRACTION

    Minimum travel (mm): 1.5

    Enable combing: YES

    Minimal extrusion before retracting (mm): 0.02

    Z hop when retracting (mm): 0.0

    SKIRT

    Line count: 1

    Start distance (mm): 3.0

    Minimal length (mm): 150.00

    COOL

    Fan full on at height (mm): 5.00

    Fan speed min (%): 100

    Fan speed max (%): 100

    Minimum speed (mm/s): 10

    Cool head lift: NO

    INFILL

    Solid infill top: YES

    Solid infill bottom: YES

    Infill overlap (%): 15

    SUPPORT

    Structure type: GRID

    Overhang angle for support (deg): 60

    Fill amount (%): 15

    Distance X/Y (mm): 0.7

    Distance Z (mm): 0.15

    BLACK MAGIC

    Spiralize the outer contour: NO

    Only follow mesh surface: NO

    BRIM

    Brim line amount: 20

    RAFT

    Extra margin (mm): 5.0

    Line spacing (mm): 3.0

    Base thickness (mm): 0.3

    Base line width (mm): 1.0

    Interface thickness (mm): 0.27

    Interface line width (mm): 0.4

    Airgap : 0.22

    Surface layers: 2

    FIX HORRIBLE

    Combine everything (Type-A): YES

    Combine everything(Type-B): NO

    Keep open faces: NO

    Extensive stitching: NO

     

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    Posted · 0.3mm added to print

    There's a very simple test you can do. If you scale your object 200%, and the error is still 0.3, then it is most likely bed leveling. If the error scales with the size of the object, then something else is going on.

     

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    Posted · 0.3mm added to print

    I just printed a 25.4mm high block, and the result was a 25.6mm high block.

    The last printing Z position in the gCode was 25.4 however.

     

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    Posted · 0.3mm added to print

    What's the thickness of your first layer (advanced settings tab in Cura)? I guess 0.3mm...

     

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    Posted · 0.3mm added to print

    0mm - so it's at 1mm as per other wall layers

     

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    Posted · 0.3mm added to print

    Maybe it's worth to print a single layer and to measure its thickness afterwards...

     

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    Posted · 0.3mm added to print

    how do I do that?

     

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    Posted · 0.3mm added to print

    You could take your block and scale the z dimension to 0.1mm using the scale feature in Cura.

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    Posted · 0.3mm added to print

    i will try that.

    would you know what values in the "full settings" equals those of the "quickprint settings"? i could start ajusting from these as well - I can't figure out to print properly with the default values in the "full settings".

    thank you,

     

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    Posted · 0.3mm added to print

    The numbers are a bit all over the place :) The settings you posted say you're printing at 0.06mm layers, with a 0.3mm first layer and with the part sunken 0.3mm into the bed.

    Next post says you're using a 0mm first layer which would then make it the thickness of your layer height, 0.06mm. But you mention 1mm which is the shell thickness (it's better to make this a multiple of your nozzle width btw).

    I'm thinking that the most likely thing that's happening is what daid suggested that the bed isn't levelled quite right. 0.2mm is teensy tiny and could easily be a matter of the bed being slightly too far from the nozzle.

    As for the test Dim3nsioneer is suggesting you could be lazy and simply abort the print after the first layer is complete.

     

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    Posted · 0.3mm added to print

    0mm - so it's at 1mm as per other wall layers

     

    No, 0 will make the first layer be the same as all your other layers - 0.06mm. Which is really too thin; it's hard to level the bed that accurately.

    The settings you posted above show that the first layer height is set to 0.3mm - which is a more reasonable value (Although anything in the 0.15-0.3 range is probably ok).

    Make sure that the first layer goes down slightly squashed into the bed. If you level too high to start with (then your print will be taller by that amount). Also make sure you are running a recent version of the firmware, as firmwares before 14.07 had some problems with how bed leveling was recorded.

    Some other things to remember: the finished object is always going to print using whole layers. So the finished height will always be equal to the first layer height, plus (n x layer height) where n is an integer.

    Secondly, the shell thickness should really be an exact multiple of the nozzle size (0.4mm) or else Cura will do funky things.

     

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    Posted · 0.3mm added to print

    Thanks for the tips.

    I will make the update on the firmware.

    As for the base layer, I actually cut the part open following my test and it is actually 1mm thick (which is why I said that).

     

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    Posted · 0.3mm added to print

    I just printed a 25.4mm high block, and the result was a 25.6mm high block.

    The last printing Z position in the gCode was 25.4 however.

     

    This tells me your leveling is off. Levelling has two purposes: making the bed parallel to the printing gantry but also setting where Z=0 is located. Evidently yours is off. I recommend you do not do any more levelling and instead simply rotate the 3 levelling screws and reprint a single layer and measure it's thickness. Try to get it perfectly to the printed thickness within your tolerance for the entire print.

    Let me explain another way. If as you say your part is 25.6mm and last Z print height was 25.4 then you need to move the glass .2mm closer to the nozzle by turning the 3 screws.

    This will have the added benefit of squishing the plastic onto the glass more and you will get the parts to stick to the glass better.

     

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