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Hello,

I have been using this Makerbot printer and am currently studying its dimensional accuracy. I was able to find a correction factor - about +0.3% - that places most of the x and y dimensions inside the tolerances, through the “scale” parameter in Makerbot Print. I am struggling with the accuracy of wall thicknesses - most of the thicknesses are 5 % to 15 % wider than desired.

Is there a way to deal with this problem? I mean, ideally, without modifying the CAD file, as that would be impractical.

Thank you very much in advance!

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Hi Pagalmo,

What wall thickness are you trying to achieve?

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How much infill you’re using?
Did you try to under extrude a little bit and see if it brings down the wall thickness?

1 Like
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Assuming your z18 is ok mechanically I would suggest turning down the speed a little bit, I think default is 80mm/s , turn it down to 60mm/s.

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I’m guessing you are using Makerbot desktop? I believe you can tune most things with that slicer. Simplify 3d makes it a bit easier though to tune the machine.

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Thank you for your answer.

I am using Makerbot Printer, the successor to Makerbot Desktop. Yes, there are several settings I can tune with it, and I am trying to find which ones will have a stronger influence on wall thickness precision.

Do you know if there is any free legal version of Simplify3D?

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Thank you for your suggestion,

I have actually set the shell print speed to 40mm/s. I will try a different value.

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Thank you for your reply,

I have been using the default 10% infill density. I guess I cannot tune it to a lower value, otherwise the walls will become too fragile.

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Thank you for your reply,

The thicknesses are in the range of 0.8 to 3.2mm.

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Thank you all.

Eventually what I found to have the strongest influence on wall thickness accuracy is the “number of shells” setting, at least in the range of 0.8 to 3.2 mm:

- with “number of shells = 2”, in the range of 0.9 to 1.2 mm, there is a void in the center of the wall, with the efective number of shells being one (i.e. a fragile wall). In the range of 1.3 to 1.6 mm the variation reached 0.3 mm, which I don’t think is acceptable;

- with “number of shells = 1” the variation was about 0.2 mm for a 0.8 mm thick sample. This deviation decreased with the increase of thickness. In the range of 0.9 to 1.2 mm there is infill instead of the void (i.e. a sturdier wall).

To sum it all up, these tests show that for small thicknesses it may be interesting to set “number of shells” to 1. The deviations still occur, but are in general half what they would be with “number of shells” set to 2.

Please do leave your comments/experiences!