Hi, i recently discovered that my prints are way too small. I printed a square thing that should have had the dimensions 100mm x 100mm and my final result was 99.75mm x 99.75mm. I do use the polymaker polylite pla which did a bit of overextrusion with the default bambu studio settings. I had to reduce the flowratio from 0.95 to 0.91. The Thing is, that i sometimes have to print very accurate holes and for me this makes a huge difference if a hole is 4mm or 3.8mm
Now there is no overextrusion, but could it be that this is the reason why my parts are too small? What could i do to fix this problem without getting bad surfaces because of overextrusion?
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0.25 in 100 is way too? Stick your PLA cube in some warm water and thermal expansion will bring it up to size.
There are overall scale errors caused by lead screw/belt pitch stretch/inaccuracy and thermal expansion. If you need that much precision do a test print and scale the model before printing again keeping everything exactly the same.
Local errors are caused by the extruded width not being what the slicer expected it to be. The slicer has settings for X-Y hole and contour compensation to deal with that.
.25MM = ~.009"
That’s actually not bad at all. Here’s an idea! Account for the shrinkage in the design! Make that square thing 100.25x100.25! Boom!
If you require holes that precise you can undersize the holes slightly in the design, print with extra perimeter walls and use a reamer to achieve precision holes! I’ve done it in the past, it just takes a little extra thought in the design and you’ll have to buy a quality reamer which can be $15-$50 depending on the size.
Hope this helps you out! 
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Industrial FDM printing has a dimensional tolerance of ± 0.15% and a lower limit of ± 0.2 mm
If 0.25mm at 100mm is bad, fdm printing is not for you.
0.25mm is litterally nothing.
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Hola tengo el mismo problema, necesito hacer un tubo de 7,3cm y me lo hace de 7cm exterior y de interior necesito 5,4cm y me lo hace de 5cm
My total tolerance range for my application is .003" diametrically. Everyone saying you should be grateful clearly hasn’t been in a situation where precision tolerances are required. That said, after testing I found to make the ID’s match I had to use .2% scaling, but for the OD’s I had to use .4%. Apparently you have to choose if you want a single consistent scale. What a shame.