ultimaker 2+ prints 1% to large in x an y and ok i z

[kenjo 3]

So I was printing a 20x20x20 mm calibration block and get 1% oversize in x and y. is there some way to input this into cura as a printer setting to fix this ?? I do not want to have to manually scale every single time. 

[ahoeben 1,431]

Unfortunately the reality is probably more complicated than a fixed percentage. Try printing a 40x40x10 block, and you'll likely get a different percentage. Print your 20x20x20 mm block at a different speed, and the percentage also likely changes (though more subtly).

 

The difference is probably mostly due to what is called "die swell". The material that gets extruded from the nozzle does not have the exact same diameter as the nozzle; due to pressure in the print head and in the bowden tube, the material expands outwards (horizontally) as soon as it leaves the nozzle. This expansion isn't constant either; it depends on the pressure and the pressure depends on print speed, and more parameters.

 

In most cases, you can use the "Horizontal Expansion" setting to get closer to the original measurements, but getting them exact is the holy grail of 3d printing.

 

[UbuntuBirdy 56]

4 hours ago, ahoeben said:

but getting them exact is the holy grail of 3d printing.

Absolutely right, but you can find it, life forever and ask yourselfe, why the next print after finding the grail turns out not as perfect as expected...

Even the room temperature and the humidity in the air can affect your printing result. But you can find settings to reach the goal allmost and often this is just what you need.

If not, you can add a few tenths of a millimeter and sand or drill or whatever your need to reach the precision you want or need to have. This additional effort will be worthwhile compared to alternative production methods.