Why aren't my prints the correct size?

Materials that you are printing with, firmware settings, or calibration can affect overall print dimensions.  

The first thing to check would be the steps per mm in the EEPROM. This value should be set to 80.

Also ABS and Nylon based materials for instance tends to exhibit significant shrinkage compared to other materials such as PLA when printing which could be part of the issue. A general rule of thumb is that the shrinkage can be around 3%. Sometimes scaling the part by .03 prior to slicing can resolve the issue.

You may also need to calibrate the extrusion width of your printer. We have created a video demonstrating how to do this. Extrusion Width Video