Problem with height of printed item

Something weird to ask... i started printing stuff not long ago , was printing out some calibration cube but i realized that the height of my prints are weird , it feels like its shorter then the actual models height , for example : i printed a 0.5mm thin wall that has a 1cm height but it came out only 0.66cm. Tested on an chess piece model also , the item printed out looks like its been squashed by something. Any idea about this problem? using Repetier and Slic3r for software.

Edited 1 time(s). Last edit at 09/02/2016 08:46AM by icyanima.

Your Z steps per mm are probably not correct, or your current on the driver is set too low and the motor is skipping steps.

In the Z direction, either the stepper motors are loosing steps or the steps per mm hasn't been set correctly.

Thanks , forgot that my original threaded rod for Z axis was M8 and im using M5 , changed it from 2560 to 4000.

lower the max feed rate on Z, default are normally to high.