Try to answer the questions asked by those trying to help you.
What accuracy are you looking for? Is it +/- 0.01 mm or +/- 2 mm?
When you says: this type of robot(krc2), which one? KRC2 is controller. You mentioned two sizes in the first post, they may have different accuracies.
Did you look into the documentation of the robot you are looking for? They have their accuracy specified for each type/size of robot. The robot also has different path accuracy, depended on the speed.
robot : kuka kr200L140 comp ed2005
i'm looking for +/-0.5mm accuracy