Repeatability is defined as the repeated motion/translation to a commanded position under the same condition. Such divergences of the theoretical position can occur due to extensions in belt drives.

 

Accuracy refers to the difference in position between the theoretical position required and actual position achieved The actual position is influenced by different factors:

• gear worm
• error of screw pitch
• unwind radius
• backlash
• loads on entire system
• step angle or angular motion error of stepper motors
• dividing error of rotary encoders or glass scales
• abbe error

Refers to the ability to keep a constant position over time.

 

The permissible force due to load vertically applied at the center of the stage.

 

The maximum centered load that can be placed directly on the stage.