The measuring accuracy of the scale is determined by following factors :
Typical Scale Position Errors :
Position error within one signal period
Position error with one signal period is mainly determined by :
a) the design and quality of Photoelectric scanning unit.
b) the dsign and quality of the signal processing unit.
c) the quality of scanning reticle glass
Position error within one signal period is have dominating effect on the machine’s position repeatability and machined part’s surface quality.
Unlike the other two errors, in actual applications, users cannot make any corrections or compensations for single signal position errors.
Therefore, improving the position accuracy of a single signal period is the most important task of a linear scale manufacturer, and it is also one of the most important parameters for users to choose a linear encoder.
Position error over the measurement range
Position error over the measurement range consist of two type of errors, they are Peroidic error and Linear error.
Position error over the measurement range have dominating effect on the positioning accuracy of the machine tool or system accuracy of the measuring equipment, but it can be effectively reduced by linear or non-linear error compensation method.
Periodic error
The periodic error is determined by following factors :
- the quality of the master graduations
- the design and quality of the photolithographic.
- the design and quality of the scale housing
Linear error
The Linear error is determined by following factors :
- the design and quality of the grating glass.
- the temperature of the inspection or usage.
The photolithography process of grating glass must be performed at a standard temperature of 20 ° C. If the process is performed at a deviation from 20 ° C, the linear scale is detected at 20 ° C and a linear error occurs.
When testing or using a temperature other than 20 ° C, a linear error may occur due to the difference in temperature expansion coefficient between the grating glass and the machine tool
All the Easson linear scale has stick the QR code label for the accuracy report. User can scan the QR code to view or download the accuracy report.
