How Linear Encoders Improve Precision Machining Tools

 

Precision Machining tools have been greatly improved by linear encoders in a number of ways. A linear encoder is a sensor, transducer or readhead paired with a scale that encodes position. It works by the sensor reading the scale and converting that encoded position into a digital signal which is then decoded into position by a digital readout. Linear encoders are used in metrology instruments and Precision Machining tools such as digital calipers and coordinate measuring machines. Linear encoders use many different physical properties to encode the position such as optical, magnetic, inductive, and capacitive.

 

Optical linear encoders are the most popular form of encoder on the market today especially for precision machining tools. A typical scale for optical linear encoders varies from hundreds of microns down to just a few. This form of scale is very accurate and precise which is why it dominates most of the market. The magnetic encoders are another favourite and they work by scales that are either active which is magnetized or passive which is reluctance. There are two main applications for linear encoders including measurement and motion systems. Measurement is specifically important when it comes to precision machining because it needs to be accurate down to the hundredth of a millimeter. Linear encoders for measurement are commonly found in coordinate measuring machines (CMM), laser scanners, calipers, gear measurement, tension testers, and digital read outs. Motion systems from linear encoder also aid precision machining because they provide accurate high speed movement.  

 

Linear encoders are either open or closed which can carry different advantages and disadvantages. Being open they are prone to dirt especially being in precision machining tools and machines. However enclosing the encoder limits it accuracy due to friction. The option of the encoder being closed or open in a machine needs to be thought about on a case by base basis.