What Influences Accuracy of Rotary Tables?

January 24, 2012

by Nathan Mathiot
HEIDENHAIN Product Specialist

 

When determining the influencing factors of accuracy on a rotary table, the first thing would be to look at the mechanics of the table itself.

A rotary table contains six degrees of freedom and this is shown in Figure 1. EXC, EYC and EZC represent the radial and axial error motion of the rotary table. EAC and EBC represent the tilt error motion whereas ECC represents the angular positioning error. Each one of these motions can add to the total amount of positioning error in the rotary table.

Typically, a rotary table is driven by a worm gear which is connected to a motor with a rotary encoder on the back of it. The table’s position can be determined by the number of pulses transmitted from the encoder to the control.

The four major error sources due to semi-closed position loop are geometrical errors, thermal deformations, elasticity and wear. The sum of these errors is known as the angular positioning error (ECC). To greatly reduce the amount of angular positioning error, the ideal position to mount an angle encoder is on the axis of rotation being measured. With an angle encoder mounted underneath the rotary table and the rotary encoder on the back motor, the position loop is now considered to be a closed loop system (Figure 2).

 

If you have any questions, please let us know.

Nathan Mathiot
HEIDENHAIN Product Specialist
847-519-3398

Want to learn more?

Contact us today

Related resources and news

New Office Provides Specialized Motion Systems with ETEL

SCHAUMBURG, IL (December 2018) — As the Silicon Valley in California and the West Coast continue to be the hub of the semiconductor manufacturing in the U.S., HEIDENHAIN has expanded its motion systems support by establishing an ETEL facility in Fremont, CA. This new 2018 office will provide product, service and support of its ETEL […]

Read more »

2019 Training Calendar Released

HEIDENHAIN provides technical training covering installation, programming and PLC programming as well as general training for distributors and end-users. Classes include engaging presentations and live machine demonstrations with the latest CNC and motion control from HEIDENHAIN.

Read more »

New Sales Ops Team to Benefit Customers

HEIDENHAIN CORPORATION’s recent creation of a Sales Operations team is one of the many ways we are creating a world-class ‘Customer First’ experience.

Read more »