Linear Stage for Better Position Control in Manufacturing Units

The linear stage is an amazing tool used in many industrial sectors to limit the movement of machines in a linear motion, as opposed to six degrees of freedom (3 rotational and 3 translational). Indeed, it allows for only one translational motion, that too in one axis.

The linear stage controls linear position using three position control methods.

Linear Stage Used Manually

Manual method is usually used through a control knob that is attached to a lead screw. This process is generally used in optics, where rotating the screw pushes the platform forward, thus achieving your purpose. A spring is used in this method, which offers restoring force to keep the platform in contact with the actuator. Hence, you get more precise motion of the stage. However, the whole arrangement is done differently when the linear stage has to be mounted vertically.

Linear Stage with Stepper Motor

This is usually used when you wish to go for automated position control. The stepper motor is employed in addition to a manual knob most of the times. It is to be mentioned here that there is greater degree of uniformity while using this method, as the motor moves in fixed increments/steps. Hence, you would get something like an indexed knob. It would be much convenient to understand with the help of a suitable example: If you use a lead screw whose pitch is 0.5 mm and the stepper motor has 200 steps per revolution, then with each revolution of the motor you would get 0.5 mm of linear motion of the stage platform. And further, each step will result in 0.0025 mm of linear motion.

Linear Stage Using DC Motor with Encoder

Then there are stages for linear motion that uses a DC motor in lieu of a manual control knob. Unlike the ones with Stepper motor, a DC motor does not move in fixed increments, and hence you as a user should employ an alternate means to determine stage position. You can use a scale that is to be attached to the internals of the stage with a linear slide and an encoder should be used to measure the position of the stage relative to the scale. This is to be further reported to the motor controller, which facilitates for motion control in set positions, reliably and repeatedly.

These are all used for linear motion control in one way; if you wish to have control in multiple directions, then more than one linear stage may be used together.

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PI is well known throughout the high-tech world as a leader in design and manufacture of motion control products, linear actuators, piezo ceramics and nanoactuators, hexapod 6DOF positioning systems, linear motor and micro robots.