Application

Ogura spring applied brake used to hold the robotic arm in position when power is removed.

Products Used

Ogura's RNB-Z zero backlash spring applied holding brake.

Size Used

RNB0.8ZG..

Description of Operation

A series of servo motors and high precision gearing move the robotic arm from the storage rack to the test area. During testing the arm is required to hold its position untill it is called upon to retrieve another disk. Rather than continuously try and hold the arm in position by applying power to the motor, current is cut from the drive system which automatically engages the spring applied brake holding it in the exact position required.

Reason for Selection of the Ogura RNB-Z Brake

The RNB-Z is a zero backlash spring applied brake. These means that there is no relative movement between the hub and the brake disc. In a very close tolerance application, such as this wafer transfer robotic arm, extreme precision is required so even a .001 variance could cause a problem. The Ogura RNB-Z holds the arm in the exact position required so there are no registration problems.

Other Applications

Besides silicone wafer robotic arms, there are many other robotic arms that require zero backlash to hold position. Devices such as x-ray equipment or specialized photographic equipments also require exact positioning because even a slight variance in degrees can cause a shift in the camera angle and change results. The easiest way to find additional applications for zero backlash spring applied brakes is to work directly with a servo motor manufacturer or a servo system designer. Ninety percent of the time, the brake is going to be mounted directly on or right next to the servo motor.