Adjustable preload can be closed looped to set extremely precise load

Accuracy testing shows error well under 0.1 degree.

The result is a rod runout of less than 10 microns, and often even less than 5 microns.

Add vacuum pick-up / gripper operation capability.
Although the use of pneumatic devices is coming to an end in electronic assembly, there still are several limited application areas.

The first is a vacuum, the most common way to pick up small, fragile parts. The vacuum flow also picks up dust that is on and around the components to be picked up. A good design for the motor is to have a shaft with a hole that runs through the motor to direct dust outside the motor and into the vacuum device which has filtration.

Grippers are often used for larger components. Grippers tend still to be pneumatic, mainly due to the lower cost. The same through-hole shaft design, combined with correct sealing, means that pressurized air can move through the motor and into the gripper.

In conclusion the long-term trend in electronics is moving toward higher-density components in smaller and smaller package sizes. Pick-and-place robots now have nominal widths of 13 mm which move to 10 mm, and very soon 8 mm. Robot makers must keep up the development pace to meet the challenge. This means 8 mm motors with 10 millinewton-meters (mNm) of torque and encoders with 20,000 steps per revolution.

Invention combined with never-ending improvement is the key. Brushless motors are following this trend for rotary motion just like linear motors are for linear movement. And this technology is spreading into robotics, particularly in end-effector evolution. That’s where there really is a need for a helping hand. Practical robotic fingers and hands will soon be a reality.