Greetings from the robot!

Communication in the business world can quickly become impersonal. A robot from the Arizona-based company Spline Product Development aims to change this. Thanks to maintenance-free linear technology from igus, it is able to write cards in human handwriting, which emotionalizes messages and ensures greater resonance.

A personal greeting card from your favorite online store? Recipients in the USA are currently receiving just such special promotional mail. The engineers at Spline Product Development have made it possible. The handwriting robot from the US developers is visually reminiscent of a compact 3D printer. At its heart are three linear axes that enable the movement of a ballpoint pen. The positioning is so precise that the robot can even imitate the nuances of predetermined handwriting. It is designed for companies that want to send their customers letters with a personal touch. According to marketing experts, these receive a much greater response than sober-looking letters from a traditional printer. The handwriting robot is currently being used by the provider Simply Noted from Tempe in Phoenix (USA).

Linear technology from igus allows robots to write as precisely as a human

As elegant and effortless as the robot's work appears, implementing its precise movements was a considerable technical challenge. Earlier models worked, but only slowly and were prone to wear and tear. This led to high maintenance costs, report the engineers at Spline Product Development. The writing results also left a lot to be desired. The experts only achieved significant progress through the use of linear technology from igus. The solution is a combination of miniature linear guides made of aluminum from the drylin T series with preloaded linear slides, dryspin spindle drive and electric stepper motors. Two of the linear guides run in parallel at a distance of around 50 cm. Linear slides move on their rails, holding and vertically positioning a third linear guide.

The pen is mounted on another carriage that moves horizontally on the third linear guide. Thanks to the synchronous interaction of the axes, it can reach any point on the writing field. When the pen begins to write, maximum mechanical precision is required. "The stepper motors use the spindle drives to achieve precise movements of the slides in the millimetre range every millisecond," explains Michael Hornung, Product Manager for drylin linear and drive technology at igus. This high level of precision is made possible, among other things, by the innovative geometry of the dryspin spindle threads. The flank angles of the threaded nut and spindle are flattened, resulting in an above-average efficiency of 82 percent, which supports the adjustment accuracy. "It is this adjustment accuracy that enables the robot to write with the same fine motor skills as a human, where over 30 different muscles in the hand, arm and shoulder work together when writing by hand."

Lubrication-free for high reliability

Linear technology from igus not only makes the handwriting robot more precise, it also requires less maintenance. The reason: the linear guides require no external lubrication. Solid lubricants are integrated into the high-performance plastics of the threaded nuts and the sliding elements used to move the linear carriages on the rails, which are gradually released during operation and enable low-friction dry running. "Thanks to this self-lubricating effect, the handwriting robot can work reliably even in dusty environments," says Hornung. "Unlike lubricated systems, there is no risk of dust and dirt from the environment combining with grease to form a mixture that negatively affects the precision of the adjustment movements." The robot can therefore write thousands of company greetings without fatigue and without disruptive maintenance work.