E-mails, messenger messages, printed greeting cards: communication in the business world has long since taken on an impersonal touch – even when the occasion basically demands something different. The company Spline Product Development in Arizona is now countering this step backwards in communication with an advanced robot. Thanks to the maintenance-free linear technology from igus, the robot is able to write cards in human handwriting, which emotionalizes messages and ensures more response.

Handwritten correspondence receives greater response

The handwriting robot from the US-American developers looks a bit like a compact 3D printer. At its core are three linear axes that allow the robot to move like a ballpoint pen. The positioning is so precise that the robot can even imitate nuances of given handwriting. It is designed for companies that want to send their customers letters with a personal touch. According to marketing experts, these letters elicit a much greater response than the sober-sounding letters from the traditional printer. The handwriting robot is currently being used by the provider Simply Noted in Tempe, Phoenix.

Linear technology allows robots to write as precisely as a human

As elegant and effortless as the robot's work appears, the implementation of its precise movements was a considerable technical challenge. Earlier models worked, but only slowly and they were also prone to wear. This led to high maintenance costs, report the engineers at Spline Product Development. The writing results themselves also left something to be desired. The experts only made significant progress by using the linear technology from igus. The solution is a combination of miniature aluminum linear guides from the drylin T series with preloaded linear carriages, dryspin screw drives and electric stepper motors. Two of the linear guides run parallel at a distance of about 50 centimeters. Linear carriages move on their rails, holding a third linear guide and positioning it vertically. The pen is mounted on another carriage that moves horizontally on the third linear guide. In this way, it can reach any point on the writing field through the synchronous interaction of the axes. When the pen starts writing, the highest mechanical precision is required. “The stepper motors use the spindle drives to precisely move the carriages in the millimeter range in millisecond cycles,” explains Michael Hornung, product manager for drylin linear and drive technology at igus. This high level of accuracy is made possible, among other things, by a new type of geometry for the dryspin spindle thread. 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 only through this adjustment accuracy that the robot can write as finely as a human, in which over 30 different muscles in the hand, arm and shoulder work together during handwriting.”

Freedom from lubrication ensures high reliability

The igus linear technology not only makes the handwriting robot more precise, but also requires less maintenance. The reason: the linear guides do not need any external lubrication. The high-performance polymers of the threaded nuts and the sliding elements, over which the linear carriages move on the rails, contain integrated solid lubricants that 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 the lubricating grease to form a mixture that negatively affects the precision of the adjustment movements.” The robot should be able to write thousands of company greetings without tiring and without the need for disruptive maintenance.

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