Scara robots are ideal to perform pick-and-place or assembly tasks in the industry. However, these dynamics have a limited lifespan due to the corrugated hoses wearing out within a very short time. Therefore, igus has now developed an alternative, which can be retrofitted with the SCARA Cable Solution, which significantly increases the service life.

Watching SCARA robots at work can quickly make you dizzy. The horizontal articulated-arm robots work fast over four axes. The inner and outer arms pivot horizontally. The component for gripping objects, the ball screw, moves rotationally and linearly. This allows the robot arm to reach almost any point in its working radius. This is fast and precise, but it means that the externally routed cables and hoses have to be replaced or serviced frequently due to the high loads. This was also the case for a manufacturer in the automotive industry who wants to optimise its energy supply - both the corrugated tube and the rotary bearing. 

"Inspired by this challenge in the market, we looked at the weak points of the hoses and connectors and developed the SCARA Cable Solution in a two-year research and testing process," explained Matthias Meyer, Head of Business Unit ECS triflex & Robotics at igus GmbH. The new development is a customised cable guide that safely guides the energy from axis 1 to the ball screw and prevents the cables from kinking even in continuous operation.

Ball bearings and an additional spine

The SCARA Cable Solution consists of three components: the rotary bearing for the moving end and the fixed end, as well as the corrugated hose with the e-rib. The special feature lies in the new rotary connection, which absorbs the torsional forces. Here, integrated ball bearings ensure a smooth-running energy supply system that is resistant even to high accelerations. The corrugated hose is reinforced with an e-rib so that it can only move in one spatial direction. The guide elements on the sides give the hose unsupported length.

SCARA Cable Solution extends service life

Tested in the 3,800 square metre laboratory at igus in Cologne, the new energy supply system is already proving itself. In cooperation with the robot manufacturer EPSON, the behaviour of the energy supply in extreme positions is tested on a SCARA robot. Up to 6G act on the system in some movements. As a result, it has already withstood over three million cycles at rotations over 5,000 degrees per minute and continues to run. "With the SCARA Cable Solution, we can increase the service life of the energy supply previously used on SCARA robots. The robots now work longer, maintenance-free and fail-safe," says Meyer. All three components are available either as a complete system that can be quickly retrofitted, directly prefabricated, as an empty tube or individually for retrofitting.

The Cologne (Germany) based igus GmbH develops and produces motion plastics. These lubrication-free, high-performance polymers improve technology and reduce costs wherever things move. In energy supplies, highly flexible cables, plain and linear bearings as well as lead screw technology made of tribo-polymers, igus is the worldwide market leader. In 2020, igus generated a turnover of Euro 727 million. Research in the industry's largest test laboratories constantly yields innovations and more security for users. In recent years, the company has expanded by creating internal start-ups, e.g. for ball bearings, robot drives, 3D printing, the RBTX platform for Lean Robotics and intelligent "smart plastics" for Industry 4.0.