GMG develops new robotic grippers with plastic plain bearings from igus

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Mohsen Saadat has all the time been creative and technically gifted. As a younger boy, the 5-year-old Iranian invented his personal toys, constructing small automobiles out of wire, for instance – with none instruments. The now 75-year-old’s ardour for know-how has by no means left.

At 19, Saadat moved to Germany, studied engineering, and taught as a professor. In 1991, he based GMG – Gesellschaft für modulare Greifersysteme in Soest, North Rhine-Westphalia. His aim was to mix greater design idea scientific strategies with state-of-the-art manufacturing processes.

“Inside a couple of years, we efficiently developed light-weight and versatile gripper methods for robots and automation methods based mostly on the human hand,” says Saadat proudly.

He satisfied quite a few industries of his know-how. The grippers, which have as much as six individually movable fingers and, in some circumstances, over 100 joints, are used to deal with automobile wheels within the automotive trade, to carry up sacks when filling them with bulk materials, or to bundle sausage and cheese within the meals trade.

A versatile and torsional inflexible tower because the lengthy arm of the gripper

Nonetheless, one of many innovations that make Saadat proudest is a multifunctional lengthy arm gripper system. The gripper can routinely pack manufactured parts – similar to brake discs – with three fingers, place them in packing containers after which place a layer of protecting cardboard over them utilizing a vacuum gripper.

“On this gripper system, a creatively designed, versatile, and torsional inflexible tower serves because the lengthy arm of the gripper,” explains Saadat.

“Relying on the duty, gripping parts emerge from this tower that mechanically picks up parts. After the work is full, the gripping and suction parts retract to their beginning place inside the tower.”

Which bearings are appropriate for finger joints?

One of many challenges within the improvement course of was to seek out appropriate bearings for the shifting steel parts of the gripper, such because the finger joints. All of the gripper parts needed to be low-friction, abrasion-resistant, upkeep and lubrication-free, and straightforward to put in. Subsequently Saadat shortly dominated out conventional rolling bearings.

“Rolling bearings are appropriate for sustained rotational movement. They require the manufacture of extra correct match, contain complicated meeting and disassembly, and end in metallic noise,” said Saadat.

These disadvantages led Saadat to go for another: plain bearings product of high-performance plastics from igus – a movement plastics specialist from Cologne that tribologically optimizes plastics for industrial functions.

“Now we have been counting on plain bearings from igus since 1991. It was, due to this fact, clear from the outset that the polymer bearings would even be used within the multifunctional lengthy arm gripper. There’s just about no various to those bearings for us in automation know-how, the place there are fixed backwards and forwards actions,” says Saadat.

One other benefit is that, in comparison with conventional steel bearings, the polymer bearings are mild, corrosion-free, and maintenance-free. They permit dry operation while not having lubrication, due to built-in stable lubricants.

“That’s a essential specification. As a result of we couldn’t count on our prospects to need to lubricate the gripper frequently,” says Saadat.

Just about no indicators of wear and tear after 200,000 cycles

The polymer bearings from igus are so strong that the bearings will outlast a gripper lifetime of round 30 years.

“This is a bonus for our multifunctional gripper, as the upkeep effort is diminished and productiveness will increase,” continues Saadat.

A take a look at within the igus in-house laboratory additionally demonstrates how wear-resistant the bearings are. The igus polymer bearings had been examined in opposition to basic steel bearings within the laboratory. Each bearing varieties pivoted on a gas-nitrided St52 metal shaft – with a load of 30MPa and a velocity of 0.01 meter per second.

“Within the case of the steel bearings, the gliding layer was worn after 60,000 cycles,” says Stefan Loockmann-Rittich, head of the iglidur bearings enterprise unit. “The iglide G plain bearings, alternatively, confirmed nearly no indicators of wear and tear even after 200,000 cycles. They’re due to this fact ideally suited to dependable and maintenance-free use over a few years.”

Specs additionally apply to a different bearing utilized in GMG’s multifunctional gripper. The gripper additionally makes use of drylin® R linear bearings, which allow a managed and secure linear motion of the gripper linkage. “The igus bearings persuade us repeatedly, so we’ll proceed to depend on the iglide polymers sooner or later,” sums up Saadat.