Rodless cylinder used to position and clamp

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Robotix has used a Hoerbiger-Origa rodless cylinder to position a scribing head above a workpiece and clamp the workpiece during the scribing process.

Rodless cylinder used to position and clampBob Jepp, founder and managing director of Robotix, has developed a high-speed workstation for scribing serial numbers onto wheel rims for earthmoving equipment. This uses a single Hoerbiger-Origa rodless pneumatic cylinder for the dual roles of positioning the scribing head and holding the rim steady in the workstation.

Wheel rims, which can vary in size from 24in dia and 15in wide to 40in by 40in, are delivered by conveyor to the scribing workstation, where V-shaped guides position them accurately.

Accurate and powerful

A large and powerful rodless cylinder mounted above the workstation descends, positioning the scribing head just above the top surface of the rim to an accuracy of 0.01mm. Mounted on the cylinder and protruding beneath it are two of Hoerbiger-Origa's linear shock absorbers; these contact the rim with sufficient force to hold the rim steady during scribing.

Jepp explains: "We have used a 50mm bore cylinder that has enough power to hold the rim firmly in place. The shock absorbers are there to prevent the cylinder from damaging the rims, and vice versa. They have to be stiff ones to transfer the holding force, and this means they will be reliable in the field too.

"The cylinder has, at 1000m, a relatively long stroke. This is to allow ease of access to the workstation by operators and maintenance engineers. It is fitted with one of Hoerbiger-Origa's Starline Guides to ensure smooth and accurate motion in this arduous application."

The actions of the cylinder and other parts of the machine are controlled by a Mitsubishi PLC, on which the display provides the operator with process and production messages.

Micro-percussion scribing

A Technifor scribing head is used, with a micro-percussion scribing drive and x-y configured servos that mark the alphanumeric characters for the serial number - for reasons of traceability. The scribing is deep enough that it can be easily read even in muddy working conditions - which means there are high forces being transmitted through the rims during scribing and hence Jepp's decision to use one of Hoerbiger-Origa's larger bore cylinders.

In fact all the pneumatic components - including valves, solenoids, air preparation equipment and secondary cylinders - are sourced from Hoerbiger-Origa. Jepp explains the reason for this: "Keeping the supplier count low is good for my build and management efficiency and also makes field servicing and maintenance easier. For operating reliability it makes sense to use the best equipment available, and when it comes to rodless pneumatic cylinders, that means Hoerbiger-Origa."

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