Lightweight for portability and easy handling, but rigid enough to be cantilevered, the HepcoMotion HDS2 Heavy Duty Slide range proved to be a good choice for an application for Sellafield. The robust components were specified by OC Robotics as a method of introducing its snake-arm robot into a confined environment to perform visual and radiological inspection, remote handling, loose material sampling and water-jetting.
OC Robotics snake-arm robots are characterised by their long, slender and flexible design. These systems can fit through small openings and around obstacles effortlessly with no prominent elbows to snag or cause damage to sensitive equipment. They are easily manoeuvred into position and retracted without disturbing their environment.
The HepcoMotion V principle has a proven track record in the nuclear industry and has been specified on previous OC Robotics projects. Low maintenance and system components that will not catastrophically fail are vital qualities in the ‘no-go’ nuclear environment.
Indeed the Heavy Duty Slide Beam had been used in Sweden to form an X-Y gantry system where again the key criteria were low mass, high rigidity and ease of modification. And these factors in combination with HepcoMotion’s ability to machine the necessary components from stock made the HDS2 product the clear front runner.
Naturally other products were considered, but ultimately it was the cost efficiency of the HepcoMotion system and the technical guidance provided by the company’s applications team that secured the order.
The HepcoMotion HDS2 product forms the spine of the system on which the rail is mounted, supporting the snake arm both vertically and horizontally. Tim François from OC Robotics explains: “The fact that HepcoMotion can precision machine 4m long beams meant that the system could be made compatible with our frame very easily. The Heavy Duty system is also very easy to maintain, requiring minimal lubricant.”
Rather than being classified as special requirements, corrosion-resistant components and stainless steel slides are both standard choices within the HDS2 range; indeed, across the entire HepcoMotion linear motion product programme. As a result, OC Robotics was able to specify a standard aluminium product to meet its low weight and corrosion-resistant requirements for nuclear use. Furthermore it needed minimal modification.
The Sellafield snake-arm weighs 70kg and is mounted to a Heavy Duty carriage. Tim François continues: “We required a positional accuracy of 0.1mm but achieved much better, repeatable results in reality”. Movement is slow and controlled, around 50mm per second.
Now fully constructed, the bespoke snake arm was recently transported to Areva in France for pre-installation nuclear trials. Tim François adds: “Because the HDS2 system was so easily mountable on any frame it made our trials very simple to accomplish.”
For more information about the HDS2 system from HepcoMotion, please visit their website at www.hepcomotion.com/.