Mechanical Technology Archive

The Efficient Engineering Group, is more than half way through the manufacture, integration and testing of 64 yokes and pedestals for the MeerKAT antennas, a pre-cursor project to Phase 1 of the SKA radio telescope. MechTech talks to Efficient’s Warwick Jackson.

MeerKAT SKA Efficient EngineeringEfficient Engineering is a dynamic engineering solutions company based in Gauteng, Africa’s economic heartland. Since its founding as a fabricator of earthmoving and materials handling equipment, the company has grown to occupy facilities spanning in excess of 28 500 m2 in Gauteng and in the Western Cape and has diversified into a broad-based engineering solutions provider.

In recent times, Efficient Engineering has been pioneering turnkey, accelerated offsite construction and the design of modular, integrated, portable or prefabricated construction solutions, which are assembled, optimised and tested prior to delivery to site.

“We were initially awarded the contract for the fabrication of the MeerKAT yoke and pedestal structures. The initial scope of the contract was limited to the structural steel fabrication. Based on a recommendation from a slew manufacturer that knew of our success with modular plant, our project scope has grown to include the manufacture and integration of a host of sub-assemblies as well as the full integration and testing of the mechanical and electrical performance of the assembled yoke and pedestal positioners,” Jackson tells MechTech.

“Driven by the desire to achieve over 75% local content, we have walked the road with a number of the world’s best global and local project participants: the local project leader, primary sub-contractors from the USA and Germany, and the client. The success of systems and the expansion of the local scope of work, I believe, can be attributed to an amicable, open, honest and co-operative approach to resolving technical problems,” he says.

Initially asked to complete the structural build for the first two prototypes, Efficient Engineering systematically worked through all of the design glitches in the most amicable and cooperative way. “There were post-qualification design enhancements, and via positive cooperation, we developed an excellent relationship with Stratosat Datacom, which won the tender as prime bidder for the MeerKAT project, as well as its subcontractors General Dynamics and

Vertex Antennentechnik.”

Early in the developing relationship, it became apparent that Efficient Engineering was much more than a steel fabricator. “We began to be offered more of the integration work – work that was expected to be beyond the scope of South African manufacturers. So, from building the yoke and pedestal structures, we were asked to meet a difficult paint specification. And while we did battle, through transparency, involvement and an open way of working with the designers and clients, we developed a way to get it right. For success in collaborative projects such as these, it is important not to hide behind issues. By getting the South African, US and German companies all aligned, a level of trust emerged that enabled us to get involved in tasks that were outside of our original scope – most notably, the vast array of sub-assemblies,” Jackson relates.

“To maximise local content, we were tasked with sourcing local equivalents for standard sub-assembly components available overseas – and we ended up exceeding expectations in terms of delivery times and quality.

“This led to us being offered the opportunity to install and integrate the sub-assemblies into the yoke and pedestal structures – the slew rings, the universal joints, the torque tube down the centre of the structure and a host of fittings and bracketry. The work involved significant numbers of machined parts and specialised stainless steel components,” he continues.

While the servo drive systems were being manufactured in Germany, Efficient Engineering also rewired electronic modules for the first four units to resolve design compatibility issues.

“All this led to one of the best decisions of the whole project for Efficient Engineering – to complete the integration and testing of all units off-site. Through our experience with modular plant, we have long been convinced of the many advantages of completing as much work as possible in the factory environment. A significant number of the delays and cost overruns associated with site-based construction can be avoided if fully functional and tested plant modules can be delivered to site. The idea is to deliver a plug-and-play solution that can be placed on a pre-prepared plinth, connected to the required utilities and immediately brought into operation,” Jackson explains, adding “debugging a system after installation on site can be a nightmare.”

So for the MeerKAT antennas, following full electrical and mechanical integration, the functionality and mechanical accuracy of each unit is tested and signed off at Efficient Engineering’s Germiston premises.

“We use a highly accurate 3D laser tracker to ascertain the various geometries of the slew bearing. The information is fed into a Roma Arm positioner and this enables us to accurately install the mounting brackets for the position encoders. A tolerance to within 50 µm is required in the x-y and z directions relative to the slew bearing’s angular position,” he informs MechTech.

The slew ring is rotated by electric motors driven by a servo system. “It is critical for the integrity of the antenna’s reception that no electromagnetic interference (EMI) noise from the drive is allowed to interfere with the receiver equipment. So the slew bearing and its drive are housed in a shielded compartment, which traps EMI interference, preventing it from reaching the radio telescope.

“The interesting part of this shielding system is the door of the compartment. Called an EMI door, it was developed by Interference Testing and Consultancy Services, another local company. It consists of a stainless steel door with a specialised copper leaf interlocking system. Sprung copper strips are used for excellent electrical continuity between the shields that trap the interference.

The inlet air filter system is an EMI filter that uses particular wave-guides sized to restrict the wavelengths and frequencies of the interference. “The air vents block the EMI signals while allowing airflow in and out of the compartment. For testing the integrity of the whole system, we place an EMI generator inside the compartment and we use a ‘sniffer’ outside to measure the levels of EMI attenuation and to certify that the compartment is sealed to the degree required,” Jackson explains. “It has been fascinating to have been involved in so many interesting facets of this project and we are proud of the quality results we have achieved,” he adds.

So far, Efficient Engineering has completed and delivered over 38 of the 64 units. “We are completing the remaining yoke and pedestals at a rate of four a month, which is well within the delivery deadlines – and we have exceeded the 75% local content target. It goes to show that, with the right attitude and approach, South African companies can work with multi-nationals across different continents and we can produce world-class quality equipment using local resources,” Jackson believes.

To achieve this, he says that integrated teams need to be established so that people don’t differentiate between their own colleagues and those from other participating companies. “A united team pursuing an honest and blame-free approach can develop solutions quickly. Hiding behind limitations or mistakes is a disaster in this environment,” he advises.

“We at Efficient Engineering have been able to contribute to such teamwork: on the technology side, to the design and, for production, implementing enhancements to make the build easier and more practical. Overall, this has been very good for us and for the MeerKAT project,” he says.

Validating Efficient Engineering’s role in the development process, the company is currently providing industry training for three technicians from the local Carnarvon area who have participated in the technician training initiative offered by SKA SA. The goal is that these apprentices will receive their National Diplomas and, hopefully, end up working on MeerKAT operations in the Karoo.

“Training is a cornerstone of our approach. We have experienced millwrights, boilermakers and other artisans who can pass on the valuable information they have to the younger generation. Including the three SKA apprentices, we have a total 36 young people currently engaged in apprenticedship programmes, which plays a big role in our B-BBEE level 2 status on the new codes,” Jackson says, adding “when Stratosat suggested training some of SKA SA people, there were absolutely no objections.”

“We have the skills and resources in South Africa to be competitive on the global stage. We are capable and the world is at our feet. It has been great to be involved from the beginning and to see how our capabilities and confidence have grown.

If we take any lessons from the SKA project, let it be that we need to believe in ourselves,” Jackson concludes.

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