Machining a future

Cryogenic and ultrasound machining are two of the new processes being championed by the University of Sheffield’s Advanced Manufacturing Research Centre (AMRC) which works closely with Boeing’s £40 million, 6,200m² factory located near the AMRC.

Boeing’s Sheffield factory began work in October 2018 and the aerospace giant had already initiated a research programme in cooperation with the AMRC to develop new manufacturing techniques. The manufacturing techniques are to enhance production efficiency and reduce costs whilst maintaining quality.

Boeing Sheffield operations senior manager, James Needham, said: “The AMRC are maturing the technology and manufacturing processes that will underpin operations in Boeing Sheffield and the AMRC will be able to support Boeing’s ambitions to expand in-house production selective technologies,” speaking during a tour of AMRC in May 2018.

Located not far from the AMRC, Boeing Sheffield is the US firm’s first manufacturing site in Europe. Boeing Sheffield is supplied in the UK with high-strength, complex and multi-core aluminium cast parts which are then machined. At full capacity it can produce about 7,000 parts a month to be assembled in Boeing’s Portland plant in Oregon. Those parts are more than 100 different actuation system components produced with a variety of machining processes for the Boeing 737 and Boeing 767 wing trailing edges.

The use of more complex geometry components made from high-performance alloys and composites with a requirement for tighter tolerances is driving the need for process improvements. It is the AMRC’s Machining Group which develops machining solutions for significant quality and cost improvements. A cost improvement is single operation machining methods that reduce manual intervention and downtime. To achieve this, AMRC researchers have used dynamic and critical path analysis, simulation, advanced fixturing and tool design and cost modelling to determine the most cost-effective method.

Hole drilling should be a single operation process. For airframe manufacturers, including Boeing, the number of holes that are required to be produced annually is estimated to be in the region of 50 million. Every hole has to be precisely positioned and machined, by either drilling, milling or via eroding strategies. The AMRC hole generation team is researching areas such as, low torque machining practices like orbital drilling; machining strategy optimisation for robotic systems; topographical and subsurface metallurgical analysis of machined components, and clean machining strategies; which either reduce or eliminate the use of oil and other fluid coolants.

Beyond hole drilling, AMRC research is also focusing on components for more efficient drives for electro, hybrid or gear-driven systems, for example. The overall goal of such work is to increase the efficiency of aircraft drives while reducing an aircraft’s noise and carbon dioxide emissions. This work is being conducted with CNC equipment manufacturer Okuma using one of its 5-axis multitasking MU-8000V-L CNC machine tools to explore advanced machining, manufacturing and materials of use to the aerospace industry.

Four machining processes the AMRC is examining are, hybrid (additive and subtractive) machining, cryogenic, ultrasonic and laser assisted. Hybrid machining combines additive and subtractive processes on one machine creating new opportunities to produce complex geometries with multiple materials. The use of cryogenic cooling liquids in machining has shown the potential to improve tool life and part quality in machining operations whilst eliminating the need for emulsion coolants. Ultrasonic machining uses vibration in the ultrasonic range and could improve final part quality. Laser assisted machining is for hard to machine alloys where lasers are used to soften material to improve its machinability and reduce the cutting forces and tool wear during machining. The process of power skiving is also being examined because it is a tried and trusted method for making gear teeth. It will also be tested with new materials.

Processes for 2050

The AMRC has been working on a Smart Factory project for Boeing to help improve operations at Boeing Sheffield. The AMRC’s Manufacturing Intelligence Group developed a virtual model of Boeing Sheffield and its machining processes to identify the opportunities Boeing has to increase productivity by up to 50%. The simulation has been used to examine the optimisation of the factory’s material flow to improve productivity, the impact of uncertainties and to test the effect of introducing new process technology.

In the future the model will become like a digital twin of Boeing Sheffield. The model will be linked with Boeing’s production data in real-time, for example, its material delivery times, machining states and maintenance and process scheduling. This real-time linkage, an aspect of Industry 4.0, is expected to improve the model’s accuracy, the real-time monitoring of the factory’s production and aid in its optimisation; based on the latest actual situation in the plant.

Another Industry 4.0 related initiative for the AMRC is its Factory 2050 facility. Launched 18 months before the opening of Boeing Sheffield, Factory 2050 is for collaborative research into, “reconfigurable digitally assisted assembly, component manufacturing and machining technologies,” according to the AMRC. The construction of Factory 2050, the University said, has benefited from additional investment from industry partners, including Boeing Sheffield and the McLaren Composites Technology Centre. Factory 2050 began with £10 million of UK government research funding and matching funds from the AMRC’s membership group, which includes BAE Systems, Rolls-Royce and Seco Tools.

Factory 2050’s research also includes digitally assisted assembly, integrated large volume metrology, robotics and automation, and manufacturing informatics. It has had a KUKA Titan heavy-duty 6-axis robot installed to allow heavy-duty machining of difficult to machine materials. The KUKA Titan is controlled by a Siemens 840DSL controller and KUKA omniMove Automated Guided Vehicles (AGVs). The AGVs, capable of carrying loads of up to 15 tonnes are being developed to work more autonomously with the wider smart factory setup.

High tolerances, complex geometries and greater productivity, the challenges for the factory at the cutting edge require critical path analysis and simulation to find the sorts of solutions that AMRC’s Factory 2050 will deliver. Whether it is cryogenic, ultrasound or skiving that is an answer to many difficult obstacles, machining techniques for Boeing Sheffield are expected to see advancement through its smart factory collaboration with the AMRC.

www.amrc.co.uk