ManufacturingSix Sigma

Client: Rolls-Royce

Assignment: Enabling Robust Design

Enabling Robust Design at Rolls Royce

The Problem

The gas turbine market is at the forefront of the debate on climate change as politicians and consumers seek to balance the demand for increased air travel with the need to cut carbon emissions. Aero engine manufacturers like Rolls‐Royce, General Electric and Pratt and Witney are constantly striving to improve all aspects of engine performance (e.g. noise, emissions, life etc.)


Pressure to accelerate the performance and lower the emission of aero engines, combined with intense competition in the market and a shift from engine and parts provision to one of total care, has had profound implications for aero engine design and manufacture. Performance needs to be balanced with ease of maintenance, longevity of service and continuous upgrade. For over 100 years, Rolls‐Royce has responded to this challenge by continuously building on its pedigree of engineering excellence. In developing and implementing their Robust Design process, which is a flavour of Design for Six Sigma (DfSS), Rolls‐Royce is better able to design-in robustness of performance and reliability from the outset and thereby not only assure higher levels of customer satisfaction but also to increase the likelihood of passing time-consuming and costly system tests.

Rolls‐Royce are well aware that maintaining a lead in the highly advanced and competitive aero engine market requires a highly skilled workforce combined with the ability to adopt and refine proven design methodologies, tools and techniques. They are also aware that these methodologies, tools and techniques are only of value if they translate into products that provide them with a commercial advantage in the marketplace. Bourton Group were approached and asked to assist them in getting “to the next level” in their utilization of statistical tools in Design and Development via Robust Design. For the eleven years we have been working closely with Rolls‐Royce, providing technical training for its designers, analysts, and management whilst also helping them refine, improve and apply Robust Design to enhance their ability to remain at the forefront of aero engine design and manufacture.

The Solution

Whilst Rolls‐Royce management has been the commercial force, Bourton had been the training and technical force, working globally with design teams across its Civil, Defense and – to a lesser extent -Marine Divisions over the years.

The aims and objectives for this particular programme were:


  • Train and support design teams to apply the Robust Design method in such a way that would realise additional tangible and demonstrable benefits.
  • Codify the new tools and techniques in a common global design methodology that could be implemented across all business streams.
  • Stimulate the organic growth of “robust design” as the standard way of working within the design community by providing thought leadership and through continuous development of highlyskilled internal mentors ‐ experts in Robust Design application and the DfSS equivalent of Master Black Belts.


The first step was to set up a pilot programme with six IPTs (Integrated Project Teams) to thoroughly test the programme and provide a base of expertise for scaling up the programme at a later date. The aim was to ensure that the IPTs had  all the  skills needed to implement a refined design process  that had its  roots in the specific DCOV  (Define – Characterise – Optimise‐ Verify) approach to Design for Six Sigma. The approach was tailored to Rolls‐Royce’s specific engineering environment by aligning the DCOV approach with RR‐specific engineering tools and their core “gated” engineering process. It quickly demonstrated benefits and huge potential. The systematic approach also aided in rapid deployment and successful embedding within the business. Ultimately, this enhances speed to market, cuts development costs and reduces costly in‐service design modifications.


With the pilot phase completed, 30‐40 Robust Design mentors were then trained, supported by a hard core of subject experts from across the design, analytical, management and engineering disciplines. The roll‐out was bottom‐up, demand‐led, with IPTs from across the business signing up for the programme. Although this was a tougher and slower adoption process than a top‐down mandatory one would have been, the programme took hold – and is still in place today. Those undertaking the training and adopting the DCOV approach did so because they believed in the approach rather than it being mandated. Rolls‐Royce management understood the culture and motivation of their design community and realised that Robust Design had to prove itself to gain widespread adoption.


Bourton was the Six Sigma thought leader for Rolls‐Royce, developing a comprehensive mentor development and certification system as well as delivering “deep dive” technical training to the would-be Robust Design internal experts. The success of the pilot and subsequent roll‐out has led to the development of courses for managers to assist the spread of the robust design programme up the organisation and the establishment of local Champions to facilitate the application of Robust Design in the face of pressure to complete tasks quickly.  As well as undertaking the full technical training, Champions also learn about their role in terms of setting goals, defining strategy and measuring embeddedness.

After 11 years, we are now in the position where the majority of our work within the Robust Design work stream is delivering training to Designers and Analysts – and Champions.

We have also recently been involved in helping Rolls-Royce to develop an on-line statistics course for their Graduates, and also in some work to codify advanced robustness quantification techniques.

The Benefits

Engineering failures in aero engines or other gas turbine applications are extremely serious matters resulting in unwanted downtime, costly fixes and potentially loss of life. By adopting robust design, Rolls‐Royce is dramatically reducing the number and impact of these failures, thus saving huge amounts of money.  It’s not all about failure, however; robustness is about consistency in things that matter to the customer – a more consistent engine is a more predictable engine.  This means that expected levels of performance are met more frequently which has many knock-on benefits for customers and the business in terms of contingency planning etc.

The longevity of our continuing involvement with Rolls-Royce indicates just how highly we are regarded for our technical expertise.

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