No / Enhancement in productivity and cost effectiveness of high value manufacturing requires a process based management strategy. This paper introduces a Manufacturing Failure Mode Avoidance (MFMA) framework based on 4 high level process steps and underpinned by a sequence of engineering and process analysis tools to support a structured function-based decomposition of complex manufacturing processes and a continuous flow of information towards the development of robust control plans. The approach draws from experience in the automotive industry, where Failure Mode Avoidance (FMA) has been strategically adopted to achieve a step change in the effectiveness of business and engineering processes associated with the product creation processes. The paper presents a case study of the deployment of the MFMA framework to an aircraft manufacturing process followed by a broader discussion of the strength of the approach and its generic applicability to complex high value manufacturing engineering.

Development of new Advanced Manufacturing Technology (AMT) for the aerospace industry is critical to enhance the manufacture and assembly of aerospace products. These novel AMTs require high development cost, specialist resource capabilities, have long development periods, high technological risks and lengthy payback durations. This forms an industry reluctance to fund the initial AMT development stages, impacting on their success within an ever increasingly competitive environment. Selection of suitable AMTs for development is typically performed by managers who make little reference to estimating the non-recurring development effort in resources and hardware cost. In addition, the performance at the conceptual stage is predicted using expert opinion, consisting of subjective and inaccurate outputs. AMTs selected are then submerged into development research and heavily invested in, with incorrect selections having a detrimental impact on the business. A detailed study of the UK aerospace manufacturing industry corroborated these findings and revealed a requirement for a new process map to resolve the problem of managing AMT developments at the conceptual stages. This process map defined the final research protocol, forming the requirement for a Cost-Benefit Forecasting Framework. The framework improves the decision making process to select the most suitable AMTs for development, from concept to full scale demonstration. Cost is the first element and is capable of estimating the AMT development effort in person-hours and cost of hardware using two parametric cost models. Benefit is the second element and forecasts the AMT tangible and intangible performance. The framework plots these quantified cost-benefit parameters and is capable of presenting development value advice for a diverse range of AMTs with varied applications. A detailed case study is presented evaluating a total of 23 novel aerospace AMTs verifying the capability and high accuracy of the framework within a large aerospace manufacturing organisation. Further validation is provided by quantifying the responses from 10 AMT development experts, after utilising the methodology within an industrial setting. The results show that quantifying the cost-benefit parameters provides manufacturing research and technology with the ability to select AMTs that provide the best value to a business.

Development of new Advanced Manufacturing Technology (AMT) for the aerospace industry is critical to enhance the manufacture and assembly of aerospace products. These novel AMTs require high development cost, specialist resource capabilities, have long development periods, high technological risks and lengthy payback durations. This forms an industry reluctance to fund the initial AMT development stages, impacting on their success within an ever increasingly competitive environment. Selection of suitable AMTs for development is typically performed by managers who make little reference to estimating the non-recurring development effort in resources and hardware cost. In addition, the performance at the conceptual stage is predicted using expert opinion, consisting of subjective and inaccurate outputs. AMTs selected are then submerged into development research and heavily invested in, with incorrect selections having a detrimental impact on the business. A detailed study of the UK aerospace manufacturing industry corroborated these findings and revealed a requirement for a new process map to resolve the problem of managing AMT developments at the conceptual stages. This process map defined the final research protocol, forming the requirement for a Cost-Benefit Forecasting Framework. The framework improves the decision making process to select the most suitable AMTs for development, from concept to full scale demonstration. Cost is the first element and is capable of estimating the AMT development effort in person-hours and cost of hardware using two parametric cost models. Benefit is the second element and forecasts the AMT tangible and intangible performance. The framework plots these quantified cost-benefit parameters and is capable of presenting development value advice for a diverse range of AMTs with varied applications. A detailed case study is presented evaluating a total of 23 novel aerospace AMTs verifying the capability and high accuracy of the framework within a large aerospace manufacturing organisation. Further validation is provided by quantifying the responses from 10 AMT development experts, after utilising the methodology within an industrial setting. The results show that quantifying the cost-benefit parameters provides manufacturing research and technology with the ability to select AMTs that provide the best value to a business.

Friction Bit Joining (FBJ) is a new technology that can be used to join dissimilar materials together. This ability makes it a good candidate for creating light weight structures for the automotive industry by combining lightweight materials such as aluminum to stronger materials like advanced high-strength steels. The automotive industry and many other industries have great interest in reducing structure weight to increase fuel efficiency. The purpose of this research is to make FBJ of GADP 1180 to AA 7085-T76 a production ready process by (1) better understanding the effects of process parameters, bit design and tool design on joint strength and reliability especially as they relate to different joint configurations; (2) determining if consecutive FBJ joints on a part will be additive in strength; (3) improving surface finish for better coating adhesion so that joints can be made to withstand extended corrosion testing; and (4) determining the failure modes and fatigue life of joint components at high and low load amplitudes. No universal parameter set for optimizing peak load for T-peel, cross tension, and lap-shear tension configurations were found. Due to the extreme load conditions of T-peel and the smaller margin of safety it is better to optimize for T-peel. However, strength and reliability were still improved across the board. Cutting features and tapered shanks were found to not always be necessary. Removing cutting features from the bit design increased peak weld cycle loads, but a stiffer machine can overcome this. Consecutive FBJ joints on a part are mostly additive in nature. When the weakest joint fails, its load is distributed to the remaining joints and will limit the peak load of the whole part. If all joints are "good" then the peak load will be approximately additive. Most of the stress is localized on the side of the bit opposite of the pulling direction. Failure modes in lap-shear tend to change from weld nugget pullouts in single weld specimens to aluminum material failures in multi-weld specimens. This is because of the added stiffness that additional material and welds provide to resist coupons bending and creating a peeling action. Surface finish was improved by development of a floating carbide cutting system which cut aluminum flash as it was generated around the head of the bit. A new internal drive design provided the ability to drive bits flush with the aluminum top layer if desired with minimal reductions in strength. Flush bits provided benefits in safety, cosmetics, and coating adhesion.

Friction Bit Joining (FBJ) is a new technology that can be used to join dissimilar materials together. This ability makes it a good candidate for creating lightweight structures for the automotive industry by combining lightweight materials such as aluminum to stronger materials like advanced high-strength steels. The automotive industry is putting significant effort into interest in reducing vehicle structure weight to increase fuel efficiency and reduce greenhouse gas emissions. Joining of dissimilar materials is a challenge they face in the light weighting the body of the vehicle. The purpose of the current research is to employ FBJ in the joining of a very challenging material combination: GA DP 1180 to AA 7085-T71. In accomplishing this purpose, the goal is to move FBJ toward a more production ready process by better understanding the effects of tooling, bit design, and process parameters on joint strength and reliability as they relate to load profiles captured during the joining process. It was found that the joint strength variation was influenced strongly by the hardness and the geometric consistency of the consumable bits. Bit hardness below 45 HRC led to joint strength that was less than the required specification (5kN in lap shear tension, and 1.5kN in cross-tension and T-peel). Variation in bit height and diameter also led to excessive scatter in joint strength values, where it was not possible to meet the standard for 10 consecutive specimens (for each of the three tests). Implementation of high-speed data acquisition (1000Hz) enabled the capture of load curve profiles generated during FBJ. Load curve profiles were correlated with destructive testing results to discover the impact of process parameter combinations. Analysis of load curve profiles led to improvements in parameter selections of spindle speeds (revolutions per minute) and spindle feed-rates (inches per minute). Process parameters of 5000 RPM and 15 IPM reduced variation in load-curve profiles and destructive testing. Satisfactory joint strength was achieved in lap shear tension, cross-tension, and T-peel testing configurations with values of 10.1 kN, 4.1 kN, and 1.8 kN, respectively. The presence of wet adhesive had little impact on joint performance. Finally, the analysis of a load-curve profiles resulted in a criterion that allowed for distinguishing "good" welds from "bad" ones, where a threshold load of 6kN, or higher, during the dwell phase of welding was required in order to meet joint strength standards.

Friction bit joining (FBJ) is a new method that enables lightweight metal to be joined to advanced high-strength steels. Weight reduction through the use of advanced high-strength materials is necessary in the automotive industry, as well as other markets, where weight savings are increasingly emphasized in pursuit of fuel efficiency. The purpose of this research is twofold: (1) to understand the influence that process parameters such as bit design, material type and machine commands have on the consistency and strength of friction bit joints in dissimilar metal alloys; and (2) to pioneer machine and bit configurations that would aid commercial, automated application of the system. Rotary broaching was established as an effective bit production method, pointing towards cold heading and other forming methods in commercial production. Bit hardness equal to the base material was found to be highly critical for strong welds. Bit geometry was found to contribute significantly as well, with weld strength increasing with larger bit shaft diameter. Solid bit heads are also desirable from both a metallurgical and industry standpoint. Cutting features are necessary for flat welds and allow multiple material types to be joined to advanced high-strength steel. Parameters for driving the bit were established and relationships identified. Greater surface area of contact between the bit and the driver was shown to aid in weld consistency. Microstructure changes resulting from the weld process were characterized and showed a transition zone between the bit head and the bit shaft where bit hardness was significantly increased. This zone is frequently the location of fracture modes. Fatigue testing showed the ability of FBJ to resist constant stress cycles, with the joined aluminum failing prior to the FBJ fusion bond in all cases. Corrosion testing established the use of adhesive to be an effective method for reducing galvanic corrosion and also for protecting the weld from oxidation reactions.