Process planning of CNC machining is critical to ensure cost, time and quality parameters of manufacturing operations. At the heart of process planning is, typically the process planner, who must make a multitude of decisions regarding machines, cutting strategies, tools and process parameters etc. Today there are a number of different tools and methods available to aid the process planner. This paper explores today’s industrial use of some of these aids and outlinespotential underlying reasons for the current state. The empirical data is based on a questionnaire survey of Swedish CNC machining sub-contractors. The main conclusion is that despite a long history of development of various aids (CAD/CAM, PLM standards etc.) there is still a large proportion of the industry, which has not yet adopted these aids. By the responding companies 32% do not use any CAM system and only 2% use a PLM system. On the other side of the spectrum is a group of 25% that uses CAM in 75% or more of their planned products. The learning from this survey can be used to better understand the industrial needs and focus research and development efforts.

Process planning as an enabler of competiveness is often overlooked, but being one of the principal function in the product realisation flow it holds a key role by combining both product and production requirements into a production concept with respect to the current manufacturing system. As such the capability of process planning to a large extent dictates production cost, lead times, product quality etc. With the introduction of new demands on production, such as environmental impact and process capability, process planning must be able to manage these demands effectively. Accordingly, it is vital to study the effects that up-coming demands have on the act of process planning. The research methods employed in this work include surveys (questionnaires and interviews), industrial case studies and experiments to provide data for models developed. The main finding of this research is that there is a lack of quantified process planning performance knowledge in the industry, which leads to verification problems as to whether changes that are made render anticipated effects. Results of surveys also indicated a low level of digitalisation of product data and limited use of computer aids (CAM, feature-based CAM and PLM) in Swedish industry based on 144 companies' response. A concept to improve process planning performance through operation classification based on process capability indices (Cp/Cpk) was suggested. The role of process planning in designing cost efficient and energy efficient machining operations has been maintained throughout the thesis by showing how tool selection and machining parameters selection influences the possibilities to achieve these objectives. This work has also showed that no inherent contradictions appear to exist between achieving cost efficient and energy efficient machining operations. This thesis has contributed to an enhanced understanding of how process planning improvements can be achieved through a holistic perspective of the process planning function, where both technical and methodological aids are included. It is however essential to understand the current situation of the process planning organisation, its internal/external relations, level of digitalisation, competency level etc. before major changes of the process planning function are undertaken in order to be successful.

The role of process planning as an enabler for cost efficient and environmentally benign CNC machining is investigated in the paper. Specific energy is used as the principal indicator of energy efficient machining and different methods to calculate and estimate this is exemplified and discussed. The interrelation between process planning decisions and production outcome is sketched and process capability can be considered as one factor of green machining. A correlation between total machining cost and total energy use was shown for an experimental case. However, to generalise conclusions, the importance of having reliable data during process planning to make effective decisions should not be underestimated.

Increasing environmental demands from governmental bodies and customers stress the importance of companies improving their environmental performance. The research presented here shows that productivity and cost efficiency improvements can be achieved alongside energy savings in a computer numerically controlled machining environment. This improves the profitability of the companies, but also leads them towards more sustainable and environmentally aware manufacturing; the relationship between machining parameters, machining costs, and energy consumption is evaluated. From this perspective, it is important that production planners etc. understand the methodological possibilities for improvements in cost and energy efficiency. The current research is based on a machining cost model and experiments where energy consumption and tool wear were monitored.

Process planning as a function for competitiveness is often neglected. However, as an intermediary between product development and manufacturing, it holds a key function in transforming product specifications and requirements into a producible process plan. Demands and requirements should be met concurrently as manufacturing costs and lead times are minimised. The focus of this thesis is the act of process planning, where the use of better methodologies, computer-aids and performance measurements are essential parts. Since process planning has the function of transforming demands and requirements, changing customer and regulative requirements are vital to regard. Since environmentally benign products and production increases in importance, the research presented in this thesis includes a CNC machining cost model, which relates machining costs to energy consumption.  The presented results in this thesis are based on quantitative and qualitative studies in the metal working industry.

This thesis has contributed to an enhanced understanding of process planning to achieve better performance and important areas for improvements. Despite a 50 year history of computerised process planning aids, few of these are used in the industry, where manual process planning activities are more common. Process planning aids should be developed around the process planner so that non-value adding activities, such as information management and documentation are minimised in order to allow more resources for value adding activities, such as decision making. This thesis presents a study of systematic process planning in relation to perceived efficiency. This correlation could however not be verified, which opens up for further studies of other possible explanations for process planning efficiency. Process planning improvements in the industry are difficult to make, since there is little focus on process planning activities and limited knowledge about actual performance hereof. This means that measures taken regarding process planning development are difficult to verify.

The paper presents an investigation regarding the potential and the readiness for implementing performance indicators and performance measurement systems of the process planning work for metal working companies. The paper is based on a questionnaire survey distributed to process planners in the Swedish metal working industry. The main outcome of the investigation is a foundation for understanding the implementation of performance measures of the process planning work for CNC machining. The survey revealed a few strengths and short comings in the studied companies.

Process planning is the link between design and manufacturing and consequently an important function, since it influences many of the company objectives. However, many companies have little knowledge about their process planning function and the efficiency is thus not optimal. The paper focuses on the automation level of process planning as a mean to improve process planning efficiency. Six CNC machining companies was interviewed and accordingly analysed through a five dimensional automation level model to understand their process planning work. The main findings are that the automation level is low and concurrent engineering is lacking in many of the investigated companies.

General cost for CNC machining and the associated energy cost are set in the context of making economic and environmental improvements. This creates an incentive for manufacturing companies to investigate the energy efficiency of manufacturing processes. The paper presents a costing model, based on machining experiments. The model is accompanied with an industry based case to estimate the cost savings. The results show that substantial cost savings with respect to energy efficiency is unlikely, since energy costs in CNC machining comprises a small cost component. However significant cost savings can be achieved if the production output is increased as a consequence from higher material removal rates due to optimised machining parameters.

The aim of this paper is to present how Green machining can be established in the metal working industry for taking immediate actions towards a more environmental friendly manufacturing, but also to address areas for research in order to advance towards a more sustainable manufacturing industry. An often overlooked approach is to use the knowledge about the specific cutting energy and its dependency upon machining parameters in order to establish a machining strategy that leads towards a more energy efficient production, but also contributes to increased productivity and thereby improving the bottom line as well. The paper has a production preparation perspective and thus presents the areas where a green machining strategy is applicable.

This article presents a brief state of the art in the Swedish metal working industry regarding the production preparation process for the machine centre. The article is based on a relationship model from which a questionnaire was developed. The model incorporates the perceived preparation process efficiency, the amount of systematic preparation work, in relation to the companies’ premises as possible causes. The investigation is based on a general hypothesis that a more systematic approach in the preparation process leads to higher preparation process efficiency. This hypothesis was supplemented by two more hypotheses and additional analyses to create an understanding of the situation. The main finding in this investigation is that there appear to be no relationship between increased  ystematic preparation work and perception of higher preparation efficiency. The investigation also indicates that many metal working companies have little knowledge about the performance of their preparation process and that there is an efficiency improvement potential of nearly 30%.