Generating milling tool paths for prismatic parts using genetic programming

AbstractThe automatic generation of milling tool paths traditionally relies on applying complex tool path generation algorithms to a geometric model of the desired part. For parts with unusual geometries or intricate intersections between sculpted surfaces, manual intervention is often required when normal tool path generation methods fail to produce efficient tool paths. In this paper, a simplified model of the machining process is used to create a domain-specific language that enables tool paths to be generated and optimised through an evolutionary process - formulated, in this case, as a genetic programming system. The driving force behind the optimisation is a fitness function that promotes tool paths whose result matches the desired part geometry and favours those that reach their goal in fewer steps. Consequently, the system is not reliant on tool path generation algorithms, but instead requires a description of the desired characteristics of a good solution, which can then be used to measure and evaluate the relative performance of the candidate solutions that are generated. The performance of the system is less sensitive to different geometries of the desired part and doesn’t require any additional rules to deal with changes to the initial stock (e.g. when rest roughing). The method is initially demonstrated on a number of simple test components and the genetic programming process is shown to positively influence the outcome. Further tests and extensions to the work are presented

Balancing Global Customer Needs and Profitability Using a Novel Business Model for New Model Programmes in the Automotive Industry

AbstractBusiness models need to evolve and respond to changing customer requirements and this is only further exaggerated when considered in the context of a ‘Global Market’ which has shifted in the last 60 years from ‘Manufacturer’ led to ‘Customer’ led ‘fashion’ based industry. The automotive industry is one example of an emerging fashion based industry.The objective of most viable businesses is to make a profit for their shareholders but, given the typical gestation period between concept establishment and the start of the production volume build, it is a challenge to establish a structured method to ensure programme and business profitability against the backdrop of a fashion based market. In this paper, a data driven methodology is proposed which focuses on data, structure, and the customer to maximise the probability of profitability. To achieve this goal, joins between Multi Criteria Decision Analysis, Parametric Cost Estimating and ‘Should’ Cost Estimating are explored. ‘Margin engineering’ is thus proposed as a new foundation for a future business model to guide medium term (one to six years) development projects towards a profitable outcome

Daydreaming factories

Optimisation of factories, a cornerstone of production engineering for the past half century, relies on formulating the challenges with limited degrees of freedom. In this paper, technological advances are reviewed to propose a “daydreaming” framework for factories that use their cognitive capacity for looking into the future or “foresighting”. Assessing and learning from the possible eventualities enable breakthroughs with many degrees of freedom and make daydreaming factories antifragile. In these factories with augmented and reciprocal learning and foresighting processes, revolutionary reactions to external and internal stimuli are unnecessary and industrial co-evolution of people, processes and products will replace industrial revolutions

Three dimensional modelling of interaction between surface and Darcy flow regimes through soils

The present paper deals with the impact of surface flow on hydrodynamic conditions in saturated underground domains. A three dimensional finite element scheme has been used to simulate underground flow resulting from the flow of water over a saturated land. The results clearly show the effects of the surface flow on the hydrodynamic conditions of the subsurface porous regions. This analysis is an important prerequisite for the prediction of contaminant mobility in soils and hence provides a convenient tool for the prediction of interaction between surface and subsurface flow processes. For low permeability cases, considered here, the governing equations consist of water continuity and Darcy equations. These equations are solved using a robust and reliable finite element procedure

Methane and Other Hydrocarbon Gas Emissions Resulting from Flaring in Kuwait Oilfields

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Cryogenic CNC machining of individualised packaging

With the continuing growth in the high value product manufacturing sector there is a need to provide new ways to store and transport high value precision parts without damage and contamination. Traditional packaging is produced from foams and elastomers using forming techniques. This provides difficulty for producing individualised packaging solutions as individual moulds and forming tools would be required. In addition present solutions do not provide adequate packaging as they can cause damage to the part in some cases. This paper explores the design and manufacture of precision machined individualised neoprene foam packaging using cryogenic CNC machining technology. Cryogenic CNC machining is discussed and an example case study is presented showing the viability and efficacy of the proposed design and manufacturing method

Determination of machinability considering degradation of accuracy over machine tool life cycle

AbstractThe emergence of financially an environmentally conscious manufacturing has resulted in a need for efficient process planning in today's manufacturing system. Process planning based on nominal machine tool specifications, limits predictive capabilities with regard to the final part quality. More efficient process plans can be achieved once an accurate machine tool capability profile has been defined. Machine tool capability profiles deliver up-to-date resource attributes such as availability, health and applicability into the process-planning stage. A manufacturing resource's health degrades continuously throughout its life cycle due to environmental factors, part wear, operator competence, etc. Identifying and compensating for these factors during process planning may alleviate material wastage and machining estimate production time and cost via decision-making mechanisms. In this paper, the STEP-NC Standard is used to represent a model of machining resources, including worktable, spindle and tool status during a machine tool's operational lifespan. A prototype of machine tool capability profile enabled process planning system is then presented and tested to highlight the advantages of this approach