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

STEP-based Conceptual Framework for Measurement Planning Integration

AbstractMeasurement aims to check the product conformance or to control the manufacturing processes’ parameters. It needs to be planned in an integrated and interoperable manner with other manufacturing activities. Integration of measurement planning is based on the information provided by the design phase. This paper aims to assist the interoperability of the measurement plans through introducing the resource-independent measurement specifications (RIMS) concept. The paper presents a conceptual framework for representing a STEP-based measurement features from the coordinate metrology perspective. The proposed framework supports the direct formulation of the measurement process specifications in an operation-based manner and the realization the process control functionality of the measurement processes

A multiscale finite element space-time discretization method for transient transport phenomena using bubble functions

A space-time finite element discretization method for unsteady transport phenomena is formulated using a variational multiscale finite element scheme. The described discretization is based on the utilization of bubble function enriched finite elements. The scheme is applied to model unsteady diffusion and convection-diffusion equations. It is shown that any temporal and spatial instabilities can be removed by appropriate enrichment of linear Lagrangian finite element approximations in the context of the standard Galerkin method. The proposed scheme is compared with widely used time stepping method. Numerical results generated by the proposed scheme are validated via their comparison with the analytical solution of a bench mark problem