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

Comparative Performance between Two Photogrammetric Systems and a Reference Laser Tracker Network for Large-Volume Industrial Measurement

This paper determines the capability of two photogrammetric systems in terms of their measurement uncertainty in an industrial context. The first system – V-STARS inca3 from Geodetic Systems Inc. – is a commercially available measurement solution. The second system comprises an off-the-shelf Nikon D700 digital camera fitted with a 28 mm Nikkor lens and the research-based Vision Measurement Software (VMS). The uncertainty estimate of these two systems is determined with reference to a calibrated constellation of points determined by a Leica AT401 laser tracker. The calibrated points have an average associated standard uncertainty of 12·4 μm, spanning a maximum distance of approximately 14·5 m. Subsequently, the two systems’ uncertainty was determined. V-STARS inca3 had an estimated standard uncertainty of 43·1 μm, thus outperforming its manufacturer's specification; the D700/VMS combination achieved a standard uncertainty of 187 μm

Audio-visual-olfactory resource allocation for tri-modal virtual environments

© 2019 IEEE. Virtual Environments (VEs) provide the opportunity to simulate a wide range of applications, from training to entertainment, in a safe and controlled manner. For applications which require realistic representations of real world environments, the VEs need to provide multiple, physically accurate sensory stimuli. However, simulating all the senses that comprise the human sensory system (HSS) is a task that requires significant computational resources. Since it is intractable to deliver all senses at the highest quality, we propose a resource distribution scheme in order to achieve an optimal perceptual experience within the given computational budgets. This paper investigates resource balancing for multi-modal scenarios composed of aural, visual and olfactory stimuli. Three experimental studies were conducted. The first experiment identified perceptual boundaries for olfactory computation. In the second experiment, participants (N=25) were asked, across a fixed number of budgets (M=5), to identify what they perceived to be the best visual, acoustic and olfactory stimulus quality for a given computational budget. Results demonstrate that participants tend to prioritize visual quality compared to other sensory stimuli. However, as the budget size is increased, users prefer a balanced distribution of resources with an increased preference for having smell impulses in the VE. Based on the collected data, a quality prediction model is proposed and its accuracy is validated against previously unused budgets and an untested scenario in a third and final experiment

A Calibrated Olfactory Display for High Fidelity Virtual Environments

Olfactory displays provide a means to reproduce olfactory stimuli for use in virtual environments. Many of the designs produced by researchers, strive to provide stimuli quickly to users and focus on improving usability and portability, yet concentrate less on providing high levels of accuracy to improve the fidelity of odour delivery. This paper provides the guidance to build a reproducible and low cost olfactory display which is able to provide odours to users in a virtual environment at accurate concentration levels that are typical in everyday interactions; this includes ranges of concentration below parts per million and into parts per billion. This paper investigates build concerns of the olfactometer and its proper calibration in order to ensure concentration accuracy of the device. An analysis is provided on the recovery rates of a specific compound after excitation. This analysis provides insight into how this result can be generalisable to the recovery rates of any volatile organic compound, given knowledge of the specific vapour pressure of the compound

Effect of machining environment on surface topography of 6082 T6 aluminium

Environmental and health issues associated with the use of conventional cutting fluids in machining operations is an ever growing concern among industries, workers, environment activists and governments. The aim of this paper is to explore the effects of alternative environmentally friendly approaches on the machinability of 6082 T6 aluminium alloy as compared to traditional flood machining. The experimental studies indicated that the best surface roughness (Ra) can be produced by dry machining followed by flood. However, microscopic analysis of the surfaces revealed that the surfaces produced in dry and flood conditions suffer from micro defects such as ductile deformation, smearing and chip redeposition, which have been eliminated through using cryogenic cooling techniques.</p

A low pH enzyme linked immunoassay using two monoclonal antibodies for the serological detection and monitoring of breast cancer.

A new, simple and sensitive low pH ELISA method has been developed to measure serum levels of tumour associated antigens detectable by monoclonal antibodies HMFG1 and HMFG2. We examined sera from healthy controls, patients with neoplastic and non-neoplastic conditions of breast, liver and gastrointestinal tract. The majority of patients with metastatic breast cancer had elevated serum antigens (69% HMFG1, 72% HMFG2) compared to healthy controls (6.3% HMFG1, 3.0% HMFG2) or patients with benign breast disease (17% HMFG1, 4% HMFG2). There was no discrimination using these assays between patients with neoplastic and non-neoplastic conditions of liver and gastrointestinal tract. This new method promises to be of value in the assessment and management of patients with breast cancer

A novel product representation to highlight cross-assembly dependencies and product robustness

AbstractManufacturing industry has traditionally used Bill of Materials (BOMs) and Product Lifecycle Management (PLM) tools to track components and sub-assemblies within a product. These apply a hierarchical structure to product assemblies and sub-assemblies. Impacts of change to one or more components can easily be traced throughout the assembly tree; however, changes impacting another component not directly or explicitly connected to the first are not considered. Here the authors present the novel Kendrick Reticulated Ontology Model (KROM), a mesh component network to highlight cross-assembly dependencies. Nth–order connections are considered through user inputted links between otherwise unconnected components. Unexpected emergent behaviours can therefore be anticipated. Network analysis was applied to the resulting graph, quantifying the design's robustness though centrality measures. Considering both product components and assembly associated tooling and jigging demonstrates the true propagating impact of design change. It is shown that core component connectedness order is changed when tooling becomes part of the network. This is particularly significant when considering the regular omission of tooling in BOMs. Here, a disconnection between Design Engineering and Production Engineering after design finalisation has been determined and a solution presented

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