A frame for a computer aided inspection planning system

Coordinate Measuring Machine (CMM) inspection planning is an activity performed by well-trained operators, but different measurement techniques, using the same data analysis algorithms yield in different measurement results. This is a well-recognized source of uncertainty in coordinate measurement. A CMM, provided with an automatic inspection planning (CAIP) system, permits to implement more accurate and efficient operating procedures and to fit higher quality assurance standards and tighter production timings. In this paper we present a frame of a CAIP system, able to deal with almost all the decisional stages of CMM inspection. Moreover, original approaches have been developed and presented in inspection feature selection, part set -up, probe configuration, and path planning

Knowledge Capture in CMM Inspection Planning: Barriers and Challenges

Coordinate Measuring Machines (CMM) have been widely used as a means of evaluating product quality and controlling quality manufacturing processes. Many techniques have been developed to facilitate the generation of CMM measurement plans. However, there are major gaps in the understanding of planning such strategies. This significant lack of explicitly available knowledge on how experts prepare plans and carry out measurements slows down the planning process, leading to the repetitive reinvention of new plans while preventing the automation or even semi-automation of the process. The objectives of this paper are twofold: (i) to provide a review of the existing inspection planning systems and discuss the barriers and challenges, especially from the aspect of knowledge capture and formalization; and (ii) to propose and demonstrate a novel digital engineering mixed reality paradigm which has the potential to facilitate the rapid capture of implicit inspection knowledge and explicitly represent this in a formalized way. An outline and the results of the development of an early stage prototype - which will form the foundation of a more complex system to address the aforementioned technological challenges identified in the literature survey - will be given

Development of a knowledge base for the planning of prismatic parts inspection on CMM

Inspection on coordinate measuring machines (CMMs) is based on software support for various classes of metrological tasks, i.e. Tolerances. Today, the design of a uniform inspection plan for a measuring part presents a rather complex issue due to the following: (i) metrological complexity of a measuring part; (ii) skills and knowledge of a designer / inspection planner; and (iii) software for CAI model, considered as a part of an integrated CAD-CAPP-CAM-CAI system. This issue could be addressed by the usage of expert systems that generate a conceptual inspection plan for a measuring part, based on which the inspection plan for a selected CMM could be automatically developed. This paper presents the development of a model of an automatic inspection planning system for CMMs, and, in particular, the developed knowledge base model

Development of a knowledge base for the planning of prismatic parts inspection on CMM

Inspection on coordinate measuring machines (CMMs) is based on software support for various classes of metrological tasks, i.e. Tolerances. Today, the design of a uniform inspection plan for a measuring part presents a rather complex issue due to the following: (i) metrological complexity of a measuring part; (ii) skills and knowledge of a designer / inspection planner; and (iii) software for CAI model, considered as a part of an integrated CAD-CAPP-CAM-CAI system. This issue could be addressed by the usage of expert systems that generate a conceptual inspection plan for a measuring part, based on which the inspection plan for a selected CMM could be automatically developed. This paper presents the development of a model of an automatic inspection planning system for CMMs, and, in particular, the developed knowledge base model

Feature-based hybrid inspection planning for complex mechanical parts

Globalization and emerging new powers in the manufacturing world are among many challenges, major manufacturing enterprises are facing. This resulted in increased alternatives to satisfy customers\u27 growing needs regarding products\u27 aesthetic and functional requirements. Complexity of part design and engineering specifications to satisfy such needs often require a better use of advanced and more accurate tools to achieve good quality. Inspection is a crucial manufacturing function that should be further improved to cope with such challenges. Intelligent planning for inspection of parts with complex geometric shapes and free form surfaces using contact or non-contact devices is still a major challenge. Research in segmentation and localization techniques should also enable inspection systems to utilize modern measurement technologies capable of collecting huge number of measured points. Advanced digitization tools can be classified as contact or non-contact sensors. The purpose of this thesis is to develop a hybrid inspection planning system that benefits from the advantages of both techniques. Moreover, the minimization of deviation of measured part from the original CAD model is not the only characteristic that should be considered when implementing the localization process in order to accept or reject the part; geometric tolerances must also be considered. A segmentation technique that deals directly with the individual points is a necessary step in the developed inspection system, where the output is the actual measured points, not a tessellated model as commonly implemented by current segmentation tools. The contribution of this work is three folds. First, a knowledge-based system was developed for selecting the most suitable sensor using an inspection-specific features taxonomy in form of a 3D Matrix where each cell includes the corresponding knowledge rules and generate inspection tasks. A Travel Salesperson Problem (TSP) has been applied for sequencing these hybrid inspection tasks. A novel region-based segmentation algorithm was developed which deals directly with the measured point cloud and generates sub-point clouds, each of which represents a feature to be inspected and includes the original measured points. Finally, a new tolerance-based localization algorithm was developed to verify the functional requirements and was applied and tested using form tolerance specifications. This research enhances the existing inspection planning systems for complex mechanical parts with a hybrid inspection planning model. The main benefits of the developed segmentation and tolerance-based localization algorithms are the improvement of inspection decisions in order not to reject good parts that would have otherwise been rejected due to misleading results from currently available localization techniques. The better and more accurate inspection decisions achieved will lead to less scrap, which, in turn, will reduce the product cost and improve the company potential in the market

Latest Developments in Industrial Hybrid Machine Tools that Combine Additive and Subtractive Operations

Hybrid machine tools combining additive and subtractive processes have arisen as a solution to increasing manufacture requirements, boosting the potentials of both technologies, while compensating and minimizing their limitations. Nevertheless, the idea of hybrid machines is relatively new and there is a notable lack of knowledge about the implications arisen from their in-practice use. Therefore, the main goal of the present paper is to fill the existing gap, giving an insight into the current advancements and pending tasks of hybrid machines both from an academic and industrial perspective. To that end, the technical-economical potentials and challenges emerging from their use are identified and critically discussed. In addition, the current situation and future perspectives of hybrid machines from the point of view of process planning, monitoring, and inspection are analyzed. On the one hand, it is found that hybrid machines enable a more efficient use of the resources available, as well as the production of previously unattainable complex parts. On the other hand, it is concluded that there are still some technological challenges derived from the interaction of additive and subtractive processes to be overcome (e.g., process planning, decision planning, use of cutting fluids, and need for a post-processing) before a full implantation of hybrid machines is fulfilledSpecial thanks are addressed to the Industry and Competitiveness Spanish Ministry for the support on the DPI2016-79889-R INTEGRADDI project and to the PARADDISE project H2020-IND-CE-2016-17/H2020-FOF-2016 of the European Union's Horizon 2020 research and innovation program

Investigation Of Suitable Solutions For A Digital Chain For Tactile On-Machine Measurement Based On Solutions For Coordinate Measurement Machines

The trend towards customer-specific products remains strong. The modern industry faces the challenge of meeting significantly higher quality requirements in the context of variant-rich production. The traditional process for machined workpieces consists of inspection on coordinate measuring machines after the machining is done. For machining processes that require quick response and early quality assurance, a tactile on-machine inspection is more suitable. This approach allows real-time control within the process, enabling high levels of automation on the shop floor and minimizing manual rework. The increased complexity of this system lies in the preparation of the measurement task, which involves selecting the measurement strategy, planning the inspection task and creating an inspection program. This paper explores existing computer-aided inspection planning approaches for coordinate measuring machines and assess their suitability for on-machine inspection. This enables a valuable component for enabling automated quality assurance of customer-specific products and highlights existing gaps in the process

Towards the automation of product geometric verification: An overview

The paper aims at providing an overview on the current automation level of geometric verification process with reference to some aspects that can be considered crucial to achieve a greater efficiency, accuracy and repeatability of the inspection process. Although we are still far from making this process completely automatic, several researches were made in recent years to support and speed up the geometric error evaluation and to make it less human-intensive. The paper, in particular, surveys: (1) models of specification developed for an integrated approach to tolerancing; (2) state of the art of Computer-Aided Inspection Planning (CAIP); (3) research efforts recently made for limiting or eliminating the human contribution during the data processing aimed at geometric error evaluation. Possible future perspectives of the research on the automation of geometric verification process are finally described

Computer Aided Inspection Planning For Automation Of On-Machine Inspection Of Customised Milling Parts

Customised products force manufacturing systems to operate efficient at batch size one. Automation in upstream processes and on shop floor increase productivity. Besides value-adding processes, quality management to sustain product quality must be considered regarding automation and consistency from 3D model to the execution on shop floor. Computer aided inspection planning addresses the automation of measurement operations. The inspection planning starts with a customised 3D model and realises a simple execution of the measurement task on shop floor level. A method for implementation of computer-aided inspection planning for tactile on-machine inspection will be presented to realise potentials like tool deviation and work piece correction based on measurement results. The developed method focuses on ensuring automation of computer aided inspection planning and sets up the basis for a self-controlling manufacturing system of customised milling parts. A validation was performed at a manufacturing company for customised drilling tools and enabled less downtime and rework time for milling machines