Standard For The Exchange Of Product Research Articles

Recursive autoencoder network for prediction of CAD model parameters from STEP files

Databases of 3D CAD (computer aided design) models are often large and lacking in meaningful organisation. Effective tools for automatically searching for, categorising and comparing CAD models, therefore, have many potential applications in improving efficiency within design processes. This paper presents a novel asymmetric autoencoder model, consisting of a recursive encoder network and fully-connected decoder network, for the reproduction of CAD models through prediction of the parameters necessary to generate a 3D part design. Inputs to the autoencoder are STEP (standard for the exchange of product data) files, an ISO standard CAD model format, compatible with all major CAD software. A complete 3D model can be accurately reproduced using a STEP file, meaning that all geometric information can be used to contribute to the final encoded vector, with no loss of small detail.In a CAD model of overall size 10 × 10 × 10 units, for 90% of models, the class of an added feature is estimated with maximum error of 0.6 units, feature size with maximum error of 0.4 units and coordinate values representing position with maximum error of 0.3 units. These results demonstrate the successful encoding of complex geometric information, beyond merely the shape of the 3D object, with potential application in the design of search engine functionality.

Milling Features Recognition Methodology of Rectangular Fillet Blind Pocket for Universal Data Structure

Various studies have focused on developing an interface system that could integrate the machining process with CNC (Computer Numerical Control) machine tools by producing tool paths using STEP (Standard for the Exchange of Product model data) file as an input function. Studies to recognize features in STEP file by encoding the data of geometric entities of a CAD (Computer-Aided Design) design has been done by many researchers. However, they only focus on Cutter Location (CL) which eventually describes the machining profile in the x and y planes without considering the depth of the machining feature in the z-axis. Identifying and recognizing machining features in the STEP file is important since STEP is a platform for converting industry-standard CAD systems and software data models. The aim of this paper is to identify profiles of geometric machining features for rectangular fillet blind pockets using the Geometric Data Extraction (GDE) approach. Three cases have been carried out namely single rectangular fillet blind pocket, double rectangular fillet blind pocket and triple rectangular fillet blind pocket. The results were verified by manual graph plotting and automatic graph plotting using CPM 3D Plotter.

Approaching STEP file analysis as a language processing task: A robust and scale-invariant solution for machining feature recognition

Machining feature recognition is a key task in the intelligent analysis of 3D CAD models as it represents a bridge between a part design and the manufacturing processes required for manufacture and can, therefore, increase automation in the manufacturing process. As 3D model files do not naturally conform to the fixed size necessary as the input to most varieties of neural network, most existing solutions for machining feature recognition rely on either transforming CAD models into a fixed shape representation, accepting some loss of information in the process, or employ rigid rules-based feature extraction techniques prior to applying any learning-based algorithm, resulting in solutions which may display high performance for specific applications but which lack in the flexibility provided by a purely learning-based approach. In this paper, we present a novel machining feature recognition model, which is capable of interpreting the data present in a STEP (standard for the exchange of product data) file using purely learning-based algorithms, with no need for human input. Our model builds on the basic framework for feature extraction from STEP file data proposed in Miles et al. (2022), with the design of a decoder network capable of using extracted features to perform the complex task of machining feature recognition. Model performance is evaluated based on accuracy at the task of identifying 24 classes of machining feature in CAD models containing between two and ten intersecting features. Results demonstrate that our solution achieves comparable performance with existing solutions when given data similar to that used during training and significantly increased robustness when compared to existing solutions when presented with CAD models which vary from those seen during training and contain small features.

Recursive encoder network for the automatic analysis of STEP files

Automated tools which can understand and interface with CAD (computer-aided design) models are of significant research interest due to the potential for improving efficiency in manufacturing processes. At present, most research into the use of artificial intelligence to interpret three-dimensional data takes input in the form of multiple two-dimensional images of the object or in the form of three-dimensional grids of voxels. The transformation of the input data necessary for these approaches inevitably leads to some loss of information and limitations of resolution. Existing research into the direct analysis of model files in STEP (standard for the exchange of product data) format tends to follow a rules-based approach to analyse models of a certain type, resulting in algorithms without the benefits of flexibility and complex understanding which artificial intelligence can provide. In this paper, a novel recursive encoder network for the automatic analysis of STEP files is presented. The encoder network is a flexible model with the potential for adaptation to a wide range of tasks and finetuning for specific CAD model datasets. Performance is evaluated using a machining feature classification task, with results showing accuracy approaching 100% and training time comparable to that of existing multi-view and voxel-based solutions without the need for a GPU.

Integrated Interface System of STEP Data Models for the Tool Path Generation

The STEP (STandard for the Exchange of Product model data) is a worldwide standard for exchanging products between diverse computer systems and industrial applications. STEP files (ISO 10303) contain 3D data in the universal data format with a boundary representation (B-rep) that allows the exchange of data models between CAD, CAM, and CNC systems. Traditionally, G-code generation relies on CAM software as an add-on, which incurs significant installation costs. The purpose of this paper is to describe the development of an Integrated Interface System (I2S) for Tool Path Generation (TPG) for the CNC milling operations utilizing neutral STEP files.The algorithm was interpreted in Hypertext Preprocessor (PHP) programming and produced a computer interface system that is capable to convert STEP file geometric data to G-code format.The geometric features of the sample block were modeled using a 3D CAD model. The result was validated using machining simulation, and the machining is performed on a three-axis CNC milling machine with a PC-based controller.In modern manufacturing systems based on Open Architecture Controller (OAC), the development of the I2S provides an alternative to generating machining tool paths and G-code by intercepting CAM software.

A review of G code, STEP, STEP-NC, and open architecture control technologies based embedded CNC systems

Computer Numeric Control (CNC) is a significant pillar of manufacturing for decades. These systems are an essential part of future manufacturing. In the urge towards the development of next-generation manufacturing systems, various technologies have been introduced. Moreover, based on those technologies, numerous systems have been developed all around the world. In order to assist in future research, the related major technologies and developments are discussed in this content. This paper presents the review of basics CN), Computer-Aided Design (CAD), Computer-Aided Process Planning (CAPP), Computer-Aided Manufacturing (CAM), G codes (ISO 6983), Standard for the Exchange of Product (STEP) model data (STEP), STEP-numeric control (STEP-NC), and open architecture control (OAC) technologies. The in-depth discussion on the development and implementation of the STEP and STEP-NC technologies is also addressed. The review also highlights the benefits and role of the open architecture control technology in the CNC system development. Apart from that, the paper also presents the last 17 years of embedded CNC systems development in tabular form, which shows the cocktail of various technologies and ISO data interface models. Finally, the paper concludes with future directions and recommendations.

Integrated Inspection System STEP-Compliant for the Exchange of Dimensional Metrology Data

To meet the demands of information virtualization promoted by the fourth industrial revolution, the processes of manufacturing and quality require an architecture that facilitates the integration of processes. The objective of this article is to present an alterna- tive solution, framed in the concept of interoperability, to link the results obtained in the inspection of a part with the data generated in Compliant-STEP Systems CAD/CAM/CNC. For the implementation of the solution, a closed-loop architecture for manufactu- ring and inspection it was designed that uses as a mechanism of integration a data model in a neutral format. The measurement results are homogenized both semantically and syntactically to be handled by each of the systems involved in the closed-loop Manufacturing. Dimensional metrology data are used to create a compensation strategy and correct identified manufacturing errors in the inspection process. A framework was designed to manage the exchange of information. The main contribution of the article is the detailed description of the development of the adherent system to the standard ISO 10303 known as STEP (STandard for the Exchange of Product model data). Finally, an analysis is done based on a case study that involves definition and extraction of design specifications, used for both manufacturing and measurement. The solution presented allows the use of measurement data within a closed manufacturing loop, ensuring the integrity of information and access so that each system can use it for different purposes.

Review of STEP-NC System Controlled by Android Platform Through Wifi

STEP (STandard for the Exchange of Product model data, ISO 10303) data for numerical control (NC), or the new standard STEP-NC (ISO 14649), is intended to provide full product and process data interoperability between computer-aided manufacturing systems and machine tool controllers. Wireless networks have been widely developed compare to wired network, and the wireless communication removes the restriction of wired connections. One of successful wireless networks architecture is WiFi (wireless fidelity) and it is very popular in providing different data services. Integrated WiFi network is a great potential for the future due to the high data transport capacity of WiFi. Google’s Android platform is a widely anticipated open source operating system for mobile phones and the idea to integrate with NC machine through WiFi will be a contribution for manufacturing industries. This research focuses to explore the theories and techniques behind procedure of STEP-NC system controlled by android platform through WiFi. The developed application controller enables the machine tool to be controlled based on wireless communication, android platform and STEP-NC data generated from CAD/CAM systems.

A rule-based methodology to extract building model views

Abstract In this paper, we present a novel approach called IfcView that relies on Semantic Web technologies for creating building views. To do so, we consider an ifcOWL ontology proposed by buildingSMART. The ifcOWL is an Industry Foundation Classes (IFC) based ontology. By combining the ifcOWL ontology with logical rules (expressed in Semantic Web Rule Language, SWRL), we demonstrate through several case studies that our approach can perform a more intuitive and flexible extraction of building views when compared to the Model View Definition (MVD) approach. This is because our rule-based approach dynamically creates sub-graphs (i.e. views) by specifying the IFC elements to extract as Globally Unique Identifiers (GUID), relationships or entities. Another benefit of our approach is the fact that it simplifies the maintenance and definition of building views. Once our rule-based system extracts such a building view (i.e. sub-graph), this view can be exported by using STEP (STandard for the Exchange of Product) or Turtle (a Resource Description Framework (RDF) syntax) formats.

Do Mechanical Advantages Exist in Relining Fiber Posts with Composite Prior to its Cementation?

To evaluate two different techniques for glass fiber-reinforced resin post (FRC) insertion by assessing the stress distribution under polymerization shrinkage or masticatory loading and measuring the pull-out bond strength to dentin. A model of an endodontically treated maxillary central incisor was used for three-dimensional simulation with two conditions: conventionally cemented (FRC) and relined (RFRC). The volumetric solids were exported to analysis software (ANSYS 17.2, ANSYS) in STEP (Standard for the Exchange of Product Data) format. All contacts were considered perfectly bonded between the geometries. Numerical models received a load of 100 N (45 degrees) on the lingual surface. The composite cement polymerization shrinkage was simulated by thermal analogy to obtain Von Mises, maximum principal stress, and shear stress. For in vitro evaluation, a pull-out bond strength test (n = 20/N = 40) was performed (50 Kgf, 1 mm/min) after mechanical cycling (in water at 37°C, 84 N, 2 bar, 45 degrees, 106 cycles, 4 Hz), and failure analysis was subsequently performed. The results were analyzed using one-way ANOVA and Tukey's test (α < 0.05). The FRC group showed more stress concentration in the cement layer. The RFRC group [(32 ± 13); (288 ± 129)] presented better performance than the FRC group [(6 ± 7); (152 ± 87)] for stress distribution and bond strength (p < 0.05). Adhesive and mixed failures occurred in both groups. Relined fiberglass posts reduced the stress generated by polymerization shrinkage and showed greater bond strength to dentin.

A study of 3D model similarity based on surface bipartite graph matching

PurposeThis study aims to compute 3D model similarity by extracting and comparing shape features from the neutral files.Design/methodology/approachIn this work, the clear text encoding document STEP (Standard for The Exchange of Product model data) of 3D models was analysed, and the models were characterized by two-depth trees consisting of both surface and shell nodes. All surfaces in the STEP files can be subdivided into three kinds, namely, free, analytical and loop surfaces. Surface similarity is defined by the variation coefficients of distances between data points on two surfaces, and subsequently, the shell similarity and 3D model similarity are determined using an optimal algorithm for bipartite graph matching.FindingsThis approach is used to experimentally verify the effectiveness of the 3D model similarity algorithm.Originality/valueThe novelty of this study research lies in the computation of 3D model similarity by comparison of all surfaces. In addition, the study makes several key observations: surfaces reflect the most information concerning the functions and attributes of a 3D model and so the similarity between surfaces generates more comprehensive content (both external and internal); semantic-based 3D retrieval can be obtained under the premise of comparison of surface semantics; and more accurate similarity of 3D models can be obtained using the optimal algorithm of bipartite graph matching for all surfaces.

Step-by-step guide to building an inexpensive 3D printed motorized positioning stage for automated high-content screening microscopy

High-content screening microscopy relies on automation infrastructure that is typically proprietary, non-customizable, costly and requires a high level of skill to use and maintain. The increasing availability of rapid prototyping technology makes it possible to quickly engineer alternatives to conventional automation infrastructure that are low-cost and user-friendly. Here, we describe a 3D printed inexpensive open source and scalable motorized positioning stage for automated high-content screening microscopy and provide detailed step-by-step instructions to re-building the device, including a comprehensive parts list, 3D design files in STEP (Standard for the Exchange of Product model data) and STL (Standard Tessellation Language) format, electronic circuits and wiring diagrams as well as software code. System assembly including 3D printing requires approx. 30h. The fully assembled device is light-weight (1.1kg), small (33×20×8cm) and extremely low-cost (approx. EUR 250). We describe positioning characteristics of the stage, including spatial resolution, accuracy and repeatability, compare imaging data generated with our device to data obtained using a commercially available microplate reader, demonstrate its suitability to high-content microscopy in 96-well high-throughput screening format and validate its applicability to automated functional Cl−- and Ca2+-imaging with recombinant HEK293 cells as a model system. A time-lapse video of the stage during operation and as part of a custom assembled screening robot can be found at https://vimeo.com/158813199.

A Portrait of an ISO STEP Tolerancing Standard as an Enabler of Smart Manufacturing Systems

The International Organization for Standardization (ISO) has just completed a major effort on a new standard ISO 10303-242 titled “Managed Model Based 3D Engineering.” It belongs to a family of standards called STEP (STandard for the Exchange of Product model data). ISO 10303-242 is also called the STEP Application Protocol 242 (STEP AP 242, for short). The intent of STEP AP 242 is to support a manufacturing enterprise with a range of standardized information models that flow through a long and wide “digital thread” that makes the manufacturing systems in the enterprise smart. One such standardized information model is that of tolerances specified on a product’s geometry so that the product can be manufactured according to the specifications. This paper describes the attributes of smart manufacturing systems, the capabilities of STEP AP 242 in handling tolerance information associated with product geometry, and how these capabilities enable the manufacturing systems to be smart.

Developing a 3D intelligent object model for the application of construction planning/simulation in a highway project

This study proposes a 3D intelligent object model in highway construction to electronically represent a large amount of information in highway projects based on the international standard ISO 10303. Also known as STEP (Standard for the Exchange of Product), ISO 10303 is an open standard, and has been used for data exchange in building projects of the AEC industries. Motivated by the success from the building industry, this research attempts to apply an object based intelligent model in 3D highway modeling. In order to test the feasibility of the proposed approach, a prototype was developed and tested on a highway project in Seoul, Korea with a team led by Korean Institute of Construction Technology (KICT). The proposed 3D intelligent model was applied to build a 3D model and automatically derive cost/schedule estimates from the 3D object model. To develop a 3D object model in highway road construction, this paper explores different options such as Industry Foundation Classes (IFCs) and LandXML and establish a comprehensive object model for highway structures with different components such as roads, a bridge, and a tunnel as well as topographical representations that could be used for cost/schedule estimation.

System integration for kinematic data exchange

Industry needs a system neutral solution for exchange of kinematic models. In this article, the first known valid implementation of kinematic mechanisms based on ISO 10303 Standard for the Exchange of Product (STEP) is presented. The result includes an implementation framework and two developed prototypes. Two major challenges of standard-based development are identified and generalised: data integration and system integration, which are solved by the framework. The two prototypes are implemented to establish kinematic data exchange between Siemens NX® and STEP-NC MachineTM via STEP AP214 files. Experiences of design and development of the applications are presented, and a validated case study of data exchange using the developed applications is shown. There are other attempts of using STEP as basis for modelling, but as the first valid STEP implementation on kinematics, this approach demonstrates the feasibility of pure STEP-based data exchange for kinematic mechanisms. The prototypes also show potential of utilising the framework for general standard implementations. The research is expected to motivate deeper understanding and extensive applications of the STEP standard in industry and academia.

Migrating product structure bill of materials Excel files to STEP PDM implementation

It is important for manufacturing companies to provide a standard for product data exchange between diverse computer systems. Past attempts to develop neutral format standards for data exchange have had limited success, and have led to the development of STEP (Standard for the Exchange of Product) as a data exchange standard. The STEP standard makes it easier to integrate systems that process various product life-cycle functions, such as design, engineering, manufacturing, logistics support, and will help to facilitate concurrent engineering. The goal of this paper is to facilitate the computer-readable exchange of the product bill of materials (BOM) information for product data management (PDM). In this paper, the STEP ISO 10303-21 is implemented to share the product data information in a manufacturing environment. A structural product bill of materials is first transformed into an Excel file format, then a PDM Schema Exporter is utilized to export a BOM Excel file to a STEP Part 21 file. A C# program decodes the STEP file into BOM information to update the PDM databases in SQL server for product data management. Also, SAS code is written to generate the indented bill of materials from the BOM information, to draw a tree diagram to present an accurate structural view of a product, and to export to PDM databases for product data structural view.

Modeling the TrueBeam linac using a CAD to Geant4 geometry implementation: Dose and IAEA‐compliant phase space calculations

To create an accurate 6 MV Monte Carlo simulation phase space for the Varian TrueBeam treatment head geometry imported from CAD (computer aided design) without adjusting the input electron phase space parameters. GEANT4 v4.9.2.p01 was employed to simulate the 6 MV beam treatment head geometry of the Varian TrueBeam linac. The electron tracks in the linear accelerator were simulated with Parmela, and the obtained electron phase space was used as an input to the Monte Carlo beam transport and dose calculations. The geometry components are tessellated solids included in GEANT4 as GDML (generalized dynamic markup language) files obtained via STEP (standard for the exchange of product) export from Pro/Engineering, followed by STEP import in Fastrad, a STEP-GDML converter. The linac has a compact treatment head and the small space between the shielding collimator and the divergent are of the upper jaws forbids the implementation of a plane for storing the phase space. Instead, an IAEA (International Atomic Energy Agency) compliant phase space writer was implemented on a cylindrical surface. The simulation was run in parallel on a 1200 node Linux cluster. The 6 MV dose calculations were performed for field sizes varying from 4 x 4 to 40 x 40 cm2. The voxel size for the 60 x 60 x 40 cm3 water phantom was 4 x 4 x 4 mm3. For the 10 x 10 cm2 field, surface buildup calculations were performed using 4 x 4 x 2 mm3 voxels within 20 mm of the surface. For the depth dose curves, 98% of the calculated data points agree within 2% with the experimental measurements for depths between 2 and 40 cm. For depths between 5 and 30 cm, agreement within 1% is obtained for 99% (4 x 4), 95% (10 x 10), 94% (20 x 20 and 30 x 30), and 89% (40 x 40) of the data points, respectively. In the buildup region, the agreement is within 2%, except at 1 mm depth where the deviation is 5% for the 10 x 10 cm2 open field. For the lateral dose profiles, within the field size for fields up to 30 x 30 cm2, the agreement is within 2% for depths up to 10 cm. At 20 cm depth, the in-field maximum dose difference for the 30 x 30 cm2 open field is within 4%, while the smaller field sizes agree within 2%. Outside the field size, agreement within 1% of the maximum dose difference is obtained for all fields. The calculated output factors varied from 0.938 +/- 0.015 for the 4 x 4 cm2 field to 1.088 +/- 0.024 for the 40 x 40 cm2 field. Their agreement with the experimental output factors is within 1%. The authors have validated a GEANT4 simulated IAEA-compliant phase space of the TrueBeam linac for the 6 MV beam obtained using a high accuracy geometry implementation from CAD. These files are publicly available and can be used for further research.

Implementing ISO standard 10303 application protocol 224 for automated process planning

Gashed application landscape and heterogenic systems are still preventing efficient and automated product development. Process planning especially is an important step that determines most of the costs in production or the success of obtaining a potential order. As the step between design and production, process planning is important for manufacturing a product in an economic manner. This paper provides a discussion about necessary requirements for automated process planning and an efficient product development. Additionally we present our intended idea to innovate the product design under the focus of automated process planning. Therefore we present some aspects relating to feature based design , standardized product data representation with ISO 10303 and neutral data exchange with STEP (Standard for The Exchange of Product model data). Relating to this, we are focusing the application protocol (AP) 224 and, because of missing implementations, we reveal our approaches for the implementation of this protocol. This includes the generation of a feature library with the GeneSEZ generator framework that applies the Model-Driven Architecture (MDA) framework developed at the University of Applied Sciences, Zwickau. Another point is the description of an ACIS based library that realizes the visualization of the related geometry. Finally, our implemented EXPRESS interpreter is introduced, which generates necessary files for data exchange with STEP-files. This Design Module (DM) is described in detail.

SU‐GG‐T‐407: Modeling a New Varian Linac Using a CAD to Geant4 Geometry Implementation: Dose and IAEA‐Compliant Phase Space Calculations

Purpose: To (1) use accurate CAD linac treatment head geometry for Geant4 Monte Carlo calculations to minimize the errors due to approximations of the linac treatment head components used in previous studies, (2) investigate the CAD to Geant4 linking procedure through 6MV dose calculations, and (3) provide IAEA‐compliant patient‐independent phase space files. Method and Materials: Geant4 v4.9.2.p01 was employed to simulate the treatment head geometry of the newest Varian linac for a 6MV beam. The geometry components are tessellated solids included in Geant4 as GDML (Generalized Dynamic Markup Language) files obtained via STEP (STandard for the Exchange of Product) export from Pro/Engineering, followed by STEP import in Fastrad, a STEP‐GDML converter. An IAEA‐compliant phase space writer was implemented between the shielding collimator and the upper jaws on a cylindrical geometry due to the compact treatment head and the divergent arc of the jaws. The simulation was run in parallel on the SLAC cluster. The dose calculations were based on a combined total of 26 billion histories. The voxel size for the 60×60×40cm3 water phantom was 4×4×4 mm3. Results: For the percent depth dose profiles, the agreement between experiment and Monte Carlo is within 2% for 4×4, 10×10, 20×20, 30×30 and 40×40 cm2 field sizes. For the lateral dose profiles, the agreement is within 3%. The fractional uncertainty of the average dose for the voxels with dose larger than 0.5 of the maximum dose decreased from ∼4% to ∼2% for field sizes increasing from 4×4 to 40×40 cm2. Conclusions: We have developed and validated the Geant4 simulated IAEA‐compliant phase space of the new Varian linac for the 6MV beam obtained using a high precision geometry implementation from CAD. These files will be made publicly available and could be used for further dose calculations. Supported in part by Varian Medical Systems

Step Based Geometric and Topological Similarity Assessment of Mechanical Parts

In this paper, an approach has been developed to assess geometric and topological similarity between 3D mechanical parts using their face-edge relation matrices. The approach relies on the STEP (Standard for the Exchange of Product Data Model) graphic standard to obtain the geometric and topological data belonging to parts designed in a CAD system. The CAD model of any part is automatically translated into a STEP file and entities represented in the STEP file of it are mapped into face-edge relation matrix. Face-edge relation matrix is a square matrix and sized according to number of faces on a part. In the similarity assessment stage, the closest matrix in the database corresponding to matrix of the new part is retrieved and matched as matrix of the candidate part. Similarity factor between the new and candidate parts is calculated with respect to the matched faces and total faces in both matrices. Similarity assessment is useful for many CAD/CAM applications such as especially variant process planning, cost estimation and group technology. The algorithm has been applied to some real parts to demonstrate its efficiency and capability.