Modelling and Simulating the Digital Measuring Twin Based on CMM

In order to perform the inspection planning process on the coordinate measuring machine (CMM), it is necessary to model the measuring system with workpiece, CMM and fixture. The metrological analysis of the workpiece is then conducted, followed by the creation of a measurement program for simulation on a virtual measuring machine in a CAD environment. This paper presents the modelling and simulation of a virtual measuring system based on a real CMM using PTC Creo Parametric 5.0 software. The simulation involved programming the measuring path and generating a DMIS (*.ncl) file, which represents the standard modelled types of tolerance. The analysis of the metrology of the measuring part for the given forms of tolerance (location, perpendicularity, flatness, etc.) was performed. The components of the CMM and the assembly with defined kinematic connections are also modelled. Following the simulation and generation of the output DMIS file in PTC Creo using the virtual CMM, the real CMM was programmed and used for actual measurements. Subsequently, a measurement report was generated. The main result of this paper is the modelling of an offline Digital Measuring Twin (DMT) based on the DMIS file

Ants Colony Optimisation of a Measuring Path of Prismatic Parts on a CMM

This paper presents optimisation of a measuring probe path in inspecting the prismatic parts on a CMM. The optimisation model is based on: (i) the mathematical model that establishes an initial collision-free path presented by a set of points, and (ii) the solution of Travelling Salesman Problem (TSP) obtained with Ant Colony Optimisation (ACO). In order to solve TSP, an ACO algorithm that aims to find the shortest path of ant colony movement (i.e. the optimised path) is applied. Then, the optimised path is compared with the measuring path obtained with online programming on CMM ZEISS UMM500 and with the measuring path obtained in the CMM inspection module of Pro/ENGINEER® software. The results of comparing the optimised path with the other two generated paths show that the optimised path is at least 20% shorter than the path obtained by on-line programming on CMM ZEISS UMM500, and at least 10% shorter than the path obtained by using the CMM module in Pro/ENGINEER®

Verification of the CMM Measuring Path Based on the Modified Hammersly's Algorithm

This paper presents a CAI verification of the measuring path for inspection of prismatic measuring parts (PMP) which consists of the basic geometric features. The aim of the verification is to visualize collision check between the measuring sensor and the workpiece. The simulation of the measuring path was realized on the configured virtual CMM in the CAD environment. The generated measuring path for inspection planning at the CMM consists of three sets of points. The first set of points, measuring points, is generated based on the modified Hammersly's algorithm for distribution of measuring points by the features from which the workpiece consists. The other two sets, nodal points, are collision fee points, which are generated on the basis of the developed model that analyze accessibility to features at the level of one feature and based on the principle of collision avoidance when pass from one feature to another (requirement of tolerance). On the basis of these three sets of points, the total measuring path without collision is generated. The measuring path generated in this way is verified by simulations on a configured virtual CMM through several examples of standard forms of tolerance

Geometric inspection planning as a key element in industry 4.0

In the context of Industry 4.0, inspection is fundamental: if manufacturing opens the loop by converting digital parts into physical parts, inspection closes the loop by turning physical parts into information. The difference between an effective and a useless inspection is its planning. A well-planned inspection will provide the required data and information without wasting time and money. In this work, we discuss the current role of geometric inspection planning, showing that not only it is a must for Industry 4.0, in order to guarantee a good link between the physical and digital world, but it can take advantage of this framework to improve itself. Methodologies for optimal inspection planning have been already conceptually proved and are just waiting for the required amount of data and information to be available, and Industry 4.0 will be the enabler to fill this gap