PurposeThe purpose of this paper is to establish a general method for achievable speed and accuracy evaluation of additive manufacturing (AM) machines and an objective comparison among them.Design/methodology/approachFirst, a general schematic is defined that enables description of all currently available AM machines. This schematic is used to define two influential factors describing certain parts' properties regarding the machines' yield during manufacturing. A test part is defined, that will enable testing the influence of these factors on the speed and accuracy of manufacturing. A method for implementing and adapting test parts is established for individual machine's testing. This method was used to test four different machines that are predominantly used in Slovenia at the moment.FindingsResearch has proven that the machine's yield had a predominant influence on the achievable manufacturing speeds of all the tested machines. In addition, the results have shown different ranges of achievable manufacturing speeds for individually tested machines. Test parts' measurement results have shown comparable achievable accuracies for all the tested machines.Research limitations/implicationsSpeed evaluation is based on a 2k factorial design that assumes the linearity among individual points of the experiment. This design was chosen to keep the method as simple and quick as possible, in order to perform testing on those machines otherwise used in industrial environments. Accuracy evaluation was limited by a rather small sample size of ten fabricated test parts per machine.Practical implicationsThe presented evaluation method can be used on any existing or future type of AM machine, and their comparative placement regarding achievable manufacturing speed and accuracy.Originality/valueThe presented method can be used to evaluate a machine regardless of the AM technology on which it is based.

Non-contact optical three-dimensional measuring, scanning and digitising are increasingly present in quality assurance systems. Simple scanning procedures, high density of data acquired in a single scan, and the possibility of integrated reverse engineering and inspection, are all advantages of optical scanning compared to conventional measuring methods. Due to the three-dimensional acquisition of measuring data, an optical scanner is often considered to be an alternative possibility for coordinate measuring machines. However, the accuracy of the measured data acquired by optical scanning (even with a high-end system) is still far below the level achieved by high-level coordinate measuring machines. This paper examines the possibilities of using a three-dimensional scanner for workpiece inspection. The first part presents a special field of workpiece inspection in which, even with currently achievable accuracy, optical scanning is a viable solution for the inspection of manufactured parts. In addition, the achievable dimensional accuracy of an optical scanner is tested by scanning several gauge blocks. In conclusion, a head to head comparison with a coordinate measuring machine is made by scanning and verifying a sphere.

If you would like to write for this, or any other Emerald publication, then please use our Emerald for Authors service information about how to choose which publication to write for and submission guidelines are available for all. Please visit www.emeraldinsight.com/authors for more information. About Emerald www.emeraldinsight.comEmerald is a global publisher linking research and practice to the benefit of society. The company manages a portfolio of more than 290 journals and over 2,350 books and book series volumes, as well as providing an extensive range of online products and additional customer resources and services.Emerald is both COUNTER 4 and TRANSFER compliant. The organization is a partner of the Committee on Publication Ethics (COPE) and also works with Portico and the LOCKSS initiative for digital archive preservation. AbstractPurpose -The purpose of this paper is the selection of production parameters in selective laser sintering -SLS for the production of quality products (e.g. good mechanical properties). The manufacturing procedure affects the properties, which is especially significant in additive procedures, as the products are not cheap and the procedure and material need to be optimally selected. Design/methodology/approach -The paper presents an analysis of the fabrication parameters in selective laser sintering (SLS) that affect the flexural properties of the finished product. Findings -The influence of a new parameter has been found, the overlay ratio, and using the mathematical and scheme method, the selection of parameters for obtaining the optimal flexural properties has been proposed. Originality/value -The paper presents a new mathematical model for the calculation of the processing parameters in SLS of polymer products and gives a diagram for the determination of which parameters are the best to use for practical purposes.

With the rapid development and expansion of devices for the production of both traditional (cutting) procedures and layered technologies (also known as 3D printers or rapid prototyping/manufacturing), the question arises as to how to find the appropriate production technology. Article describes the basic features of the CAD output file STL. The STL file format is a widelyused file format developed for layered technologies and, as such, a basis for analysing and developing methods when determining the complexity of a model. For the analyses of basic STL data, and complexity determination, several real-life models are presented. Actual manufacturing procedures suitable for the manufacture of unique products or serial production are presented, with accentuation towards layered technologies. Technological test models are analysed based on the fundamental properties of manufacturing and certain manufacturing processes are chosen using complexity estimation. The results are comparable with those choices of manufacturing procedures on the basis of experts' estimates. Complexity evaluation is also used for post-processing time determination for several layered technologies.

Products made by additive manufacturing are increasingly replacing the products made by classical procedures of polymer processing. The current market requires the products to be of good mechanical properties, low prices, and complicated geometry. With the procedures such as Fused Deposition Modelling and Laminated Object Manufacturing it is possible to produce a product of relatively low price and good mechanical properties. In practice it is impossible to avoid using the products in various atmospheric conditions (e.g. UV radiation and humid environment) either intentionally or unintentionally. The UV light, the Sun being its usual source,, and the average humidity of countries worldwide can vary from 20% to 90%, depending on the weather, day and geographic location. It is therefore necessary to determine how UV light, after a longer exposure, affects the final mechanical properties of the products. A comparison of tensile strength and elasticity module of the test specimens in FDM and LOM procedures has been performed.

Preliminary notesArticle presents the development and manufacture of a new generation of thermal manikins that can be used for testing different personal protective equipment as used under extreme environmental conditions. The demonstrated steps from the initial idea towards the final product were taken with the help of modern CAD/CAM tools and CNC manufacturing procedures. This article also presents some of the problems that occurred and had to be solved during the designing, manufacturing and assembly of the thermal manikin. Keywords: extreme environment; personal protective equipment; safety; thermal manikin Početna analiza razvoja termalne lutke za uporabu u vodi i njezina proizvodnja iz punih blokovaPrethodno priopćenje U radu se opisuje razvoj i proizvodnja nove generacije termalnih modela (lutaka) koji se mogu koristiti za ispitivanje različite osobne zaštitne opreme kada se rabi u ekstremnim uvjetima. Sve od početne ideje do konačnog proizvoda provedeno je uz pomoć suvremenih CAD/CAM alata i CNC proizvodnih postupaka. U radu se iznose i neki problemi koji su se pojavili tijekom konstruiranja, izrade i sastavljanja termalne lutke, a trebalo ih je riješiti.

Abstract:The investment casting of metal parts is a rapid tooling/manufacturing method for small series production, where wax pattern is produced separately and then extracted from the mould. The wax parts commonly used as patterns are usually obtained after wax casting silicone rubber moulds. The time needed for the wax to solidify is critical and difficult to predict. This article presents an experimental method for cooling-time determination using a simplified applicable solution (needed in hash industrial environment and short deadlines) based on real-life parts experience.