Comparison of methodologies for identification of process parameters affecting geometric deviations in plastic injection molding of housing using Taguchi method

This paper examines parameters that could influence geometric part deviation (shrinkage and warpage) of the Housing (Cycoloy, PC/ABS, Grade C2800) produced by plastic injection molding. Five parameters (temperature of molded plastic, injection time, cooling time, holding pressure, holding pressure time). Influence of the parameters is compared by simulation and real experiment with the results measured at five points. Taguchi's orthogonal array method is used. The simulation leads to unreliable results, with too many parameters influencing geometric deviation. Factor that has major influence is holding pressure time (HPT). The real experiment identifies holding pressure (HP) as a parameter with major influence. For further examination, the real experimentation is recommended, whenever it is possible

Robotic assembly of rebar cages for beams and columns

In the paper, the design and method of operation of a robot cell for the assembly of rebar cages for beams and columns is described. The input elements are pre-manufactured rebars, and the output consists of rebar cages. Inside the robot cell, assembly is performed by robots equipped with tools for grasping the rebars, tools for bending the stirrups, and tools for welding the stirrups to the longitudinal bars. Various mechanisms for supplying the robots with rebars and supporting them during the assembly process have also been designed. Because of the specific nature of the assembly process, where robots have to successfully avoid various obstacles, mass-produced robots cannot be used for the assembly of rebar cages. For this reason, special robot configurations have to be designed. The robot cell described in this paper is at present at the design stage. It was modelled and simulated using the program  3 for robot simulation, which makes it possible to study, optimise, and design in detail the proposed robot systems. The figures in the paper describing how such a system works have also been taken from this simulation.

Changeability and agility enablers in one-of-a-kind product development and design processes

The smart factories that are already beginning to appear employ a completely new approach to product creation. Smart products are uniquely identifiable and know both their current status and alternative routes to achieving their target state. Smart factories allow individual customer requirements to be met, meaning that even one-off items can be manufactured profitably. In smart industry, dynamic business and engineering processes enable last-minute changes to design and production, delivering the ability to respond flexibly to disruptions and failures on behalf of suppliers. This paper presents a case study of product development and design process renovation according to changeability paradigm in one-of-a-kind industrial environment. It demonstrates how integration of changeability with agile design strategies crucially contribute to improve the operations of a highly individualized product development business. Successful management of ‘never-ending’ engineering changes appears to be the most important aspect in this field. Contribution of the presented work is a generalized framework that demonstrates how companies in such specific environments can improve competitiveness through the utilization of changeability concepts. The included case study validated the proposed changeability model and offers valuable insights into how to implement this in practice

Prognozowanie uszkodzeń statków powietrznych dla celów obsługi konserwacyjnej na podstawie ich parametrów oraz danych z eksploatacji

Aircraft maintenance and repair organizations (MROs) have to be competitive and attractive for both existing and new customers. The aircraft ground time at MROs should be as short as possible and cost effective without reducing the quality of the work. Process optimization in MROs requires the continuous improvement of processes and the elimination of non-value-added activities during maintenance checks. There is, on the one hand, an obligation to follow the prescribed procedures and, on the other hand, pressure for time and cost reduction. The aircraft servicing process has been analysed according to a lean methodology. The optimization of logistics processes is recognized as the most promising method for reducing the maintenance service time and costs of spare parts. The probability of aircraft faults is calculated on the basis of historic data from previously completed service projects. Aircraft parameters, such as aircraft type, operator, aircraft age, flight hours, flight cycles, engine type and operation location, are taken into consideration in the fault forecasting. The fault probability is used as an indicator for defining a priority list for the accomplishment of jobs included in the aircraft maintenance service. The proposed methodology was validated and confirmed on four different projects.Organizacje zajmujące się konserwacją i naprawami statków powietrznych (MRO) muszą dbać o swoją konkurencyjność i atrakcyjność zarówno dla istniejących jak i nowych klientów. Czas trwania obsługi naziemnej w MRO powinien być jak najkrótszy a konserwacja powinna pociągać za sobą jak najmniejsze koszty, bez konieczności obniżania jakości pracy. Optymalizacja procesów przeprowadzanych w MRO wymaga ciągłego doskonalenia oraz eliminacji nieuzasadnionych czynności przeglądowych. Z jednej strony pracownicy MRO muszą przestrzegać określonych procedur, z drugiej zaś strony, ciąży na nich presja redukcji czasu i kosztów obsługi. Proces obsługi statku powietrznego analizowano zgodnie z metodologią szczupłego utrzymania ruchu. Optymalizację procesów logistycznych uznaje się za najbardziej obiecujący sposób redukcji czasu obsługi serwisowej oraz kosztów części zamiennych. Prawdopodobieństwo wystąpienia uszkodzeń statku powietrznego obliczano na podstawie danych historycznych z uprzednio przeprowadzonych prac obsługowych. W prognozowaniu uszkodzeń, uwzględniano takie parametry statku powietrznego, jak typ statku, jego operator, wiek, liczba godzin w powietrzu, liczba cykli lotów, typ silnika oraz miejsce stacjonowania. Prawdopodobieństwo wystąpienia uszkodzeń wykorzystano jako wskaźnik do hierarchizacji zadań obsługi technicznej statku powietrznego. Przydatność proponowanej metodologii zweryfikowano i potwierdzono na przykładzie czterech różnych projektów

Simulations of single charged particle motion in external magnetic and electric fields

In this paper we present a software package for computational modeling of single particle motion in static and dynamic external magnetic and electric fields and show applications of our package to general cases and particular cases of space, laboratory and fusion plasmas. In addition we further elaborate on the properties of a new concept named Larmor Center Trajectory that we introduced in our previous work [D. Erzen, J.P. Verboncoeur, J. Duhovnik, N. Jeli, Int. J. Multiphys. 1, 419 (2007)] as a generalization of the well known guiding center approximation, and show the ranges of applicability of this concept, especially in strongly inhomogeneous fields when adiabatic approximations break

Parametric numerical study of wind barrier shelter

This work is focused on a parametric numerical study of the barrier's bar inclination shelter effect in crosswind scenario. The parametric study combines mesh morphing and design of experiments in automated manner. Radial Basis Functions (RBF) method is used for mesh morphing and Ansys Workbench is used as an automation platform. Wind barrier consists of five bars where each bar angle is parameterized. Design points are defined using the design of experiments (DOE) technique to accurately represent the entire design space. Three-dimensional RANS numerical simulation wasutilized with commercial software Ansys Fluent 14.5. In addition to the numerical study, experimental measurement of the aerodynamic forces acting on a vehicle is performed in order to define the critical wind disturbance scenario. The wind barrier optimization method combines morphing, an advanced CFD solver, high performance computing, and process automaters. The goal is to present a parametric aerodynamic simulation methodology for the wind barrier shelter that integrates accuracy and an extended design space in an automated manner. In addition, goal driven optimization is conducted for the most influential parameters for the wind barrier shelter