The development of visionary integration concepts for the aircraft cabin is essential for the reduction of assembly times. In this paper the results of multiple joint research projects between the Hamburg University of Technology and Airbus Operations GmbH are presented. Based on an extensive as-is analysis, first concepts were set up applying prevalent design for assembly guidelines and resulting in the definition of top-level-requirements for the design and installation processes of aircraft cabins. Further research contained an analysis of the assembly processes of the cabin components in relation to their product structures. Concepts were generated using the PKT own developed modularization method. The method considers all relevant strategic perspectives of a company, one of which is the assembly. At the end a final assembly line optimized concept was defined. The concept mainly concentrates on the over-head storage bins, the so called Hatracks, the passenger service units (PSUs) and the lining panels. Since in the common way, all components are separately handled and mounted, their installation turned out to be the bottle neck of the assembly process. According to the developed measures, the degree of pre-assembly is raised. Thereby time intensive assembly tasks are parallelized and performed independently outside of the aircraft in earlier production phases. Due to the geometric dimensions and weight of the resulting cabin modules in this context, the utilization of a handling device becomes obligatory. The positive effects on the overall lead time reduction are evaluated. For all developed concept aspects technology demonstrators were constructed representing the overall installation process. Tests were performed in order to validate the estimated benefits.

In relation to how the complexity of modern assembly technology increases, requirements for precise, fast and relevant information specifically for the assemble process also increase. Automation allows the fast and precise measurement of various parameters, assessment of the values obtained and the implementation of the required measures in real time. Automation tools allow evaluation, parameter measurement, comparison and application via computer technology and various software resources. One of the aims of the VEGA 1/0206/09 Intelligent assembly cell project solution as per our institute is the creation of a means of forming assembly cells, their duly defined critical placements, verification of the assembly process as a dynamic system of consistency from a technological, handling and control sub-system point of view via means of 3D models in CATIA environment software. Authors of this paper are members and experts of project group (VEGA 1/0206/09) interested in robotics, manipulators and technological devices. Whereas mechanical production trends in the 21st century tend to focus more on resilience and flexibility, the authors of this article have taken into consideration the possibility of re-evaluating the above-mentioned data — which is an essential element in terms of raising flexibility, thus definitively contributing to increased competitiveness.

The paper proposes an SPC approach for automatic forecasting and monitoring of sensor signals in presence of cycle-based data (i.e. signal data which periodically repeat themselves) which can be observed in different machining processes, such as milling, forming or water-jet cutting. The monitoring system exploits an univariate time series analysis and monitoring technique based on an Exponentially Weighted Moving Average (EWMA) Control Chart for auto-correlated data coupled with the Holt-Winters exponential smoothing method, that is used to forecast future signal behaviour given its past history. The approach allows one to exploit only data coming from the on-going process and avoids the need for a-priori knowledge about signal pattern. Furthermore the control limits are automatically defined on-line by using only statistical moments of the currently monitored time-series. A case study is proposed to demonstrates the feasibility of monitoring the condition of the tool in milling processes by on-line analysis of cutting force signals.

A 3-D Dynamic explicit finite element model of metal shear spinning, is developed and solved for different nose radii and feed rates. Several amounts are applied to spinning roller nose radius and feed rate, then Axial, tangential and normal forces are calculated for each combination of parameters. The results are checked with a series of experimental tests in which the process parameters are varied according to the finite element model. The experimental values are shown to be in relatively good agreement with the outcomes of the finite element model.

Nowadays researchers focused their attention on design for manufacturing, design for assembly, design for cost or design for quality,....., design for X, etc., but they didn’t address design for manufacturing complexity. Design for complexity is a systemic approach that simultaneously considers design objectives (i.e., optimize complexity level)), variables and constraints. In this paper, a guideline is presented to show the design requirements. Based on this requirement, the complexity levels will be analyzed through four fundamental levels: design for manufacturing systems vision complexity, design for manufacturing systems structure, design for manufacturing systems operating complexity, and design for manufacturing systems evaluating complexity. The new measuring is suggested for determining the level of complexity. This complexity level is measured and optimized in terms of issues count based on the designer/analyst view. This will represent the degree of freedom of manufacturing system designer to identify which issue is more important than others. The ultimate goal of this paper is to provide the manufacturing system designer with such complexity information throughout the analysis process that an efficient design requirement produces in the first instance. This analysis shows that the design for manufacturing systems complexity should be optimized and taken into considerations when designing manufacturing systems.

In job shop and batch manufacturing, both process planning and production planning are responsible for the effective allocation and utilization of resources. Integration of process planning and production planning functions is necessary to achieve superior overall system performance. This paper proposes a model for the integration of process planning and production planning for cylindrical parts that can be implemented in the aggregated production planning (APP). The developed model considers simultaneously the technology-related constraints and shop floor constraint determined by the available time. In this approach, part machining time and cost are new variables for APP. In this model, the maximum depth of cut and feed for each feature are selected with regard to technology constrains, and the spindle speed is selected in aggregated production planning. The introduction of the overtime in the optimization process allows for the generation of improved planning according to several performance measures. The proposed optimization model is non-linear, unicriterion and multi-variable. A modern evolutionary algorithm, i.e., the particle swarm optimisation (PSO) algorithm, has been modified and applied to solve it effectively. A numerical example demonstrates the feasibility of applying the proposed model to APP problem.

Fine blanking is a near net shape process that is used for manufacturing of final product. In the fine blanking process, V-ring indentation is applied to create hydrostatic pressure and prevent premature fracture in an undesired direction. Furthermore, a small clearance between the punch and die is employed along with a counterforce punch that causes concentrated strain in the sheared band region. This process generally applies for sheet metal up to 6 mm. Application of this process for blanking of sheets thicker than 6 mm require some precautions for sound production. In the present research work, finite element analyses have been performed to investigate the effects of thickness variations on the shear band localization and shear surface quality in the fine blanking process. Simulations have been performed for two thicknesses of 6 and 8 mm. As blank materials, steel sheets of AISI 1045 have been used for numerical investigations.

Ultrasonic assisted grinding of hard materials is a novel technique which is used in order to decrease grinding forces and energy. Grinding force is in direct connection with wheel wear, grinding accuracy, grinding temperature and surface integrity. In this paper the effects of ultrasonic vibration in creep feed grinding process which is superimposed to the workpiece in feed direction has been represented. The mechanism of grain-workpiece interaction in the presence of ultrasonic vibration has been investigated both analytically and numerically. The cutting path of a single grain in ultrasonic assisted grinding has been derived using equations of motion and has been compared to the grain cutting path in ordinary grinding. Using displacement equations of a single grain in ultrasonic assisted grinding and drawing the motion path, it has been shown that there exist a multiple-impact between grain and workpiece. By implementing a 2-D finite element modeling, the mechanism of chip formation in ultrasonic assisted grinding and ordinary grinding has been compared. Furthermore the effects of longitudinal workpiece vibration on the grinding forces have been investigated. FE analysis of grain-workpiece interaction in case of using ultrasonic vibration has shown a reduction of about 40% of grinding forces compared to ordinary grinding.

Most of products may be manufactured by different processes. However, different process will yield slightly different products. In particular, similar geometric deviations will characterize parts produced by a specific process. It may then be stated that parts show a “manufacturing signature”, i.e. parts manufactured by the same manufacturing process will show similar, but not identical, local geometric deviations. Signature analysis has several applications, including process monitoring, tolerancing, inspection strategy planning for geometric tolerance verification, and failure identification. In past years, several signature models have been proposed for form error. However, models proposed so far are not adequate to describe the signature when orientation, location and run-out tolerances are of interest. These geometric tolerances involve a toleranced feature, plus at least one datum feature, so relation between these feature is relevant. In this work, a methodology for simultaneously modeling both toleranced and datum features will be proposed. The overall model will be constituted by a model for the toleranced feature, a model for the datum feature(s), and a model for the relation between toleranced and datum feature. A case study will be proposed involving orientation tolerances.

Reliability and Maintainability analyses are becoming an increasing competitive advantage in machine tool design. In particular, the goal of machine tools for Ultra High Precision Machining is to guarantee high specified performances and to maintain them over life cycle time. A structured reliability approach applied to such complex and innovative systems must be integrated in the early phase of the design. In this paper, the reliability characterization of an adjustable platform for micromilling operations is presented. The platform is intended to improve the surface finishing of the workpiece, through a broadband Active Vibration Control device based on high performance piezoelectric multilayer actuators. The study intends to assess the capability of the system to maintain along the life cycle the appropriate reduction of the chattering vibrations without any shape error. By dividing the system through a morphological-functional decomposition, the critical elements are detected and their reliability issues are extensively discussed. Their lifetimes are described through opportune distributions and models. The study is completed by the quantitative reliability prediction of the overall system. Finally, a sensitivity analysis is performed and reliability allocation implications are evaluated to determine the effect of every component on the system reliability characteristics and life cycle cost.

The article points out on new trends in the bending technology, elimination possibilities of defects originating in bending and it deals with designing of forming line for hooks production by bending technology. It was suggested change of previous manner of production and material of produced bearing hooks as well. In previous manner of production the unfinished surface of semi product in form of roll sheet was galvanic zinc coated, it was thereafter sheared on needed length with shearing machine, followed punching in fixture, roll bending by sequence bending by help of fixture. Suggested forming line is dedicated for processing of zinc coated roll strip in automation production cycle. Forming line enables the automation work flow which includes the uncoiling of strip, feeding and leveling of strip, punching of holes and shearing of strip, roll bending of pressed part, repeated feeding of strip by leveler. Forming line consists of two-sided uncoiler without drive, feeding leveler, block of forming tools, rotary roll head. It is possible to set production of hook according to required dimensions, forming line is able to produce several dimensions of hooks with several numbers of holes. The bearing hooks from suggested original zinc coated roll strip have higher surface quality without defects. Production innovation with feeding of automation in comparison to previous manner of production enables savings of four or five workers, increasing number of produced parts per hour, to achieve repeated pressed part precision,, less manual work, increasing operation safety, minimized noise level, reducing of production costs and production of time.

Predicting of the optimal machining conditions for experimental results and dimensional accuracy plays an important role in process planning. In addition, whenever there is a new unknown process, great importance has to be placed on the estimation of all operative conditions with rational and logical planning methodologies. The aim of this work is to obtain feasible conditions for Electron Beam (EB) technology, using a welding machine, which is then converted for additive manufacturing processes. At the beginning of the research there was a state of uncertainty about the influencing parameters and the use of EB for rapid manufacturing process; a multi-disciplinary and integrated methodology was then performed in order to carry out the work. The proposed methodology is composed of several techniques, including a method to support multi-decision making problems and a statistical approach.

This paper describes the material flow in shear zone by using a thermo mechanical model. The material is an isotropic, viscoplastic rigid material; its behavior is described by a J–C law. The contact length between the chip and the tool and the temperature distribution at the tool–chip interface which has an important effect on the tool wear. Using the thermo-mechanical model and the temperature friction law, the tangential forces, friction coefficient and contact length on the cutting element as a function of radius, for different feed rate and cutting speed, are obtained. The results of proposed model are compared with experimental results and good agreement is obtained.

This paper comprises a theoretical and experimental investigation dealing with the simulation of closed die forging of turbine blades. The theoretical part was achieved numerically via the well known finite element package (ANSYS). For simulation purposes, the material used for blade manufacture was high purity lead (99.99%), which was pressed between two dies with the required shape of the turbine blade. An optimum flash-less die shape was obtained with a parting line angle of 16°.

In this paper, an erosion-based model for abrasive waterjet (AWJ) turning process is presented. In the AWJ turning process a particular volume of material is removed by impacting of abrasive particles to the surface of the rotating cylindrical workpiece. This volume is estimated according to the modified Hashish erosion model; thus radius reduction at each revolution is calculated. The distinctively proposed model considers the continuous change in local impact angle due to change in workpiece diameter, axial traverse speed of the jet, the abrasive particle roundness and density. The accuracy of the proposed model is approved by experimental tests under various traverse speeds. The final diameters estimated by the new model are in good accordance with the experiments.

The feasibility of friction stir welding has been studied on medium density polyethylene blanks. The design and analysis of experiments have been performed with Taguchi method. The mechanical properties of the joints have been analyzed based on two parameters of rotation speed and tool tilt angle. The optimum welding condition has been determined. It has been demonstrated that rotation speed and tool tilt angle have key roles in the seam elongation and strength respectively. By applying this method of welding on polyethylene blanks 70% of the base material strength is achieved. SEM micrographs show microstructural changes of the weld zone which result in the reduction of the seam weld strength and elongation.

Selective laser melting (SLM), a powder metallurgical (PM) additive manufacturing (AM) technology, is able to produce fully functional parts directly from standard metal powders without using any intermediate binders or any additional post-processing steps. During the process, a laser beam selectively scans a powder bed according to the CAD data of the part to be produced and completely melts the powder particles together. Stacking and bonding two-dimensional powder layers in this way, allows production of fully dense parts with any geometrical complexity. The scanning of the powder bed by the laser beam can be achieved in several different ways, one of which is island or sectoral scanning. In this way, the area to be scanned is divided in small square areas (‘sectors’) which are scanned in a random order. This study is carried out to explore the influence of sectoral scanning on density, surface quality, mechanical properties and residual stresses formed during SLM. The experiments are carried out on a machine with an Nd:YAG laser source using AISI 316L stainless steel powder. As a result of this experimental study, it is concluded that sectoral scanning has some advantages such as lower residual stresses and better surface quality. However, the selection of parameters related to sectoral scanning is a critical task since it may cause aligned porosity at the edges between sectors or scanned tracks, which is very undesired in terms of mechanical properties.

The effect of double side technique in friction stir welding of polyethylene blanks has been studied. Experiments have been designed and analyzed with the full factorial method. The process parameters were rotation speed and tool tilt angle. The optimum welding condition has been determined. It has been demonstrated that double side FSW can improve the weld quality by decreasing the problem of stress concentration in the root of the joint. By applying this technique, 80% of the base material strength is achieved. Considerable reduction in elongation and toughness of the seam weld is due to crystallinity changes of the weld zone which are indicated in the DSC test results.

In this paper, a feed-forward back-propagation artificial neural network (BP-ANN) and analysis of variance (ANOVA) are applied to a hot metal extrusion process, establishing a black box model as well as analyzing the effects of relevant process parameters on required forging load, under different operating conditions. Some finite element simulation data on extruding ck-45 steel, adopted from a published research paper, were used to train the neural model employing Levenberg-Marquardt learning algorithm. Die angle (15°–75°), friction coefficient between billet-die material pair (0.4–0.8), punch velocity (168–203 mm/s), and billet temperature (1000°C–1260°C) were selected as the inputs, while the extrusion load (tone) was considered as the network’s output. Based on the results during modeling attempts, a 4-10-10-1 size neural network has been decided on as the appropriate architecture of the process model. Testing predictive accuracy of the developed model was also done using a new data set (8 data samples), which has not been used in the training phase. The comparative errors with respect to the desired FEM simulations are all in acceptable ranges (less than 12%) thereby the network’s generalization capabilities were confirmed. Having established the appropriate neural model, analysis of variance (ANOVA) technique was then applied to the original training data base to find and recognize the level of importance of each parameters and their possible dual interactions on the extrusion loading force within 95% of confidence interval (α = 0.05). Based on the obtained inferences, the best optimal combination of parametric settings which leads to the minimum required extruding load was then revealed and recommended. The optimally minimized extrusion force was then predicted by the trained network model. Neural network tool box (NNET) of the Matlab software and design of experiments module of Minitab software were employed as platforms to develop neural simulations and ANOVA technique, respectively. The overall results indicate the feasibility and effectiveness of the proposed approach in a real manufacturing environment and eliminate the need to carry out expensive as well as time consuming trial and error experimentations to reach to the optimum operating conditions.

Radial forging is an open die forging process used for reducing the diameters of shafts, tubes, stepped shafts and axels, and for creating internal profiles in tubes. In this study, the effect of the workpiece rotation (the circumferential feed) on the strain and residual stress distribution in the inner surface of the tube in the cold radial forging process is investigated using nonlinear three dimensional finite element modeling. To verify the model, the predicted radial forging load is compared with the published experimental data which shows a good agreement. It is shown that for achieving a more favorable residual stress distribution in the workpiece inner surface, the rotation angle associated with each stroke should be reduced. Furthermore, a total rotation angle of 90° seems to be sufficient for finalizing the strain and residual stress distribution in the workpiece inner surface and using additional rotation is just a waste of time and energy in this respect.