Door Assembly Research Articles

Rapid Response Diagnosis of Multi-stage Assembly Process with Compliant non-ideal Parts using Self-evolving Measurement System

This paper introduces the novel concept of self-evolving measurement system with the aim of rapidly identifying and localising defect patterns in multi-stage assembly systems with compliant non-ideal parts. This allows to enhance the level of diagnosability which cannot be achieved using fixed and static pre-determined measurement systems. The proposed methodology helps to identify and select new measurement points to increase the likelihood of isolating root causes of defects. This happens by automatically classifying defect patterns and associating them to critical key control characteristics. The methodology integrates supervised machine learning tools with first principle engineering simulations. It is based on the principle of pattern similarity, taking into account data generated by the self-evolving measurement system. The methodology is demonstrated and validated using the results of an automotive door assembly system.

ドア組付作業支援パートナロボットD-PaDY

ドア組付作業支援パートナロボットD-PaDY

On the Evolvement of Limiting Positions as a Result of the Interaction of Tolerances and Compliant Systems

When talking about a large batch production of a certain mechanical product it generally comes along with specific requirements in terms of dimensional management to guarantee a consistently high product quality ensuring that customer requirements are met. Therefore, this contribution is about the effect that the elasticity of the observed assembly has on the formation of the limiting positions of the considered key product characteristics arising from tolerance analysis. On the example of an automotive door assembly a developed approach based on existing methodologies is explained in detail containing CAT and FEM simulations.

Influence of Tolerancing Methods and Aspects of Perceived Quality on Side Closures of Luxury Cars

For a customer, one of the most appealing areas aesthetically in a passenger vehicle is the frontal and side closure of the vehicle. Especially the way the precision tolerances are achieved in cars. Hence the precision tolerance gives the aesthetic appeal for gap and flushness. It plays a vital role in the saleability of the vehicle. There are three priority areas of a passenger car which influences the prospective customer. The priority 1 includes the front-rear door and headlamp-hood interfaces. The priority 2 includes the A pillar to roof and front wind shield interfaces. The priority 3 includes door to rocker moulding and hood to grille interfaces. Here the importance is given to the customer's view perspective. For example, in a side closures (car door assembly), the front-rear door interfaces which lies between the B pillar and the rear door region is given importance since it has the high priority as seen by the customer (Priority1).Whereas the door to rocker moulding interfaces which lies on the bottom surface of the car is given low priority (Priority 3). Based on these priorities the gap and flushness effectively achieved through the tolerance management. This research paper aims to investigate the influences of tolerancing methods and aspects of perceived quality on the side closures with respect to computer aided tolerancing, hinge positioning, Striker and hinge adjustments and hemming. These influences in turn gives the side closures superior aesthetic appeal, loyal customers and winning edge in the saleability of luxury cars in the global market.

Topology Optimization of an Automotive Tailor-Welded Blank Door

Bidirectional evolutionary structural optimization (BESO) method has been successfully applied for a wide range of topology optimization problems. In this paper, the BESO method is further extended to the optimal design of an automotive tailor-welded blank (TWB) door with multiple thicknesses. Different from the traditional topology optimization for solid-void designs, topology optimization of the TWB door needs to identify the weld lines which joint sheets with different thicknesses. The finite element (FE) model of the automotive door assembly is established and verified by a series of stiffness experiments. Then, the proposed optimization procedure is applied to the optimization of the automotive TWB indoor panel for the optimal thickness layout and weld lines locations. Numerical results give guidelines for the lightweight design of TWB components to some extent.

An Approximate Analytical Method to Evaluate the Performance of Multi-product Assembly Manufacturing Systems

The automotive industry is characterized by the continuous and frequent adoption of cutting edge technologies in manufacturing. The introduction of new technology often entails a system level investigation to determine whether it meets expected production requirements. Many system design alternatives are usually considered at this stage, and a fast performance evaluation tool is desired to quickly obtain the optimum system configuration. In this paper, we introduce an analytical tool that was developed for this specific purpose.The investigated manufacturing system is a multi-product, automated, assembly production line composed of unreliable machines decoupled by finite buffers. Each product is an assembly of two components that are produced in sub-assembly lines before being assembled at an assembly machine. The performance of this system needs to be evaluated for different configurations that arise mainly due to the integration of a remote laser welding technology. This new technology promises, among other advantages, a much faster assembly than existing technologies. This makes it feasible to share assembly among many products with different possible production policies. The processing machines including the assembly machine are liable to fail randomly in operation thereby necessitating an evaluation method capable of accounting for stochastic behavior.To solve this problem, we develop a decomposition-based approximate analytical method. We use the continuous material flow approximation, which allows to model machines having deterministic but inhomogeneous processing times as in the investigated real system. We also account for multiple machine failure modes and introduce new techniques to incorporate the assembly of multiple products with different policies of switching between products. Comparison with simulation results shows the good accuracy of the model in estimating system throughput and work-in-progress. The model has been successfully utilized to evaluate the performance of an automotive door assembly manufacturing system and the main results of this case study are reported.

Multi-objective Early-stage Design of Automotive Hybrid Assembly Lines

Hybrid assembly lines include multiple assembly technologies, such as RSW (Resistance Spot Welding) and RLW (Remote Laser Welding). The early-stage design of these automotive assembly lines is a critical, multi-objective task. The design process is typically carried out in industry by continuous iterations between the process design department and the simulation and systems engineering department. This results in a time consuming and cost-inefficient procedure. This paper presents a novel approach and a software platform to support the early stage design of hybrid assembly lines. It relies on the integration of a Process Concept Generator and a System Configuration Module, which is based on analytical performance evaluation models, thus drastically reducing the overall time and cost of the design procedure. The effectiveness of the proposed approach in industrial settings is shown by a real door assembly line in the automotive industry, analyzed within the EU FP7 funded project RLW Navigator.

Rapid deployment of remote laser welding processes in automotive assembly systems

Remote laser welding (RLW) has received increased attention in the recent years due to its benefits in terms of processing speed, lower investment, cost per stitch, and process flexibility. However, its potential in automotive assembly remains under exploited, mainly due to challenges involving system, process and fixture design, and part variation challenges. In this paper, an integrated rapid deployment framework for RLW process is proposed to improve ‘right-first-time’ implementation of RLW in assembly systems. It enables closed-loop optimization of system layout, task assignment, fixture layout, process parameters, robot path planning and programming as an interlinked iterative approach. The results are demonstrated in an automotive door assembly pilot study.

Hierarchical synthesis of multi-level design parameters in assembly system

This paper proposes a novel methodology to optimize heterogeneous design tasks with competing parameters. It is based on the principle of design parameter sensitivity, taking into account the notion of robustness at an early phase of process design. The aim is to improve the quality of the assembly system in order to make it less sensitive to variations/changes of design parameters. The methodology is based on the development of: (i) analytical design task function; (ii) inner- and outer-sensitivity; (iii) design parameter sensitivity; and (iv) decision making module. The methodology is demonstrated using results involving an automotive door assembly.

Fixture Design Optimisation Considering Production Batch of Compliant Non-Ideal Sheet Metal Parts

Fixtures control the position and orientation of parts in an assembly process and thus significantly contribute to process capability that determines production yield and product quality. As a result, a number of approaches were developed to optimise a single- and multi-fixture assembly system with rigid (3-2-1 fixture layout) to deformable parts (N-2-1 fixture layout). These approaches aim at fixture layout optimisation of single ideal parts (as define by CAD model). However, as production yield and product quality are determined based on a production volume of real (non-ideal) parts. Thus, major challenges involving the design of a fixture layout for assembly of sheet metal parts can be enumerated into three categories: (1) non-ideal part consideration to emulate real part; (2) ‘N-2-1’ locating scheme due to compliant nature of sheet metal parts; and, (3) batch of non-ideal parts to consider the production process error at design stage.This paper presents a new approach to improve the probability of joining feasibility index by determining an N-2-1 fixture layout optimised for a production batch of non-ideal sheet metal parts. The proposed methodology is based on: (i) generation of composite parts to model shape variation within given production batch; (ii) selection of composite assembly representing production batch; (iii) parameterisation of fixture locators; and (iv) calculation of analytical surrogate model linking composite assembly model and fixture locators to probability of joining feasibility index. The analytical surrogate model is, then, utilised to maximise the probability of joining feasibility index starting from initial fixture locator layout. An industrial case study involving assembly process of remote laser welded door assembly illustrates and validates the proposed methodology.

A software platform for the multi-objective early-stage design of automotive assembly lines

The early-stage design of automotive assembly lines is a critical, multi-objective task. This design process is typically carried out in industry by continuous interactions between the process design and the simulation and systems engineering departments, resulting in a time consuming and cost-ineffective procedure. This paper presents a novel approach and a software platform to support the early stage design of hybrid assembly lines including multiple assembly technologies, such as Resistance Spot Welding (RSW) and Remote Laser Welding (RLW). This platform relies on the integration of an Assembly Layout and Process Estimator and a Configuration Optimization, based on analytical performance evaluation models. With the platform, it is possible to reduce drastically the overall cost and time required by the design procedure. A real door assembly line in the automotive industry shows the effectiveness of the proposed approach in industrial settings, analyzed within the EU FP7 funded project RLW Navigator

Random field modeling with insufficient field data for probability analysis and design

Often engineered systems entail randomness as a function of spatial (or temporal) variables. The random field can be found in the form of geometry, material property, and/or loading in engineering products and processes. In some applications, consideration of the random field is a key to accurately predict variability in system performances. However, existing methods for random field modeling are limited for practical use because they require sufficient field data. This paper thus proposes a new random field modeling method using a Bayesian Copula that facilitates the random field modeling with insufficient field data and applies this method for engineering probability analysis and robust design optimization. The proposed method is composed of three key ideas: (i) determining the marginal distribution of random field realizations at each measurement location, (ii) determining optimal Copulas to model statistical dependence of the field realizations at different measurement locations, and (iii) modeling a joint probability density function of the random field. A mathematical problem was first employed for the purpose of demonstrating the accuracy of the random field modeling with insufficient field data. The second case study deals with the assembly process of a two-door refrigerator that challenges predicting the door assembly tolerance and minimizing the tolerance by designing the random field and parameter variables in the assembly process with insufficient random field data. It is concluded that the proposed random field modeling can be used to successfully conduct the probability analysis and robust design optimization with insufficient random field data.

Research on Structural Optimal Design of a Car Plastic Back Door

This paper takes a passenger car back door as an example with the use of glass fiber reinforced PET to replace steel. The sampling space is sampled by the optimal Latin hypercube experimental method and according to the experimental data, it establishes the polynomial response surface (RSM) model. Select NSGA −∏ genetic algorithm to optimize the back door assembly thickness of multi-objection with the purpose of lightweight.

Transfer Function of Assembly Process with Compliant Non-ideal Parts

Efficient modelling and analysis of geometric variation is crucial for quality control of assembly processes with compliant parts used for example in automotive and aerospace industries. Since most current computer-aided design (CAD) and Variation Simulation Analysis (VSA) systems are based on ideally sized, ideally located rigid or compliant geometry, they are unable to accurately model or predict the effects of variations in parts, fixturing and joining. This results in product failures due to un-modelled interactions between Key Product Characteristics (KPCs) of parts/assemblies and Key Control Characteristics (KCCs) of assembly process. Therefore, it is important to develop a generic variation simulation approach for assembly processes with complaint parts which will take into consideration non-ideal part geometries as caused by fabrication processes.This paper develops the Assembly Transfer Function (ATF) approach to model and simulate assembly process with compliant non-ideal parts. The proposed ATF is developed as an integration of three critical response functions of assembly process: (i) modelling non-ideal parts and its response to part fabrication errors; (ii) modelling n-2-1 fixture and its response to non-ideal parts; and (iii) modelling part-to-part joining process and its response to n-2-1 fixture. The ATF is developed in three steps: (i) use of the aforementioned three individual response functions; (ii) sampling of individual response functions; and, (iii) integration of the three response functions into an overall assembly process transfer function with capabilities to directly map input KCCs to output KPCs and ultimately to key performance indicators for assembly processes with compliant non-ideal parts. The developed ATF is demonstrated by using an industrial case study of automotive door assembly with remote fiber laser welding joining process.

Human Factors Analysis of Virtual Assembly Car Door Based on the CATIA Virtual Environment

Based on CATIA software to create a virtual car assembly line, the virtual assembly technology briefly analyzed state development, pointed out the role of actual production used virtual assembly technology, combined an instance of the car door assembly works with lots of human factors analysis. Through assembly modeling, simulation, analysis and optimization, aimed to reduce labor intensity, decline action fatigues, acquire the best assembly path to improve the productivity and quality of assembly of the car assembly quality.

Total Energy Estimation Model for Remote Laser Welding Process

The issues in the energy-efficiency process have much interest in the automotive industry. The energy criteria are also important in machine selection as well as productivity when new equipment is introduced on a shop floor. Remote laser welding having benefits for productivity and for energy saving is receiving attention in automotive assembly lines, but introducing this innovative equipment is a significant decision because of high initial cost in spite of the advantages. This paper specifically provides an estimation model of the total energy which is consumed by a robot arm, laser source, and cooling system. It considers the energy determined by robot operation parameters, arm path, and welding parts instead of the one for the laser melting phenomenon. Operational parameters and kinematic models are adjusted by comparison with experimental data of a car door assembly process. By developing an estimation model the major factors and devices determining consumed energy were found. This model will contribute to finding the effective process which will be improved by applying remote laser welding robot to legacy welding processes.

Assembly Sequence Planning for Aircraft Component Based on Improved Clashes Matrix

The aircraft parts contain the information of a great number of curves and surfaces, which makes it a big challenge for the aircraft components’ Assembly Sequence Planning (ASP) processes. The traditional interference matrix has limitation of expressing the assembly direction and can easily lead to the failure of ASP optimization. Hence, an improved interference matrix is provided in this paper to deal with the aircraft ASP problem based on the Genetic Algorithms (GA). With the mainly consideration of assembly time according to the assembly sequence evaluation criteria, the objective function is established and evaluated. This paper presents an application of the method in the aircraft cabin door assembly process supported by an 863 program. Meanwhile, the verification of the approach is shown in the practical example on MATLAB platform.

Analysis and optimisation of a network of closed-loop automobile assembly line using simulation

The work presented in this paper describes the development of a decision support system based on a discrete event simulation model. The model is aimed at a specific class of production lines with a four closed-loop network configuration of automobile assembly and preassembly lines connected by conveyors. The total number of pallets on the conveyors (which also act as intermediate buffers) remains constant, except for the fourth loop, which depends on the four-door car ratio implemented between the door disassembly and assembly stations of the car body. Some governing equations of the four closed loops are incompatible with the capacities of several intermediate buffers for certain values of the four-door car ratio. The simulation model can be used to assess the impact of variation in the length of the conveyors (hence, the size of the intermediate buffers) on the performance of the line. In addition, this paper also presents a proposal for the alteration of the length of the intermediate buffers that can maximise the performance of the production line and improve the availability of the manufacturing system for any value of four-door car ratio.

Automotive airbag inflator analysis using the measured properties of modern propellants

An airbag is composed of a housing assembly, door assembly, cushion assembly, and an inflator. The inflator is an essential part that generates gas for the airbag. When an airbag is activated, it effectively absorbs the crash energy of the passenger by inflating a cushion. In the present study, tank tests were performed with newly synthesized propellants with various compositions, and the results are compared with the numerical results. In the simulation of the inflator, a zonal model has been adopted which consisted of four zones of flow regions: combustion chamber, filter, gas plenum, and discharge tank. Each zone was described by the conservation equations with specified constitutive relations for gas. The pressure and temperature of each zone of the inflator were calculated and analyzed, and the results were compared with the tank test data. The similarity of the pressure curve and closed bomb calculation show that the modeled results are well correlated with the experimental data.

Design, Manufacturing, and Testing of an Improved Watertight Door for Surface Ships

Designed in the 1950s to be watertight during flooding and airtight under normal operating conditions, the Navy standard watertight door for surface ships is inexpensive to manufacture but expensive to properly install and maintain. Furthermore, by today's requirements, it is too heavy. The need for a lightweight, affordable, low maintenance watertight door led to a collaborative project involving the Applied Research Laboratory at Penn State University, Naval Surface Warfare Center, Carderock Division, Ship Systems Engineering Station, and Northrop Grumman Corporation Newport News to design, fabricate, and test an improved watertight door for surface ships. The design and manufacturing of this door is entirely new and based on advances in laser cutting and welding technology. Its novel design reduces the number of dogs (latches) and linkages of the Navy standard watertight door, decreasing the weight of the complete door assembly from 290 to 213 lbs. The door is fabricated from corrosion resistant stainless steel, and its opening and closing forces are extremely low, reducing the potential for mechanical and gasket wear. Pending successful completion of certification testing and with technical warrant holder approval, the new door will offer an attractive choice for insertion by Acquisition Program Managers and Fleet Maintenance Managers.