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Article

Raed El-Khalil

The paper presents a benchmarking analysis that investigates the efficiency gap in relation to spot welding robots in automotive body shops at foreign and domestic…

Abstract

Purpose

The paper presents a benchmarking analysis that investigates the efficiency gap in relation to spot welding robots in automotive body shops at foreign and domestic companies in North America. The main purpose of this paper is to determine body shop efficiency improvement opportunities for the domestic companies or the Big Three, therefore reducing the competitive gap and improving business performance.

Design/methodology/approach

The following paper is an extension of an earlier dissertation study conducted by EL-Khalil that focused on improving body shop overall efficiency. The Harbour Report was utilized to determine the best in class facilities that must be visited for benchmarking purposes. The data and information presented were obtained from the facilities visited through observations and interviews. The research utilized the corresponding facilities' labs in order to perform measurements and inspect product welding efficiency. The data obtained were a result of a two-year benchmarking study.

Findings

The inspection results of spot welds applied on the door flange do not justify the utilization of additional spot welding arm designs and/or robots for the domestic companies. The data presented provide a good opportunity for improving business performance at the body shop Big Three facilities. In order to reduce the current competitive gap, decrease cost, and improve utilization, the Big Three must adopt new strategies (i.e. communization of specific vehicles parts).

Research limitations/implications

The benchmarking study was limited to the aperture area. Researchers are encouraged to test the propositions further on different types of vehicles and different areas of the vehicle body.

Practical implications

Based on the actual findings, this paper presents a case that impacts the improvements of the body shop overall performance in relation to reducing the number of spot welding arm and robot designs at the automotive industry in North America.

Originality/value

The presented gap analysis on body shop spot welding efficiency for automotive companies in North America was not conducted previously. Therefore, the data can be utilized as a benchmark target to drive improvements at the domestic automotive body shops.

Details

Benchmarking: An International Journal, vol. 21 no. 3
Type: Research Article
ISSN: 1463-5771

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Article

Cengiz Deniz and Mustafa Cakir

The purpose of this study is to design a robotic inline measurement system for spot welding quality control to achieve process requirement without any operator during the…

Abstract

Purpose

The purpose of this study is to design a robotic inline measurement system for spot welding quality control to achieve process requirement without any operator during the manufacturing flow.

Design/methodology/approach

A robot manipulator carries a stereo-camera and an ultrasonic control probe. The center position of the spot welding point is determined by evaluating the results of the edge, gradient and symmetry approaches from the methods proposed up to now in the literature to increase reliability. The center position of the spot welding point, determined in the camera reference plane, is transferred to the robot base plane coordinates with the hand–eye calibration proposed in this manuscript. Weld quality is checked by the ultrasonic test probe located at the spot welding point.

Findings

While operators can only control welding quality, the developed station can also evaluate the quality based on geometric accuracy by processing the deviation of the position of the spot welding points. The proposed calibration method and the results of other methods in the literature are presented in this study by comparing it with synthetic data in simulations and in practical application.

Research limitations/implications

The quality control is performed not only for the spot welding made with robots but also for the manual welds as well. Because of vision configuration, and reliability issues, maximum allowable offset by the correct spot position is limited to 20 mm to position the manipulator for testing. The installation and pretest works of the developed robotic welding quality control station are completed in the Body Shop Area of Ford Otosan factory in Kocaeli/Turkey. The results of the robotic control process are monitored by the quality assurance team. Integration of automation with the production line will be completed and an inline measurement will be done.

Originality value

In this paper, a new hand–eye calibration method based on simple and closed-form analytical solutions has been presented. The objective function is defined as reducing the deviation in the point projection, rather than reducing the error in the calibration equation. To increase reliability, combining the results of existing centering algorithms for the detection of the strongly deformed spot welding spot center, although it is normally in a circular form, has been suggested.

Details

Industrial Robot: An International Journal, vol. 45 no. 1
Type: Research Article
ISSN: 0143-991X

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Article

Ing. E. Reichel

THE first electrical welding tests by the Arado firm were carried out at Warnemiinde in the year 1933 with a Rudolf welding machine. These tests were suggested by the…

Abstract

THE first electrical welding tests by the Arado firm were carried out at Warnemiinde in the year 1933 with a Rudolf welding machine. These tests were suggested by the welding of seaplane float frames by the Heinkcl firm, under the direction of Koppenhöfer, with machines of the same type. The results obtained with this welding machine were not very satisfactory since it was not possible, owing to the mechanical operation of the switch, to obtain uniform spotwelds. The machine had the further disadvantage that the commutator contacts became badly overheated and had to be frequently cleaned. In order to improve the spotwelding by this machine an agreement was reached with the I. G. Farbenindustrie in Bitterfeld in the autumn of 1933; as a result of which further tests were made with this same machine by the I. G. concern itself at Bitterfeld.

Details

Aircraft Engineering and Aerospace Technology, vol. 13 no. 2
Type: Research Article
ISSN: 0002-2667

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Article

Robert W. Messler

Weld‐bonding combines the physical force‐based process of welding with the chemical force‐based process of bonding or, more properly, adhesive bonding. When done properly…

Abstract

Weld‐bonding combines the physical force‐based process of welding with the chemical force‐based process of bonding or, more properly, adhesive bonding. When done properly, the claim is that a hybrid process results which offers the best of both processes; the high joint efficiency, resistance to diverse and complex loading, and temperature tolerance of welding; the load‐spreading, stress concentration‐softening, and structural damage tolerance of adhesive bonding. And, beyond these individual process attributes, there are claims, or at least predictions, of synergistic benefits in the form of improved energy absorption and fatigue life for demanding applications. However, it is difficult to find reliable data in the open literature to support these real or potential benefits. Furthermore, complications in performing the hybrid process in practice place an even greater premium on process control than normal. This paper explores the question, “Is it all worth it?” The paper delves into the theory underlying weld‐bonding, the facts concerning the process including pluses and pitfalls, and considers where the process could or should go from here.

Details

Industrial Robot: An International Journal, vol. 29 no. 2
Type: Research Article
ISSN: 0143-991X

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Article

Gordon H. Field and H. Sutton

The following items were examined:

Abstract

The following items were examined:

Details

Aircraft Engineering and Aerospace Technology, vol. 13 no. 1
Type: Research Article
ISSN: 0002-2667

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Article

Esraa Saleh Abdel-All, Matthew Charles Frank and Iris Violeta Rivero

This paper aims to present a friction stir molding (FSM) method for the rapid manufacturing of metal tooling. The method uses additive and subtractive techniques to…

Abstract

Purpose

This paper aims to present a friction stir molding (FSM) method for the rapid manufacturing of metal tooling. The method uses additive and subtractive techniques to sequentially friction stir bond and then mill slabs of metal. Mold tooling is grown in a bottom-up fashion, overcoming machining accessibility problems typically associated with deep cavity tooling.

Design/methodology/approach

To test the feasibility of FSM in building functional molds, a layer addition procedure that combines friction stir spot welding (FSSW) with an initial glue application and clamping for slabs of AA6061-T651 was investigated. Additionally, FSSW parameters and the mechanical behavior of test mold materials, including shear strength and hardness, were studied. Further, scanning electron microscopy (SEM)/elemental map analysis (EDS) of the spot weld zones was carried out to understand the effect of FSSW on the glue materials and to study potential mixing of glue with the plate materials in the welded zone.

Findings

The results indicate that FSM provides good layer stacking without gaps when slabs are pre-processed through sand blasting, moistening, uniform clamping and FSSW using a tapered pin tool. The tensile shear strength results revealed that the welded spots were able to withstand cutting forces during machining stages; however, FSSW was found to cause hardness reduction among spot zones because of over-aging. The SEM/EDS results showed that glue was not mixed with slab materials in spot zones. The proposed process was able to build a test tooling sample successfully using AA6061-T651 plates welded and machined on a three-axis computer numerical control (CNC) mill.

Originality/value

The proposed FSM process is a new process presented by the authors, developed for the rapid manufacturing of metal tooling. The method uses additive and subtractive techniques to sequentially friction stir bond and then mill slabs of metal. The use of FSSW process for materials addition is an original contribution that enables automatic process planning for this new process.

Details

Rapid Prototyping Journal, vol. 23 no. 1
Type: Research Article
ISSN: 1355-2546

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Article

P. Sathiya, N. Siva Shanmugam, T. Ramesh and R. Murugavel

Friction stir welding (FSW), a process that involves joining of metals without fusion of filler materials. It is used already in routine, as well as critical application…

Abstract

Friction stir welding (FSW), a process that involves joining of metals without fusion of filler materials. It is used already in routine, as well as critical application for the joining of structural components made of Aluminum and its alloys. Indeed it has been convincingly demonstrated that the process results in strong and ductile joints, some times in systems, which have proved difficult using conventional welding techniques. The process is most suitable for components that are flat & long (plates & sheets) but it can be adapted for pipes, hollow sections and positional welding. The welds are created by the combined action of frictional heating and mechanical deformation, due to a rotating tool. Recently, a new technology called friction stir spot welding (FSSW) has been developed that has a several advantages over the electric resistance welding process widely used in automotive industry in terms of weld quality and process efficiency. This welding technology involves a process similar to FSW, except that, instead of moving the tool along the weld seam, the tool only indents the parts, which are placed on top of each other. The conditions under which the deposition process in FSSW is successful are not fully understood. However, it is known that only under specific thermo‐mechanical conditions does a weld formation occur. The objective of the present work is to analyze the primary conditions under which the cavity behind the tool is filled. For this, a fully coupled thermo‐mechanical three‐dimensional FE model has been developed in ABAQUS/Explicit using the adaptive meshing scheme and the Johnson‐Cook material law. The contact forces are modeled by Coulomb’s law of friction, making the contact condition highly solution dependent. Temperature graph in the radial direction as well as stress, strain plots are presented.

Details

Multidiscipline Modeling in Materials and Structures, vol. 4 no. 1
Type: Research Article
ISSN: 1573-6105

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Article

Jernej Černelič, Robert Brezovnik, Primož Sukič and Martin Petrun

This paper aims to present two hysteresis-control algorithms designed for medium-frequency, direct-current, resistance-spot-welding (MFDC RSW) systems. The first proposed…

Abstract

Purpose

This paper aims to present two hysteresis-control algorithms designed for medium-frequency, direct-current, resistance-spot-welding (MFDC RSW) systems. The first proposed control algorithm (MSCHC) eliminates the short switching cycles that can occur when using the existing hysteresis-control algorithms. This control minimises the number of switching cycles that are needed to generate the selected welding current. The welding-current ripple can be high when using this control algorithm. Therefore, a second algorithm (HCRR) is presented that reduces the welding-current ripple by half.

Design/methodology/approach

The proposed hysteresis controllers consist of the transformer’s magnetic-flux-density hysteresis regulator and a welding-current hysteresis regulator. Therefore, the welding current must be measured and the saturation of the iron core must be detected. The proposed hysteresis controller supplies the inverter with the signals needed to generate the supply voltage for the RSW transformer, which then generates the selected welding current.

Findings

The proposed MSCHC algorithm produces the smallest possible number of switching cycles needed to generate the selected welding current. The high welding-current ripple can be reduced if the number of switching cycles is increased. The observed number of switching cycles and the welding-current ripple change if the welding resistance and/or inductance change.

Originality/value

The number of switching cycles can be minimised when using the first proposed control algorithm (MSCHC), and so the switching power losses can be minimised. If the welding-current ripple produced by the first control algorithm is unacceptable, the second control algorithm (HCRR) can reduce it by increasing the number of switching cycles.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 36 no. 3
Type: Research Article
ISSN: 0332-1649

Keywords

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Article

Robert W. Messler, Scot Bohnenstiehl, John Levene, Erika Johnson and Luo Chen

Being inherently a non‐pressure fusion process, laser‐beam welding (LBW) has been shown to have difficulty compared to resistance spot welding for weld‐bonding Al alloy…

Abstract

Being inherently a non‐pressure fusion process, laser‐beam welding (LBW) has been shown to have difficulty compared to resistance spot welding for weld‐bonding Al alloy structures, despite the many structural and manufacturing productivity advantages. Study of laser‐beam weld‐bonding of Al‐alloy structure for automobile assembly has led to a technique that appears to have both technical feasibility and production utility. The use of LBW through a hole in a pressure‐applying probe has proven to allow the production of contamination‐free spot welds through pre‐applied pre‐cured structural adhesive. The general approach, along with some details to still be overcome, is presented for both information and solution.

Details

Assembly Automation, vol. 24 no. 4
Type: Research Article
ISSN: 0144-5154

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Article

S. Müller

In this report, accounts will be presented on the experience obtained from approximately 100 practical applications of industrial robots. The industrial robots used derive…

Abstract

In this report, accounts will be presented on the experience obtained from approximately 100 practical applications of industrial robots. The industrial robots used derive partly from the company's own production as well as from other domestic and foreign robot manufacturers.

Details

Industrial Robot: An International Journal, vol. 5 no. 2
Type: Research Article
ISSN: 0143-991X

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