Active Thermography for Quality Assurance of joints in automobile manufacturing

Šrajbr, Christian; Tanasie, Gheorghe; Dilger, Klaus; Böhm, Stefan

doi:10.1007/bf03321312

Cited by 11 publications

(3 citation statements)

References 2 publications

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“…To increase the welding speed and weld quality, the energy director is usually recommended to direct and focus the ultrasonic weld energy to a smaller contact area (Refs. 15,16). However, due to the difficulty in locating the energy directors in the lapped workpieces with a robot, ultrasonic welding of the workpieces without energy directors was assessed.…”

Section: Introductionmentioning

confidence: 99%

“…To inspect the weld quality, various methods (e.g., destructive such as the chisel test) or nondestructive testing (e.g., ultrasonic technique (Ref. 15)) have been applied to assess the weld quality. Although the chisel test has some advantages, such as its relative ease of use, low cost, and usability on the shop floor, the tests are qualitative and subjective.…”

Section: Introductionmentioning

confidence: 99%

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Online Inspection of Weld Quality in Ultrasonic Welding of Carbon Fiber/Polyamide 66 without Energy Directors

2018

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In this study, a method of inspecting the weld quality (i.e., static strength) in ultrasonic welding of 4-mm-(0.16-in.-) thick carbon fiber/polyamide 66 (C f / PA66) composite with 30 wt-% fiber without energy directors was investigated. The transient horn displacements and dissipated powers were recorded to correlate with the weld quality. It was found that the transient horn displacement of the joint during the ultrasonic welding process displayed four distinct stages: C f /PA66 expansion phase (stage I), unsteady melting phase (stage II), equilibrium phase of the materials melting and melt outflow (stage III), and the material cooling down phase (stage IV). The weld quality was closely related to the horn displacement and duration in stage III of the ultrasonic welding process. Target horn displacement and duration in stage III were determined by desired static strengths of the welded 4-mm-(0.16-in.-) thick C f /PA66 composite. The horn displacements and durations of the welds in stage III were recorded and the measurements were compared with the target values during welding. A quality weld was determined by judging whether the measured values of horn displacement and duration in stage III were within the tolerance range of the target values. Consequently, an online inspection method to evaluate the weld quality was developed based on target horn displacement and duration.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Online Inspection of Weld Quality in Ultrasonic Welding of Carbon Fiber/Polyamide 66 without Energy Directors

2018

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“…[Color figure can be viewed at wileyonlinelibrary.com] transient of heat diffusion inside the material, induced by pulsed inductive heating, is depicted by the transient temperature profiles on the surface of the material. [6,7] The resulting heat flux through the sample is disturbed by areas with thermally insulating properties, for example, voids. The evaluation is carried out by means of a frequency-dependent phase diagram which is produced by a pixel-wise executed discrete Fourier transformation (DFT) of the recording sequences.…”

Section: Eddy Current Pulsed Phase Thermographymentioning

confidence: 99%

Non‐destructive indication of delaminations under thick organic coatings using active IR‐thermography

Schmitt

Lenzmann

Schneider

et al. 2017

Materials & Corrosion

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The integrity of organic coatings can be impaired by disbondment due to permeation of water vapor in temperature and osmotic gradients between the outer environment and the base metal surface, due to cathodic protection at locally destructed coatings or simply by poor adhesion. For thin coatings the degree of delamination is easily determined by the intensity of blisters which generally arise already after short exposure periods. However, thick coatings with thicknesses above 2 mm take much longer for blistering and larger delaminations, and develop visible blisters only in an advanced state. The degree of delamination is generally detected by mechanical destruction of the coating. The present paper presents a new non‐destructive test (NDT) method for detecting delaminations and blisters in or under organic coatings with thicknesses up to 6 mm already at stages when the defects are not yet visible. This is accomplished by active IR thermographic methods with induction and/or optically excited lock‐in thermography. The potential of the method is exemplified in this paper for blister determination formed under ΔT‐test conditions and for non‐destructive quantification of the length of delamination after standardized cathodic disbondment laboratory tests.

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Decomposition of ultrasonically welded carbon fiber/polyamide 66 and its effect on weld quality

et al. 2017

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Active Thermography for Quality Assurance of joints in automobile manufacturing

Cited by 11 publications

References 2 publications

Online Inspection of Weld Quality in Ultrasonic Welding of Carbon Fiber/Polyamide 66 without Energy Directors

Online Inspection of Weld Quality in Ultrasonic Welding of Carbon Fiber/Polyamide 66 without Energy Directors

Non‐destructive indication of delaminations under thick organic coatings using active IR‐thermography

Decomposition of ultrasonically welded carbon fiber/polyamide 66 and its effect on weld quality

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