Combination of friction drilling and form tapping processes on dissimilar materials for making nutless joints

Abstract

In this article, a new method for the rapid and economical production of 'nutless' bolted joins is presented, using a combination of two hole-making techniques, namely, form drilling and form tapping. The combined method achieves a quick way for the production of threaded holes on couples of dissimilar metal alloys, as it is the case of steels and aluminium alloys. After the simultaneous form drilling on the aluminium-steel pairs and followed by form tapping, a fastener can be introduced and screwed for achieving a tight bolted joint, without any necessity of nut. However, form drilling and threading are performed consecutively in the same machine tool, reducing the whole process time. The process parameters were studied for reducing the gap between surfaces and producing a good cup for making the posterior threading. Then, mechanical testing of several test pieces resulted in a similar behaviour than traditional bolted joints. Finally, corrosion tests were performed for a better understanding of the joint manufactured. In this way, savings in time and money are derived from the application of the approach. Target markets for the new approach are the light boilermaking industry in order to eliminate either welding beads or classical bolted joints using nuts.

Opportunities for Industry 4.0 to Support Remanufacturing

“…In addition, energy-efficient remanufacturing processes could also be achieved through collecting real-time energy consumption data and implementing an energy management system accordingly. Further innovative technologies, such as additive manufacturing, 3D scanning, automated guided vehicles, inspection drones, hybrid manufacturing/process [14,15], and augmented reality tools, will continuously drive down the cost of remanufacturing operations while also delivering substantial improvements in the quality of the repaired product. Taking aerospace remanufacturing as an illustration, worn airfoils can sometimes be repaired using the laser metal deposition technique, an additive process where metal powder is melted by a computer numerical control (CNC) laser on a robot arm to form a direct fusion-bonded deposit on the blades.…”

Feature Size Effect on Formability of Multilayer Metal Composite Sheets under Microscale Laser Flexible Forming

“…In the experiments, the materials were cut to specimens of 10 mm × 20 mm. As Urbikain et al [34] presented in their work, galvanic corrosion is generated when the metal composite sheets contact electrolyte, but nothing occurs when they are worked in a dry atmosphere. In this research, the combination and forming procedure of the composite materials were conducted in a dry environment, so the galvanic effects were negligible.…”

Investigation of the process of thread extrusion using the ultrasound

“…In article [18], authors devised a new method for rapid and economical manufacturing of bolt joints, exploiting a combination of the processes of formation and shapeforming. The developed method makes it possible to swiftly make the threading holes in the joint of metallic alloys, such as steel and aluminum alloys.…”