In 2006, according to International Federation of Robotics (IFR) the number of industrial robots supplied in India almost doubled from 2005, to around 850 robots, 56 per cent of which were industrial robots for welding applications. When compared to the developed markets, this represents a small investment, but given the dramatic escalation within such a short period this only reinforces the potential of this growing market. Robots are used to handle the parts that need to be welded and perform the weld. Robots are generally used when you want to do welding of high quality, greater consistency and high productivity. The chief components of robot welding station are robot, welding power source, sensors, software for integration and programming, fixture and manipulators and safety system.
The selection criteria of fixtures, manipulators and safety are many. High accuracy is required for tracking fixture to insure consistency in input component. Welding fixtures eliminate distortion while welding. Manipulator–single, double or multiple axis try to carry out maximum possible welding in down-hand position.Robot positioning helps increase the work envelope of the robot.Operator safety while loading and unloadingOperator safety while welding (accidental exposure)System safety from external damageFume extraction system
Process and status of robotic welding
Robotic welding in India can be relatively expensive, difficult for some industries to bring in more investment and upgrade their level of automation. To employ robots to weld in place of human beings could be expensive in short run but would definitely yield profit for the organisation in the long term. Some of the benefits to use robotic welding are better and consistent quality, less time consumption, minimal or no human interference and round the clock functioning The robot in general have two parts: the robot and the controller which is also called as the ‘brain’ of the operation and together they actually perform the application.
Integration of sensors in a welding system enhances the quality of the welds produced. Variations in three welding process parameters - weld bead width, penetration depth, and torch position -were monitored using an infrared sensor. Intentionally induced variations in each of these welding parameters were found to affect uniquely the plate surface temperature distributions measured by the infrared sensor. The effects of weld bead width and torch position perturbations on the temperature distribution were separated so as to identify and control these two weld process parameters simultaneously. Robotic welding systems which cannot adapt in real time to changes in the joint geometry along the weld seam and to the seam position itself have only limited success in many welding applications, due to heat distortion of the weld to an overall shift in the weld seam caused by fixturing errors. A solution to this problem requires the application of some form of adaptive joint geometry sensing system for guidance of the welding torch. Research is described that addresses the general aluminium welding problem by integrating a laser-based part-profiling sensor with a welding robot. An adaptive system has been developed for this kind of process. A PC-compatible microcomputer serves as the system supervisor, commands the motion of the robot directs and processes the sensor scans, and establishes the required weld parameters. In the aircraft industry, joining technologies get more and more importance, because they represent a high expense factor when components have to be assembled. Riveting is the current state-of-the-art joining method due to its very safe and robust application. However, it is a time- and weight-consuming technology as it requires overlapping sections that have to be drilled in order to place the rivets in up to three rows. Thus, the aircraft industry currently evaluates several welding technologies to reduce production and maintenance cost as well as the weight of aircrafts for longer range and higher efficiency. Friction stir welding (FSW) represents an innovative joining technology that allows the welding of all aluminum alloys of interest with excellent seam properties and with thicknesses from 0.3 to 50 mm and more. The substitution of automated riveting by FSW can lead to a significant reduction of process time and a cost reduction of up to 20 per cent. In contrast to conventional welding techniques FSW requires high process forces, which act on the joining partners and the actuator. Thus, usually special and individual machines have been designed and built, leading to significant investment costs and the risk of missing reliability after delivery caused by the low production rate and the lack of experience with the individual machine type.
Kuka playing major role
Kuka Robotics is one of the worldwide leading suppliers of industrial robot technologies. It has an installed base of more than 600 robots in India and out of which majority are used for different welding operations. Robotic welding has emerged as one of the prime applications as of today in the Indian market because of the fact that the robots can work faster, efficiently, repeatedly and more importantly in harsh conditions as well to produce a good and consistent product. Moreover, the Indian industries have also realised that the use of human beings particularly for the welding applications is inhuman in nature and also not productive.
The company has supplied number of robotic welding systems to the Indian industry be it an OEM or heavy metal industries for different applications like spot welding, arc welding, etc. Some of the key customers are TATA Motors, Volkswagen India, and WRI Trichy, etc.
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