Dr Vijeesh V.,
Department of Mechanical Engineering
Dr Shashikantha Karinka,
Department of Mechanical Engineering
Dr. Niranjan N. Chiplunkar,
The demand for skilled welders is ever increasing in India as the country is moving towards sustainable income from manufacturing. But, non-availability of standard methods to impart welding skill to the youth create a huge gap in the required man force. Unlike other shop floor jobs, welder training programs are expensive, and it is hardly run by any institutes. In this context, virtual welding machines could be effectively used for welder training programs without any material consumption or health hazardousness and literally with zero material cost. This article is aimed at introducing the virtual welding machine to the shop floor workmen emphasizing its key features and benefits.
Arc welding is a widely accepted joining process in the workshop floor, especially for steels and its alloys. Depending on the required manufacturing rate, quality and automation, the arc welding equipment are augmented to match the requirements. From common stick welding (shielded metal arc welding) to advanced Metal Inert Gas (MIG) and Tungsten Inert gas (TIG) welding’s the fundamental principle of these machines is same, and the skill is to maintain constant arcing throughout the welding. However, it is widely accepted that the skill for the welding could only be attained by core practicing. Advanced process such as MIG & TIG would require progressive skill and knowledge in the subject. Additionally, welding sophisticated units such as pressure vessels and reactors requires certification from authorities.
FIG 1: Fronius made Virtual Welding machine at Center for Welding Technology (CWT), NMAMIT, Nitte.
Majority of the welders in India gain their skill by shop floor practice as an apprentice trainee. Hence, a mainstream welder may begin as a helper and initially would learn about machine parameters and consumable specifications. Gradually, apprentice would get hands on practice in common stick welding during job breaks and free times. Further practices may gain him skill required for the job. However, such training requires large time period to attain perfection. Moreover, the manufacturers hardly entertain such training as it would cost them extra material and consumables. Unfortunately, very few skill development programs on welding are run by universities and professional bodies citing above mentioned expenses. Besides, skill of such amateur welders is rarely assessed by any agencies. Perhaps, there is no standard technique to asses the practicing professional welders as well.
Virtual welding is a newly developed technology for training welders with help of electronic sensors interfaced with a computer. The software associated virtually simulates the welding process by sensing the movement of electrode with reference to the job. A real time compilation would enable the operator to adjust the electrode position for proper welding and deposition. Figure 1 shows a photographic image of the Fronius Virtual welding machine in the NMAMIT, Nitte. Real advantage of virtual welding is that there is no consumption of materials at all, moreover, the technology provides a platform to practice welding. Compared to conventional welding training, the virtual welding would yield saving of about 75%. Though, the margin would increase with the life and usage. However, initial cost of the sensors and software’s is relatively higher than the conventional welding machine. Add-on’s such as TIG and MIG will relatively increase the cost further.
Technically, an arc welder should have control on three welding process parameters such as welding speed, gap (electrode and work piece) and electrode angle. While conventionally these skills are attained by non-corrective practices with material consumption, virtual welding offers easy corrective practices with recording and grading system. A trainee could improve himself by analyzing the videos and grades. Figure 2 shows the training of these three skill sets using virtual welding machine.
FIG 2: Three different training modules in Fronius Virtual Welding machine.
The software also has an option to record the simulated training video for future analysis and grading as shown in the Figure 3.
FIG 3: Recording and video playback option in virtual welding.
Highlight of training is that the machine will offer real time assistance and guidance with respect to the preprogrammed welding conditions. Such an assistance, is reference for trainee to perfect the welding. Apart from above three training modules, the virtual welding could simulate the real welding for practicing without any assistance as shown in the Figure 4.
The grading system associated with the virtual welding act as tool for grading the practicing professional welders, eliminating the necessity for on-site welder testing and certification. The score calculation shown in the Figure 5, the virtual machine uses the above-mentioned welding parameters as reference. Adoption of such an advanced technique have enabled in the creation of a standard procedure for welding training and grading.
FIG5: Score system in virtual welding for analysis and grading.
To impart training in further advance welding process and positions, the Fronius virtual welding at NMAMIT has add on for TIG and MIG welding as well. Although the primary sensors such as job and helmet remain same, the electrode holder assembly changes for TIG and MIG as shown in the Figure 6.
FIG 6: TIG welding training using FRONIUS virtual welding machine.
The wire feeder mechanism of MIG welding is virtually simulated by machine, while, for TIG welding a virtual simulation of wire feeding is achieved by a non-consumable wire. Apart, the virtual welding could also be effectively used to train welders on different weld position such as 1G, 2G, 3G, 4G, 1GF, 2GF and 3GF.
Overall the virtual welding machine brings new dimension in welding training programs for beginners and working professionals. Apart from technological benefits, the virtual welding opens new doors for institutes and industries to impart skill development programs to youth in welding and to periodically access the skill of the welder
Acknowledgement: Authors would like to thank Dr. Niranjan Chiplunkar, Principal NMAMIT, Nitte and Dr Shashikantha Karinka for their kind support in setting up welder training lab in NMAMIT, Nitte.