Welding processes form the core of heavy engineering and fabrication industries. L&T Heavy Engineering holds several global benchmarks in delivering some of world’s largest reactors and pressure vessels to more than 40 countries.
This scale is possible by harnessing highly critical and sophisticated welding processes based on advance metallurgical practices deploying state-of-the-art facilities and welding stations. Electro Slag Strip Cladding (ESSC) is one such welding technology, which has been successfully developed by only a select few organizations in the world.
ESSC is a welding process where one metal with specific characteristics is overlaid over a base metal. The main purpose for weld overlay is to enhance corrosion resistance or wear resistance. While the base metal provides strength requirements, the overlay provides surface protection allowing the equipment to operate in a cost effective manner.
The ESSC process is undertaken by a specialized and mechanized welding station. Nevertheless, the ESSC welding station has been controlled manually with involvement of at least three to five personnel at any point in time.
Employee safety poses major concern
The company identified several areas for improvement. The base metal needs to be heated up to 200-250 degree Celsius and this temperature has to be maintained throughout the cladding process.
“As a result, the operator has to position himself near the hot machine for setup, monitoring and control that posed health and safety hazards,” says Sanjay Chakraborty, head–IT and organizational excellence of L&T Heavy Engineering.
Additionally, key parameters had to be maintained within specified tolerances to achieve desired mechanical and chemical properties in cladding process. Being a manually controlled process, it calls for skilled operators and close supervision to avoid repair, rework or rejection.
The frequent visits to stores by the operators for issuing welding consumables were resulting in loss of productive time. The management information system was controlled by the shop supervisor including productivity and quality data, which had the probability of errors of recording and judgment.
Smart welding station to rescue
A strategic initiative was taken up for deployment of Industry 4.0 digital initiatives for enhancement of operations. The project was executed by an in-house team comprising about eight engineers and IT professionals. IoT as a solution was pursued to address the issues and to create a world-class smart welding station.
“This smart welding station is connected with the IT datacenter for advance analysis, needs operator’s authentication to prevent access to any unauthorized or non-qualified personnel,” adds Chakraborty.
Sensors for real-time capture of all key welding process parameters and weld visual cameras for remote monitoring, setup and control ensured that operators need not be seated near the heated machine. A single touchscreen based pendant was built for the operator connected to his mobile device that enabled shop supervisors to monitor the machines remotely.
Reaping the benefits
The remote monitoring not only saved operators from health hazards but also increased productive hours with a real-time dashboard for operational parameters. As a result, the company also managed to save manpower as one person can now achieve the work earlier undertaken by three to five people.
The organization experienced a productivity improvement of 20-25 percent by avoiding manual controls, and providing workmen a better and safe environment to operate. Quality improvement was ensured by reduction in rework to near nil.
Additionally, a significant cost benefit was also achieved by transforming the existing welding station into a smart welding station by in-house development team. The smart welding station also enabled a cycle time reduction, enhanced production resources and a 15 percent higher capacity for handling business volumes.
The success of this project is being replicated across ten other smart welding stations by March 2018.