Design and development of automatic system for transformer core stacking.

Project Title

Design and development of automatic system for transformer core stacking.

Project Area of Specialization RoboticsProject Summary

Automation of the industrial transformer core assembly process is highly desirable. This project aims to design a cost-effective automation system for core assembly from pre-cut lamination stacks was consequently undertaken. The major hurdle for automating the existing manual process was identified as the difficulty in reliably handling and accurately positioning the constituent core laminations, which number in their thousands, during transformer core construction. Technical evaluation of the proposed pick-and-place core assembly system, having a robotic arm with a vacuum gripper. A robotic gripper, having the capability to selectively pick steel laminations concurrently from a stack to form the desired transformer core. It has the potential to significantly increase productivity. The main scope of this project is to reduce labor cost in PEL Power Transformers. Currently, PEL using three workers for stacking two core assembly per day. This automation can increase productivity to four-core assembly per day, approximately 50% increase in productivity and decrease labor cost to only one worker a table, just to arrange the lamination sheets from where robotic arm pick the sheet and place it in desired location.

Project Objectives

1. The main Objective of Project is to stack laminated cores of Transformer according to design with the automatic robotic arm.
2. To reduce time consumption.
3. To reduce Labor cost.
4. To increase Flexibility.
5. To Increase accuracy and precision of stacked cores.
6. To be more efficient.
7. It involves a lot of precise and fine operations which used to be possible only for skilled workers to execute or operate.
8. Reduce the use of motors in comparison with robotic arm to get output which can reduce input power.

Project Implementation Method

The 4 DOF robotic arm is designed for the automation process of transformer core stacking. First degree of freedom is at shoulder in x-axis. Second degree of freedom is applied at Elbow I in y direction. Third degree of freedom is applied at Elbow II in z direction. Fourth degree of freedom is applied at wrist in z direction. In this robotic arm the vacuum gripper for pick and place of cores are used.

Servo motors are used in this 4 degree of freedom robotic arm. With the first degree of freedom which is at shoulder, the arm moves forward and then with the help of second degree of freedom which is at elbow I, it moves downward to pick the cores which is at distance from assembly and then it moves upward and backward with the help of shoulder and place it above the pins. The third and fourth degree of freedom which is at Elbow II and wrist, gives rotation in z direction to place the cores in different positions according to sequence. This is a continuous process which is done by Arduino in which programming is encoded which control the servo motors of shoulder, elbows and wrist to complete the stacking process.

Arduino is used for the automation, in this 4 DOF robotic arm in which the code installed. In coding, the details about the angle of shoulder and Elbow I in which they bent have to be installed. In addition, Elbow II, wrist angles to rotate for proper pick and place of the cores. Furthermore, the detail about how much the shoulder and elbow bent to pick the core and in what distance it places in right position has to be installed. The robotic arm uses four servomotors to move the arm. Servomotors are controlled by Arduino and connected to the PWM (Pulse –width modulate) The Arduino does not have a built-in digital-to-analog converter (DAC), but it can pulse-width modulate (PWM) a digital signal to achieve some of the functions of an analog output. The function used to output a PWM signal is analog Write (pin, value). Pin is the pin number used for the PWM output. Value is a number proportional to the duty cycle of the signal pin of Arduino.

Benefits of the Project

1. High accurate stacking.
2. Repeatable stacking quality.
3. Reduced Mechanical Stress.
4. Reduced Transformer Losses which occur because of manual stacking.
5. Labor cost savings as well as reduce stacking time.
6. With the help of two grippers two laminated sheets stacks at a time.
7. Another feature of this machine is communication with other processes and departments within the plant. For example, quality department can check at any time the cores stacked each day, how many times the automation stop and what was the reason.
8. Productivity can be increased according to market demand.
9. The main benefit of project is consistency of production.
10. It can reduce amount of operator error.
11. Robotic workers never get tired.
12. Pick and place robots can provide great return on investment (ROI) for manufacturers because of the productivity benefits they can provide.

Technical Details of Final Deliverable

In this project, four servomotors are used. In automatic control system, servomotor is used as an actuator to convert received electrical signal into angular displacement and then convert it into output. The whole robotic arm will be assembled through pvc pipe. In this robotic arm, two elbows and shoulder which are connected by elbow joints are used. Vacuum gripper will be used to pick and place of metal sheets. It uses vacuum cup as a gripping device that is also called as suction cups. This type of gripper will provide good handling if the object is flat. These cups will be developed by means of rubber or other elastic materials. The power source of 24V will be used. The base connected with robotic arm with the help of gear mechanism. The most common technique used in stacking laminations is the alternate method. The alternate method is where one set of laminations, such as an E and I, are assembled. Then, the laminations are reversed. This technique, used in stacking, provides the lowest air gap and the highest permeability.

This pick and place robotic arm can increase productivity up to 50% in PEL industry. In the current process PEL manufacture 2-core assembly per day. This is because of frequent brakes of labor and depend on capability of workers. With the help of automation, the productivity increase as there is no frequent brakes and consistency of working can increase productivity up to 4-core assembly per day.

Final Deliverable of the Project HW/SW integrated systemCore Industry Energy Other Industries Others Core Technology RoboticsOther Technologies OthersSustainable Development Goals Decent Work and Economic Growth, Industry, Innovation and Infrastructure, Life on LandRequired Resources

Item Name	Type	No. of Units	Per Unit Cost (in Rs)	Total (in Rs)
			Total in (Rs)	69000
Arduino/Control unit	Equipment	1	5000	5000
Servo Motor	Equipment	4	6000	24000
Robotic Arm body	Equipment	1	10000	10000
Bluetooth Module	Equipment	1	2000	2000
Power Adapter	Equipment	1	1000	1000
Vacuum Gripper	Equipment	1	15000	15000
Gear System	Equipment	1	5000	5000
Base	Equipment	1	5000	5000
Transportation	Miscellaneous	1	2000	2000