How To Increase Production And Enhance Shop Productivity

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This article features an innovation project at Wheel and Axle Plant (WAP) of Durgapur Steel Plant on designing, fabrication and installation of a low-cost, electronic wheel counter with a large LED display at wheel forge and wheel mill area to motivate people for higher production and enhance shop productivity.

It is said that India moves on DSP (Durgapur Steel Plant) wheels as Durgapur Steel Plant of the state-owned steel giant Steel Authority of India (SAIL) is the primary supplier of forged wheels and axles for Indian Railways. Wheel forging area is one where a wheel takes birth from its mother steel block and undergoes the infantry stage of getting the desired primary shape for its further journey. Hence, it is an important area in the wheel manufacturing process, where all sorts of precautions and care are required for the smooth birth and growth of the wheel before it is sent for machining for finishing operations.

Moreover, total wheel production target has to be achieved while maintaining critical aspects. The entire production area has inter-related sub-sections or workstations where line production of the forged wheel takes place.

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Sub-sections or workstations under the production line of forged wheels are furnace, forging press, wheel mill, dishing press, stamping press and so on, as shown in Fig. 1.

Process of making wheels
Fig. 1: Process of making wheels
Fig. 2: Fabrication and testing of author’s prototype of the big-size automatic digital wheel counter
Fig. 2: Fabrication and testing of author’s prototype of the big-size automatic digital wheel counter

All these sub-sections/workstations are required to operate in a completely synchronised manner to produce forged wheels, which later undergo heat treatment and machining to produce finished wheels.

The challenges

Before taking up this project, there was no common display system for the entire wheel forge shop to view the production status (that is, digital counting display of forged wheels), which is required for proper feedback and control towards higher production. Only manual counting by the stamper or operator at other places was done, which made it difficult for employees and shop-floor mangers to know the shift/daily forged output at any point of time.

During productivity improvement studies, it was felt that a modern digital counting and display system that is visible to all employees of the wheel forge shop would help get rid of this problem. This was necessary not only for the correct accounting of produced wheels but also for motivating employees towards higher production, primarily through feedback.

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Hence, an innovation project was taken up to develop a digital wheel counter with a jumbo-sized LED display, without any considerable capital investment. Accordingly, a complete three-digit electronic digital wheel counting system with a giant seven-segment display was successfully designed, fabricated and installed at Wheel and Axle Plant (WAP) Wheel Forge Shop, which is working well, and is giving several tangible and intangible benefits.

Fig. 3: Installation and testing of the jumbo seven-segment display above stamping press control cabin
Fig. 3: Installation and testing of the jumbo seven-segment display above stamping press control cabin

Salient features of the innovative three-digit electronic wheel counter are as follows:

  • Display size is big enough (digit height is 45.7cm, or 1.5 feet) to be visible from all corners of the wheel forging and rolling section.
  • The circuit and the entire automatic display system have been designed, developed and fabricated inhouse using waste materials and low-cost items.
  • Display brightness and LED matrix density is visible from far as well as from a close distance.
  • Any reputed supplier/contractor is likely to charge an amount not less than 400,000 to 500,000 rupees for installing such an automatic wheel counting system with giant display. This innovative digital counter with giant LED display costs only 4500 rupees (approximately).
  • The seven-segment display has been developed from common household items like plastic wiring casing, decorative LED strips and ply board, among others.
  • The electronic digital counter circuit and giant LED display board have been developed using easily-available ICs and other electronic components.
  • IC bases have been used for easy replacement of ICs in case of damage.
  • Increment of wheel counter can be made by pushing the manual push-button switch as well as automatic limit switch, which gives a pulse during punching of the identification number on the hot wheel.
  • There is an auto/manual selector switch for convenience, and a reset switch for resetting the digital counter to zero for shift or day start.

Benefits of the project

The innovative digital counter with three-digit jumbo display was successfully developed, fabricated and installed on the roof of the stamping area cubicle at the wheel forge area. Some of its benefits are given below.

  • The counter display gives instantaneous production status of the wheel forge section, where time is directly proportional to wheel production numbers.
  • The common display maintains production synchronisation among various workstations in the shop. It binds all workstations at the wheel forge section in a single thread, and has improved coordination among these, which has maximised production and minimised wastage of time.
  • It helps in changing the mindset, improving work culture and shop productivity.
  • The displayed wheel production figure can be referred by everyone working in the chain of the line production system at the wheel forge section.
  • The displayed wheel production figure is visible through CCTV from various locations of the plant.
  • The tool helps central agencies like plant control, higher management, etc for monitoring total wheel production.
  • Display of instant production at a section like wheel forge helps convert ninety-plus forging/rolling shift output figures to hundred-plus.
  • It helps in better utilisation of available time.
  • It has instilled healthy completion among shifts to reach day targets.
  • It helps in the flow of real-time production data at all times, to different levels of plant management.
  • The display system provides a better means of communication and works as a score board of performance.
  • Envisaged direct financial benefit. As Durgapur Steel Plant produces different types of wheels with different weights—for simplification, let us consider average weight of a wheel to be 500kg. Then, only a single-wheel extra production/shift at this stage of the wheel manufacturing process gives a financial impact of around sixty million rupees annually.
  • Actual increase in revenue generation is expected to be manifold, as extra production will be more than a single wheel in a shift. Its impact/effect is cumulative. Sensitivity analysis for the extra wheels produced is given in the table.
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Schematic layout and the process of wheel forging and wheel milling

The process of wheel forging and rolling is described below.

Forging area and wheel forging process.

In the mill providing section of WAP—an upstream unit of wheel forge—required-sized blocks are cut from input ingots received from the steel-melting shop. These blocks are then sent to the entry door area of the furnace (rotary hearth type) through the roller table. The rail charger picks up the blocks one by one and places them in the furnace. From the discharge door, mobile charger G2 takes the soaked blocks and places them on the descaling platform.

After descaling by shaking on the platform, G1 picks up the blocks and places them on the anvil of 63/12MN forging press. In the forging press, the blocks are given the shape of the wheel by punching a hole in the centre in three stages.

After punching, blocks are taken away by G2 at wheel mill side for placing in the furnace on the other side.

The whole operation is shown in the schematic layout given in Fig. 4.

Fig. 4: Schematic layout for the wheel forging process
Fig. 4: Schematic layout for the wheel forging process

Wheel mill area and rolling process

Forged wheels are taken from 63/12MN forging-cum-punching press by G2 and placed in the second furnace for re-heating, to raise the rolling temperature for rolling in the wheel mill. From the second furnace, hot wheels are sent to wheel mill by G2 for rolling, and a final shape (profile) is obtained.

Rolled wheels are then taken by mobile charger M1 and put on the dishing press for dishing. Dished wheels are moved to the stamping press by M1 for stamping—this is done for identification of the wheels. After stamping, finished forged wheels are placed on the floor by M1.

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M2 moves these hot wheels to the hot bed in stacks of two for cooling. Wheels after preliminary cooling are moved by the crane to the heat treatment area. Entire operation is shown in the schematic layout given in Fig. 5.

Fig. 5: Schematic layout for the rolling process
Fig. 5: Schematic layout for the rolling process
Fig. 6: Circuit diagram of three-digit digital wheel counter
Fig. 6: Circuit diagram of three-digit digital wheel counter
Fig. 7: Electrical wiring diagram of three-digit digital wheel counter
Fig. 7: Electrical wiring diagram of three-digit digital wheel counter

Conclusion

The automatic digital wheel counter with jumbo-sized seven-segment displaying system has been working well at the forging shop of W&A Plant for the last two years. Production of forged wheels has increased substantially after installation of the display system. It is helping in harnessing the higher potential of the wheel forge shop.

Even though this digital counter is made for counting the number of wheels manufatured at the wheel plant of Durgapur Steel Plant of SAIL, it can be used anywhere for automatic counting and displaying purposes in a large area.


Gautam Kumar Mandal is deputy general manager, Industrial Engineering Department, Durgapur Steel Plant (Steel Authority of India)

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