1. Metal tapping with vehicles as a part of lean production approach
Presented at Aluminium Middle East 2013

2. Need for restructuring/optimisation
The Market Situation
Primary production over-capacity
Provision of Recycled metal
Estimated 10Mt of aluminium in warehouses
Stringent environmental standards
Need for restructuring/optimisation
While the global players have responded by significant cuts in production, the market still suffers from over-production and in some areas inefficient smelters are kept in service, supported by local policy initiatives such as the buy-back of low-cost aluminium, special power prices and so on.
March 2013

3. Stringent challenges for primary producers
Cost of energy
Cost of primary materials and manpower
Impact on the environment
Fair employment and safety in the workplace
Shareholders’ satisfaction
Although the cost of energy is – in most cases – a result of geographic location, even in energy-rich countries with abundant supplies of gas, oil or water, energy prices cannot dip below a certain level as energy producers can easily find other buyers.
Aluminium producers are constantly seeking out better and cheaper primary materials and adding more value to their end products through co-operation with local downstream manufacturers
March 2013

4. Returning money back to shareholders
The key point is how to return money back to shareholders.
The only way is a rational approach to production of aluminium
March 2013

5. Improving overall plant efficiency
Tendencies of technology
Higher amperages
Higher current density
Sophisticated controls to manage the pot (magnetic field, heat balance, cathode effect and so on)
March 2013

6. Tendencies of technology
March 2013

7. Material flow and processes
The generalised side-by-side lay-out of reduction cells imposes the use of cranes for most pot-tending operations (anode changing, anode covering and crust breaking)
March 2013

8. Material flow and processes
Many tasks are still performed only with vehicles: it is important to establish a correct definition for plant logistics and vehicles traffic in order to stabilise processes, reduce the cost of potroom equipment, secure a high level of safety and control of emissions.
March 2013

9. Analysis of the processes optimisation
While computerised simulations of material flows in the potroom can be a good way of assessing the number of resources necessary to accomplish a task a strict and perfect control or an optimization of processes made by machines and software is rigid and difficult, at least with today’s technology.
March 2013

10. Anode changing and metal transporting
In newer side-by-side smelter layouts – where there is no room for the vehicles – the job of anode changing went back to the cranes
The crane has become an integrated pot-tending machine (PTM) capable of handling anode changing, crust breaking and anode covering.
March 2013

11. Anode changing and metal transporting
But there are still some tasks where vehicles are required, such as the removal of spent anodes from the potroom and the installation of new ones
March 2013

12. Metal tapping and transporting with vehicles
Metal tapping operations can be performed with overhead cranes in conjunction with transportation vehicles or with special metal tapping vehicles (MTVs).
March 2013

13. The Lean production philosophy
This approach aims to reduce waste (muda), excess (muri) and irregularities (mura) on production processes
Combined with a systematic implementation of Just in Time effort, a lean production approach exposes quality problems that are otherwise hidden by buffer stocks.
March 2013

14. The Lean production philosophy
Forcing smooth flow of only value-adding steps uncovers problems, which must be dealt with explicitly.
March 2013

15. The Lean production philosophy
Lean production is indeed, for a large amount, an approach devised for the “human beings hands, attention and skills”
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17. A complete closed Tapping System
Hot Crucible Cleaner
Tube cleaner, Inside
Siphon Tube Preheater
March 2013
HMR Hydeq

18. Metal Tapping with Vehicles
March 2013

19. Metal Tapping with Vehicles
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23. Comparing different approaches
METAL TAPPING WITH VEHICLES (MTV)
METAL TAPPING WITH CRANE +VEHICLES
March 2013

24. METAL TAPPING WITH VEHICLES (MTV) METAL TAPPING WITH CRANE +VEHICLES
Detaching metal tapping from crane operations reduces time losses and waste due to the ‘over dimensioning’ of the crane (load capacity and number of cranes). It reduces the movements of vehicles and hence efficiency.
A pot tending crane is used to bring the crucible to the pot to be tapped. When full, the crucible is loaded on a truck.
March 2013

25. METAL TAPPING WITH VEHICLES (MTV) METAL TAPPING WITH CRANE +VEHICLES
The metal is delivered to the cast house by MTVs Just in Time. Cast house calls for metal and information on the amount to be delivered and cells to be tapped are directly broadcasted to the MTV driver. The process is clean and clear as it is controlled only by the MTV driver.
A pot tending crane is used to bring the crucible to the pot to be tapped. When full, the crucible is loaded on a truck.
March 2013

26. METAL TAPPING WITH VEHICLES (MTV) METAL TAPPING WITH CRANE +VEHICLES
Crucibles are taken to the cleaning station and directly cleaned Just in Time by the driver. No local storage of crucibles is created. Possible problems on cleaning have to be solved immediately in order to respect the scheduling.
Crucibles are usually not cleaned Just in Time. A stock of several crucibles waiting for cleaning is easily produced.
March 2013

27. METAL TAPPING WITH VEHICLES (MTV) METAL TAPPING WITH CRANE +VEHICLES
MTV driver performs tapping according to cast house requests. No other floor personnel are required.
A crew attends the tapping operations by the crane. Additional manning for trucks.
Maintenance and substitution of tapping and discharge tubes are performed by MTV driver.
A separate shop is usually dedicated to the cleaning of tubes.
March 2013

28. METAL TAPPING WITH VEHICLES (MTV) METAL TAPPING WITH CRANE +VEHICLES
No need for a tilter in the cast house as the MTV discharges the metal by itself. No additional equipment required. Active suspension tilts vehicle to optimise discharging efficiency.
A tilter (or emptying system) with crew is necessary in the cast house.
March 2013

29. METAL TAPPING WITH VEHICLES (MTV) METAL TAPPING WITH CRANE +VEHICLES
The crucible stays on board the MTV at all times. It is released only for cleaning and maintenance, when it is picked up by the vehicle without the use of additional equipment or manning.
The crucible is transferred from the crane to the truck, then to the casthouse tilter (or emptying system). A lifting device is necessary to unload the crucible from the truck and vice versa at the cleaning station.
March 2013

30. Considerations
Metal tapping with vehicles requires disciplined and skilled drivers. A continuous training programme should be established and monitored in order to check and improve the ability of drivers.
March 2013

31. Considerations
As for all vehicles and equipment a robust program of training on daily routine checks made by drivers should be established, run and monitored. Reports coming from drivers should integrate preventive maintenance programmes.
March 2013

32. Considerations
Focus should be put on all processes involved in the use of vehicles: spare parts purchasing, maintenance, operator training with continuous reporting, review and improvement in order to reduce problems and costs and increase efficiency.
March 2013

33. Considerations
The equipment supplier should be treated as a resource. Two-way communication and feedback on the product may improve and reduce operation costs.
March 2013

34. Summary
The only mandatory way of securing long-term smelter profitability is to improve overall plant efficiency. HMR believes that the lean production approach is the best way to improve a process.
March 2013

35. Summary
Where lean production is concerned, it appears evident that metal tapping with vehicles is preferable as it results in a smoother process with fewer risk zones. It also exposes problems and calls for systematic solutions instead of buffer stocks.
March 2013