Award-winning breakthrough

Source: Exchange Magazine | Photo: Robert Nilsson | Text: Daniel Dasey | Location: Shanghai, China

Just about any process can be made more efficient if you try hard enough. Dedicated work in Shanghai has more than halved burn-loss during remelting, earning the team responsible a 2017 Gränges Company Award.

Aluminium alloy remelting lies at the heart of nearly every Gränges product. Given the enormous amounts of raw material processed and alloy subsequently produced, even the tiniest of inefficiencies in the remelting process can have significant impacts on the company’s profitability.

That’s why in 2014, a team at Gränges Shanghai decided to take a close look at the amount of burn-loss experienced during remelting in the casting workshop, to see if it could be reduced.

“We knew that metal was the biggest single production cost and that burn-loss was a key factor in our metal costs,” says team leader Ge Sun, who at the time was Casting and Hot Mill Manager at the Shanghai plant. “We wanted to see what could be done to improve the process and lower production costs.”

Put simply, burn-loss is the undesirable loss of materials during remelting due to the alloy interacting with either the furnace wall or refining agent. While the flame furnaces used at Shanghai can theoretically produce burn-loss rates as low as 1.5–2 percent, in 2014 some 4.5 percent of material was being lost.

Ge Sun says to address the problem, a multidisciplinary team was assembled with staff from areas that included maintenance, projects, production, processes, and planning. The team studied every aspect of the burn-loss problem for a year.

“In the end, we found that several factors can influence burn-loss, including the type of furnace used, the type of raw material used and the remelting process, and how efficiently the furnace is used,” says Ge Sun.

The jury’s motivation

“Shanghai has reduced burn-loss from 4.5 percent in 2014 to 2.1 percent in 2016. This result was achieved by improving all aspects of the process from solid-scrap handling to remelting to dross handling. A multi-functional team including the production, maintenance, planning, process and project departments have worked together to achieve this result. The project has resulted in major cost savings in 2016.”

We wanted to see what could be done to improve the process and lower production costs.
- Ge Sun Quality and EHS Manager, Gränges Shanghai

Because so many factors were involved, it was decided to form three teams to address each area. One team worked to optimise the remelting process by working on factors such as material loading, temperature, skimming, and the casting plan, as well as trialling an electronic skimmer and new refining agent. Another team worked to improve machine utilization by reducing unplanned stop times, establishing circuit inspection rules for maintenance and production operators, and regularly reviewing performance. Finally, a team worked to optimize raw materials by sorting materials, ensuring the baling machine was fully utilised, and improving the layout of the scrapyard.

Gränges Company Awards

The yearly awards program is part of Gränges’ efforts to encourage staff to continuously improve the business. Areas that the Gränges Company Awards recognize include efforts made to share knowledge and tips, the spread of information about business improvements, and achievements and the creation of ideas that could set new benchmarks for the whole group

The efficiencies achieved by the work of the three teams had a remarkable effect on burn-loss rates. From 4.5 percent in 2014, the rate was reduced to 2.1 percent in 2016, resulting in significant material and cost savings of CNY 8.8 million (SEK 11.2 million) for the year.

The remarkable achievement was recognised at the 2017 Gränges Company Awards where the Shanghai team won the Operational Performance Award.

Ge Sun, who is now Quality and Environmental Health and Safety Manager in Shanghai, says the award is a great recognition of the team’s persistent effort and makes them very proud. They remain convinced that even more can be achieved.

“Using this kind of furnace, the theoretical ideal burn-loss rate is 1.5–2 percent, so we haven’t reached maximum efficiency yet,” he says. “There’s potential to save even more!”