July 10, 2015
After six months of preparations the Construction Tools’ factory in Ruse, Bulgaria, is now producing reversible plate compactors like never before. This is the story of how LEAN came to Atlas Copco’s factory.
Once upon a time, assembling a forward and reversible plate at the Atlas Copco factory in Ruse, Bulgaria, required a lot of moving. In some cases a subassembly could be done in one end of the factory, transported to the other and then moved all the way back to be placed in the final product. Identical components for different versions of the forward and reversible plate compactors could be found in as many as four different locations.
There was room for improvement.
An international group, representing all production factories within Construction Tools division, came together to make the necessary changes.
“Since this was the first LEAN project within the division we wanted to make a useful pilot out of it,” says Nick Evans, General Manager at Atlas Copco Lifton EOOD, and continues: “We have a lot of knowledge within the Group and sharing it is crucial to succeed.”
Together co-workers from Sweden, India, China, Germany and Bulgaria went from theory to practise and came home with a whole new way of thinking. Their most important tools have been patience, communication and training. During their journey they profoundly changed the assembly of forward and reversible plate compactors. Their labor now saves money, time and workers’ backs.
Before LEAN, the forward and reversible plate compactors were assembled on four separate lines. There was also an additional workspace for a special model. The solutions gave high work in progress, low transparency, overproduction and high level of inventory.
Today a 20-meter long assembly line handles all models. Instead of stocks divided into four different locations, components are now stored in one supermarket. It is designed to make frequently used parts easy to pick and is fitted with visual signals for refilling.
All parts for any forward and reversible plate model are brought to the assembly line on two kit carts. On the cart, the assembler only finds parts for the specific product he or she is building. This is a part of the Poka-Yoke method*, developed by Shigeo Shingo for Toyota in the sixties to minimize mistakes. Each station also has a monitor showing assembly instructions for quick reference. The 20-meter line has seven workstations with a Takt time of thirty-two minutes. Every thirty-two minutes a machine leaves the line.
“The project has been both successful and inspiring,” says Nick. He also reveals that a LEAN project will never be fully finished. “But if you want to create change, the first step is always the most important.”
* Poka-Yoke is a method that helps preventing mistakes, or error-proofing. Typical examples are designing a part that cannot be installed in the wrong way or plates that contain specifically designed holes to fit the parts that need to be assembled. Any parts remaining on the plate after assembly indicate a possible error.
The forward and reversible plate compactor is a range of walk-behind compactors. Forward and reversible means that you do not have to turn the compactor at the end of a row that you compact but it is also working backwards. You can push or pull it.
With their high speed and world-class compaction efficiency, the reversible plate compactors have become popular and economical alternatives – or complements – to rollers for the compaction of soil in confined areas such as trenches or parking lots.
A second LEAN line for assembly of power packs, floor saws and drive units is already in operation. All lines in the factory will be converted to LEAN in the future.