Since the beginning of 2011, production efficiency has increased significantly at the hot coiling facility of Hanson Springs in Mellor Street, Rochdale, following the installation of a 25-metre-high storage tower from Kasto to house the bar from which the springs are made. They are used globally for flow control applications in the oil and gas, petrochemical and power generation sectors, all of which are currently buoyant and demanding more springs in faster delivery times.
John Hanson, a director of the company, commented, "Whereas it used to take us up to three hours to find material buried at the bottom of conventional racking, bar is now available from the tower within three and a half minutes of calling it up on the computer control screen.
"This is a maximum cycle time; mostly the stock is delivered to the output station much faster.
"Previously, we planned our manufacture around bar that was reasonably accessible at any given time. However, if an urgent order came in requiring access to elusive bar, staff had no alternative but to spend time searching for it.
"Using the automated storage and retrieval system, flexibility of production has improved and lead-time is reduced, sometimes dramatically."
The typical size of a batch of springs is in the range two- to 50-off, requiring frequent changeover of the coiling plant. Use of this expensive plant is maximised by prompt arrival of cut-to-length steel bar. Fifteen tonnes are processed daily and increased profitability will readily amortise the £1 million investment in the storage tower and associated civil engineering work.
Many additional benefits accrue from enhanced logistics. For example, a 23-ton truck previously took around three hours to unload because the overhead crane progressed with each batch of bar at slower than walking pace along the conventional racking. Stocking the Kasto tower takes 40 minutes - four to five times faster - as the store's input / output station is just inside the door.
Further advantages of the tower store include better security of the raw material, which can only be accessed by PIN code. Another benefit is reduced risk to crane operators, since they less frequently have to reach around bundles of bar on conventional racks to put on lifting straps. Some racks have been retained, however, to store material over 10 metres long - the tower's maximum capacity.
Each of the 212 cassettes in the KASTOunitower are 10,000 mm long by 300 mm high by 600 mm deep and can hold up to 3.5 tonnes of material, giving the store a theoretical capacity of 742 tonnes. There is a stock control facility built in to the tower controller, although Hanson Springs uses its own computer system for this function.
The round section, carbon steel bar ranges from 20 to 80 mm diameter. Below this size, bar is delivered in coils and Hanson Springs is now considering buying a Kasto automated plate storage system to hold this type of material.
John Hanson went on to explain the background to installing the KASTOunitower 3.5 storage system at the Mellor Street site, a long, narrow building that the company moved into 12 years ago. A warehouse was added at the back seven years later and quickly the whole facility reached capacity. It was not efficient to manufacture hot coil on site and transport it to another location for storage, so extra space had to be liberated to allow expansion.
Originally, John and his father, Malcolm, who founded the company in 1967, had considered installing cantilever pallet racking with a moveable base. However, it would have necessitated clearing out the building for a new concrete foundation to be laid, which was deemed impracticable.
They first considered a KASTOunitop solution, an automatic bar store with an operator crane travelling over the top, but this did not fit in the available space. However, a KASTOunitower could be built with weatherproof cladding so that it could be positioned outside the building, creating spare space inside. They were aware of existing Kasto storage system customers like seal manufacturer, AESSEAL and Böhler, one of Hanson Springs' steel suppliers, which provided reassurance that Kasto was a reliable potential partner.
In the first three months of operation, two-thirds of Hanson Springs' bar stock was transferred to its tower, which freed about half of the warehouse area. In the process, useable bar remnants were unearthed from the bottom of various racks, providing a windfall worth several thousands of pounds.
The spare space in the warehouse will be used to expand the spring production area, with a bandsaw and either a bar peeling or grinding machine shortly to be installed.
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