A horizontal machining centre (HMC) designed specifically so that it can be expanded easily and inexpensively in the field has ‘eased the growing pains’ of Crediton-based Adaero (www.adaero.co.uk), a sub-contractor that has been so successful in recent years that its factory is ‘bursting at the seams’. The company invested some £600,000 in capital plant during 2015 alone.

Installed last October, the four-axis HMC is an Akari HS-450i high-specification twin-pallet model with a 120-position chain-type tool magazine. Supplied by UK agent Whitehouse Machine Tools Ltd, Kenilworth (www.wmtcnc.com), it has a working envelope of 640 x 610 x 680mm and will be retrofitted in the coming months with a six-pallet pool and a 100-tool extension to the magazine.

Normally, a manufacturer would take advantage of this expandability by installing the entry-level configuration while developing its customer base and increasing the level of business, then adding the cell extensions when production throughput had grown to an appropriate level.

In Adaero’s case, the company already had the work, but it simply could not fit the 6-APC machine onto its 7,600ft2 shopfloor. The company has now rented an additional 7,500sq ft factory unit a few hundred yards away and plans to relocate a number of machine tools in the coming months.

Operations manager Jack Wilson said: “For some years, we have adopted a policy of automating as much production as possible. In 2009, we installed our first multi-pallet cell — a 40-taper four-axis horizontal machining centre with 15 pallets and dedicated fixturing for the production of a specific part.

“A couple of years ago, we bought the latest of many Brother vertical machining centres from Whitehouse Machine Tools. A 30-taper five-axis model, it was equipped with a System 3R automated multi-level storage and retrieval system, with 84 pallets carrying vices for securing a wide variety of components. Last year, when the time came to replace an ageing stand-alone HMC featuring a 40-taper spindle and a 60-tool magazine, we decided to go further down the automation route.”

Several HMC alternatives were considered from a number of potential sources, including the supplier of the previously installed 15-pallet cell, but either the footprint was too large or the cost was too high. The Akari offered the ideal combination of being economically priced and able to be expanded when space became available.

Built in Taiwan by Averex — a specialist manufacturer established specifically to build only high-speed HMCs — the 12-tonne machine incorporates top quality components. These include single-piece FCD600 castings for the
spindle and pallets, Tsubaki ballscrews, THK heavy-duty roller guideways, a Tsudakoma rotary table, a high-torque temperature-controlled Fanuc spindle motor with BIG Plus 40-taper tool interface, Kosmek tapered cones on the automatic pallet changer and a Fanuc 31i NANO control.

Also included is thermal management of the base casting, ballscrew nuts, thrust bearings, Y-axis servo mounting and spindle cartridge. Another notable feature is the machine’s swarf management.

The twin-conveyor unit, which comprises both scraper and hinge belt systems, offers advanced filtration that allows it to separate particles above 150µm while handling copious amounts of coolant. Adaero produces components for a number of different industry sectors from a range of materials including aluminium, plastic, stainless steel, bronze and brass, and all types of swarf are handled efficiently.

Mr Wilson says: “The HS-450i is a fast machine, with a 15,000rev/min 22kW direct-drive spindle and 1g acceleration to a maximum cutting feed rate 60m/min. Tool change is completed in 1sec, or 3sec when exchanging our Renishaw probe for workpiece set-up or the Marposs tool-setting probe.

“Compared with the HMC that it replaced, the Akari is reducing cycle times by an average of 30% using the same programs, simply by increasing the feeds and speeds.”

Gary Raymont, Adaero’s managing director, adds: “Ours is a high-precision high-mix production environment involving the machining of a few thousand different prismatic parts. Quantities can vary from small prototype batches to high-volume production runs.

“Working alongside our customers, we also offer a hybrid kanban continuous manufacturing process using the latest production scheduling systems; and with customers constantly demanding that prices be held or reduced while quality is maintained or increased, we have to be a part of their design teams to engineer out cost and improve methods of manufacture.

“Automation using multi-pallet cells like the Akari has the advantage of allowing unmanned running overnight, raising output for a fixed overhead and hence lowering manufacturing cost per part.”