Less lubricant, more productivity

It is estimated that on large scale production sites, lubricant can comprise nearly 20% of total manufacturing, purchasing, maintenance and disposal costs - a significant factor when evaluating a machine's operating costs. A typical ‘wet' machining application may require 10-10,000 litres/hour of lubricant and although much is recycled, there can be almost 3-15 litres/hour in wastage from spray in the atmosphere, as well as coolant carried away in swarf sent for recycling.

Bielomatik's MQL systems deliver precise measured quantities of lubricant to the cutting tip which means that in the same machining operation, only 100-150 ml/hour is consumed. This significant reduction in lubricant usage means obvious financial savings and enables increased productivity.

Upgrading to Bielomatik's MQL two-channel system paved the way for more efficient automated manufacture of wing panels for the A380 at the Broughton facility, enabling components to pass through various drilling, countersinking and riveting operations without any residue tool cutting lubricant remaining.

With Bielomatik's MQL high-speed valve solution, oil deliveries as low as 3-5ml/hour can be achieved. This means that whilst drilling, countersinking and spot facing operations are lubricated, the actual lubricant used is dissipated leaving the dry swarf to fall away from the component surface more readily. This is precisely the type of delivery required on the Airbus wing assembly line, where no oil is allowed to remain in a drilled hole prior to riveting.

With a span nearly as long as a football field, producing a single Airbus A380 wing involves precisely positioning this massive structure to drill, rivet and bolt approximately 180,000 holes. The structures are a framework of spars and ribs covered with curved, aluminium alloy skin panels reinforced by stringers that ensure shape and strength.

Wing assembly requires a highly automated process in which riveting-bolting machines traverse the panels attaching stringers to the skin. Once the stringers have been attached to the wing sections, special-purpose machine tools drill, countersink, rivet the subassemblies together, then spot face the rivet head flush to the outer surface in one continuous process. For the lower wing, holes as large as 1.25” diameter are drilled for bolting the lower wing skins to undercarriage reinforcements.

To create a ‘near dry' machining operation, Airbus installed a Bielomatik MQL system. Here, a pressurised, small bore ring main delivers oil from a reservoir simultaneously, but separately with a controlled air supply to a special rotary transmission unit. A specially designed ‘quick valve' attached to the rotary transmission unit then precisely controls the amount of lubricant released for optimum cutting performance, improved quality of finish and extended tool life.

On the A380 Airbus assembly line, lubrication is delivered via the MQL system through the cutting and countersinking tool whilst it is applied externally for the spot facing operation. This has created a vastly improved processing performance, optimising tool life and cycle times. The added benefit is that resultant swarf is oil-free and can be recycled more easily and at lower cost.

For companies interested in switching to MQL technology, Bielomatik offers a test rig, allowing users to judge for themselves the potential environmental and cost savings on offer. Incorporating the Bielomatik MQL system has proved a major advance over the previous lubrication operation that was messy and required the wings to be cleaned after drilling and countersinking.

www.bielomatik.co.uk