Magnesium cutting fluid is more versatile than dry machining

Citation

(2003), "Magnesium cutting fluid is more versatile than dry machining", Aircraft Engineering and Aerospace Technology, Vol. 75 No. 6. https://doi.org/10.1108/aeat.2003.12775fab.004

Magnesium cutting fluid is more versatile than dry machining

Magnesium cutting fluid is more versatile than dry machining

Keywords: Fluids, Cutting, Magnesium, Machining

Castrol customer FR-Hitemp of South Molton in Devon, UK, is a member of the Flight Refuelling Group, a major company in air-to-air refuelling and the supply of fuel system components to commercial aircraft manufacturers.

The company's machine shop is equipped with over 50 CNC machines including a number of CNC turning centres, two-axis lathes, four- and five-axis mills and general machines, such as grinders and centre lathes. Components are mainly machined in aluminium, titanium and a range of stainless steels.

Six months back, FR-Hitemp became involved in the development of a specialised component that needed to be machined from magnesium, a metal with which the machine shop had limited experience. When the project began, Production Engineer Steve Symons faced three seemingly insurmountable problems.

First, wet machining was not thought viable because neat oils were considered messy and unsuitable for use with other materials, and conventional water-soluble cutting fluids react with magnesium making machining difficult.

Second, dry machining, which had seemed to be the only viable option, generates a lot of heat and can cause deformation of the work piece. It can also cause fires due to high stock removals thereby resulting in high temperatures.

Finally, nine magnesium components in the initial batch were to be machined in the Rapid Response cell on a five-axis mill and a lathe, both of which were also used to manufacture components in aluminium and stainless steel. This either meant using the two machines exclusively for small-scale magnesium production runs, or cleaning them down every time magnesium was machined.

Fortunately, a call to Castrol Regional Sales Manager, James Bayliss by Gerry Benning, Team Leader of the Rapid Response cell produced a single solution to all the three problems – Castrol Hysol MG.

James says: "Hysol MG is a water-soluble cutting fluid specially formulated for machining magnesium alloys. Whilst it is used in the same way as conventional fluids, its unique chemistry prevents the magnesium from breaking down the mixed fluid during machining."

He adds that for FR-Hitemp there is the added bonus that it can also be used to machine stainless steel and aluminium, so the machines do not need to be interrupted and productivity is not affected.

Prior to starting magnesium machining the mill and lathe were cleaned and refilled with Hysol MG. After 6 months, Steve reports that the results are excellent; there has been no splitting of the emulsion and the potential for fire in the machines has been greatly reduced.

Castrol Hysol MG is designed specifically for machining magnesium alloys but is also said to be suitable for machining aluminium and steels. It reportedly overcomes problems such as poor pH control, unstable emulsions, hydrogen evolution, staining and hard deposits that are normally associated with machining magnesium whilst improving feeds and speeds, gives an excellent surface finish and increases tool life and productivity.

Castrol Hysol MG is stated to be chlorine- and boron-free. Its advanced additive technology is reported to provide very stable emulsions and prevents fungal and bacterial infections resulting in exceptional sump life.

Details available from: Castrol (UK) Ltd. Tel: +44 (0)1 793 452356; Fax: +44 (0)1 793 486083; E-mail: thrussc@castrol.com; Web site: www.castrol.com