Coventry-based Metallic Protective Plating (MPP), part of the PMD Group, is one of the few specialist precision hard chrome platers in the UK. MPP operates to the highest quality standards.
Traditionally, the company has employed trichloroethylene (‘trike’ or ‘TCE’) for the removal of the residual wax, which is usually left after a component has been through an initial de-waxing process following selective plating. The wax coating is used to mask-off areas that do not require plating.
The de-waxing process involves physically stripping-off the wax and then immersing the components in boiling water to boil-off remaining material. However, this leaves a residual thin coating of wax – entrapped in recesses, for example – and further cleaning is essential.
Trike has proved very effective at removing this residual wax, but MPP needed to reduce its consumption of trike to below the one metric tonne per year limit required by the Solvent Emission Directive. The company was also keen to eliminate the use of chlorinated sol¬vents for environmental and health and safety reasons.
One alternative would have been to install a sealed vapour degreasing machine but this was considered prohibitively expensive for this particular application, so MPP investigated other methods of achieving the required level of surface cleanliness.
The company trialled a number of solvent and aqueous-based alternative cleaners and – with the assistance of component cleaning specialist, Stowlin Croftshaw – eventually opted for ‘BIOACT® 280E’, a biodegradable precision cleaner, which outperformed the other products tried.
After the initial physical stripping and boiling water treatment, the plated parts are now immediately immersed in hot (80º to 90º C) BIOACT® 280E for about five minutes, followed by a cold water spray rinse and then cold water immersion, prior to drying.
The BIOACT® process tank was designed by MPP itself. It incorporates a simple immersion heater arrangement, and was relatively inexpensive to manufacture. Parts of up to two metres long are accommodated by the tank.
The process was tested and installed in under two months and, says Barrie Tooze, managing director of MPP, has proved a successful alternative to the use of trichloroethylene. Barrie has long experience in the plating industry and is a Member of the Institute of Metal Finishing. “The new cleaner is slightly slower-acting than trike, but speed is not a major element for most of the complex plating work we undertake, and the switch to ‘non-risk phrase chemistry’ is a major benefit to the company, both in terms of reducing solvent emissions and complying with the impending REACH legislation,” commented Barrie.
Biodegradable and non-hazardous
BIOACT® 280E precision cleaner has a long bath life and requires only minimal replenishment. The cleaner was specifically developed for removing high-melting-point soils such as waxes, pitches, greases, fixturing compounds and buffing compounds. It is a special blend of aliphatic esters and surface-active agents, formulated to offer an effective alternative to chlorofluorcarbons, chlorinated and brominated hydrocarbons, caustic cleaners, and petroleum-derived solvents in precision cleaning applications. Its high flash point, combined with low odour, low toxicity, and low vapour pressure, allow it to be used safely in demanding applications where maximum operator safety and minimal environmental impact are important.
The product is non-corrosive, does not contain carcinogens, is readily biodegradable and is not classed as hazardous waste. It is approved for use by leading manufacturers across a wide range of industries including aerospace, automotive, optics and electronics.
