While factors such as speed, price and delivery have a major influence on most major capital expenditures, in the case of cleaning and degreasing equipment there is largely only one point for consideration: the ability to produce clean parts to the required standard, time and time again. This was certainly the thought train for Southend-based Honeywell MK Electric, when it sought to find an alternative degreasing solution to remove pressing oil from its decorative, metal-clad facia and flat plate light switches and sockets. The company previously used an atmospheric (open top) trichloroethylene degreasing plant, but wanted a replacement, due to increasing legislative pressure and protocols, such as the VIC (Voluntary Industry Commitment).
Image: SAFECHEM and Kumi Solutions, with Pero technology, solved Honeywell MK Electric's problems
"Initially, we looked at aqueous alternatives, but couldn't avoid water-mark residues on the parts," says manufacturing engineer Ian Howe. "We approached SAFECHEM (01384 296613) for advice and, ultimately, settled on switching to perchloroethylene, which is a lower risk category solvent." The next step was to identify a replacement machine, preferably one that was 'universal' and could accommodate a range of solvents, such as methylene chloride, hydrocarbons and specially modified alcohols, to protect against future legislative changes. According to Mr Howe, the Pero range from Kumi Solutions (02476 350360) was one of the few able to offer this safeguard.
The latest Pero Solvent degreasing systems cut VOC emissions to 80-90% below that of current and forthcoming regulations – including 1999/13/EC.
"The Pero R1 is also very fast – other machines could either match our existing cycle times or improve them by up to 50%, but the Pero R1 could improve our productivity by up to 75%," says Mr Howe. "As a result, our flat plate products have reduced from a 12 minute cycle time to just 3 minutes, while our metal clad front plates take just 6 minutes, where previously they took 17." Another benefit of the German-built Pero R1 is a huge reduction in solvent usage.
"Because the machine constantly recycles, solvent only depletes slightly over time. Instead, we simply monitor solvent acidity and alkalinity, using a SAFECHEM database and add stabilisers if and when necessary. But, to date, we haven't had to do anything," states Mr Howe.
Another company recently to replace open-top trichloroethylene plant is Starna Scientific of Hainault, Essex, a manufacturer of ultraviolet and infrared optical products. The company is reporting major production benefits following its recent adoption of 'EnSolv' cleaning solvent from EnviroTech Europe (0208 281 6370). The solvent is deployed in a fully sealed MEG machine from Italy, supplied by Core-Chem (01753 819496).
Image: Starna Scientific replaced open-top trichloroethylene plant
Starna uses EnSolv to remove wax-based products or 'blocking wax', which is employed for holding glass and quartz optical components onto production tooling, and to thoroughly clean the parts prior to subsequent assembly or coating processes. In many instances, cleaning cycle times have been cut from over 30 minutes to just a few minutes.
EnSolv, which is non-flammable and non-carcinogenic, provides the same solvency power as trichloroethylene and operates at a lower temperature (69°C), which is high enough to break down the heavy wax, while also avoiding the danger of thermal shock and cracking of the delicate components.
Dewaxing is also the aim at Ramsgate-based aerospace overhaul and repair specialist AEM – in this case, dewaxing components that have been plated. This is normally a messy job, involving removal of wax in a tank of heated water, followed by further cleaning and degreasing, traditionally in hot trichloroethylene. However, Turbex (01420 544909), in collaboration with AEM, has developed a much cleaner, faster and more ecologically friendly alternative.
Image: Turbex technology allows wax removal the modern way
In what is believed to be a world first, an aqueous washing machine has been adapted to remove the masking wax and then degrease components in a continuous, 30-minute process. The secret to its success lies in the system's ability to keep the wax molten while inside the cleaning machine. This is achieved, first, while the wax droplets are held in suspension in the hot water/detergent mixture; then, as they float to the top to form an oily layer, and, finally, as the wax moves through a separation unit before dropping into a container, where it solidifies.
Benefits of the new technique include not having to shovel wax by hand into sacks and significantly less mess in the working environment. The potential for hazardous trichloroethylene emissions into the workplace and atmosphere are eliminated, and there is no longer any need to remove masking wax that used to end up in the trichloroethylene tank.
Another aqueous system has been selected by West Yorkshire-based heat treatment specialists Keighley Laboratories, where an Aqua-Save Junior from the Aqua-Save Technologies division of MecWash Systems (01684 271600) is helping to meet production efficiency and environmental objectives.
Image: Heat treatment specialists Keighley Laboratories is saving water, and money, with AquaSave
The machine uses evaporation to process a range of wastewaters – from machining coolants and wash solutions, through to floor scrubbings and compressor condensate – separating water from material for disposal. Typically, only 5% of the original solution volume then needs to be removed from site, with the rest available either for re-use or, with appropriate permissions, discharge to drain. In some cases, operational costs may be further enhanced, because users of Aqua-Save systems can qualify for the government's Enhanced Capital Allowance (ECA) scheme.
"The Aqua-Save Junior has been operational for more than six months now and, during this time, there has been no requirement to empty the 1,500 litre capacity wash tank within the aqueous washer," says Keighley Laboratories' David Wright.
The aqueous option, this time in combination with ultrasonics, is also the winning formula for a company that needed to remove swarf and machining oil from a range of hydraulic components to the strict cleanliness standard ISO4406:1999. The solution arrived in the form of a Kerry Microclean multi-tank aqueous cleaning unit from Guyson International (01756 799911).
Image: Guyson aqueous and ultrasonic technology make things clean
The four-stage system includes a high intensity ultrasonic cleaning tank, immersion rinse tank, high intensity ultrasonic rinse tank and warm air drying system. An Autotrans work transfer system moves the baskets between cleaning stations automatically, while an Autotrans Major transporter integrates with both feed and exit conveyors for a fully automatic operation.
Mykal Industries (01933 402822) has also had success with solvent-free, ultrasonic cleaning, having recently supplied a solution based on its Aquasolv Ultrasonic Cleaner-Plus (Aqua 22) to an aerospace company when it needed to replace trichloroethylene and reduce VOC emissions.
Having decided on an ultrasonic alternative, the next step was finding a suitable cleaner that would provide the level of cleaning performance required. Due to the heavy duty nature of the lubricants present, Mykal proposed its Aquasolv Ultrasonic Cleaner-Plus (Aqua 22), a highly concentrated cleaner, designed to remove difficult contaminants. During trials, Ultrasonic Cleaner-Plus was used at 5% concentration levels for 5 minutes at between 60-70°C before the components were given an ultrasonic hot water rinse and then dried. Trial success resulted in the purchase of several ultrasonic tanks and regular orders are now being placed for Ultrasonic Cleaner-Plus.
Some companies, however, find that certain component features prohibit the effectiveness of aqueous solutions. One such is Oglesby & Butler of Carlow, Ireland, which recently replaced an aqueous washer with a Dürr Ecoclean Minio 85C from Geo Kingsbury (023 9258 0371) to remove particulates from machined parts with 60 micron holes.
The machine uses a non-halogenated, hydrocarbon solvent in a closed system and it successfully cleans tens of millions of parts every year, with cycles taking from 10 to 12 minutes.
First published in Machinery, July 2011