8 min read · Power Clean applications team
POWER CLEAN has a strong affinity for oil and loosens contaminants from the part. Most of the oil then floats to the surface, where it is removed by a skimming wheel or belt, an absorption blanket, or vacuuming. Switch off the agitation and solid particulate and metal fines settle to the bottom, to be filtered off as sludge by a recycling filtration system.
Heat and agitation
Parts spray washers
A significant improvement in both safety and performance over the caustic powders once common in spray degreasing. At a dilution of 3% (1:30) with water, heated to approximately 60 °C, POWER CLEAN effectively removes contaminating oils, and the spray nozzles stay clear of contaminate build-up. Because no rinsing is required, an economical single-stage washing system is practical.
Ultrasonic systems
A 5% solution removes oils, dirt and fine metal particulate. Combined with the implosive action of ultrasonics, the result on small holes, long tubes and delicate pieces is remarkable — and it is safe on all substrates, with no damage to anodising and no alteration of the surface topography.
Heated dip tanks
A 5% solution heated to about 63 °C replaces the hazardous caustics and acids used in submersion washing. Parts washed and thoroughly dried are protected from rust for approximately 7 to 15 days, after which they can be coated or bonded with no further treatment. Existing vapour degreasing tanks can be converted to POWER CLEAN submersion systems quickly and at little expense — conversion is recommended to improve agitation.
Agitated immersion tanks
Turbulation during the wash cycle dramatically increases efficiency, produced by mechanical pumps and jetting action. A 5% concentration heated up to about 70 °C suspends and disperses soils and prevents re-deposition, while corrosion inhibitors and wetting agents help water sheet off the surface. Plants still running vapour tanks can adapt existing equipment with recirculation pumps at low capital cost.
Rinsability and rust protection
POWER CLEAN leaves a minimum of non-volatile residue, and that residue provides corrosion protection — in most cases it does not have to be removed before subsequent metal finishing. Once parts are completely dry they are protected from rust for approximately 7 to 15 days.
Recycling and disposal
Cleaning quality deteriorates quickly if contaminants stay in the washer tank, and an un-recycled bath creates large waste volumes and disposal costs. Decanting, membranes and micro-filtration units all remove suspended oils and extend bath life. Oil can also be separated from a cold, non-agitated tank by skimming, and mechanical filtration allows the solution to be recycled in a closed system.
Note the exception: where particulate materials such as chips, fines or certain organic chemicals are present in the bath, the spent solution must be processed and managed as hazardous waste. Always dispose in line with local effluent regulations.
Alkaline soak cleaning
Alkaline soak cleaning is the most widely used form of cleaning ahead of electroplating. It removes oil, grease, waxy solids, metallic particles, dust, carbon particles and silica by emulsification, dispersion and saponification, usually helped along by agitation — either moving the work or moving the solution.
What determines cleaning bath life
- The amount and type of soils introduced to the bath.
- The drag-out rate.
- Maintenance procedures and how often they are carried out.
- Concentration, chemical make-up and operating conditions.
The first two vary the most — they depend on the prior process chemistry, part size and geometry, and production rate — and they largely determine the third. A simple check on cleanliness is the water break test: a properly clean metal surface will hold an unbroken film of water. Unit cost is best derived from daily operating data: throughput, the amount and type of chemical additions, waste treatment cost, and dump frequency.
Applying it to different substrates
Most of the above is written for low carbon steel. The same alkaline soak cleaners and conditions generally work for high carbon steels, cast iron, high strength alloy steels, stainless steels, nickel and nickel alloys, and copper and copper alloys. Zinc and zinc-alloy die castings can often be cleaned but need lower temperatures and short immersion times to avoid etching. Aluminium needs a substantially different cycle — typically shorter times, lower temperature, or a desmutting step.
Finally, aqueous cleaning has its own disciplines: deionised process water, thorough drying, and appropriate rust and corrosion inhibitors. POWER CLEAN is low residue and free-rinsing, but its built-in inhibitors protect for a limited period — parts held longer, particularly high carbon steels, should be given a dedicated rust preventive.
