Why is perchloroethylene the industry benchmark for degreasing?
Why Perchloroethylen?
When it comes to high precision cleaning – particularly degreasing for applications where large amounts of oils and/or parts with complex geometry are involved – perchloroethylene (Perc) remains the benchmark thanks to its many unique properties, in particular:
• High stability
› Perc remains largely unaffected by boiling or distillation, resulting in long solvent lifespan/fewer bath exchanges > extremely economical usage
› Highly effective re-stabilization system: Among all the stabilizers developed for both halogenated and non-halogenated solvents, stabilizers for Perc are regarded to be the most efficient on demanding applications
• High process safety
› Highly compatible with all metal working oils (e.g. critical additives and evaporating oils) with only very few exemptions
›› Bath quality and bath lifespan remain unaffected
›› The very few constraints relating to the choice of metal working oils also enable a faster and more efficient production process
• Easy measurement possibilities
› Easy on-site monitoring of the stabilizer concentration (e.g. acid acceptance, alkalinity and pH value) via test kits to minimize risk of acidification of the solvent and corrosion of the cleaning machine
› By measurement of the density (Perc: 1.62 g/ml vs corrosion protection oil: 0.8-0.9 g/ml) the quantity of corrosion protection oil in the corrosion protection tank can be easily, reliably and precisely determined. There is practically no simpler nor more reliable method for measuring corrosion protection in other solvent types as for Perc.
• Very good creeping abilities to get into tight places like crevices and blind holes with excellent drying properties – making Perc a superior cleaning media for tiny tubes and deep-drawn components
• Non-flammability
• Particularly effective for applications where a large amount of oil needs to be cleaned off – with much less waste generated (< 5% of Perc residue in waste stream) thanks to efficient recycling behavior > economic efficiency!
• The high density of Perc means it can more effectively remove small particles such as chips compared to other solvent types, and facilitate the use of ultrasonic in cleaning machines
Is it safe to use Perchloroethylene?
Like all chemicals, Perc must be handled with care. The unique properties of Perc can also pose certain risks to workers and the environment. Its good creeping abilities, for example, can present risk of penetration through the ground.
HOWEVER – Not every cleaning application with Perc can be replaced by an alternative substance. Substitution may lead to insufficient degreasing results that are not acceptable for product/parts quality.
Solvent risk management is therefore fundamental to ensuring the safe and sustainable use of Perc.
The use of modern closed (vacuum type) cleaning machine represents the core of a proper risk management approach. Solvent emissions can be reduced to an absolute minimum (also thanks to the recovery of activated carbon). The hermetically sealed construction means there is no risk of contaminating ground water with maximum worker safety standards. The built-in distillation unit can continuously recover and purify used Perc particularly well, thereby significantly reducing solvent consumption (hence human contact with the chemical) as well as waste while lowering overall cleaning costs.
Nowadays, machine manufacturers are offering both modern closed cleaning systems for chlorinated solvents (Perc), as well as multisolvent cleaning machines capable of running chlorinated solvents or modified alcohols. This provides users greater flexibility and reassurance in their machine purchase decision.
The use of the SAFE-TAINER™ System, a closed loop solvent delivery system representing the best practice model for safe and responsible handling of Perc, further facilitates virtually emission-free and spill-free transport and storage of Perc. Used in combination with closed cleaning equipment, the SAFE-TAINER™ System is considered to be the best available technology (BAT)1 for safe handling of solvents.
1 Validated by FH Münster University of Applied Sciences, 2018
Perchloroethylene remains the industry benchmark for degreasing
Perc enables a high level of process stability and degreasing of critical complex components, and is especially effective for cleaning applications where there is high oil entry with high throughput requirements. These unique properties make Perc an exceptional cleaning agent for high-value manufacturing sectors such as aerospace and defense, medical technology, precision engineering and automotive since there is very low tolerance of contaminant or rinse water residue in parts.
Another significant advantage is cost efficiency – cost per cleaned part can be much lower for Perc compared to other solvent types (and much lower still compared to aqueous cleaning) – thanks to its efficient recycling behavior and long solvent lifespan.
Used with modern cleaning equipment and a proper risk management solution (e.g. the SAFE-TAINER™ System), combined with the right solvent maintenance practices (enabled by test kits and stabilizers), Perc remains an excellent technical solution that is both economical and sustainable.
