Good solvent degreasing practice – Part 2

Grinding with Oest oils

How to save £1000’s per annum.

In my last article, “What is good solvent degreasing Practice – part 1“, I discussed the foaming problem faced by manufacturers when oil companies sell their wares for one task only, cutting or forming metal components.  The expert approach as taken by The Oest Group is to consider what happens next to the component, and typically this is cleaning with detergents or solvent degreasing. The reasons are many, all are important, and here are just a few common examples: –

  • The component will be assembled with other parts prior to shipping up the chain of supply.
  • Inspection on a CMM. Oily parts make a mess, contaminate precision equipment and yield false measurements
  • Plating, Alochrom, painting, anodising, weld, brazing and bonding all need clean surfaces to minimise failure rates.

Would you run a CNC with a 40,000 rpm spindle using cheap tools and substandard coolant?  Spraypaint a car body without first removing all oils and greases? Cross the road without looking left and right first?  No, No, and No, so why do so many companies put parts in a cleaning machine with the expectation everything will turn out fine, day in day out?

Oest recognised that bad chemistry impacts solvent degreasing systems having a real effect on a businesses bottom line.

Twenty years ago, Oest, working with solvent producers like SAFECHEM, developed a range of manufacturing oils with their OSC additive package built-in that provided the necessary manufacturing qualities combined with high cleanability levels and compatibility with solvent degreasing systems.

We already know foaming is a potential issue, but the Oest OSC additive package covers many other aspects. But what else does a good quality manufacturing oil offer?

Co-boiling is a condition where the base oil or one or more of the additives boils at a similar temperature to the solvent.  This results in these fractions distilling with the solvent, remaining in the system and not being removed.  They build up in the system to a point where the parts washed start to show signs of inadequate cleaning.

Thermal decomposition

Happens when oils are held at elevated temperatures in the vapour generator (boiler, still).  Oils start breaking down into undesirable compounds that can form a hard coal-like crust inside the vapour generator. This crust acts like insulation reducing the heating capacity of the boiler.  The heating works at 100%, more of the time maintaining temperature, accelerating the crust baking effect.  Some decomposed oils remain liquid and can become co-boilers.

Another effect of thermal decomposition

Is the production of acidic or alkalines.  These are managed by the solvent stabilisers, which is fine but can become costly if the decomposition is continuous and severe.

Metal types

Machined or formed also impact the additives used in manufacturing oils, additives such as corrosion inhibitors to protect iron and ferrous metals from staining and discolouration.

So what does this mean for the end-user operating a regular size solvent degreasing machine?

Here’s an example from a company manufacturing parts that go through a grinding operation.

  1. Their solvent degreasing machine has a 350l first fill of solvent at an approx. £2600.
  2. The machine operates 3 shift, 7 days, 52 Weeks pa  (8760 hrs/pa) and removes a neat grinding oil
  3. In house maintenance overhead £26/hr (if you need the OEM to carry this out it will cost £60-£160/hr plus travel costs)
  4. The system suffers co-distillation and reaches a point of no return at 6 months of operating, requiring a bath exchange.
  5. It also suffers thermal decomposition requiring the vapour generator to be cleaned monthly.
  6. As decomposed oil builds up on the inside of the vapour generator, it increases the heating demand by an average of 3% at £0.14kWh
  7. The thermal decomposition means 30% more stabiliser is required than the 6 litres pa expected.

Point 1 Assuming the machine is already filled, the additional solvent would cost approx. £5200.00 pa.

Point 4  Emptying and refilling the machine with fresh solvent 4 hrs £104.00

Point 5 Machine downtime, labour to clean the vapour generator.  An average total time of 3.5 hours x 12 times/pa £1029.00

Point 7 The additional heating load adds approximately £1,300/pa to the electricity bill

Point 8 A 30% increase in stabiliser can add up to £400/pa additional cost.


Suffering these avoidable problems costs the company over £8,000.00 per annum.

This headline figure is only the tip of the iceberg. Issues like this lead to damaged heat exchangers increased wear and tear on valves and vacuum pumps, all of which will require replacement or servicing, adding to the downtime, and putting pressure on maintenance staff and production volumes.

In a single step, companies remove these unwanted costs without impacting the operating overheads or performance by switching to an Oest product with their unique OSC additive package.  If you have a solvent degreasing machine costing more to run than you would expect or it shows up in production meetings all too often contact us and we will help you reduce cost and production problems