Neat Cutting Oil - Filtration or Separation?

Neat cutting oil filtration is the key to ensure that they work as intended to provide optimum performance in critical machining operations. Proper filtration and reclamation of oil can offer real cost savings and pay dividends to the end user.

Neat cutting oils, also referred to as ‘straight oils’, are not diluted with water and are used where lubricity and superior cutting performance are key. Manufactured using mineral oil compounds they are often formulated using animal and vegetable oils to further improve lubrication and wetting properties. Having no water phase these oils do not offer the same cooling properties as water soluble coolants so are best avoided for high speed applications.

Gear cutting, broaching and deep hole boring are all examples of applications where neat oils usually offer better performance than water soluble products. Further fortified with extreme pressure additives they are capable of taking on higher loads and heavy stock removal without destroying the machine tool or component. Providing a superior surface finish and longer tool life is also a claim made by many neat oil suppliers.

Another important factor in making the decision to go with neat oil is the machine tool itself. Sliding head machines and multi spindle cam autos are examples where the design of the machine tool relies on the neat oil for slideway lubrication. Water soluble may not be the best choice here.

While good filtration is important to stop particulate re-circulation to the cutting zone it can also perform another function. Where neat cutting oils are used to machine recyclable materials such as brass or copper the swarf needs to be recovered, dried and packaged. This can be achieved automatically with a central management system sending only clean filtered oil back to the process. Recovered oil and swarf is pumped to the central filtration plant where the separated swarf is dried and briquetted. Recovered neat oil is returned to the central plant.

Neat oils dissipate heat more slowly than water soluble products. Having a centralised management system allows a chiller to be used centrally to prevent the cutting oil overheating allowing it to perform as the manufacturer intended.

This efficient operation, while representing an initial investment, can pay back quickly adding to a company profit line many times above its original purchase cost.

Central Cutting Oil Filtration - DinoFilter

The DinoFilter is ideally suited to form the basis of a Centralised Cutting Oil Management System. A supply and return pipework system is deployed to connect machine tools, each installed with a return pump station which replaces all existing filtration equipment. Neat cutting oil and swarf chips returning to the central DinoFilter are processed through the filter tank which contains several filter drums with exchangeable stainless filter cloth. Coolant is pumped from the inside of each drum, the decompression causes grinding fines to build as a filter cake on the outside of the filter mesh.

The drums are self cleaning, periodically each drum will turn against a stationary brush to remove the filter cake to the bottom of the DinoFilter tank to be removed by scraper. Clean cutting  oil is automatically supplied to the machine shop while  any loss from the the system from evaporation or drag out is made up as required by the topping up system.

The option to install oil recovery systems such as a briquette machine will ensure that not only is expensive material recovered but reclaimed neat oil can be sent back for reuse.

A typical DinoFilter installation to recover material for recycling through a briquette machine. Reclaimed cutting oil is returned to the process and new top up neat oil is added automatically.

The system operates 24/7 without the need for human intervention allowing engineers to get on with the manufacturing process.

This unit is capable of flow rates in excess of 2000 l/m. Each DinoFilter is manufactured to suit the application. Flow rates of 10,000 l/m are not uncommon.

A DinoFilter Central Management System using two units side by side to recover aluminium chips from the manufacturing process.

Equipped with specially modified skips to separate and return fluid back to the DinoFilter tanks the swarf is dry enough to be recycled.

It would be easy to add a briquette machine to this system if required in the future.