Please find below a list of FAQs related to our products and services for Shell Metalworking. If your question is not on this list, please  contact us.
|
|
1) How do I mix a water extendable coolant?
|
2) What are possible reasons for foam problems with water soluble coolants?
|
3) Why do emulsions sometimes have a "Monday Morning” smell" ?
|
4) Why can water miscible fluids lose their corrosion protection performance?
|
5) What are emulsifiers?
|
6) Is there a fire risk associated with the use of neat cutting oils?
|
7) When do you use water solubles and when the neat cutting oils?
|
8) What are the advantages using ester- or vegetable oils?
|
| 9) What are multi-functional oils?
|
10) What are the 5 main factors that influence the performance of a soluble oil?
|
 |
1) How do I mix a water extendable coolant?
|
- Both water and concentrate should be at room temperature. Big differences in temperature lead to instability of the resulting mix. - The coolant concentrate must be added to the water while continually stirring, never visa versa. - The use of an automatic mixer is strongly recommended.
|
|
 Back To Top |
|
2) What are possible reasons for foam problems with water soluble coolants?
|
- The emulsion is instable due to incorrect mixing or from bacterial attack. - The coolant sump is too small or not filled to an appropriate level, giving the entrapped air not enough time to dissipate. - The pump is sucking air - cavitating. - The concentration is too high. - Contamination with surfactants, e.g. from machine cleaners. - Incorrect product selection for the existing water quality.
|
|
| Back To Top |
|
3) Why do emulsions sometimes have a "Monday Morning” smell" ?
|
This smell is caused by a microbial attack of the emulsion by bacteria, yeast and fungi. Reasons for the attack are: - Reduced biostability due to low concentration. - Tramp oil on the surface of the emulsion and poor aeration promote the growth of anaerobic bacteria. - Instable emulsions (see item 1) have low bio resistance. - The mixing water has microbial contamination. - The machines and systems have not been cleaned before the refill.
|
|
| Back To Top |
|
4) Why can water miscible fluids lose their corrosion protection performance?
|
- The concentration is too low. - Salts accumulate due to top up with hard water. - The emulsion is unstable due to wrong mixing. - The pH has fallen due to biological attack. - Tramp oil may give the wrong concentration readings.
|
|
5) What are emulsifiers?
|
Emulsifiers are chemical molecules which allow the stable distribution of oil droplets in water. There are 3 main groups which can be classified by their polarity: - Anionic (Potassium or Sodium soaps, Amine compounds and Sulphonates) - Nonionic (Ethoxylated fatty alcohols, fatty acids and fatty amides) - Cationic (Quaternary Ammonium Compounds) are rarely used in water soluble coolants.
|
|
| Back To Top |
|
6) Is there a fire risk associated with the use of neat cutting oils?
|
Yes. All mineral oils, as well as vegetable oils or esters, have an explosion range. For Mineral oils it is commonly between 0.6 and 6.5 vol%. Within this range there is a danger of explosion if there are ignition sources such as broken tools. The mix of oil and air in a machine tool should be kept either below 0.6 vol% by using local exhaust ventilation (LEV) units or above the upper explosion limit by heavy flooding. As the flashpoint of neat cutting oils is mostly far above 100 °C, this value usually has a smaller impact when fire occurs.
|
|
| Back To Top |
|
7) When do you use water solubles and when the neat cutting oils?
|
- Water soluble coolants have 4 times higher cooling power compared to neat oils and are used when cooling is the major demand. - Neat oils have the advantage of higher lubrication power.
|
|
| Back To Top |
|
8) What are the advantages using ester- or vegetable oils?
|
- The high polarity of these products allows high wetting of the cutting zone and gives excellent lubrication. - Compared to mineral oils of similar viscosity, they have a much smaller tendency to create oil mist and vapour. This results in lower consumption and a cleaner working environment. - Their composition is similar to the protective layer of the skin, therefore they have better compatibility than mineral oil. - They are produced from renewable material and are therefore more environmentally friendly.
|
|
| Back To Top |
|
| 9) What are multi-functional oils?
|
- Multi-functional oils are coolants. The coolant concentrate is also suitable for hydraulic, spindle and slideway lubrication. - Multi-functional oils can be used undiluted or as water soluble coolant. - Contamination of the coolant by "tramp oils" are no longer a problem.
|
|
| Back To Top |
|
10) What are the 5 main factors that influence the performance of a soluble oil?
|
- The water quality - Tramp oil - Microbiological attack (bacteria, yeast, fungi) - Chemical reaction with the machined material - The temperature being too high or too low
|
|
| Back To Top |
|