Choosing a Fluid For Metal Cutting

There’s lots to think about when selecting a lubricating fluid for a metal cutting process. If you’ve been using cutting lubricants previously and have had trouble then you’ll need to diagnose what the problem has been with current or previous materials, which can be more complicated that it might at first seem. To help you know what to consider for your machinery here are some of the most important factors to consider for looking at current problems with cutting fluids and considering investing in new ones.

Metal and Material

This is one of the most important considerations to make. If you’re working with harder metals, such as stainless steel, or an alloy that is geared towards strength in particular, then you will probably have more trouble selecting a metal cutting lubricant that works for you. For such instances, finding a lubricant which is engineered towards performance at really high pressures will be necessary. As such, the simpler oil based lubricants may not suffice and instead a lubricant with additives such as chlorine may be required in order to perform under the demanding conditions of working with these types of metals.

Softer metals including brass and aluminium however aren’t as demanding, and using simpler oil based fluids will suffice. You will need to ensure however, as Machinery Lubrication magazine point out, that you are not using staining fluids. Most lubricants used for this purpose will specify that they are ‘non-staining’ oils. Lubricants for the aluminium extrusion process for example, tend to be synthetic rather than oil based. Whilst aluminium as a metal is soft and workable, because it needs to be heated to very high temperatures as part of the extrusion process. This requires metal working fluids used to ease the aluminium through the extrusion process (it is driven through a die by intense pressure) the fluid has to be able to perform at very high temperatures, as described here.

Budget and Cost

This shouldn’t be your priority when choosing a fluid, but it does play a part. Whist some metal cutting fluid solutions can be very expensive, often the simpler oil based solutions that don’t require a great deal of additives or engineering can provide cost effective solutions. Our advice on this point would simply be only buy a complicated fluid if your sure you need one. Examine the metals and processes you’re working with, and see if a straightforward cutting fluid will be enough. If so, you could make a good saving.

If you prioritise cost when you ought to have invested in a better and more suitable cutting fluid should have been used, you can quite easily end up costing yourself more in the long run, in poor performing processes and damage. Use a simple fluid where you can, but don’t take a risk with cutting corners.

Environmental Regulation

Something that can be overlooked until the later stages of selecting a fluid solution are the environmental regulations that surround your work site. Look at the guidelines for drainage and water contamination around the industrial site you work on. Some chemicals that are used in the more complex lubricants aren’t permitted for use, as well as some oil based lubricants, because solvents then need to be used to mix them with water for cleaning and drainage.

It’s best to get this work out of the way at the start of the project, to make sure you don’t hit a snag later on and have to rethink your choice once you’ve invested time, effort and money into working on a solution.

Machinery Process

Different machinery processes will require different fluids. Not just the metal you’re working with, but what you’re doing with it. Again, as Machinery Lubricant magazine illustrates, a screw machine risks cross contamination between the different fluids used in the process. To solve this problem, businesses have had to develop solutions with fluids which serve two or three different purposes at once. This means that the same fluid is used in different areas of the machinery. As such, if they end up mixed, no difference is made given that it’s the same material.

If you’re using machinery that’s likely to cause contamination of fluids during its processes, its worth bearing in mind that having a specialised fluid developed that can do more than one job can solve the problem of having three different materials mixing.