To maintain machine tool accuracy and productivity, it’s vital to minimise friction in slideways and prevent wear. This can be a challenge, however, because of the tendency of slideways to exhibit slip-stick motions.
When a slideway system has elasticity, the force needed to expand or compress a spring will likely differ from the force needed to move the desired object, resulting in a certain jerkiness in the movement. For example, when the mass is being pulled by spring, it will not move immediately because friction with the surface will resist it. Instead, the force will be loaded onto the spring until it overcomes this friction. At this point, the force held in the spring will be more than what is needed to move it, resulting in the jerky movement. This is where good lubrication comes in.
When selecting a slideway lubricant, there are a few factors to consider.
Vertical and horizontal slideways
Vertical and horizontal slideways typically require different properties from a lubricant to prevent it from escaping too quickly. In particular, vertical and inclined slideways are more inclined to runoff, so an oil with greater tackiness and viscosity, such as Mobil Vactra 3 or 4, will generally be more suitable than their horizontal counterparts like Mobil Vactra 2.
While it may often be overlooked, it’s important to pick a lubricant that’s compatible with the surface materials it’s protecting. Different metals may require different additives or varying levels of lubrication, so you will want to pick one that’s designed for those metal (or even non-metal) surfaces.
Is the OEM-suggested lubricant always the best?
OEMs will generally recommend a particular lubricant for their machines, but this is not necessarily the optimal choice for every environment. If you are experiencing excessive wear with a machine, an expert may be able to suggest a better alternative lubricant. To avoid invalidating any warranty, make sure you obtain permission from the OEM before switching fluids.
Is a hydraulic oil needed?
If a slideway uses hydraulic systems, you may need oil that combines the desirable properties of slideway oil with those of a hydraulic oil. Mobile Vactra 2, for example, is suitable for use with horizontal slideways and as a moderate-duty hydraulic fluid.
Other desirable properties
Once you have identified some potential lubricants, there are a few characteristics that are also generally desirable. Adhesiveness, for example, will prevent a lubricant from being removed from important surfaces, while anti-wear and anti-corrosive additives can protect your equipment. You should also look for good load-carrying performance and general