Did you know that the slinky was invented by accident when naval engineer Richard Jones was trying to make a meter to monitor power on naval battleships? Jones dropped a tension spring and just like that a world-wide phenomenon was born. But what about those accidents that are less happy, the one’s you don’t notice until it’s almost too late? Here, Chris Johnson, managing director of specialist bearing supplier SMB Bearings, explores how to keep the ball rolling when standard bearing lubrication lets you down.
Original equipment manufacturers have a difficult job. Not only are they expected to design and introduce innovative products to market, they also have to meet regulations, pass testing requirements and stay on budget. So it’s not surprising that, occasionally, even the best OEM can overlook something, especially when it comes to the little things — like bearings.
Is standard good enough?
Choosing the right bearing for your machine is vital. For example, selecting a ceramic bearing for use in a machine that handles heavy loads may result in machine failure. Selecting the right material, size and type of bearing to suit your needs can be a long, complex process, so it’s hardly surprising that lubrication can be overlooked.
Quite often, OEMs will accept the lubrication that is supplied as standard with their bearings. However, standard lubricant only goes so far and if you are expecting your machine to operate in challenging environments you need to pay closer attention. For example, in high temperature applications, lubrication choice can have as much of a detrimental effect on your machinery as if you’d specified the wrong bearing altogether.
Shielded stainless steel bearings are capable of performing in temperatures up to 150 degrees Celsius. However, the standard lubrication that is often supplied with these bearings is only operational up to 110 degrees Celsius. So, while you think you’ve specified a bearing that can cope, the lubrication will let your machine down and performance will suffer.
Have you assessed all angles?
The ambient environment your machinery needs to perform in isn’t the only thing that can get your lubrication hot under the collar. Let’s consider a food processing setting for a moment. Machines are subjected to regular wash down and are often exposed to steam, not to mention the fact that any leaking lubrication that makes its way into food products can lead to very expensive product recalls.
So, when you’re designing machinery for this sector you need to consider all angles when it comes to bearing lubrication; particularly whether your lubricant will stick to those angles. For example, in bearings being used on a vertical shaft a common problem is grease coming to rest on the bottom bearing shield and eventually leaking out.
In this scenario, not only do you risk contaminating food, you are also losing lubrication and machine performance will be adversely affected. You need to specify a grease that is stiff enough to stay in place, can withstand washout and is also certified as NSF food-grade.
When standard won’t do
It’s easy to overlook some of these factors. For instance, we worked with a client that supplied security cameras for use in a hot climate. It wasn’t until the cameras were in place that anyone realised that the bearing lubricant was evaporating into the unit the camera was enclosed in, rendering the camera ineffective.
In these instances, there’s no need to panic. You simply need to follow the path this client took and speak to a bearing supplier to specify the best replacement lubricant and re-lubricate your bearings. Small accidents in original equipment design and manufacturing are never truly the disaster they seem. After all, we always learn something; and everyone does love a slinky.