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With the high price of quality lubricants and the demand placed on machines to run harder and faster, there is a great need for high-performance lubricants. We expect lubricants to arrive on-site as they were advertised at the time of purchase: having the proper viscosity, base oil, performance characteristics, and last but certainly not least, the ability to meet certain contamination cleanliness targets. However, assuming every lubricant that arrives on the dock meets those expectations would not be reasonable-in fact, it would be downright dangerous.
The process of refining base stocks, blending these base stocks with additives at a blend plant, and delivering finished lubricants to a customer is quite lengthy and has significant potential for error. The base stock, being the main portion of the lubricant, can pose one of the biggest problems from the start as not all base oils are compatible with each other. Most lubricants are formulated from two to three different base stocks-a simple mix up of base oils in the blend plant could result in catastrophe right from the start. If the wrong additives are mixed in along the way, it only makes things worse. Many different lubricants may also be mixed at the blend plant using the same pump or hoses, and failure to flush the used equipment can result in cross-contamination. By now, you should have an idea of the many issues that can occur before you ever receive the lubricant on your dock. This is only magnified when the point-of-fill into drums occurs further down the supply chain.
A quality control process can help prevent bad lubricants from making their way into machines. The process should include a flow path that establishes where lubricants are to be delivered onsite, who oversees the quality process and what actions should be taken if a product is wrong or fails certain tests. A key objective of this process is inspecting the lubricant package and properties. This can begin even before a lubricant arrives on the receiving dock by requesting quality certificates from your lubricant supplier. These certificates generally come in the form of an oil analysis report that shows the approval of the batch by the manufacturer’s QA/QC department. The report will usually look different from that of an in-service lubricant as these are very specific to the lubricant’s composition.
Inspecting products is one of the easiest steps in the quality process, yet it is the step that is most often missed. Lubricants can be delivered in many ways. Greases are generally delivered in small boxes containing several tubes, while lubricating oils can be delivered in bulk by a truck, bulk totes, barrels, buckets and even quart jugs. If you are receiving bulk lubricants, it is critical that you obtain a quality control certificate as most vendors will not let you detain their truck to further examine the lubricant they are delivering. However, there are a few things that can be done before the lubricant is offloaded. You can verify that the pump they will offload with has been properly flushed and ensure that any other lubricant transfer equipment is capped or stored in a way that reduces the possibility of introducing contaminants.
Greases and the other smaller oil-filled containers mentioned above, such as barrels and buckets, also need to undergo an inspection. Key things to look for include the product name, expiration date and any physical abnormalities of the container. The product name should match exactly what was ordered, and if a viscosity is listed, it should also match. The expiration date should not be passed and in general should be more than a year in the future. Improper bung fit and rust on the threads should be questioned on oil barrels, as well as any missing seals on barrels and buckets. When inspecting a grease package, check the box for oil, as this is most likely a sign of the oil leaking out of the grease thickener and should be cause for concern.
Depending on factors such as the number of lubricants, criticality of equipment and availability of onsite laboratory equipment, we can go a step further than an inspection of the package and perform lubricant analysis on lubricants received. The level of analysis performed also depends on the previously mentioned factors. For instance, if you only have two lubricants onsite totaling 200 gallons, it is probably not cost-effective to have a laboratory full of oil analysis equipment. With that being said, there are some inexpensive tools that can be used to measure different properties of a lubricant, which can then be used as indicators of whether or not the lubricant supplied meets expectations. Viscosity is the most important physical property of a lubricant; every delivered lubricant should be tested to make sure it has the right viscosity. As I stated earlier, making lubricants is a long process and it is not unheard of to have a lubricant arrive that has a different viscosity than the one mentioned on its container. A simple visgage or viscosity comparator can be used on each delivery for a quick “go/no-go” acceptance test.
Depending on the size of your program, another tool you can use to test incoming lubricants is a particle counter. This will tell you how clean your oil is — remember, not all new oils are clean oils. For more critical machines, you might even decide to send samples to an offsite laboratory before putting newly-delivered lubricants into service. An oil analysis laboratory can give you a deeper understanding of the lubricant to confirm that it is up to specifications.
So, what happens when abnormalities are found with lubricant deliveries? This is usually going to depend on the contract terms that you have with your lubricant vendor and what the issue is with the lubricants. If there were problems found with the packaging such as broken seals or base oil leaking out of grease tubes, you can probably ask for a straight exchange for the same product. When it comes to more in-depth inspections such as an oil analysis report, if the report came up showing a different viscosity or incorrect additives, these should be sent back. Risks like this are a good reason to quarantine your lubricants while they are being analyzed; if you fill a bulk tank with bad lubricant, you could potentially cascade the issue and now at least have more problematic oil than just the initial barrel, even if the contamination isn’t spread into your plant’s machines. If you have a cleanliness contract with your vendor stating how clean your lubricants should be when they arrive, and they bring them to you with a higher level of contaminants, you might be able to filter them yourself and get a credit towards your next purchase. This is generally done because the problem can be fixed, and a barrel exchange can be avoided.
Implementing a quality control process at your plant can save time, money and potential headaches. Creating a step-by-step guide that details the key members and their roles in the process will help to ensure it is a success.