September 20, 2016 / best practices, blade failure, blade life, continuous improvement, Cost Management, operator training, preventative maintenance, resource allocation, ROI, strategic planning
Most metal-cutting professionals agree that lubricants are a critical part of any sawing operation. As explained in the reference guide, User Error or Machine Error?, insufficient sawing fluid can cause a host of metal-cutting issues, from premature blade failure to poor cut quality.
Metal-cutting fluids save maintenance time, improve cut quality, and extend tooling life. However, not all lubricating options are created equally. As this blog post describes, managers have a wide range of lubrication options available to them. And while fluid selection may seem like a small detail, it should be treated like any other operational purchase—with both strategy and cost in mind.
One lubricant choice that many machine shops overlook is Minimum Quantity Lubrication (MQL). This alternative option sprays a very small quantity of lubricant precisely on the cutting surface, eliminating any cutting fluid waste. In fact, many consider it a near-dry process, as less than 2 percent of the fluid adheres to the chips.
MQL is great for smaller saws and for structural applications, but it is also versatile enough to be used in both precision circular sawing and band sawing operations. To help machine shops determine whether or not MQL is a good fit for their operation, below are just a few of its key benefits:
- Lower long-term costs. Although MQL fluids typically cost substantially more per gallon, less than 1/10,000 of the amount of fluid is used. It also eliminates the need to invest in reclamation equipment such as sumps, recyclers, containers, pumps, or filtration devices.
- Less waste. Another major benefit is that MQL is a much more sustainable option. As an article from Fabricating & Metalworking discusses, metal chips produced during MQL machining are much cleaner than conventional approaches. Near-dry chips are easier to recycle and more valuable as a recycled material. Conversely, “wet” processes like flood coolants produce “increased and on-going lifecycle costs in the form of energy consumption, chemical maintenance, water make-up, disposal of used cutting fluids, and then starting the cycle of waste/recovery all over again by replenishing consumed fluids,” the article states.
- Less maintenance. The smaller amount of coolant means that less fluid sticks to the part. This reduces the need to clean parts after cutting. Also, MQL fluids do not have to be diluted with water. Flood coolants, however, have to be mixed with water, and operators need to monitor the concentration as fluid is lost, water evaporates, etc.
Of course, changing over to MQL is not as simple as just plugging in a new lubrication system. Implementation will require some research, training, and upfront investment. In fact, as a recent article from Modern Machine Shop points out, MQL can also present some manufacturing challenges. According to the magazine, operations managers should consider the following before deciding to implement MQL:
- MQL does not have comparable chip evacuation abilities to those of wet machining.
- MQL is still not well suited for deep-hole drilling, energy-intensive processes such as grinding, special operations like honing and small-hole drilling, or for difficult-to-machine materials such as titanium and nickel-based alloys.
- MQL still produces a very fine mist, which can be more difficult to filter.
- MQL implementation may require changes to the machine tool and processing strategy.
Although MQL may not be suitable for every shop, in many cases, it can offer significant advantages to your business, your employees, and the environment—three major reasons to at least consider using it in your metal-cutting operations.
For more information about what is needed to use MQL, including equipment requirements and some “rules of thumb,” you can download a copy of The MQL Handbook here.