Exploring Innovative Lubrication Techniques in Metal Forming

“Wear caused by friction is one of the main reasons for the failure of equipment and parts,” states one Scientific Reports article. Lubricants themselves play a crucial role in the metal forming process for this reason, with fiction reduction working to minimize wear and tear in addition to preventing overheating (while also contributing to lower energy consumption). Due to the valuable role that they have in improving efficiency in the metal forming process, the research of lubricants has attracted many innovators in terms of finding new and efficient options — from eco-friendly solutions to those that involve differing techniques.

Exploring environmentally conscious options

While metal fabrication plays an essential role in several sectors, it’s imperative to realize its immense, general impact on the environment. Current statistics for 2023 show that for every ton of steel produced in the world, a concerning 1.83 tons of CO2 is emitted. As a result, the metal industry (in part) contributes 3.3 million tons to global emissions over the courses of a year. Companies in the metal fabrication industry are becoming more aware of their carbon footprint, however, bringing to light more sustainable practices. Environmental processes that offer more sustainability to the metal fabrication industry, for example, include those such as the use of recycled aluminum, copper, or steel, while some companies are now investing in renewable energy sources for their operations.

While various types of lubrication techniques are used in machining processes for enhancing machining performances, the conventional way of lubrication requires higher coolant, waste, and disposal cost. The result is a negative impact on the environment as well as operator health, according to a comprehensive review on different cooling and lubrication techniques in metal cutting. In the metal cutting sector, cooling and lubricating technologies that are appropriate for environmentally friendly manufacturing include nanofluid, solid lubricant, high pressure coolant, dry condition, near dry/MQL, and ionic liquids, to name just a few. Research published in Sustainable Materials and Technologies, Volume 36, points out that cutting fluids (CFs) perform various important roles (including lubrication and cooling) — however, the metal cutting industry “uses virtually solely mineral lubricants, which are not biodegradable and frequently include chemicals that are harmful to the environment and living beings.” This reality is noted to be largely due to the cost, as such lubricants are cheaper. As such, the research notes that “it is of the utmost importance to incorporate traditional CFs into the recycling process while maintaining the necessary conditions,” going on to note that recycling CFs can be done physically, chemically, and biologically.

In regard to sheet metal forming operations, research published by the National Library of Medicine regarding the tribological performance of eco-friendly, biodegradable lubricants notes that an increase in the cost of petroleum-based lubricants as well as environmental law regulations “has caused vegetable oils to become increasingly attractive in a wide range of metal-forming applications.” This includes a variety of natural and environmentally friendly oils, such as sunflower, coconut, and peanut oils among others. One of the approaches to reducing friction in a boundary lubrication regime involved using a diluted solution of saturated fatty acids in vegetable oil. The research goes on to state that Cortes et al. evaluated the tribological characteristics of sunflower oil, which was modified with titanium dioxide and silicon dioxide nanoparticles as lubricant additives. “It was found that the rheological behavior of the sunflower-based lubricant is dependent on the type and concentration of nanoparticles.”

Unique techniques for preventing tool wear

A research article by Tomasz Trzepieciński from the Department of Manufacturing Processes and Production Engineering at Rzeszow University of Technology in Poland explores various techniques for preventing tool wear in the sheet metal forming process. This includes the possibilities of increasing tool durability through the application of coatings produced by laser techniques, though the article delves into chemical vapor deposition as well, with “great emphasis” placed on self-lubricating and functional materials and coatings. For example, the research highlights several findings and underlines various points. Among many were the discovery that the use of Ni-based self-lubricating coatings contributes to a “more stable frictional behaviour in the functionalised 3D-printed tools,” while the related technique of selective laser melting is also beneficial when it comes to the preparation of functional materials with protective coatings (and with the incorporation of solid lubricants).

Structured and textured tool surfaces are another area explored in Trzepieciński’s research article.“Surface finishing may improve the tribological conditions between the tools and sheets,” states the article, which goes on to note that “Besides mill finishing, shot blasting and laser beam texturing, electrical discharge texturing (EDT) is the most common technology used for the surface finishing of metal sheets.” To further underline how the efficiency of lubrication can be increased under high-pressure conditions, it’s explained that the combination of modern coatings and the construction of self-lubricated tools (which contain microchannels and pockets “constituting a reservoir of lubricant”) are ‘very promising and effective.’

Lubrication plays an integral role in the metal forming process, playing key roles in aspects such as protecting tools from wear and tear, preventing overheating, etc. Due to its importance, innovative approaches seek to elevate efficiency — from eco-friendly solutions to unique techniques such as those that involve lasers.