February 2022 Volume 4

MAINTENANCE

Forging Lubrication FAQ and Troubleshooting, Part 1 By Matt Natale and Frank Sobnosky

High-temperature metalforming is a complex and nuanced process with many common issues associated. Engineers and forging personnel spend their careers solving these problems and work diligently to solve new ones which arise. Often though, changes in processes and specifically in lubricant technologies being used in the plant cause issues which are solved through the cooperation of the forging personnel and the lubricant manufacturer. Throughout AML Industries’ 33 years in business, we have encountered numerous issues and questions in the field. As a result, we can solve lube-related forging problems quickly and efficiently. Despite this, there are still problems to be solved due to variables, both known and unknown, in the forging process. In this article, we will be highlighting several common problems that we have found in the field and advice on solving them. These solutions are not by any means comprehensive, but may help lead to further, more specific solutions. But without further ado, let’s solve some forging problems! How Do I Prevent My Spray Nozzles from Clogging with Dried Lubricant? Spray nozzle clogging is among the most common problems AML sees in the field. When a graphite based forging lubricant is used, small graphite particles and particle agglomerates can fall out of dispersion in the spray nozzle leading to an inability for the lubricant to flow through the spray nozzle properly. This occurs when solid particulate becomes lodged in the spray nozzle area. This solid buildup prevents proper spray patterns and negatively affects volume output, both of which are key to performance. To prevent this in a reciprocating system, the best practice is to spray lubricant when the reciprocator moves into the forge press and spray an alternating combination of warm water and air as the reciprocator withdraws from the press. This will reduce the buildup of solid material in the system. During downtime it is also advantageous to flush the lubricant lines with water, clean out existing nozzles, and replace these nozzles regularly. Many have different definitions of “downtime,” but in our experience an hour of downtime is best treated the same as a whole week when it comes to nozzle cleaning. By having fluid flowing through the system constantly, clogging issues can be greatly minimized. While it takes a great deal of effort to mitigate clogging, properly flowing lubricant is essential to a proper forging.

What are Some Best Practices for Mixing Diluted Lubricant? Our advice for mixing diluted lubricant is best looked at as a guideline rather than a rule. Several variables must be considered, including the size and shape of the tank, the fluid being mixed and howdiluted the lubricant beingmixed is, the viscosity and properties of the fluid, the blade being used for mixing, and other factors as well. When a tank is a shape other than a circle, care must be taken so that solids that fall out of dispersion do not build up in the corners of the tank. This leads to a loss of valuable solids that should be put onto dies as well as a harbor for potential bacteria in the tank. Additionally, the blade should be simple in nature with only mixing and not shearing action. AMLUBE lubricants are sheared and well dispersed when they leave the plant, and dispersion is not required by the customer, only agitation. Additionally, the RPM’s needed to mix the fluid is not a mathematical calculation that is worth doing. Empirical testing of mixing speed is best, and our advice is to mix the fluid enough that the fluid folds over itself but does not cause a vortex in the tank. When a full vortex shows in the tank, air can be entrained in the dispersion which can lead to problems in the lubricant. Additionally, when the fluid is overmixed, particles can become sheared and lead to damage of the binder system which can be fatal to the lubricant technology. When undermixed, settlement can occur which leads to a loss of solids in the dispersion which can ruin the lubrication action.

FIA MAGAZINE | FEBRUARY 2022 24