Simple Solutions That Work! Issue 8

Lubricant spraying is a necessary and critical function to ensuring a high quality manufactured part. Understanding the capabilities of the spray solution and tailoring how to adjust the spraying equipment to meet the specific spraying requirements for the casting or forging is therefore paramount. Lubricants provide a film formation and wetting on the mold surface. Primarily, the lubricant serves as a release agent, but furthermore, reduce corrosion, surface pitting, non-fill, porosity and solder in your castings. Finally, when using water soluble lubricants, the dilution ratio is adjusted to maintain the thermal balance of the tooling and the process speeds, input temperatures, and desired surface finish. Die casting dies and forging dies require spray with release agents not only for release and formability but for cooling purposes as well. Dies must be clean and free of excess lubricant, slag and or flash. Castings must have minimal porosity; excess coating of release/ forming lubricants can leave casting/forging with porosity and can result in blistering as well. While there are many factors that could result in a poor surface finish, this article will discuss how proper spraying solutions can result in the repeatability of clean and defect- free high-quality castings or forgings. Lubricants help to release the metal part from the mold. If too much lubricant is used – then porosity becomes a problem along with a poor part surface finish. If not enough is used – then the part may not properly release, causing defects and or serious die damage. Complex parts or high tolerance castings are more sensitive to spray inputs and can be negatively impacted by improper lubricant application. Some surface defects can be immediately obvious where as other defects are only discovered after machining or other secondary finishing processes. Surface porosity often shows in small holes in the surface, a defect that is often caused by humidity or excess die spray release agent on the surface. Another serious problem related to spray is solder. Solder can be caused from excess heat and insufficient lubricant protection. Conversely, if too much lubricant is applied, excess cooling may cause metal to pre-maturely freeze off resulting in improper fill and/or laminations of metal in the casting or forging. However, spraying evenly across the die area is often easier said than done. Particular parts with irregular shapes and various wall thicknesses, can create a challenge for the spray application. Unfortunately, to address the hot spots or challenge areas, over spraying is a natural instinct that may lead to increases in part problems and surface defects. Proper, precise spraying is critical, along with adjustability – to ensure intense spraying in hot areas versus low temperature areas. Therefore, how can we determine the right kind of spraying equipment that would work best for your ever-changing part production? We suggest thinking ahead in regard to what parts TROY TURNBULL President INDUSTRIAL INNOVATIONS ARTICLE TAKEAWAYS: • Lubricant spraying solutions provide important benefits and are critical to surface finish • How to spray evenly – especially with complex parts • Spraying is critical to clean, defect-free castings & forgings SPRAY SOLUTIONS THE KEY TO METAL FORMING 52