August 2023 Volume 5

EQUIPMENT & TECHNOLOGY

The Evolution of Tool and Die Making for Forges By Dean M. Peters

The modern forging tool and die industry began its technological journey about 160 years ago with the advent of specialized tool alloys that can withstand the harsh conditions to which they are subjected. During the decades since, die materials and customized thermal treatments were developed to provide longer die life. The techniques by which dies are sunk have also followed an extraordinary evolutionary path, as technology propelled basic machining practices into a world of CAD/CAM designs being digitally fed into CNC machining centers with multiple axis capabilities. Complex die patterns can now be machined into raw die blocks faster and more accurately, then coated by various means to better resist the wear and tear of the forging process.

Tool steels and the dies made from them are the bedrock of the modern forging industry. These are the materials from which are made the impressions that a modern forge would, through the controlled application of force by a forging press or impact by a forging hammer, shape a material into a wrought metal component. The application of tool steels to die making is a tricky and sophisticated business. According to ASM International’s Metals Handbook Desk Edition: “No single tool material combines maximum wear resistance, toughness, and resistance to softening at elevated temperatures. Consequently, the selection of the proper tool material for a given application often requires a trade-off to achieve the optimal combination of properties.” Given this, the tool and die industry is one driven by science and technology. It succeeds on the merits of the experienced people engaged in the manufacture of forgings working in tandem with those engaged in the design and execution of tools and dies for each specific application. They are craftsmen and artisans all. Until about 150 years ago most tool steels were of the plain carbon variety, but shortly after the Civil War tool steel alloys became more complex. The need to meet harsher and tougher service demands resulted in the use of alloying elements such as tungsten, molybdenum, vanadium, manganese, chromium, and others. Alloy formulations helped tool steels last longer by preventing cracking in service and under cyclical elevated thermal conditions. Alloying trends continue into modern times, as tool steels must withstand the harshest of conditions, such as rapidly applied extreme loads, at elevated temperatures, cycle after cycle, and without cracking or premature wear. High alloying, in turn, requires careful processing of tool steels as they are forged and/or rolled. Generally, die blocks ready for sinking have been carefully inspected for hardness, grain size, and other metallurgical parameters after closely controlled thermal treatments have been applied. As ASM puts it, these “precise production practices and stringent quality controls contribute to the high cost of tool steels, as do the expensive alloying elements they contain.” For the most part, modern tool and die makers are machine shops that employ talented and experienced machinists. These machining

professionals develop and hone their skills through many years of experience. This happens in an industrial environment in which technological advances in machinery, materials, cryogenic and thermal treatments, digitization, non-contact measurements, higher speed machines and cutting tools, the use of coatings and other techniques have changed the landscape of their working environment. It's All About the Tool Path We spoke with tooling professionals who experienced the modern evolution of tool and die making firsthand. John Misuraca is vice president of sales for Forge Die and Tool Corp. (FDTC), Farmington, Mich., a supplier of tools and dies to the forging industry in support of the aerospace, automotive and heavy equipment industries. He started his career in the industry nearly 50 years ago as a machinist. “Back when I started in this industry, we were using Cincinnati Hydrotel milling machines, which used patterns and templates to sink dies,” said Misuraca. “We had about 60 of these in our shop before computers came into play. The 1980s marked the advent of NC and CNC machine tools, which were driven by designs executed via CAD/CAM programs such as Catia and Unigraphics to machine tooling dies for the forging companies or forgers.” During this technological shift, highly-skilled machinists who ran the Hydrotels had to re-focus their skills and apply them to CNC machines, into which were fed CAD/CAM die designs. The work done by 60 Hydrotels, which required one operator per machine, could now be done by about a dozen CNC machines that were not as operator-intensive. Also, most of the CNC machines have the same control system, so any trained operator could program and run all similar machines in the shop, thereby improving overall plant efficiency and on the shop floor and the utility of the machinists. At FDTC they sink dies from 12-in. square to 200-in., with the largest dies weighing up to 220,000 lbs. The company claims some of their dies are among the largest made anywhere. Most of their larger machines can handle unlimited weight because the tables are stationary. The company has eight very large milling machines that can handle extraordinary weights, and more than 20 smaller

FIA MAGAZINE | AUGUST 2023 16