b'high-horsepower cuts, and complex geometries often were created using form tools. Before CNC machines, form tools were the standard method for creating complex geometries, so their use on the first CNC ma-chines was a natural progression.CNC machines and programmingUsing form tools to generate complex geometries have changed how cutting toolswas especially normal for large manufacturers, which are made and maintained. frequently had rooms full of tool grinding equipment, along with teams of craftspeople to operate the machin-ery. Companies that did not make their own tools could W hen I started my career in metalworking 28 yearseasily find local shops that specialized in cutting tools.ago, machine shops were in a transformationalForm tools have several benefits. The tools combine period. Small shops still relied heavily on conventionaloperations, reducing cycle times and the number of machine tools and the skill of the craftspeople whoinputs needed at machines. Most importantly, form ran them. But CNC machine tools were becoming af- tools decrease opportunities for mistakes. But the fordable, and these shops quickly were adopting thetools can increase lead times for part introductions, technology. inflate inventory costs and become obsolete with en-Automation and productivity always have been thegineering changes.most significant attributes of CNC equipment, andMarket conditions and concepts like lean manufac-they were the primary selling points in the early days.turing have altered the way that parts are manufac-It was multi-axis interpolation, or the ability to drivetured. The desire to reduce inventory costs has driven a cutting tool through curves and angles, that be- reductions in manufacturing lot sizes and demanded came the foundation of the next series of technologi- lower lead times. Success in these changing condi-cal advances. Machine tool builders realized that low- tions requires shops to be agile, and using custom volume shops were an untapped market, so builderstools can inhibit agility.started looking for technologies that would be advan- As machine tool programming advanced, machine tageous. Simplified programming was considered ashops began to migrate away from complex form tools. feature that would allow machine tool builders to pen- It is now common for engineers and programmers to etrate the small-shop market. Machine tool buildersrely on modern CAM systems that use off-the-shelf began introducing technologies like conversationalcutting tools to create complex geometries. An exam-controls and easy-to-use canned cycles, which madeple is cutting O-ring and lock ring grooves on a lathe. programming easier and allowed small shops to tran- Groove geometry for O-rings and lock rings varies sition to CNC machine tools. with each part. In the past, a tool would be ground to Advances in CNC programing also included afford- the exact shape of a groove, making the tool part-spe-able graphical CAM software that is now commoncific. It is possible today to use a single indexable tool at all types of machine shops. Before the advent ofto make an infinite number of groove shapes through graphics-based CAM packages, programmers wouldmodern programming techniques. This eliminates the write code by hand, copy and edit existing programsneed for custom tools, inventory, maintenance costs and the possibility of obsolescence.It is now common for engineers and programmersCNC advancements modified not only to rely on modern CAM systems that use off-the- work at the machine shop but the way that shelf cutting tools to create complex geometries. cutting tools are manufactured. Before, tool grinding shops both large and small relied on highly skilled craftspeople. The or use complex text-based CAM programs. Advance- people who make cutting tools are some of the most ments in programming have significantly improvedtalented individuals in manufacturing. Tool grind-productivity and made the creation of complex ge- ing with conventional machines takes years to mas-ometries easy. ter. Craftspeople had to learn how to set up and op-These changes in CNC technology profoundly im- erate complex tool grinding machines, as well as un-pacted the way that cutting tools were manufacturedderstand machining, to make tools that would cut well. and how tool and cutter grinding was performed. These workers also had to be proficient with trigonom-When I started programming in 1993, cutting toolsetry and geometry so they could set up machines to were not much different from those of the 1960s. Toolscreate complex shapes.and machines were designed to take deep, heavy,Old tool and cutter grinding equipment had a 34AUGUST 2021 ToolSharpening.indd 34 7/19/21 11:14 AM'