b'Toolholders when microdrilling isnt the time to go cheap.smear the cobalt and cause coatingCutting tools for micromachin- production department with dedi-adhesion problems. ing (are) not just about downsiz- cated grinding machines and well-Rutherford said although any un- ing the diameter but require experteducated tool grinders, a team of necessary roughness causes fric- know-how, Gotti said. In order totechnical engineers experienced tion and increases the amount ofachieve the highest-quality stan- in micromachining, and high-end heatcarbides nemesisat thedard, several factors must be takenmeasuring instruments for quality tool/workpiece interface, a clean,into consideration: a specializedcontrol.CTEground surface with a fine finish eliminates the need to polish flutes and the risk of smearing cobalt.Gotti said the risk of excessive edge radiusing and other tool dam-age is an additional reason to avoid polishing.The polishing process is not ap- Drilling and milling in small dimensions:plied when manufacturing micro-drills since the flute surface to beNow with inch, its a chinchtreated is extremely small, he said. Extremely fine grinding wheels are used to generate polished flutes that allow excellent chip evacuation. cool toolsSimilar to other machining oper-ations, successful microdrilling re-quires a systematic approach that includes not only the tool substrate,NEW !!!geometries and coatingor lack thereofbut the machine tool andSWISS CUTTING TOOLS IN its CNC, coolant, fixturing and tool- FRACTIONAL INCHESholders. For example, Gotti rec-For tough materials:ommends high-quality toolholders with a runout of less than 3 m, such stainless steel, titanium, superalloysas high-precision collet, shrink-fit Small diameters starting from .004and hydraulic toolholders.Rutherford said those holders High performance: speed and feed typically come with a premium price tag, but the extra cost is justified.Toolholders when microdrilling isnt the time to go cheap, he said.In addition, Rak said the holders should be regularly cleaned and maintained to prevent hard-to-see chips from becoming lodged inside.Another element of the system-atic approach to microdrilling re-quires having top-of-the-line in-spection, Rutherford said, because a toolmaker cant be confident thatMikron Corp. Monroeits microdrills meet tight tolerancesMonroe, CT 06468and other demanding specifica- [email protected] if it is unable to adequatelywww.mikrontool.commeasure the tools.ctemag.com/cteguide.com21SmallParts.indd 21 6/17/21 11:09 AM'