The occurrence of tool vibrations in the micromilling process is undesirable because of its negative influence on the quality of microstructures. Due to the small dimensions of the undeformed chip parameter, the influence of the cutting edge on the chip formation and on the regenerative effect seems to be larger than in macrodimensions. Within this paper the results of an experimental investigation with micro end-milling cutters (d = 1 mm) are presented. Additionally, the influences of the cutting edge radius, the corner radius, and the feed per tooth on the tool vibration trajectories, the process forces, and chatter and its causes are discussed.

Micromilling is a suitable technique for the manufacturing of microstructured parts. The downscaling of the milling process leads to problems, which are caused by the low stability of microtools and their manufacturing. Tool vibrations and runout occur, resulting in poor surface qualities and undesirable surface location errors. The presented results of the experimental analysis include a stability diagram for the spindle speed range of n = 60,000 -120,000 rpm and tool vibrations measured in the xy-plane. Micrographs illustrate the influence of tool vibrations on the quality of the generated surface structures. In addition, the dynamic runout is characterized and its effects are discussed.

In this paper the results of an experimental investigation to analyze the machinability of a hardened, carbide-rich cold-work tool steel 1.2379 (approx. 62 HRC) with coated micro end-milling cutters are discussed. Fundamental experiments were performed to determine a cutting-parameter set, which enables an economic manufacturing of dies by 3-axis micromilling with commercially available cemented-carbide tools. The evaluation of the applicability of different tool types is conducted by analyzing the process forces, the tool wear, the surface quality, the material removal rate, and the entire chip volume. Design of experiments was used to significantly reduce the number of experiments and to model the active and passive forces. Concerning the design of tools for the micromilling of such difficult-to-machine materials, it is shown that cemented-carbide tools with robust cutting edges are applicable for this kind of machining. Furthermore, test microstructures were manufactured with the intention of validating the determined cutting-parameter set in combination with the selected tool types. In addition, the dimension and shape accuracy of the microstructures are analyzed.

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