The present market of metal laser cutting machines is mainly dominated by laser sources that emit radiation in the wavelength range around one micron. The majority of these lasers generate radiation through pumping of ytterbium doped fiber or ytterbium doped disks, or directly from gallium arsenide (GaAs) semiconductor diodes. The latter direct diode approach has been increasing its market share due to a significant increase of beam quality. A few years ago, high-power direct diode lasers were used for applications where low brightness (BPP between 20 — 30 mm mrad @ 4 kW) was sufficient, such as laser brazing and hardening. With the latest improvements in beam quality, reaching 4 mm mrad and below, direct diode lasers are now suitable for laser cutting applications, which are dominated currently by other laser types. This article investigates cutting quality and speed using the II-VI Highyag laser cutting head BIMO-FSC in combination with a direct diode laser. In addition, the machine controlled and independent adjustment of focus position and diameter of the BIMO-FSC have been analyzed in regards to optimization of the piercing process.