Metallic degradable biomaterials have attracted a huge attention lately for orthopedic fixation applications. Binary magnesium and calcium (Mg-Ca) alloys have emerged as a promising choice in terms of biocompatibility to avoid stress shielding and provide sufficient mechanical strength. In this paper, efficient and ecologic machining of a lab-made Mg-Ca alloy with 0.8 wt% calcium, cutting speeds of up to 47 m/s, and without coolant are investigated. Polycrystalline diamond inserts are applied and the possibilities of flank built-up formation, chip ignition, and tool wear are sought during the cutting experiments with the aid of a developed on-line, optical monitoring system. Chip morphology characteristics produced by different combinations of cutting parameters, i.e. cutting speed, feed, and depth of cut are studied.