This work contributes to research improving performance in a human-CNC machine interface environment. A salient contribution of this study is the use of a load cell to measure human-performance. Based on a Taguchi experimental design, a full factorial design consisting of 27 experiments was used to collect data on human performance. The collected data were analysed using grey relational analysis, analysis of variance and the F-test. ANOVA was performed using Design-Expert software. This study represents an effective approach for the optimisation of a female-CNC machine interface environment with multi-performance characteristics. The following main conclusions were drawn from the analysis: 1) the combination of parameters and their levels for the optimum multi-performance characteristics of a HCMI environment using female operators were A1B2C1 (i.e., a CNC machine panel height of 90 cm, a panel angle of 60 degrees and a working distance of 10 cm); 2) an improvement of 33.06% in the multi-performance characteristics, i.e., the grey relational grade was achieved through this approach.