Development of Accuracy Evaluation Method for Open Loop Educational CNC Milling Machine




Educational, CNC Milling Machine, Accuracy Verification, Fringe Counting, He-Ne Laser, Interferometry


The open-loop educational computer numerical control (CNC) milling machine requires accuracy verification in order to ensure its accuracy and functionality. In this paper, the new verification method is proposed based on the length measurement using the fringe counting of He-Ne laser interferometry. The ideal translation length is defined by the number of electric pulses generated by the micro-stepping driver, while the actual length is measured using He-Ne laser interferometry. In the experimental process, the data of the fringe pattern of the He-Ne laser and the number of electric pulses which drive the stepper motors were simultaneously acquired using an oscilloscope. Hence, the data has been analyzed to obtain the ideal and actual lengths by using an in-house program developed in Python. By comparing the actual translation and ideal length, the accuracy of the educational CNC milling machine has been evaluated to be 50 µm for the length up to 200 mm.

Author Biography

Agustinus Winarno, Universitas Gadjah Mada

Agustinus Winarno is a lecturer at Department of Mechanical Engineering, Vocational College, Universitas Gadjah mada. He received adoctoral’s degree in precisiong engineering from the University of Tokyo, Japan. His current field placement is with Universitas Gadjah Mada


WAGNERA, U., ALGEDDAWYB, T., ELMARAGHYB, H., MÜLLERA, E., “The State-of-the-Art and Prospects of Learning Factoriesâ€, Dalam: Procedia CIRP, Vol.3, pp. 109 – 114, Athens, Mei 2012.

ANDERSEN, H. V., PITKÄNEN, K., “Empowering educators by developing professional practice in digital fabrication and design thinkingâ€, International Journal of Child-Computer Interaction, Vol. 21, pp. 1–16, Mei 2019.

ROPIN, H., PFLEGER-LANDTHALERA, A., IRSA, W., “A FabLab as integrative part of a Learning Factoryâ€, Dalam: Procedia Manufacturing, Vol. 45, pp. 355–360, April 2020.

DREESSEN, K., SCHEPERS, S., “Foregrounding backstage activities for engaging children in a FabLab for STEM educationâ€, International Journal of Child-Computer Interaction, Vol. 20, pp. 35–42, June. 2019.

SIDI, P., THORIQ WAHYUDI, M., “Aplikasi Metoda Taguchi Untuk Mengetahui Optimasi Kebulatan Pada Proses Bubut CNCâ€, Jurnal Rekayasa Mesin, Vol.4, No.2, pp. 101-108, 2013

STANOJKOVICÌ, J., RADOVANOVICÌ, M., “Influence of the Cutting Parameters on Force, Moment and Surface Roughness in the End Milling of Aluminum 6082-T6â€, Facta Universitatis, Series: Mechanical Engineering, DOI No. 10.22190/FUME180220002S, 2018.

ISO 230-1:2012, Test code for machine tools — Part 1: Geometric accuracy of machines operating under no-load or quasi-static conditions, 2012.

ISO 230-1:2012, Test code for machine tools — Part 2: Test code for machine tools — Part 2: Determination of accuracy and repeatability of positioning of numerically controlled axes, 2014.

ISO 10791-1, Test conditions for machining centres — Part 1: Geometric tests for machines with horizontal spindle (horizontal Z-axis), 2015.

ISO 10791-2, Test conditions for machining centres — Part 2: Geometric tests for machines with vertical spindle or universal heads with vertical primary rotary axis (vertical Z-axis), 2001.

ISO 10791-4, Test conditions for machining centres — Part 4: Accuracy and repeatability of positioning of linear and rotary axes, 1998.

ISO 10791-6:2014, Test conditions for machining centres — Part 6: Accuracy of speeds and interpolations, 2014.

OTSUKI, T., SASAHARA, H., SATO, R., “A Method for Evaluating the Speed and Accuracy of CNC Machine Toolsâ€, Dalam: Proceedings of International Conference on Leading Edge Manufacturing in 21st century: LEM21, Vol. 2017.9, pp 34-40, Jan. 2017.

WINARNO, A., et al, “Absolute measurement of gauge block without wringing using tandem low-coherence interferometryâ€, Measurement Science and Technology, Vol.23, 125001, Okt. 2012.

WINARNO, A., TAKAHASHI, S., MATSUMOTO, H., TAKAMASU, K., “A new measurement method to simultaneously determine group refractive index and thickness of a sample using low-coherence tandem interferometryâ€, Precision Engineering, Vol. 55, pp 254-259, Jan. 2019.