Micromachining of PMMA—manufacturing of burr-free structures with single-edge ultra-small micro end mills

Abstract

Nowadays, the prototypes of microfluidic systems are generally produced via micromilling of thermoplastic polymethyl methacrylate (PMMA). The main limitations are the design of micro tools with diameters D ≤ 50 μm adapted for each application, and the understanding of the machining process itself. The objective of this research work is to contribute to mastering the process of PMMA micromilling with tool diameters D ≤ 50 μm on a 3-axes precision milling machine. For this purpose, the process design must include the complete process chain—from the CAD/CAM data up to the final structure geometry. The main requirements are the manufacture of microfluidic structures with Ra < 60 nm on the groove bottom and a top burr overhang h0 < 3 μm. Based on the experimental results, milling parameters were established and the influence of the tool geometry on the burr formation was determined. Finally, CAD/CAM machining strategies were recommended.