A Deep-Hole Microdrilling Study of Pure Magnesium for Biomedical Applications

Area of Science:

• Materials Science
• Manufacturing Engineering
• Biomedical Engineering

Background:

• Pure magnesium (Mg) is a promising material for biodegradable medical implants.
• Developing precise micro-scale features, such as those required for intraocular drug delivery devices, presents manufacturing challenges.
• Microdrilling is a key process for creating these intricate features.

Purpose of the Study:

• To investigate the mechanisms of deep-hole microdrilling in pure Mg.
• To identify optimal machining parameters for prototyping intraocular drug delivery devices.
• To understand the influence of cutting parameters on hole quality.

Main Methods:

• Experimental study using 0.20 mm and 0.35 mm microdrills.
• Full factorial design varying cutting speed (vc) and feed per tooth (fz).
• Analysis of chip formation, hole diameter, burr height, and surface roughness.

Main Results:

• Burr height increased with higher cutting speeds due to thermal plasticization of Mg.
• Hole entrance diameters exceeded nominal tool diameters due to tool runout, exacerbated by high vc and fz.
• Inner surface roughness of the holes increased with higher feed rates (fz).

Conclusions:

• Microdrilling pure Mg requires careful parameter selection to manage burr formation and achieve desired hole quality.
• Higher cutting speeds increase thermal effects, leading to greater burr height.
• Feed rate significantly influences surface roughness and hole diameter accuracy.