Enhancing the Weld Quality of Polylactic Acid Biomedical Materials Using Rotary Friction Welding.

Area of Science:

• Materials Science
• Biomaterials Engineering
• Additive Manufacturing

Background:

• Polylactic acid (PLA) is a biodegradable biomaterial with potential in medical devices.
• Current additive manufacturing (AM) of large PLA devices requires component fragmentation and reassembly.
• Traditional assembly using nuts and bolts poses risks of loosening and dislodgement in medical apparatus.

Purpose of the Study:

• To investigate rotary friction welding (RFW) as a superior joining technique for PLA components.
• To enhance the joint strength and integrity of large PLA-based medical devices.
• To evaluate the mechanical properties and surface characteristics of RFW-welded PLA.

Main Methods:

• Fabrication of PLA polymer rods using additive manufacturing.
• Application of rotary friction welding (RFW) under various rotational speeds.
• Assessment of bending strength, surface hardness, and temperature profiles of welded joints.

Main Results:

• RFW significantly improved the mean bending strength of PLA components, exceeding the base material by up to 41.94% at 4000 rpm.
• The average surface hardness at the weld interface was 1.25–3.80% higher than the base PLA material.
• Variable rotational speed RFW resulted in higher surface hardness compared to fixed speed RFW; higher temperatures were observed at the outer edge.

Conclusions:

• Rotary friction welding offers a robust and effective method for joining PLA components, enhancing mechanical properties.
• This technique addresses the limitations of conventional assembly, improving the reliability of large AM-produced medical devices.
• The RFW process aligns with Sustainable Development Goals due to its energy efficiency and low environmental impact.