A comparative investigation on wear characteristics of polymer and biopolymer gears

Abstract

Plastic gear applications are rapidly increasing in transmission systems in automotive, domestic and kitchen machineries. Biopolymer gears are now being preferred over polymer gears due to its biodegradable properties. Hence, a comparative investigation of wear characteristics between polymer and biopolymer gears is studied. Injection molded biopolymer, PLA (polylactic acid) gear and polymer, ABS (acrylonitrile butadiene styrene) gear have been fabricated with appropriate properties. Gears are experimentally tested for the period of 3 h at three different rotational speeds (500, 1000 & 1500 rpm) with and without load (1 kg). Wear debris, material loss, thermal damage and microstructure surface condition monitoring have been investigated. PLA presents better adhesive wear resistance and shows thermal deformation and tooth breakage. Biopolymer gives better thermal and wear resistance than polymer gear. At low rotational speed of 500 rpm under no-loading condition, both PLA and ABS show higher weight loss and wear rate due to thermal damage occurred due to gear pump effect. Whereas when load is applied, PLA shows wear loss at all rotational speeds due to inferior thermal conductivity and ABS shows wear loss at high rotational speeds of 1000 rpm or 1500 rpm due to loading effect.