NTU Trainings - Virtual

The fundamentals of plastic gears

The plastic gears are continuing to displace metal gears in a widening arena of applications. Their unique characteristics are also being enhanced with new developments, both in materials and processing. This training provides a vision into the fundamentals of plastic gear design and calculation, manufacturing, tolerancing, implementation and the basic skills to examine, and recognize common plastic gears failure modes.


Upon completion of the training, the attendants will be able to carry out the following:

  • Understand the whole process of making a gear,
  • Identify the theoretical and practical elements that are essential for producing quality gears and guarantee their service life Examine the different aspects of gear failures.
  • Assess and interpret common gear failure modes of plastic gears.


6th June 2023


09:00 – 17:00 (GMT+8) Singapore

Who should attend?

Plastic gear designers, engineers and technicians in methods, control, quality and manufacturing departments. More generally all those (project managers, sales engineers and buyers) who want to know about plastic gears.




The teaching method alternates theory and practise through case studies or works directed.

Course outline:

  • Basic concepts on the geometry of gears to “Teeth in involute”
    • Spur and helical gears
    • Meshing (contact ratio, interference, sliding)
    • Tooth modifications (profile and helix)
    • Contact pressure and tooth rupture calculations
  • Manufacture of plastic gears
  • Principles of tolerancing and control
  • Failure modes in plastic gears
    • Adhesive or “Normal” Wear
    • Abrasive
    • Pitting
    • Plastic Flow
    • Fracture
    • Thermal Cyclic Fatigue
  • Questions / answers.


This course will be conducted by Robert SHANDRO.


Principal Consultant with CETIM - MATCOR in the field of mechanical, power transmissions and materials engineering. A Specialist in failure investigation, forensic engineering and condition assessment with more than 30 years of consulting experience in Energy, Aerospace, Transportation, Shipbuilding and Public Works. Involved in close to 2,500 failure analysis and consulting services for litigation. Member of French delegation for ISO TC60 (Technical Committee), Expert in load capacity calculation of gears, terminologies, notation, strength and quality of materials for gears.
Member of IES (Institute of Engineers Singapore).

Areas of Expertise

  • Failure analysis of a wide range of mechanical equipment/components and structural facilities
  • Design, verification and failure analysis on mechanical power transmission components
  • Condition and remnant life assessment of mechanical power transmission components
  • Expert witness for litigation and insurance claims
  • Expert consultant and technical support on patent litigations
  • Standardization works (ISO TC60)



  • 5 years as Design Engineer (electric motors and generators)
  • 12 years as Technical Advisor (Judicial Expertise)
  • 13 years as Project Manager at CETIM
  • From year 2019 – Principal Consultant at MATCOR


  • Master of Engineering (MEng) UPT 1986
  • Master in Materials Science (MSc) ISMCM 1992