October 14, 2020


Gears are everywhere. From a delicate wristwatch to massive turbines, gears are found to be functioning in almost every mechanical equipment.

The main functions of gear are:

The teeth of a gear wheel connect with another gear or a rack and converts the circular motion into linear motion. Additionally, ‘Torque management’ is one of the main functions of a gear. Often, a motor spinning very fast can provide power for a device, but not enough torque. A Gear is used for the conversion of energy into useful torque.

There are various types of gears:

A gear has multiple elements such as teeth, size of teeth, center distance, etc. However, the efficiency of conversion is decided by the Gear Ratio. Gear ratio is the distance between the center of the gear to the point of contact. For the gear to deliver the optimum performance, the Gear ratio needs to be consistent.

To explain the importance of Gear ratio, let’s imagine the most primitive types of gears, the wheel with wooden teeth. The problem with this type of gear is that the distance from the centre to the point of contact varies with each tooth. This means the gear ratio is changing as the wheel is turning. This variation has an impact on motion and transmission. Imagine if you used such a wheel in a car gearbox transmission, the car would experience acceleration and deceleration at the same time, and that would be an extremely uncomfortable situation.

The need for consistency, robustness, compliance with standards, and design is where inspection function comes into play.

Why is quality control (QC) important?

The most significant differentiating factor in any manufacturing company is gear quality. Gear quality needs to comply with global standards set by associations such as American Gear Manufacturers Association (AGMA), International Standards Organization (ISO), and the Deutsches Institute Normale (DIN)

Quality inspections of gear ensure conformance to the criteria for a given design and application. The bigger the equipment moved, the higher the need for quality gears. Improper tooth or ratio can result in unnecessary mishaps. Gear quality is influenced by many factors, e.g., quality of metal, forming process (forged vs. cast), hardness, and depth. Four main parameters accounted in gear quality are:

  • Tooth lead or alignment
  • Involute profile variation
  • Pitch or spacing variation
  • Radial runout

The methods of inspection differ depending on the type of gear. But some standard methods are:

  • Size measurement: The traditional method of inspection is by using the Micrometer to measure the correct size over pins and balls.
  • Runout: It is the variation between the surface of the revolution and the datum surface. It is measured with the help of a dial indicator.
  • Composite: This type of inspection is executed by ‘rolling’ the tested gear through contact with a master gear. It’s a shop friendly method that helps determine the size, runout, tooth-to-tooth rolling action and detect nicks.
  • Profile: Under this method, the shape of the gear is inspected. The shape covers the design from the root to the tip of the gear.
  • Helix: The method which determines the deviation between the measured helices and the design helices.

But there are many other factors that need to consider beyond the above parameters. A gear manufacturing process can introduce surface finish anomalies like nicks and burrs, handling damage, and in the case of assembled gears, misalignment and contamination.

Damage and nicks require visual inspection. They are executed by experienced hands and eyes.

Fast forward to the current times, and visual inspection can be replaced by intelligent machine vision.

Introducing OPTIVITY

OPTIVITY® is a platform that takes advantage of advanced image processing and machine learning capabilities to detect anomalies that cannot be seen by the naked eye. OPTIVITY® assists in:

  • Checking size, profile, dimension, and tolerances of gears
  • Identify surface defects, deformities, and scratches
  • Machine learning allows for improved data traceability

Griffyn Robotech developed OPTIVITY® ; an innovation-driven organisation focused on leveraging the latest technology to create the best of the class quality inspection tools for multiple sectors.

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