Fixing Broken Gears: Partners Improve Sustainability of Automated Repair

In a recent partnership, RoboDK, Force Technology, and Hexagon Manufacturing Intelligence worked together on a project to determine whether automated repair processes could be made more sustainable. In this project, “more sustainable” was defined as using less energy and generating less waste than traditional processes. Not only were they able to accomplish this, but they were also able to do so in a way that saves time in the long run, requiring less downtime on equipment.

 

Damaged gear teeth require repair or replacement, sometimes involving multiple gears in the set. Image used courtesy of Adobe Stock

 

Gear Repair

Gears often fail at the tooth roots, as this is where the stress is the highest. Often the gears lose teeth or parts of teeth, either due to them slamming into each other or just general wear. Metallurgically speaking, the gears are usually a tough alloy to handle some of the stress, but the teeth are made harder to improve wear resistance. The hardening process is a combination of thermal aging and additives, such as carburization (case hardening), which improves wear resistance, but does tend to make them more brittle.

As these teeth crack, it is sometimes more cost-effective to repair the gears rather than completely replacing them. To perform this repair, filler material must replace the broken tooth and then have the surface hardened. Regardless of whether a chunk of metal is welded to replace the tooth, or whether additive manufacturing is used to sculpt a new tooth profile, the tooth must be the exact size, shape, and weight of the original. Otherwise, the gear will be out of balance, add to vibration, and will wear much more quickly. Furthermore, too much heat in the wrong place can damage the heat treatment used to make the teeth hard.

 

Automation as a Solution

To automate the process of gear repair, three automation technology companies worked together, each bringing their own expertise to the problem.

RoboDK provides simulation software to determine tool paths of equipment, such as 3D print heads and milling bits to ensure the safest and most efficient travel.

Force Technologies specializes in energy reduction and efficiency improvement in manufacturing processes, with extensive experience in optimization of 3D printing, welding, and other techniques.

Hexagon’s Manufacturing Intelligence experience includes autonomous processes and motions which drastically reduces the time required to evaluate and perform the repair when compared to traditional methods.

 

Digital twin and tool path simulation of the damaged gear. Image used courtesy of RoboDK

 

To complete this project, the team focused on using laser welding as the repair mechanism. Before welding began, a digital twin of the damaged part was created. Then, on the digital twin, the weld head’s path was determined and potential material usage tracked. Once these were optimized for minimal waste and enhanced sustainability, the actual weld could be performed, using the paths generated in simulation. The end result was repaired gears with little waste.

 

Images showing before and after repairing the real-world part. Image source RoboDK

 

Automated Gear Repair

By leveraging the assets of all three companies, repair processes used less energy, generated less waste, and were completed in shorter times than traditional repair processes. While this test focused specifically on gear repair, it could be applied to many common repair processes. In the future, this type of collaboration could include more artificial intelligence (AI) or machine learning (ML) to diagnose some of the necessary repairs or predict future repairs.