Catch Surface Anomalies Early in Gear Production

Even the most quality-obsessed gear manufacturers sometimes see corrosion, discoloration, and contamination on their gears after heat treatment or during bouts of heat and humidity. The problems range from aesthetic annoyances to surface structural degradation.

These problems can be compounded because many companies contract with outside heat-treatment vendors. When parts come back in-house and head directly to the next processing step, gear grinding, cylindrical grinding, and other machining operations can increase damage from corrosion or contamination and make correcting it difficult or even impossible.

Luckily, a few changes to early processing steps can prevent issues from blossoming into costly rework.

Blast it
Adding a media-blasting step immediately after heat treating can ensure corrosion and discoloration don’t persist on parts during downstream processing. Media-blasting forms range from those that gently remove contamination to ones that change surface stress states with peening action or remove enough material to change part dimensions.

For postheat-treatment blasting, stick to gentle, cosmetic cleaning. The goal is a uniform and clean surface on all areas that are not ground, including gear root diameters, where appropriate. Hand blasting gives operators the control needed to prevent part damage. High-volume blasting techniques like tumble blasting are not recommended.