Gear grinding machines are used for precision grinding of gears and other mechanical parts, and are used in industries such as aerospace, automotive, and machine tool manufacturing. Here are ten manufacturers that are well-known for producing gear grinding machines:

1. Liebherr
2. Reishauer AG
3. Kapp Technologies
4. HOFLER GmbH
5. DVS-Group (DVS TECHNOLOGY AG)
6. Gleason Corporation
7. Star SU LLC
8. Samputensili S.r.l.
9. Monnier + Zahner AG
10. Koepfer America L.L.C.

This list is not exhaustive and in no particular order. It is based on market share, reputation and industry standards in specific countries and industries. Additionally, depending on the specific type of gear grinding machine (ex: continuous generating grinding, profile grinding, and so on) the ranking can vary and some other manufacturers like Hofmann Maschinen GmbH, Niles-Simmons-Hegenscheidt GmbH, and Csepel Machine Tool Manufacturing LLC could be added to the list.