Project Details

Red Ring SF-500 Gear Grinder Rebuild

MTB has done four of these SF machines so far, two SF-500’s, one SF-900 and one SF-2500. Some were done with Siemens, others with Fanuc systems. Two were done directly for the former Red Ring Company now owned by Nachi America.

Original Condition

This machine came to MTB with very unreliable controls, old and dry rotten cabling, worn out way bearings and a worn dresser unit. The CNC was a dinosaur with very limited programming storage and a crude programming system. The machine was capable of grinding both internal and external gears, and was equipped with two heads, one for each type of gear.

The Partial Rebuild Process


The partial rebuild consisted of the following.
¨      Replace all vertical axes ways and roller bearing assemblies.
¨      Replace all horizontal axes ways and roller bearing assemblies.
¨      Rebuild the work head assembly.
¨      Rebuild the Normac Dresser.
¨      Rebuild all grinding spindles.
After the reassembly it was necessary to verify and adjust the machine alignments as well as the dresser accuracies and it’s placement on the machine center lines. For safety reasons, the guarding was returned to OEM design and a new electro mechanical interlock was placed on the operator door and limit switches were installed on all the service doors. This machine was also fully cleaned at the customer’s request, but not painted. However painting is an optional service which does not have to be done on every machine.
The Recontrol Process
As part of the recontrol project Machine Tool Builders designed and manufactured a completely new electrical cabinet and we rebuilt much of the Pneumatic and Lubrication systems. We replaced many machine mounted components and cables due to the dry rot. We installed all new motor power and feedback cables.  We engineered and manufactured the mechanical adaptations required to convert the machine from the old DC servos into a fully digital system.
The new control system was centered on a Siemens 840D CNC and a PCU 50 front end with Windows XP Pro and the drives were all changed to new Siemens 611D servos. All new Heidenhain absolute encoders and scales were installed so that no homing was required. This combination of controls was extremely cost efficient, offered short lead times and was very easy to implement, which translated into savings for the customer.
The Conversational Software
We installed our newest version of MTB GearCAM software which allows for very easy Windows based programming for the gear, wheel and process information. The software is structured around a database concept, where you can store multiple gears, wheel and processes. Then at the click of a mouse, you can select any combination of gears, wheels and processes to be recalled and executed. Storage and retrieval of the completed programs is made easy due to the Windows environment and the PCU 50’s onboard hard drive.