C.R. Onsrud Routers
Ball screw service to C. R. Onsrud 3 and 5-Axis routers. There are a bunch of different models of the Onsrud CNC routers serviced: G-Series, S-Series, C-Series, and E-Series. Ballscrew Guys specialized in the refurbishment and rebuilding of loose or damaged Bosch Rexroth ball screw systems found in these machines. Many of the Onsrud CNC routers were rack and pinion based on the X and Y-Axis systems, but others had the ball screws.
Bosch Rexroth drive assembly was installed to the gantry for an Onsrud 5-Axis CNC Router. Here, the drive pulley and rotation bearing were housed. The ball screw shaft from Rexroth had four ball bearing tracks. The ball nut itself only operated on one of these. This meant that even though the ball screw might have failed and damaged one track, there were others to position the ball nut onto, allowing for a few more failures before the ball screw shaft was actually worn out.
Here, the entire ball screw shaft assembly was pulled for inspection and refurbishment. Noted the length of this part. One of the reasons why Ballscrew Guys field service was so competitive was simple logistics. There was no need to pull the ball screw, then build a long custom crate for it, then insure and pay the exorbitant amount for shipping it with insurance, hoping it arrived at the competitor's shop and returned unharmed and still straight. In many cases, the cost of Ballscrew Guys service was less than the simple cost of making a crate, shipping, and insuring two ways.
The Bosch Rexroth ball nut was found in an Onsrud CNC Router. This particular model was the German-made R15034965 65423.028. This was a relatively simple ball screw that attached to a separate external rotation bearing on the Onsrud 3 and 5-Axis Routers. Ballscrew Guys had decades of experience refurbishing and repairing these ball screw assemblies. The service manufactured its own ball bearing recirculation inserts and seals. If the ball screw shaft was in good shape with at least one clean, undamaged track, contact was encouraged. It may have been possible to have the ball nut overnighted for rapid refurbishment. Upon receipt, the ball nut was fully refurbished and then overnighted back on a mandrel that could be threaded onto the ball screw.
Side view of the ball nut rotation bearing housing which connected to the Onsrud X-Axis table. Noticed the Bosch Rexroth ball nut flange sandwiched between the drive pulley and the rotation bearing housing. This design made it difficult for the ball nut to get adequate lubrication over time. As operation hours built up, so did the dust and debris from routing. Over time, this assembly got packed so full that it was no longer lubricated at all, giving the machine owner a choice: let it fail or clean it out.