Internal Collar Failure

Question

I bought a replacement screw from one of your competitors about 3 months ago. It worked great until we had this catastrophic failure shown in the photo. Now my complete plant is shut down and I need a replacement from KWS ASAP!! Why did this screw fail after only 3 months?

Answer

Thanks for contacting KWS and for sending the photo of the failed screw section. The screw failed because of improper welding of the internal collar to the center pipe of the screw. The internal collar broke loose from the center pipe of the screw causing the pipe to fail in torsion. The center pipe of the screw and internal collars must handle torque from the drive unit as a welded assembly. If the welds between the center pipe and internal collar fail, the complete screw section will fail causing an interruption to production.

KWS understands the importance of creating a permanent connection between the center pipe of the screw and internal collars by providing four plug welds per bushing, with two plug welds located on each side 180-degrees apart. Plug welds provided on KWS screws are permanent, will not break loose, and are guaranteed for the life of the screw.

Also, KWS can supply a replacement screw in less than 3 working days to get you back up and running. Our large manufacturing plant utilizes the latest in automation and CNC technology. Along with Lean Manufacturing techniques, KWS can deliver equipment before our competition sends you a quote for the work.

Please see the following video – The Importance of Internal Collar Plug Welding for Screws