A manufacturer was machining connectors made of Steel 4340 using a CMZ TA-20 CNC Lathe. The connectors required a 12 Ra microinch (0.3 Ra) finish or better on the 60 degree inclusive taper. The customer needed to produce over 1,000,000 connectors a year, so cycle times were crucial to their ability to reach this goal.
Previously they were sub-contracting other firms to grind the connectors down which resulted in lead times that were too slow to achieve their goal. Here are the statistics of their turning operation before we recommended burnishing:
Speed: 1200 RPM
Feed: 0.008”/rev (0.2mm/rev)
Finish achieved: 32 Ra microinch (0.8 Ra)
OUR SOLUTION
We recommended an ID angle roller burnishing tool made by Elliott Tool Technologies. Here are the statistics of the burnishing operation:
Speed: 1200 RPM
Tool is fed onto the taper at 0.002”/rev (0.05mm/rev))
Rapid retract tool
FINAL RESULTS
The multi-roll burnishing tool achieved the required surface finish of 12 Ra microinch (0.3 Ra), all while being manufactured in-house, avoiding sub-contracting. The process was also stable and repeatable, saving our customer a lot of time and money on every connector they manufactured.