Boeing Corporation came to Vector Automation with an interesting project regarding the painting of helicopter drive shafts.
The drive shafts had to be painted with primer green internally. The drive shafts are hollow and six to seven feet long and made of aluminum and machined with splines on each end of the shaft.
Vector Automation developed a paint withdrawal system that would lower a special coned shaped spray nozzle into the inside diameter of the drive shaft and then withdraw the paint cone at a specified rate. The withdrawal rate was controlled via a servo controlled device. This was done so a certain mil thickness could be achieved (2 mill thick paint coating).