Quality & Process Control

Posted on Wednesday, October 9, 2013 in UEA Blog

Within the walls of UEA, process and quality control are of the utmost concern. In the hydraulic swivel division, we monitor and control every process from manufacturing, part cleaning, assembly and testing.

After the part quantities for swivel assembly are taken from the bill of material, all the parts are laid out on a table for inspection and assembly in our pharmaceutical grade clean Cleam Roomroom. When assembling the swivel, the spool is pushed into the housing. This is done by turning a hand crank which extends the ram and slowly pushes the spool in place. Because the press utilizes a manually actuated hand wheel to apply the downward pressure, the operator can feel the feedback to insure that there is no excessive resistance during this process. The operator also monitors the pressure by watching for any excess force that may occur during this process. Excess pressure may signal something internally could be wrong and needs to be addressed.

After assembly is complete, the swivels move to testing in our in-house designed and built rotary test stand. Each swivel requires a drive plate, assorted port fittings and hoses. First, a low pressure test is run at 100 psi. The pressure level is monitored with a pressure transducer for a designated amount of time. If the pressure drop doesn’t exceed two psi, it has passed. Then the swivel is filled with hydraulic fluid to lubricate the seals and run the torque test. The housing is restrained and the spool is rotated both directions. The torque to rotate the spool is recorded for both directions.  Next, a high pressure test is run at a pressure 1.5 times the required operating pressure. Two pressure transducers monitor the pressure level. If the pressure drop is less than 200 psi over a certain period of time, it’s passed. Visual inspection is also done to identify any potential external leaks.

A data acquisition system is used to record both the low and high pressure test, along with rotational torque required to rotate the spool. All data is then saved and stored for historical quality records specific to each serialized swivel. If an unaccepted pressure drop is detected during any of these steps, or if the torque reading is outside the tolerance of a predetermined mean average, that swivel is removed from the batch and disassembled for a root cause analysis and corrective action. At UEA we thoroughly test and inspect each and every hydraulic swivel we manufacture to ensure the highest quality product to all of our valued customers.

Tom Van Veldhuizen