Sensing system improves valve assembly

• inspection during assembly boosts output
• consistency in meeting tight tolerances

Valve manufacturers today are able to inspect parts during assembly, rather than afterwards, to produce near-perfect fluid check valves. The key to the process is a design development of Promess, Inc — an electromechanical assembly press (EMAP) controller with integrated sensors. EMAP uses no pneumatics or hydraulics itself; instead, press motion is initiated by a servomotor and ball screw. The EMAP package includes press head, motors, amplifiers, multi-axis controller, motion control, cabling, enclosure, PC, and a complete Windows NT software package — ready for assembly to a production line press machine.

The computer monitors the press’ ram position and pressing force, and accepts data from additional monitoring devices. To make the check valve, the EMAP is fitted with an attachment that pumps fluid through the valve at 1.2 l/min while the valve is in the press. Sensors relay information on fluid flow and valve release pressure to the EMAP’s controller. While the valve is assembled, the system monitors the valve release pressure.

The EMAP compensates for variations in the valve components that affect release pressure by compressing the spring inside the valve to increase its resistance. Using a press-measure-press cycle, the EMAP forces the insert into the valve body until the target release pressure of 1000 psi is reached.

The new process lets the check valve company make valves with a ±2 psi tolerance. Consistency in maintaining tight tolerances and integration of assembly and gauging steps make EMAP suitable for use in a wide range of applications, including spring assemblies, control arms, injector nozzles and battery manufacturing.