Closed-loop flow control compensates for viscosity changes
During the conformal coating process, Qadence automatically compensates for viscosity changes, says Nordson Asymtek, which has introduced the closed-loop system.
Qadence combines the capabilities of Nordson Asymtek’s conformal coating hardware and software to selectively apply coating to specific areas of a circuit board consistently throughout production. The Qadence flow control system maintains stable fluid application, flow rates and performance by automatically compensating for viscosity changes related to temperature, humidity, and batch-to-batch variation. It eliminates the need for frequent operator adjustments and downtime to recalibrate the process, adds Nordson Asymtek.
There are set process limits to achieve target flow rates and precise application volumes. When process limits are set, target flow rates are continuously monitored throughout production. If the process falls outside precise application volumes, a control routine (patent pending) is activated to make corrective adjustments – reducing downtime and limiting operator intervention, claims Nordson Asymtek. The flow meter and tighter resolution contribute to accuracy and tighter process controls. Data and measurements are tracked and can be exported and evaluated by SPC software.
Qadence software is implemented by entering process parameters and setting performance limits. The Flow Calculator in Nordson Asymtek’s EasyCoat 6 software calculates the target flow rate. A normal one-hour setup can be completed in 30 minutes and a 30-minute setup in less than 10 minutes, Nordson Asymtek reports. Each valve is separately controlled. Matching flow rates between applicators enables similar valve performance when changing valves or across two valves in a single application.
Automated process controls increase machine up-time and throughput and reduce the cost of operation. When flow rates are optimised, more precise volumes are dispensed and less fluid is wasted. Improved coating accuracy and reliability reduce the need for masking and rework.
The Qadence system is compatible with the Select Coat SL-940 conformal coating system, EasyCoat 6 software, and Nordson Asymtek conformal coating applicators.