Application of Proportional Electric Proportional Valve on PC Board Scraper

The PC board fabrication machine uses a doctor blade to control the thickness of solder applied to the board. In this very sensitive application, the force of the doctor blade must be kept constant. High resolution and repeatability are a must. This sketch shows the QPV1 controlling the pressure of the Air-Pel cylinder. These are frictionless glass-lined cylinders used to control the force on the scraper. They achieve this "frictionless" state by letting some air escape constantly. This makes the gas pressure application a "constant flow" process, which is ideal for QPVs at these flow rates.

The manufacture of thick film ceramics also has similar requirements for doctor blade applications. QPV1 is suitable for both applications due to its high resolution (up to +/-0.005% of full scale) and repeatability of +/-0.02% of full scale calibration.