Using the 790HP valve
Case history of an I&J Fisnar system comprising an Extruder Pump, a material flow regulator, and and I&J Fisnar Inc 790 HP valve to dispense a line of silicone with a robot.
At the start of the line there was an extra quantity of silicone dispensed, which was not acceptable.The first reaction was that it was simply a problem in programming the robot, but :
1) The programmer started to move and dispense without delay : no effect
2) The programmer started to move with dispense off then at a passing point I opened the valve : it reduced but still there was an extra quantity at the beginning of the line.3) It was apparant that this “extra material “ come from the diameter of the piston of the 790 HP which tended to force the extra material when the valve is opened.
The solution is to program as 2) but also to reduce the pressure on the dispenser and to open the valve slowly.
The result – perfect.
In this application a good pressure is 4,2 bars, but it could be different depending on the spring of the valve and the pressure of the material.
The way to find the correct pressure is to gradually reduce until the valve doesn't open then slowly increase until it does.
www.ijfisnar.com
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