Wexxar WF30T, Operation And Service Manual

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WF30T Case Former Controls
4-24
4.6 Pneumatic Valve Operation
The WF30T Case Former utilizes both solenoid valves and servo-
pneumatic valves for precise component motion control. Note that case
corrugate thickness (especially double or triple wall corrugate) will cause
cycle times to change. Case size and weight will also change the speed
of the solenoid- and servo-driven cylinders, so it is important to ensure
that you calibrate servo settings on the HMI touchscreen when making
significant case size changes.
4.6.1 Solenoid Valves
The solenoid valves are located on the pneumatic valve bank. The valve bank is located on the
operator’s side of the machine on the main frame, where the valves can be individually actuated
by hand. Precise speed regulation with solenoid valves is performed by adjusting the exhaust air
flow controls, such that the machine can be sped up or slowed down. Each machine movement
is able to be performed immediately once the previous pneumatic function has been completed,
reducing machine cycle times.
4.6.2 Servo Valves
All of the machine’s other valves are servo valves, which are located in close proximity to the
servo-driven cylinders in order to maximize the available pressure. The speed of all servo-driven
pneumatic functions can be precisely set by adjusting the parameters, such that the machine can
be sped up or slowed down without having to manually adjust each valve setting. Servo valve V1
(Jawplate Assembly) is mounted on a connecting plate, which is mounted on the side of servo
valve V3 (Mast Assembly) on the sliding frame assembly near the mast on the rear of the
machine.
Servo Valves have 2 inputs. The first is a supply of 24VDC which powers the valve and allows it
to move its shuttle around. The second input is a reference voltage to the valve. The reference
voltage, an analog signal, indicates to the valve where to hold its shuttle. At 5VDC, the valve will
let no air through to either side of the cylinder. Variations from 5VDC, such as 3VDC or 7VDC,
will cause the cylinder move in a particular direction. The larger the variation from 5VDC, the
more open (in a particular direction) the valve is.
The WF-30s use this property and send a reference signal (which is not constant to the servo
valve) in order to cause it to accelerate and, more importantly, to decelerate the jawplates when
opening the case. When applied correctly and running ‘in tune’, the jaws operate more smoothly.
Therefore, the case doesn’t flex or vibrate as much (particularly with larger cases), allowing a
more reliable descent into the major flap folders. The servo valve also allows the jaws to open
quickly without ripping the case off the pins due to the acceleration that the case experiences.
Figure 4-3: Solenoid
Valve Bank
Figure 4-4: Mast and Jawplate Servo Valve Locations
Jawplate
Assembly
Servo Valve
(V1)
Connecting
Plate
Mast
Assembly
Servo
Valve (V3)