Wexxar WF30T, Operation And Service Manual

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WF20T Case Former Installation
4-17
4 THEORY OF OPERATION
All motions of the WF30T Case Former are controlled by the PLC (Programmable Logic
Controller), which is located in the main electrical control enclosure. Inductive and optical
proximity sensors are used to detect the position of the machine’s components and the cases
being formed. Interlock switches are used to ensure that the doors are closed while the machine
is in operation. The touchscreen and switches on the control panel form the user interface. The
sensors, switches, and panel provide the input signals to the PLC. The PLC then decides upon
the next stage of machine operation, and sends electrical signals to the pneumatic solenoid
valves. These valves control the flow of the compressed air to the pneumatic cylinders that move
the different machine components.
4.1 Sequence of Operations
The WEXXAR Model WF30T Case Former is an automatic machine designed to form corrugated
cases and seal the bottom flaps with tape. Flat cases are loaded into the magazine and the
machine forms them at a consistent speed, upon demand, without requiring further operator
input. The steps involved in the case formation are:
1) Case Supply:
A case magazine holds the folded cases ready for erecting, and feeds them into the
machine. The cases stand edgewise on two red feedbelts which steadily move them
towards the case forming section, where they are selected one at a time for processing.
The magazine pusher is also part of the feed system. It applies constant pressure to the
top rear of the case stack to ensure proper operation of the case separator and case
injector.
2) Case Separation:
The case separator, located above the case blanks, selects the first case from the
magazine stack. It moves downwards, causing a small step on its rear surface to catch
the case edge and drive it down into a slot at the inward end of the magazine feedbelts.
This slot is formed by the calipers and the injector, and its width is set to suit the
thickness of the flat corrugated case blank. When the case is securely pushed into the
caliper slot, the separator returns to the
UP
position, allowing the top of the separated
case to move forward, clear of the separator and ready for the next operation.
PLC
Analyses inputs and sends
instructions about which pneumatic
valves need to be opened/closed
Sensors, Switches
Buttons
Senses current machine status and
user inputs and sends information
Pneumatic System
Moves the machine components
into their next state