Magnus VLF Automatic Pallet Loader

Control/settings
  For the latest conrolled release firmware that supports APL, see the Control/settings page.
Drawings/photos
  For APL drawings and photos, see the Drawings/photos page.
FCOs
  For APL related FCOs, see the FCOs by Subassembly page.
Installation
  For APL installation procedures, see the Installation page.
Maintenance
  For APL maintenance procedures, see the Maintenance page.
Specifications
  For APL specifications, see the Overview page.
Parts/tools
  For information on parts and spares kits, see the APL parts page.
Procedures
  For APL adjustment and repair procedures, see the Procedures page.
Reference
  For APL related Technical Bulletins, customer Visual Reference Guides, and White Papers, see the Reference page.
Troubleshooting
  For APL troubleshooting procedures, see the Troubleshooting page.

Overview

The Automatic Pallet Loader (APL) option for the Magnus VLF replaces the MCU and provides automatic loading of plates from a plate stack located on a pallet. The APL consists of a one segment, two segment, or three segment option and can be configured to support dual pallets in one bay. The major subsystems are:

• Picker Gantry (photo 3) – This is the main support structure for the picker and pusher and moves the picker and pusher in X direction over the appropriate segment location. The X motion is provided by latching to the table X and going along for the ride.
• Picker - Picks the front corners of the plate and also uses vacuum to grab the slipsheet and prevent it from moving during the plate transfer.
  
• Pusher - Hooks the plate and transfers it to the plate transfer table. It also grabs the slipsheet and disposes it in the slipsheet bin.
  
• Table Gantry – This is the main support structure for the plate transfer table and moves the table to the appropriate position.
• Plate Transfer Table – Accepts the plate from the pusher and rises to the load height for transfer to the base machine. The table is raised and lowered in Z by a cylinder. The lower limit of travel of the cylinder is set by a stop, whose position is accurately controlled by a stepper motor. This stop may only be moved when the table is in the up position.
  
• Shutter – The shutter provides support to the plate during the plate transfer to the fetcher. It also locks in the closed position to prevent access to the base machine from within the APL during Manual or CL operation.
  
• Fetcher – The APL requires a new version of the fetcher which actuates in the vertical direction to accept the plate from the higher transfer height.
  

Inductive sensor

The inductive sensor detects metals using a high frequency electromagnetic field. It is used to detect the height and location of the plate stack.

Load cell sensor

The load cell sensor is a strain gauge that is used to measure weight. The sensor is factory calibrated and comes with an amplifier as a matched pair. The sensor is used to detect and measure the weight of the plate on the P-cup when the P-cup has the plate corner raised. This measurement is then used to determine if the P-cup has one or more plates. If it only has one plate the device will continue picking, if not the P-cup will lower and attempt the pick again.

Plate sensor array

The sensor array consists of three reflective sensors positioned in an array such that the device can determine if it is in the correct pick position. The inductive sensors have already determined the approximate pick location. When the picker moves to this position it will pick the plate corner up with the P-cup and the array will be used to ensure the picker is in the correct position based on the sensor readings reflected from the plate corner. If it is not in the correct position, the picker will adjust the X and Y positions accordingly.

Hover Cart

The hover cart is an optional device that is used for loading plate pallets into the APL where the space in front of the APL is limited and to reduce operator work load while loading plate pallets. The hover cart rides on a frictionless film of air provided by air bearings on the underside of the hover cart. The hover cart also uses pneumatic lifters for lifting and lowering plate pallets for transport. For movement parallel to the front of the APL, a rail is fixed to the floor to guide the hover cart. For maximum effectivity of the hover cart, the floor surface must be flat, smooth, and without cracks or crevices. For details on the floor and air requirements, see the site preparation document for APL: Magnus VLF with APL Site Preparation Guide, English.
The main components of the hover cart are the control handle, the frame, the lifters (in the left and right legs of the frame), and the internal pneumatic control system.

Control handle

The control handle is used by the operator to adjust the air bearing pressure, turn the lifters on and off, actuate the air bearings, and for directional guidance of the hover cart. The handle can be used in the upright position (straight or rotated) or in a tilted position.

Air bearing pressure: A control knob on the lower part of the handle is used to adjust the air bearing pressure while moving the hover cart. Adjust the pressure to 30 psi. If the cart oscillates, then adjust the pressure down until it smoothes out. If the cart is sticking on the floor somewhere, then adjust the pressure slightly higher.
Lifters On/Off: A switch on the lower part of the handle used to turn the pneumatic lifters on and off. After moving the hover cart in under a plate pallet, turn this switch on to lift the pallet off the ground. When the pallet is in position inside the APL, turn this switch off to lower the pallet onto the ground.
Handle tilt: A lever on the left side of the handle used to release the handle for tilted operation. It is often easier to control the movement of the hover cart with the control handle tilted—pull the lever to release the handle. When raising the handle again, it will automatically lock in place in the upright position.
Air bearing trigger: A trigger on the right side of the handle used to turn the air bearings on and off. Squeeze the air bearing trigger to move the hover cart with or without a plate pallet. You may need to adjust the pressure while moving the cart (see 'air bearing pressure').
Handle rotate: A lever on the lower part of the handle used to release the handle for rotated operation. Use this lever when you wish to rotate the control handle 90 degrees for operation in tight spaces. For example, while moving the cart along the tracks parallel to the APL.

Internal pneumatic settings

The pneumatic components are housed inside the hover cart frame. Amongst these components are four adjustable air flow control valves (one for each air bearing), and one adjustable control valve for the air lifters.

Air flow control valves: Four adjustable control valves for the four air bearings. These valves adjust the height of the hover cart above the ground. Although these valves are adjusted at the factory, they may need to be adjusted if hover cart is not equally level with the floor during operation. For example, one corner may constantly be getting stuck. The valves are located below two small panels on the hover cart frame—each panel contains two valves for that side of the hover cart.

Lifter control valve: The pressure in the four air lifting bladders is controlled by one adjustable control valve. The higher the pressure, the higher the lifting capacity of the hover cart. To maximize the life of the air bladders, the pressure must only be high enough to lift the customer's largest (heaviest) plate pallet. Using the largest plate pallet, adjust the control valve until the hover cart lifters raise the pallet off the ground plus another half turn. The lifter control valve is located below one of the small panels that house the air flow control valves.

Firmware

See the Control/settings page for the latest conrolled release firmware.

APL Pick Sequence

This is a high level overview only. The operator has loaded the pallet(s) of plates into the APL—justified to one side of a segment. They have locked the panels and updated Print Console with the configuration of the loaded pallet(s). The X, Y, and Z directions are along the drum, perpendicular to the drum, and vertical respectively.

1. The APL will determine the plate stack location and height:
   1. The pusher will move over the middle of the expected plate stack and move down in the Z direction to determine the plate stack height via the inductive sensor.
   2. The pusher will travel in the x and y direction to find the edge of the plate using the inductive sensor. The approximate location of the plate stack is now known.
2. The Picker moves to the pick position:
   1. The picker will move to the approximate x direction. The picker will move forward to the proper pick position as determined by the measurements.
3. The Picker picks the plate corners and slipsheet:
   1. The picker P-cup turns on and the arm moves down to pick the plate and then returns up with the plate. Separator air jets are used to fan the top of the plate stack similar to those on the Magnus VLF MCU.
   2. The arm has a load cell sensor to determine if the P-cup has picked a plate, and not more than one plate via the weight measured.
   3. Each picker’s plate sensor array is then used to check the plate location relative to the P-cup. If the plate is in the proper location the pick will continue.
   4. The picker extends forward underneath the picked plate.
   5. The blower is turned on and the picker grabs the slipsheet from above or below and is checked via a vacuum sensor. It will retain the slipsheet until the plate has been transferred.
   6. The blower routes vacuum to the picker by closing a dump valve to avoid cycling power to the blower every pick cycle.
4. The pusher moves to the plate transfer position:
   1. The pusher will move to the appropriate X position as determined by the picker tower X positions.
   2. The pusher will move in the Y direction to the front of the device to mate with the picker. The mate sensor is verified to ensure correct mate.
   3. The pusher will move down in the Z direction to the plate hooking height.
5. The Pusher transfers the plate to the plate transfer table:
   1. The pusher moves forward and hooks the plate with the pusher hooks and the picker P-cups are turned off.
   2. The pusher continues to move the plate towards the table and the pusher hook drive is engaged simultaneously to move the plate the extra distance needed to reach the plate handoff position.
   3. Once the handoff position is reached, the pusher moves back to clear the transfer table and the pusher hooks are moved back to the home position.
6. Transfer table moves to the plate handoff position.
   1. The transfer table is raised. The table Z stop is moved to the plate transfer height. The table is lowered to the transfer height, then moves in the Z and Y directions to the handoff position to the fetcher.
7. The plate is transferred to the Fetcher:
   1. The shutter is opened and the fetcher deck is raised.
   2. The plate is shifted off the table to the fetcher deck via the rodless air cylinder on the table.
   3. The plate is sensed on the fetcher deck.
8. The fetcher transfers plate to the load table:
   1. The fetcher moves the plate to the load table to the plate load position determined by the plate size.
   2. The fetcher releases the vacuum cups and moves away from the plate to drop it onto the load table.
   3. The fetcher returns to the home position.
9. The load table grabs the plate and moves the plate to the registration pins. The plate is then loaded onto the drum via the standard loading sequence.